Making Rioja Wine
last update: 14 January 2022
The visit to the winery
Included in the our stay at the Hotel Marqués de Riscal was a complimentary visit to the winery. It was probably more superficial than the tourist visits that could be booked separately, but all the visits appeared to focus on the traditional winemaking process and not modern-day industrial processes.
Using the visit as a starting point, I will try to cover the basic elements of Rioja wine production without delving too deep into the chemistry of the wine making process.
Modern oenology considers wine quality to be dependent upon the synergic "vineyard-winery" alliance, and the basic raw material is the wine grape. In particular the grape quality at harvest derives from the balance of several primary and secondary metabolites, namely sugars, organic acids, colorants and tannins substances, aromatic compounds, and their precursors. In particular, the phenolic component in red wines is key for wine characteristics since it influences colour, taste, and overall longevity. Together with aroma precursors, the phenolic compounds are mainly responsible for a wines "typicity". This is even more important when winemakers use a single grape variety as an expression of a particular territory (i.e. no possibility to find a particular sensorial balance by blending from different cultivars).
The importance of naturally occurring phenolic compounds contained in the solid parts of the berries (skins and seeds) and their essential roles on the sensorial characterisation of different red wines has been known from the 1980's. The chromatic characteristics, astringency, and bitterness of a wine are highly influenced by the content and degree of polymerisation and/or condensation of phenolic compounds. Knowing the polyphenolic content and profile of the grapes (e.g. different flavonoids, organic acids, tannins, etc.) now enables a winemaker to plan maceration and fermentation, and exploit the full potential of their vineyard. Wineries can now measure anthocyanins, polyphenols, oligomeric flavanols, and polymeric tannins, etc., but it not always easy to find a direct correlation between analytical parameters and the wines produced. However, winemakers now understand much more the underlying physical and chemical processes in make a good wine. For example, it is now known that only part of the phenolic compounds are extracted during maceration, so winemakers have increasingly turned their attention to understanding how to concentrate those compounds in the grape and how best to release them. This means understanding how anthocyanins and flavanols concentrate in the grape skin, and when and how best to extract them. This involves relating skin cell and seed maturity firstly to phenolic characteristics and then to grape ripeness, which means touching the grape, looking at its colour, and tasting it. Ripening changes the composition and structure of the cell wall, as well as the structure of the tissue, and the mechanical resistance and texture of the berry can be assessed. The grape hue and colour intensity (or colour and luminosity in layman terms) can be assessed using CIE L*a*b* colour space. And tasting the grape can provide information on the mechanical traits, the sugars/acidity ratio and even the skin and seed astringency. It requires a certain experience in order to correctly assess grape ripeness, but there are now several instruments that can be used to assess the grape texture, maturity, etc. and it is now clear that changes in grape textural properties during ripening are strongly influenced by the growing conditions and vintage (e.g. the climate of that year). So some experts conclude that "terroir" even affects the mechanical behaviour of grape skins and seeds.
So winemakers now have some new tools to objectively define grape ripeness and harvest date, in addition to the traditional measurement of sugars, organic acid and pH. This does mean that a harvest date can be based upon objective chemical-physical criteria and/or on a subjective evaluation of optimum berry ripeness, e.g. touch, taste, etc. And not forgetting the other criteria such as market constraints, commercial targets, processing capacity, etc.
The organic synthesis and accumulation of primary and secondary metabolites in the skin, pulp, and seeds during ripening are now well understood. During ripening the concentration of sugars, amino acids, phenolic compounds, and potassium increases, whereas other organic acids, particularly malic acid, decreases. Anthocyanins (one of the phenolic compounds) gradually accumulate in the berry skin from veraison (i.e. the onset of ripening), but may decrease during over-ripening. However, proanthocyanidins, oligomeric flavanoids which along with tannins influence aroma, taste, mouthfeel and astringency of red wines, are concentrated in seeds at veraison and slowly decrease until harvest. Harvesting insufficiently ripened grapes results in a more astringent wine because the seeds release higher amounts of proanthocyanidins. Primary metabolites are directly involved in the growth of the plant, etc., whereas secondary metabolites are organic compounds produced by bacteria and fungi (including yeasts). Wine faults and taints are often associated with undesirable bacteria, whereas phenolic compounds such as tannins and flavanoids (including anthocyanins) link the grape to the wines aroma, taste, etc.
Over the last 10 to 30 years harvest dates have been advancing, and wineries today collect a vast array of data, such as daily maximum and minimum temperatures and humidity, average day and night temperatures and humidity, accumulative sum of hours over 10°C, daily and accumulative precipitations, number of rainy days, leaf wetness duration, etc. which are all thought to influence berry characteristics, including skin hardness (softer skins are related to less red pigments). With all the climate-related changes, it has become increasingly hard for winemakers to set a single harvest date where technological, phenolic, aromatic and "textural" maturity is optimal. Winemakers need to known what chemical-physical parameter in going to impact the most on the wine quality for that particular vintage (year). Keeping in mind that ripening is different within a cluster of berries, between clusters on the same vine, and between vines of the same type in different areas of the same vineyard. Pre-harvest analysis can help identify the order in which different sections in the vineyard should be visited, and in many cases vines might be visited several times. It is here that precision viticulture will play an increasingly important role in the future.
The vineyard is a combination of geo-physical parameters such as climate, soil, sun exposure, altitude, etc. and growers choice of grape variety, rootstock, age, vine density and spacing, vine training and pruning, and overall vineyard management (e.g. fertilisation, pest control, irrigation and water holding capacity, etc.). Just changing one of these parameters can impact grape quality, harvest outcome, and the quality of the wine produced.
Topics covered on this webpage are:-
Setting the scene, with just a little bit of history to contextualise the present
The Rioja soil, an in-depth view of one of the most important and unique features of the region, including the "Seven Valleys of Rioja" and even a detour to look at the future with precision viticulture
"Climate Change", perhaps the most important challenge that the region will have to face in the coming years
Rioja grape varieties
EU wine legislation, a framework for defining the meaning of a Rioja wine
Rioja - a region and a wine
La Rioja is both one of 17 Spanish autonomous communities (there are also 2 additional autonomous cities), and one of the 50 Spanish provinces. Wine was so central to its history, culture, and economy that the region took its name from the Rioja wine. The name "Rioja" (from Río Oja) was first attested in 1099, although the wine growing region is actually centred on the Río Ebro.
La Rioja is one of the smallest provinces (43rd with about 5,000 square kilometres), and has one of the smallest populations (40th with a population of little more than 330,000), and they also have one of the lowest population densities in Spain. In absolute terms it is the poorest autonomous community in Spain, but given its low population density it has a GRP per capita slightly above the Spanish average of ca. € 25,000 annual (2017).
Agro-food is the most important industrial sector in La Rioja, with wine production being the dominant activity, followed by processed meats (e.g. chorizo, sausage, etc.) and canning (fruit and vegetables). Other industrial sectors include aerospace (metal parts and metal finishing services), parts manufacturing for the car industry, and footwear.
There are 174 municipalities in La Rioja, most of which have populations of less than 200 individuals. Because the municipalities are so small, they are allowed to get together to create 12 comarcas (a kind of metropolitan area) as a way to provide collectively a variety of local services. Things they get together for are waste collection, drinking water supply, sewer systems, road surfacing, etc.
Traditionally, La Rioja consisting of the nine judicial districts that existed in antiquity, corresponding to Haro, Santo Domingo de la Calzada, Nájera, Logroño, Torrecilla en Cameros, Calahorra, Arnedo, Alfaro and Cervera del Río Alhama. However, the reality is that today nearly half of the population of La Rioja live in Logroño, the capital of the province. Logroño has a population of more than 150,000, whereas the next biggest city is Calahorra with a population of less than 25,000.
It's important to differentiate La Rioja, as a Spanish autonomous community and province, from Rioja, the wine. In fact, the appellation for Rioja wines actually spans three different administrative communities, the main one is La Rioja, the other two being Álava (usually referred to as Rioja Alavesa, in the Basque Country) and the Navarre.
So there is a difference between La Rioja as a Spanish province and autonomous community, and Rioja as a wine region with a denominación de origen calificada (DOCa), the highest category in Spanish wine regulations. In fact Rioja wine is made from wine grapes grown in three different autonomous communities, La Rioja, Navarre, and the Basque province of Álava. So Elciego, home of the Bodegas Marqués de Riscal, produces Rioja wine, but is located in the Basque province of Álava, and not the autonomous community of La Rioja. The distinction between La Rioja province and the Rioja wine region is not easy to understand. For example, part of Rioja Oriental (once called Rioja Baja) is actually north of the Ebro River, and is in the autonomous community of Navarre. Whereas the part of Rioja Alta that encroaches north of the Ebro is still part of the autonomous community of La Rioja. Yet, the entire area of Rioja Alavesa, also north of the Ebro, is in the Basque Country.
Reported figures vary, but it appears that the Rioja wine region has nearly 66,000 hectares under cultivation (2020 figures), although I'm not sure if this is just for wine production, or if it also includes grapes for domestic consumption (table grapes and raisins). I've read that vineyards represent more than one-third of all agricultural land in La Rioja. The Rioja wine region actually produced in 2020 about 268 million litres of wine (red, white and rosé), so slightly less than Austria (280 million litres) and New Zealand (300 million litres), but more than Greece (220 million litres). In the past young wines were the mainstay of Rioja wineries, but today Crianza (aged), Reserva, and Gran Reserva represents about 50% of total production. Around 30% of Rioja wines go to export, with the main buyers being United Kingdom, Germany, United States, Switzerland, Netherlands, Ireland, Canada, Russia, Sweden, and Belgium. The United Kingdom takes 34% of all Rioja exports, but with Russia, they prefer the cheapest generic Rioja wines (average prices less than €4 a bottle). Germany is the next biggest imported with 12% of all exports, however the premium Rioja's (average price of about €7 a bottle) are preferred by the Swedes, Swiss and Canadians. Compared to 2019 there has been an increased demand for Rioja from Ireland (up 60%), United Kingdom (up nearly 20%), and the Netherlands (15%), and overall exports were up more than 8% in 2020 compared to 2019.
It is often quoted that Rioja wines are made up of nearly 15,000 grape growers (I presume that means vineyards), and 576 bottling wineries (2020 figures).
So setting aside the administrative divisions, each of Rioja's three wine subregions has its own distinctive character. Rioja Baja (lower Rioja, but now called Rioja Oriental) is the southern and western part, lower in altitude, with a warmer and drier Mediterranean climate. Rioja Alta (Upper Rioja) and Rioja Alavesa (in the province of Álava) are in the northern and eastern part, higher in altitude, with a cooler and wetter Atlantic climate. What we tend to forget is that the Rioja growing area actually is concentrated in a valley area on both sides of the Ebro River that is only about 100 km long and with a maximum width of 40 km (i.e. for a total of 3,425 square kilometres).
Technical documentation tends to define the climate of the Rioja wine region as being mainly continental (hot and dry summers and cold winters), with influences from the Atlantic and Mediterranean. The average annual temperature in La Rioja is 12 °C, with January being the coldest month, with an average temperature of 5 °C, and July being the warmest, with an average temperature of 21 °C. Rainfall varies from 0.4 m/year to 1.2 m/year. However in the Rioja growing region in the north of La Rioja the average temperature tends to be slightly higher, and average rainfall noticeably lower (0.3 m/year to 0.5 m/year). It's worth noting that the region can see in winter both heavy precipitations (occasionally in the form of snow) as well as occasional frosts, which can result in temperatures dropping as low as -10 °C.
We have already mentioned that the Rioja growing area is divided into three different zones, namely Rioja Oriental, Rioja Alta and Rioja Alavesa, and that it cuts across three different autonomous communities, namely La Rioja (116 municipalities), Navarre (8 municipalities), and the Basque province of Álava (15 municipalities).
Originally defines as sub-zone, the three growing areas are according to the new regulations defined as zones, i.e. "vinos de zona". Each growing area is a different size, i.e. Rioja Oriental (about 24,600 hectares), Rioja Alta (about 27,300 hectares) and Rioja Alavesa (about 13,400 hectares), for a total of 66,271 hectares, or in terms of communities, La Rioja (about 45,700 hectares), Navarre (about 7,300 hectares), and Álava (about 13,300 hectares).
Finally, in terms of the volume of wine produced, La Rioja vinified around 70% of Rioja wines, Navarre (6%), and the Basque province of Álava (24%), of which 87% was red wine, 9% white, and 4% rosé. The so-called "ageing wineries" took 68% of the 2020 production, cooperatives 27%, and the remaining 5% was produced by independent winegrowers.
Before we move on let's just remind ourselves of the global market for wine. In 2020 it was an estimated $417 billion, with Europe representing the biggest market (46%). Expected growth (2021-2028) was 6.4% annually. Another analysis was more cautious quoting a global market size of "only" $326 billion, and a growth forecast (2020-2027) of 4.2% annually. They put the United States as the biggest market at $88 billion annually, followed by France, China, United Kingdom, Italy, with Spain 15th at just over $8 billion (China was projected to be the second biggest market by 2027). In 2020 Rioja wine sales represented 32% of the Spanish domestic market by volume, and 37% by value.
It you are interested in visiting the Rioja region and its wineries, I can recommend Maribel's Guide to the Rioja.
Setting the scene
According to the history books the foundations of the oldest still active winery in Rioja were laid in 1825, when the first vines were planted on the Castillo Ygay estate, and a winery (bodega) was started in 1852 by Luciano Francisco Ramón de Murrieta, later Marqués de Murrieta. In 1878 he acquired the estate and vineyards that have become home to one of the great bodegas of Spain. The winery remained in the family until it was bought by Vicente D. Cebrián-Sagarriga, Count of Creixell, in 1983.
In 1858, Camilo Hurtado de Amézaga, Marqués de Riscal, founded the winery that still bears his title. He had been living in Bordeaux since 1836, so he decided to experiment with French varieties at his estate at Elciego and organised his winery following the French model, being the first in the country to use barriques (oak barrels). His wines soon started winning prizes, and were favourites of King Alfonso XII (1857-1885). In fact they became so popular that he had to invent the gold wire-netting for his bottles, in a bid to counteract fakes. This netting itself became so fashionable that it was then adopted as a badge of honour by other top Rioja wines.
Many other wineries were also started in the late 1800's. For example, La Rioja Alta was founded in 1890 by five wine growers from Rioja and the Basque Country, and is still owned by the same five families today. López de Heredia was founded in 1877 and their Viña Tondonia vineyard was planted on 100 hectares on the left bank of the Ebro River in 1914. They also built a winery in the Barrio de la Estación (the neighbourhood of the railway station) in Haro, next door to La Rioja Alta and other well-known names like Bodegas Bilbaínas (1901) and CVNE (1879). The railway played such a crucial part in the success of the wines that it made sense at the time to establish wineries as close to the station as possible.
Other survivors from this era include Bodegas Montecillo (1872), Berberana (1877), Bodegas Age (1881), Martínez Lacuesta (1885), Bodegas Franco Españolas and Bodegas Riojanas (1890), Bodegas Palacio (1894), and Paternina (1896).
It is commonly recognised that the quality, and thus the prestige, of Rioja wines declined in the 1970's.
Experts suggest that the vineyards were planted with younger, high-yield vines, and when coupled with a less rigorous selection and sorting, resulted in a rapid decrease in the quality of the wine grapes. Add to that the use of industrial techniques designed to favour shorted maceration cycles of barely mature fruit which produced low-quality must. This avoided higher alcohol content, but also produced a must without the aromatic compounds or tannins that could withstand ageing in oak barrels. As a result, many of the wines were acidic, thin, and dried out, i.e. with a sour or sharp taste, little flavour of the fruit, and the sensation that the wine was "flabby" or lifeless.
One explanation was that bodegas didn’t have vineyards of their own, relying on grape growers to supply them. This created a conflict of interests, because the growers, paid by the kilo, had very little interest in the quality of the grapes, concentrating instead on quantity, while wineries hoped their suppliers would do the opposite. Some of these wineries were nothing more than wine factories, and the bottles coming out of them during the 1970's and 1980's gave Rioja wine a bad name. Today most wineries believe that the ownership of vineyards and full control of viticulture are critical for their wines.
There were a few bodegas that experimented with longer maceration cycles, shorter maturation in vats, and the use of French oak barrels. Relevant milestones were the creation of Marqués de Cáceres and Contino, which pioneered the single-vineyard concept as early as the 1970's, producing wines that were darker and fruitier than the average Rioja.
In the late 1980's and early 1990's there was a noticeable move to improve the quality of the Rioja wines, by using terms such as "Rioja Alta" to differentiate themselves from the poorer quality wines. Looking back people now think that the mistake was to continue to use mediocre grapes, and try to use the oak barrels to add aromas to the wine. To underline this "better" wine they put it in a heavy bottle and added a higher price tag, but they did not address the underlying problem.
However, also in the 1990's, boutique or garage wineries started to appear, creating a renewed focus on quality wine grapes from small, artisanal producers. What was important was that an increasing number of wine makers moved away from the bad practices of the 1970's and 1980's. Some returned to the older traditions, whilst others looked for more colour, fruit, and freshness, through the longer maceration cycles and the use of French oak barrels. Some producers even abandoned the traditional designations of Crianza (aged), Reserva, and Gran Reserva.
At the time there was much critical acclaim for Pingus (a Ribera del Duero wine), with a so-called 200% new-wood treatment (100% is the use of new oak barrels, and 200% was when the wine was transferred into another new oak barrel after one year ageing). Many Rioja bodegas copied the idea, but by going too far, produced an overripe, over-extracted, and over-oaked, very dark, heavy, almost jammy, wine.
Overripe usually refers grapes that have been left on the vine to dry in the sun. It increases the sugar level and thus increases the alcohol content, but develops a raisin-like character. Extraction means obtaining the right balance of tannins, acids and aromatics during maceration. Over-extraction produces rustic or bitter tasting tannins, and occurs if the solids and liquid in the maceration are pushed together too strongly, i.e. extending skin contact by pushing the solids into the liquid is called "punching down", and pumping the liquid over the solids is called "pumping over". So with highly mechanical processes and high fermentation temperatures winemakers risked extracting tastes (notes) that they did not want. Under-extraction means that the wine ends up too light and ethereal, and won't age well. In addition, the winemaker must also balance the tannins that are added from the oak barrels. Over-oaking is when too many aromas are extracted from the oak barrels, and can leave a taste that is dominated by vanilla, and/or very dark chocolate, and/or toasting on an open woodfire. All red wines aged in oak barrels will absorb some tastes from the wood, but it should be subtile and difficult to isolate. "Jammy wine" just means that there is an over-abundance, or over-concentration, of jam-making fruit flavours (e.g. ripe strawberries, plums, blackberries, etc.). The red-fruit taste can be too concentrated and overpowering, but some people like wines with a strong fruity flavour.
Wikipedia has a whole webpage on "Wine tasting descriptors".
Fortunately by 2001 the pendulum had swung back, and producers started to focus on acidity, balance, and finesse, and not just colour, alcohol content and dense aromas. The move can be seen as a return to the style of more traditional wines, with a focus on the character and the terroir of Rioja wines. However, today the trend is to drink wines that are (too) young, and many people, including Spanish consumers, don't "lie down" (store and age) their wines. Traditionally wine was aged by the winery and released when ready, but those traditional wine making techniques made it difficult to know what a young wine should taste like, because they were never released as such.
The key today is the focus on balance and finesse in wines, even though aromatic compounds might be a little more concentrated than in the past. Wine producers consider owning their own vineyards the essential prerequisite for quality, and they try to retain tradition values whilst exploiting modern technology. For readers who might want to follow up on this little "taster" (or superficial summary), I can recommend looking at the following wineries, namely López de Heredia, Bodegas Muga (including Torre Muga, Aro and Prado Enea), Artadi (including El Pison), Bodegas Contador, Eguren Ugarte, Finca Valpiedra, Remírez de Gamuza, Palacios - Remondo, Bodegas Roda, Señorío de San Vicente, and Viña Ijalba.
Here is an excellent article dating back to 2009 on the Bodegas López de Heredia.
Experts constantly make references to the Bordeaux method of winemaking when discussing Rioja wines. But over time some fundamental differences have emerged. The first is that today there are 60 different appellations of Bordeaux (e.g. Saint-Émilion, Haut-Médoc, Margaux, Saint-Estèphe, Pauillac, Pomerol, Sauternes, etc.), covering 120,000 hectares (so about twice the size of the Rioja winer region). There are about 6,000 different wineries and vineyards, each with on average 20 hectares of vines, and they produce 900 million bottles annually (Rioja produces around 350 million bottles). Slightly less than 60% of all grapes harvested go in château bottled wines, and the rest go to négociants, cooperatives and generic-branded wines.
Bordeaux has seen some consolidation, for example, between 1995 and 2015, the number of growers has been cut in half, to about 7,000 today. The number of vineyards with less than two hectares now represent only 1% of those 7,000 Bordeaux growers (about 96% of Rioja vineyards are two hectares or less). And there are now nearly 100 Bordeaux properties that have more than 100 hectares of vines (the largest is Château La Borne with 321 hectares of vines). The result is that there are more than 9,000 different Bordeaux wines every vintage, and as an economic sector Bordeaux winemaking is worth €2.5 billion annually. One expert suggested that Bordeaux alone produces about 1.5% of the world's wine.
More than 25% of all Bordeaux wines sells for less than €3 a bottle, and less than 3% sell for more than €15 a bottle (so around 72% sell for between €3 and €15 a bottle). As you might guess its the top 3% that monopolises the attention in the press, and most people will never hear about the other 97% of Bordeaux wines. And of those top 3%, it's the famous "First Growth" châteaux that hog the limelight. There is also a trend in many of the great château wineries to increasingly allocate only the very best grapes to their "grand vin", and push the rest into the "second vin", or even 3rd and 4th wines of the estate. The more those châteaux focus on excellence, so the price goes up, and today almost every one of those bottles is for export (with China top of the list).
When we look to Rioja wines, we see immediately that it's dominated by large the bodegas. Of the 600-odd wineries the top 100 represent nearly 90% of the production, and the top four largest wineries each produce more than 10 million litres annually. More than 50% of sales come from less than 20 of the large bodegas, and probably the top 10% of bodegas count for 80% of all sales. Why do these bodegas handle such large volumes? Part of the reason is the historic role of the négociants. In Bordeaux they would buy wines of various producers, age and stores them, blend them if necessary, and takes care of the marketing. The producer therefore did not need to store several harvests, firstly in oak barrels and then in bottles. So in Bordeaux, the winegrower cultivated the vines, made the wine and sold it on to the négociants. In Rioja, négociants did not exist, so winegrowers had only to cultivate and then harvest the grapes, before delivering them to a bodega (winery). The bodegas bought the grapes, made the wine, aged and stored it, and then marketed it both nationally and internationally. Because Rioja was (and still is) dominated by a few large wineries, the very nature of Rioja's economic model is totally different from that of Bordeaux.
Oddly, another difference between Bordeaux and Rioja wines is the way the 225 litres Bordeaux oak barrel is used. The higher quality Rioja bodegas certainly import oak barrels from Bordeaux, but they use them differently. These bodegas almost always systematically extended the ageing in the barrels as compared to Bordeaux practices, in particular for the Reserva and Gran Reserva. Also the bodegas keep the wine in the bottle for longer before putting it on the market (some bodegas keep their Rioja for 10 years before sending it to market). In addition to extending the period of ageing, Rioja also does not focus on the precise location of the grape production (as in Bordeaux). The result is that Rioja and Bordeaux have a hierarchy of quality which is completely different. Bordeaux's focus is cadastral (possible right down to the plot where the grapes were grown), whereas Rioja focusses on a bottom to top hierarchy with Joven (young), Crianza (aged), Reserva, and Gran Reserva, established according to the time that the wine has spent in barrels and then in bottles in the bodega, before being marketed. So in Rioja its the length of ageing that conditions access to each of the quality categories, i.e. the longer the ageing, the higher the wine is in the hierarchy. This difference impacts the way the wines are marketed and sold. Rioja wine is ready to drink when it is sent to market. The contrast is evident with the Bordeaux en primeur sales system, where the buyer reserves and pays for the wine before it is even available, and then has to sit back and wait for the wine to age before consuming it some years later. The barrel holds such a sanctified place in Rioja that bodegas systematically underlines the number of oak barrels in their cellars, e.g. 10,000, 20,000, up to even 70,000. In fact the DOCa Rioja is proud to be the world number one for barrels, with nearly 1.4 million in use in 2020.
In conclusion, implementing the techniques used in Bordeaux made an essential contribution to the construction of the identity of the vineyards and the wines of Rioja. But many winemakers today present Bordeaux as part of the history of Rioja, and they want to now assert Rioja as a competitor to Bordeaux wines. Wine tourism is just one way to help underline the separate identity of Rioja vineyards and wines. Building on what was learned from Bordeaux in the 19th century, Rioja has focused on extended the ageing process in the oak barrels, and at the same time looking to a culture of brand regularity, rather than terroir or micro-terroir found in Bordeaux.
Above I wrote "Rioja also does not focus on the precise location of the grape production", however with the latest set of regulations this will almost certainly change. I will cover this topic later on this webpage, however it's worth noting that the new regulations are already having an impact on Rioja production practices, e.g. the number of ageing wineries has jumped by 53 since 2018 (as has stocks of wine), and even more noticeable is that yields have been reduced by nearly 20% over the last 2-3 years (as has production in millions of litres).
Rioja - soil
This section on the soil found in the Rioja growing region is surprisingly long and complex. The reason is simple, it is now thought that the soil's physical attributes, and in particular its water-holding capacity, are the closest link to both the old world tradition of terroir, and the new world of precision viticulture, soil mapping and leaf nutrient analysis.
In this section we will start by looking at Rioja soils as simply a mix of ferrous clay, calcareous clay and alluvial soil. We will then introduce the concept of soil water-holding capacity, which refers to a more complex analysis of Rioja soils using a Soil Survey Manual (often tagged "USDA Soil Taxonomy"). We will then close this section on Rioja soils, by turning to the World Reference Base for Soil Resources for yet another way to view soils in the region (an alternative set of soil descriptors often tagged "WRB/FAO"). This section will be followed by a section dedicated to precision viticulture.
The word "soil" like many common words, has several meanings. In its traditional meaning, people consider soil important because it supports plants that supply food, etc., and because it filters and stores water and recycles wastes. About 1870, a new concept for soils was introduced, as independent natural bodies, each with a unique geomorphology resulting from a unique combination of climate, living matter, earthy parent materials, terrain, and age of landforms.
If you were to cut a deep slice into the soil, you would see distinct horizontal layers called soil horizons (this Wikipedia article lists a number of different descriptions). A soil profile is a vertical section from surface to parent material and shows the soil horizons. The upper most layer is called the O-horizon. This layer is rich in organic material, as you might find on a forest floor. In desert soils, this layer may be completely absent, but in organically rich soils, this may be the thickest layer. Just beneath the O-layer, is the surface soil, or topsoil or A-horizon. The A-horizon is dark and rich in organic matter, soil life, and humus. This layer may be somewhat granular and many of its nutrients may have leached out. In some soils, a very heavily leached layer called the E-horizon, develops between the A and B horizons. The B-horizon is the light coloured subsoil beneath the A-horizon. It is illuviation rich with plant nutrients that leached down from the A-horizon. It is typically rich in iron and aluminium compounds and clay. The last horizon is the C-horizon. It contains weathered pieces of rock, and sits on top of unweathered parent material. The C-horizon is typically just below the extent of most roots and is often saturated with groundwater. Below the C-horizon is bedrock.
The geomorphology of each soil, as expressed by a vertical section through the differing soil horizons (i.e. layers), reflects the combined effects of the particular set of factors responsible for its development. When first introduced it was a revolutionary concept. One did not need to depend wholly on inferences from the underlying rocks, the climate, or other environmental factors, considered individually or collectively, but rather, the soil scientist could go directly to the soil itself and see the integrated expression of all these in its geomorphology. This concept made it not only possible but also necessary to consider all soil characteristics collectively, in terms of a complete, integrated, natural body. This view led to a concept of soil as the part of the Earth’s crust that has properties reflecting the effects of local and regional soil-forming agents (i.e. parent material, climate, biota, topography and time).
We have already mentioned that the Rioja growing area is divided into three different zones, namely Rioja Oriental, Rioja Alta and Rioja Alavesa. But what does this division really mean? The simplest description is that each of the three Rioja zones has a slightly different climate and a different combination of soils, as well as its own capital and its own unique history. However, the separation into three zones is more administrative (and historic), since the boundaries between zones don't represent well-defined frontiers in temperature, rainfall or soil types.
The concept of terroir dates back to the ancient world, in that it was important in connecting a wine to its place of origin. Today the concept of terroir is seen as relating the sensory attributes of wines (colour, aroma, taste) to the environmental conditions of the wine grapes used. Unfortunately the word terroir is also often associated with the marketing of some almost mystical features of a growing area, whereas what is really important is the technical-scientific impact on the quality of the must from grape varieties, vine training and treatment, growing conditions and yields, temperature variations, rainfall, soil types and their water holding capacity, etc. (plus the winemaking process itself, etc.).
Today terroir is based on the assumption that the combination of wine characteristics can be attributed to a delimited geographical area. For example, the label Protected Designation of Origin (PDO) defines terroir as a wine that is native to a region or a defined place whose quality or specific characteristics are essentially due to the geographical environment. To prevent confusion between the descriptive definition of '' terroir '' and the legal definition of a Geographical Indication, the International Organization of Vine and Wine (OIV) have adopted the following definition of '' terroir '': '' Vitivinicultural ' 'terroir' '' is a concept which refers to an area in which collective knowledge of the interactions between the identifiable physical and biological environment and applied vitivinicultural practices develops, providing distinctive characteristics for the products originating from this area ''. Some prefer a simpler "overall wine characteristics resulting from the soil, the grape variety, and the winemaking techniques used". Others have gone down a different route, defining terroir as a unique mix of colour intensity, astringency, fleshy/richness, and roundness. Perhaps the most convincing and pragmatic definition of terroir is simply the characteristics of a wine as established by a consensus of the wine producers in the protected area. It is the producers that selected to different grape varieties and made the technical choices concerning vineyard management and the winemaking process.
Geographically speaking, the Rioja area includes two clearly different sub-areas, namely a valley area (Depresión del Ebro) and a mountainous area to the south, the Sistema Ibérico (Iberian System with the Picos de Urbión, the Sierra de Cameros and the Sierra de la Demanda). This implies a noticeable contrast in topography, with the two sub-areas containing different morphostructural units. In addition the Rioja Alavesa's northern boundary is formed by the Sierra de Cantabria with the Sierra de Toloño, mountain ranges that separate it from the rest of Álava.
Haro is the capital of Rioja Alta (and part of Rioja Alavesa), and sits on the right bank of the Ebro River. This zone has a continental climate with an Atlantic influence, although the Sierra de Cantabria acts as a natural frontier to stop the passage of rain-bearing winds from the North. In this zone, there are various soil types, mainly ferrous clay with incursions of calcareous clay and alluvial soil. Most of the vineyards are planted on sun oriented terracing as high as 750 metres, and some of the terraces can be very steep (meaning that harvesting must be done manually). The town itself is home to a collection of centuries-old wineries located in the Barrio de la Estación, often also called the Barrio de las Bodegas. These historic wineries were built right next to the first railway station in the region, so exploiting the game-changer for exporting their wines. Around Haro you can find an enormous variety of vineyards and wineries, ranging from the 2.8 hectare plot, single vineyard, Finca Valhonta, to the 900 hectares managed by historic bodega Ramón Bilbao.
Laguardia (Biasteri in Basque) is the capital of Rioja Alavesa, and is unique in being a fortified Bastide town with a warren of 320 wine cellars (or cuevas) excavated under the homes. It is said that the town's surface area is larger underground than above ground. Set halfway between Haro and Logroño, Rioja Alavesa is the smallest zone in terms of size. It is also the most northerly, and therefore the Atlantic has a greater influence on its climate. Generally its wetter and with lower temperatures than in the other two zones, both in summer and winter. The soil is almost exclusively calcareous (often abbreviated to marl) and located on terraces or in small parcels. The Bodegas Ysios and Herederos del Marqués de Riscal are two of the most famous bodegas in this zone. Some vineyards claim to still have pre-phylloxera vines more than 170 years old.
It is said that Rioja Alta and Rioja Alavesa, due to their position higher up in the Rioja Valley and the presence of calcareous clay, produces wines which age better than wines from Rioja Oriental. The reality is that it is difficult to generalise because much depends on the exposure to the sun, rainfall, grape characteristics (age, pruning, etc.), etc. but it does appear true that vines planted on calcareous soil appear to age better.
Logroño is the capital of Rioja Oriental (ex Rioja Baja), and also the capital and largest city of the autonomous community of La Rioja. The Rioja Oriental area is bordered by the Leza River and the Sierra de Cameros, and follows the banks of the Ebro River to the Alhama River. It occupies the territories between Logroño and Alfaro, including the eight Navarrese municipalities on the left bank of the Ebro River. This is the most easterly zone, which makes the climate drier and warmer, with a Mediterranean influence (it is the hottest and driest area of Rioja). The soil are predominantly alluvial, but there are also large areas of ferrous clay, the alluvial soil is found near the rivers. The vineyards are usually larger, flatter and located at a lower altitude. The wines from this zone have greater structure (i.e. acidity, sweetness, body, tannin, etc.) and higher alcohol content than those in Rioja Alta and Rioja Alavesa.
This section is more or less dedicate to the soil types found in the different zones. Numerous sources mention the different soils as ferrous clay, calcareous clay and alluvial soil, and there are soil maps that follow that nomenclature. Many of the maps are actually based on a soils water holding capacity, which is known to impact the quality of the must (more so than small variations in temperature or altitude).
Soil is a crucial component in grape and wine production, but its effect is complex, acting on grapevine water and nutrient supply, and on soil temperature in the root zone. Although grapevines can adapt to a wide range of soil properties, grape and wine composition are significantly affected by soil type, which influences the taste of the final product. Wine quality is often strongly dependent on the soils physical properties, such as its texture and depth, due to their relationship with soil water-holding capacity (WHC), since vines behaviour and berry composition are closely related to water uptake conditions. In this sense, wine grapes grown on highly permeable soils and under the same environmental conditions with large diurnal temperature differences have faster photosynthetic rates, higher sugar concentrations, and improved chroma and palate. It has also been reported that soil can influence the aromatic composition of wines, being dependent upon geographical location, climatic conditions, hydrological regulation, and soil profile.
Apart from soil, climate is also widely acknowledged as one of the most important factors influencing grapevine development and growth. The timing and duration of the grapevine phenological stages are deeply tied to the prevailing atmospheric conditions, which also contribute to variability in grapevine yield, wine production and quality. This variability ultimately affects the winemaking process and microbiological, chemical and sensory aspects of wine. Temperature is widely known to affect vine phenology, vegetative growth and yield, and wine grape quality.
In vineyards, spatial variations in topography, climatic conditions, and physical and chemical properties of the soil are known to affect spatial variations in yield and fruit soluble solids. Given that spatial variability is very high in Rioja soil, variation in soil properties appears to be a key driver of vineyard yield and grape composition. To optimally manage vineyard variability, it is critical to delimit zones based on bioclimatic indices, soil types and lithological characteristics, or their combined influence referred to a specific geographical area.
In terms of the soil, Rioja soils are diverse, ranging from clay-limestone, clay-ferrous and alluvial, some slightly alkaline, others poor in organic matter and with moderate water availability during the summer. I've read that Rioja is composed of about 50% alluvial soil, and about 25% each for calcareous clay and ferrous clay.
Calcareous clay (clay-limestone) soils are rich in chalk, permeable and difficult to water and mechanise. It is a poor whitish soil rich in chalk, with white pebbles to a depth of about 40 cm, covering a loose sandy subsoil. This has excellent drainage (permeable), and the roots in the subsoil are well placed to receive all the nutrients they need. It is precisely the type of soil that is best suited for the production of wine, and in particular it is ideal for cultivating Tempranillo grapes. As a result, it makes very stable wines, elegant and aromatic, perfect for ageing.
Clay-ferrous soils, on the other hand, contain less chalk, has a brown to reddish colour, but is still not easy to water or mechanise. These soils are said to produce fresher wines, with less body and more acidity.
Alluvial soils are permeable and rich in nutrients, and are easy to mechanise. It is said that they produce wines with good colour.
According to the experts the most favoured soils are clay over limestone, found in Rioja Alavesa and in some parts of Rioja Alta. Ferrous clays are found south of Ebro on higher grounds. Alluvial soils are least favoured but are very fertile and found on low-lying land in Rioja Alta and Rioja Oriental (ex-Rioja Baja). They claim that these different soils, coupled with their microclimates that vary in terms of vineyard layout and exposure levels, protection from wind, etc. give the wines unique traits. And when coupled with the use of different wine grape varieties and growing techniques, you obtain wines which have different personalities yet remain within the framework of a perfectly recognisable common Rioja identity.
Looking at the way soil is classified immediately introduces an additional level of complexity. Reference to clay-limestone, clay-ferrous and alluvial soils is found in numerous texts, however agronomist working in wineries appear to classify different Rioja soil types into four groups, largely based upon their water-holding capacity (WHC), summed over the different layers (soil horizons). The four WHC groups are as follows:-
Low WHC group includes Lithic Xerorthent, Lithic Xeric Torriorthent and Xeric Torriorthent soils. These soils are shallow (25-70 cm), located usually on slopes or high flat uplands, have a low WHC and high total carbonates (35-50%).
Medium-Low WHC group corresponds to Typic Calcixerept and Xeric Haplocalcid soils. Typic Calcixerept soil is stony (35-65% of coarse fragments) with high internal drainage and medium-low WHC, and have an underlying calcic horizon (from 60-70 cm), and moderate depth (100-125 cm). Xeric Haplocalcid soils are found on stony terraces situated 40-100 metres above the Ebro River with a moderate calcic horizon that allows high water infiltration and low retention.
Medium-High WHC group includes mainly Typic Xerofluvent and Xeric Torriorthent and a few Typic Calcixerept soils. These soils are on low and medium altitude terraces without stoniness, with the exception of Typic Calcixerepts. They are generally situated 7-40 metres above the Ebro River and were deep (> 125 cm) with high WHC.
High WHC group corresponds to Typic Xerofluvent and Typic Calcixerept soils that are deep (> 150 cm). Typic Xerofluvent soils with high WHC are at valley bottoms. They receive input from sloping areas by soil erosion processes. Typic Calcixerept soils occupy hollows located in concavities or depressed areas in flat landscapes with a calcic horizon between 90 and 100 cm.
The above classification of soil types into four groups based upon the water-holding capacity involves both soil samples classification (depth, percentage sand-silt-clay, soil pH, soil-to-water ratio, organic matter, texture, potassium (K) content, etc.), and must qualitative parameters based upon grape samples (probable alcoholic content, total acidity, malic acid, tartaric acid, soil pH, potassium (K) concentration, polyphenol total index, anthocyanins, and colour intensity). There are a number of additional variables such as year-to-year climate variations, age of vines, row orientation, pruning, etc., but what emerged was that different soil types can significantly affect the composition of wine grapes and the final wine product.
Malic acid and tartaric acid are two of the principal organic acids found in wine grapes. Malic acid is essential for the health and sustainability of vines since it participates in enzymatic reactions that transport energy throughout the plant. As the grapes ripen the malic acid is metabolised, and its concentration should be lower, but still present, at harvesting (too much and the wine tastes sour, too little it tastes "flat"). During the winemaking process the malic acid is reduced through malolactic fermentation, adding complexity and softening the harshness of the malic acidity. Tartaric acid maintains the wine's stability and colour, and influences the taste (too much tartaric acid in the bottle indicates the wine will be unstable and unpleasant looking tartaric crystals may form).
Soils with higher water-retention capacity (High WHC soils) produces musts with higher total acidity mainly due to higher malic acid content. It appears that high malic acid concentrations results from vigorous vines, where grape clusters are more shaded because of excessive leaf coverage. This causes a lower bunch temperature, thus temperatures higher than 30°C are less frequent, and consequently malic acid is not eliminated. The higher level of vegetation in High WHC soils results in a lower probable alcoholic content, which is coherent with the fact that high sugar content is found in vines growing in shallow soils and with limited leaf coverage.
Medium-high WHC soils (low and medium terraces) generally produce musts with lower potassium (K) concentration, caused by lower soil potassium and clay content in the soil horizon between 10 and 35 cm (initial soil potassium content directly influences the must potassium concentration). Potassium content is related to soil pH, and a higher potassium content raises the soil pH due to the precipitation of tartaric acid to potassium bitartrate, and adversely affects the wine stability.
Low and Medium-low WHC soils are in general the only ones that produced musts with high phenolic content (i.e. positively affecting taste, colour and mouthfeel). A lighter colour is inversely related to plant vigour. This is caused by higher light exposure of the fruiting zone in low vigorous vines. The conclusion is that soils with the lowest WHC have the highest potential for making quality red wines. In deep rich soil, vines are vigorous and highly productive, but better wines are generally produced when the vines are cultivated on poor soil. Thus, wine grape quality could be high on soils that induce water deficit, reducing shoot growth, berry size and yield. These factors generally enhance grape quality for the production of red wines. Just to make life that little bit more difficult, it is known that low WHC does not automatically imply high quality and that grape composition is influenced by more complex factors. Skin anthocyanins, which play an important role in the quality determination of grapes, are affected by environmental and management-related factors such as light interception, temperature, bunch thinning, etc.
The initial descriptions for clay-limestone, clay-ferrous and alluvial soils were a good starting point, but a little too general. The focus on the water-holding capacity (WHC) of soils provided an improved understanding how specific types of soils impact directly on the vine, and then later on the wine produced. On the other hand the soil descriptors mentioned (e.g. Lithic Xerorthent, Lithic Xeric Torriorthent, Xeric Torriorthent, Typic Calcixerept, Xeric Haplocalcid, Typic Xerofluvent) are just a very small part of a very extensive soil taxonomy described in the Soil Survey Manual of the Natural Resources Conservation Service of the United States Department of Agriculture. Often the descriptors are tagged with "USDA Soil Taxonomy", and we will see later on this page that an alternative set of soil descriptors is tagged "WRB/FAO".
As an example, let's look at Lithic Xeric Torriorthent. Torriorthent (a coarse, silty entisol) is a dry orthent in a cool to hot, arid region. Entisol is just a recent soil with no distinguishable levels or horizons, and an orthent means that it an entisol on a steep slope or because it contains no weather-able minerals. Torriorthents have an aridic (arid or torric) moisture regime and a temperature regime warmer than cryic (ice cold). Both aridic (arid) and torric are moisture regimes, with aridic boarding an arid region, whereas torric is also boarding on a hot and dry region but where the limited amount of water is actually available at times when the soil temperature is optimal for plant growth. Cryic (ice cold) is one type of temperature regime, meaning a very cold soil with a mean annual temperature of less than 8°C, but does not have permafrost. Generally, torriorthents are neutral or calcareous and are on moderate to very steep slopes. A few are on gentle slopes. Many of the gently sloping soils are on rock pediments, are very shallow, have a sandy-skeletal particle-size class, or are salty. Others are on fans (i.e. shaped like a section of a shallow cone) where sediments are recent but have little organic carbon (e.g. in organic matter). The vegetation on torriorthents commonly is sparse and consists mostly of xerophytic shrubs (e.g. cacti-like) and ephemeral grasses (short lived) and forbs (grassland flowers). The vegetation on a few of the soils is saltgrass. Torriorthents are used mainly for grazing.
So Lithic Xeric Torriorthent is just one sub-group of Torriorthents, but as a sub-group it has a very precise definition, i.e. "These soils have a lithic (rock) contact within 50 cm of the surface and have more available moisture than the soils of the Lithic subgroup. And in normal years they are dry in all parts for less than three-fourths of the cumulative days per year when the soil temperature at a depth of 50 cm from the soil surface is 5°C or greater. And they have a thermic, mesic (adapted to moisture), or rigid soil temperature regime and an aridic (arid or torric) moisture regime that borders on xeric". So what this means is that the region has enough winter precipitation to be moist during late winter or early spring, but is continuously dry for most of the summer in normal years (this is why they are used mostly for winter or spring grazing). The lithic (rock) contact commonly limits the moisture-storage capacity.
The purpose of such a complex taxonomy is to ensure that an individual soil can only belong to one class of soil. What does that mean? The starting point is that the properties of soil will vary from place to place, but that the variations are not random. Natural soil bodies are the result of climate and living organisms acting on parent material, with topography or local relief exerting a modifying influence and with enough time for soil-forming processes to act. This means that soils are more or less the same wherever all the elements (parent material, climate, living organisms, local relief, time) are the same. The fundamental principle of the modern day soil survey is that under similar environments in different places, soils are the same. This is the basis for the Soil Survey Manual of the Natural Resources Conservation Service of the United States Department of Agriculture.
Above we explained one example (a taxon) taken from the US soil taxonomy, which describes one particular type of soil found in the Rioja region. It may appear complicated, but there are a lot of positives in the way it has been created. Firstly it is not difficult to pronounce, secondly it does have a distinctive meaning, thirdly it does indicate its position in the classification system, fourthly the important properties are reflected by similarities in different names, and finally the names fit into many languages without translation.
The highest level are the 12 "orders", which are easy to identify because they all end in "sol", i.e. "ent" in the order entisol means "recent soil", and "gel" in the order gelisol meaning "permafrost soil". The orders are defined by the presence or absence of features that reflect soil-forming processes, i.e. soil properties are the consequences of a variety of processes acting on parent materials over time. The orders are based upon the clearly visible features of the processes, which are facts that can be observed and measured and used as a basis for distinctions. The orders are not based upon the inferred processes themselves because new knowledge is certain to change our ideas about the processes. Thus, the distinctions between orders are based on the markers left by processes that experience indicates are dominant forces in shaping the character of the soil.
Then comes 64 different two-syllable sub-orders. The first syllable connotes a diagnostic property, and the second syllable is the formative element from the name of the order, so aquents ("aqua" plus "ent") means aquic conditions, and fluvents ("fluv" plus "ent") means very young sediments (from L.fluvius or river). Some of these sub-orders can have easy to understand definitions, such as an aquent which means a kind of wet soil formed on river banks, or eventually tidal mudflats. These are the soils in areas of recent alluvium and the soils of coastal marshes that are saturated with water and have a blue or green hue close to the surface. Whereas a fluvent is a kind of alluvial soil which does not become established and develop because of repeated deposition of sediment in periodic floods.
Continuing our example, aquents and fluvents are sub-orders of the order entisol, and there are an additional three sub-orders, i.e. arents, pesamments and orthents. The five sub-orders distinguish the major reasons for the absence of horizon differentiation. Entisol as a "recent soil" really means the absence of the major soil-forming processes. This can be because the parent material might be inert (e.g. quartz sand) or hard (no moisture) and leaving little residue (pesamment), or due to recent deposits (aquents and fluvents), or on slopes where soil erosion is faster than rate of formation (orthent), or it could even be due to very deep (1 to 2 metres) plowing (arent) that has destroyed the levels or horizons.
Then come what are called the "great groups", consisting of the name of a sub-order and a prefix that consists of one or two different "formative elements" suggesting something about the diagnostic properties of the soil. More than 300 great groups can be composed from 55 different formative elements, e.g. from extreme weathering with "acr" (Gr.arkos for "at the end"), through the presence of organic carbon with "fluv" (L.fluvius for river), to the xeric moisture regime "xer" (Gr.xeros for dry). There are only a few taxa in the order and sub-order levels, so only the most important horizons can be described, whereas at the great group level the assemblage of horizons and the most significant properties of the whole soil can be described. For example, this means that fluvents that have a cryic (ice cold) temperature regime are called cryofluvents, and fluvents that have a torric moisture regime (hot and dry) are called torrifluvents.
Below the "great groups" there are more than 2,400 subgroups consists of the name of a great group modified by one or more adjectives. Through the categories of order, sub-order, and great group, emphasis is placed on features or processes that appear to dominate the course or degree of soil development. In addition to these dominant features, many soils have properties that, although apparently subordinate, are still markers of important sets of processes. Some of these appear to be features of processes that are dominant in some other great group, sub-order, or order. In a particular soil, however, they only modify the traits of other processes. There are three kinds of subgroups. The main kind are "intergrades" or transitional forms to other orders, suborders, or great groups. The properties are the result of processes that cause one kind of soil to develop from or towards another kind of soil, or otherwise to have intermediate properties between those of two or three great groups. There are "extragrade" subgroups that have some properties that are not representative of the great group but that do not indicate transitions to any other known kind of soil (adjectives can range from abruptic (L.abruptus or torn off) meaning an abrupt textural change, to xanthic (Gr.xanthos) meaning yellow). They are named by modifying the great group name with an adjective that connotes something about the nature of the aberrant properties. Thus, a cryorthent (ice cold - true (typical) - recent soil) meaning a typical ice cold recently eroded surface, that has bedrock that is at least strongly cemented within 50 cm of the mineral soil surface, would be called a lithic (rock) cryorthent (Gr.lithos or stone). The third kind of subgroup is "typic", which represents what is thought to typify a great group, i.e. there is no other appropriate adjective, so a "typic" subgroup means that a soil has all the diagnostic properties of the order, suborder, and great group to which it belongs. This means that "typic" subgroups also have no additional properties that indicate a transition to another great group, but it does not necessarily mean that they are the most extensive subgroup of a great group.
Subgroups are most often used to describe "intergrade subgroups" where a soil belongs to one great group but has some properties of another order, sub-order, or great group. Thus, torrifluvents that have some of the properties of vertisols are called vertic torrifluvents, i.e. having some of the properties of vertisols superimposed on the complete set of diagnostic properties of torrifluvents. Vertisol means to invert (L.verto or turn) and describes a soil with a high content of expansive clay minerals that form deep cracks in drier seasons.
Before we move on let us re-validate our view of lithic (rock) cryorthent mentioned above. Working down, this is of the order entisols, sub-order orthents, great group cryorthents, and finally the subgroup lithic (rock) cryorthents.
Below subgroups, there are families, which are polynomial names. The intent is to group the soils within a subgroup having similar physical and chemical properties that affect their responses to management and manipulation for use. In some cases soil properties are used in this category without regard to their significance as indicators of soil-forming processes.
Each consists of the name of a subgroup and descriptive terms, and you find generally find three or more being used to indicate a variety of features:-
Soil temperature classes (8 classes)
and, in a few families, depth of the soil or the thickness of the soil penetrable by roots (3 classes), rupture resistance (2 classes), and classes of coatings and classes of cracks (3 classes).
And finally you have the names of series, which as a rule are abstract place names (there are more than 19,000 series recognised in the US). The name generally is taken from a place near the one where the series was first recognised. It may be the name of a town, a county, or some local feature. Some series have coined names. Many of the series names have been carried over from earlier classifications. Some have been in use since 1900. As an example, the Miami series is a taxonomic class, a concept of a narrowly defined kind of soil (calcareous and loamy, being fertile and with a moderate available water capacity). Second, one may examine a pedon (a body of soil) and say, "This is Miami", meaning that the properties in the pedon are those of the Miami series and that the pedon is a proper example. Third, "Miami" is used as part of the name of a map unit in an area that is shown on a soil map if the Miami series is dominant in that area.
Now lets return to the Rioja growing area, and rapidly summarise the 6 different soil types found there, according to the nomenclature used in the US Soil Survey Manual:-
Lithic Xerorthent - is an Orthent (an Entisol which is shallow and lacks a horizon probably due to a steep slope) that has a xeric (very dry) moisture regime and a frigid (very cold), mesic (adapted to moisture), or thermic soil temperature regime, and have a lithic (rock) contact within 50 cm of the mineral soil surface. A "thermic soil temperature regime" has a mean annual soil temperature of 15°C or more, but less than 22°C.
Lithic Xeric Torriorthent - is an Orthent (an Entisol which is shallow and lacks a horizon probably due to a steep slope) that has an aridic (arid or torric) moisture regime and have a soil temperature regime warmer than cryic (ice cold). And specifically this soil type must also have lithic (rock) contact within 50 cm of the soil surface, and in normal years, must be dry in all its parts for less than three-fourths of the cumulative days per year when the soil temperature at a depth of 50 cm from the soil surface is 5°C or higher, and a thermic, mesic (adapted to moisture), or rigid (inflexible) soil temperature regime and an aridic (arid or torric) moisture regime that borders on xeric (very dry).
Xeric Torriorthent - is an Orthent (an Entisol which is shallow and lacks a horizon probably due to a steep slope) that has an aridic (arid or torric) moisture regime and have a soil temperature regime warmer than cryic (ice cold), and have a lithic (rock) contact within 50 cm of the soil surface.
Typic Calcixerept - is a Xerept that has a calcic horizon that has its upper boundary within 100 cm of the mineral soil surface or a petrocalcic horizon that has its upper boundary within 150 cm of the mineral soil surface and are calcareous in all parts of all horizons above the calcic or petrocalcic horizon. And in addition it must not have a duripan or fragipan that has its upper boundary within 100 cm of the mineral soil surface. As a "typic" it must be different from all other types of Calcixerept, and as such represents a kind of standard or "pure" version of that soil type.
Xeric Haplocalcid - is a Calcid that has a calcic horizon with its upper boundary within 100 cm of the soil surface. These soils must not have a duripan or an argillic (i.e. clay and drains slowly), natric (i.e. sodium), or petrocalcic horizon within 100 cm of the soil surface. In addition this soil must be dry for less than three-fourths of the time (cumulative) when the soil temperature is 5°C or higher at a depth of 50 cm and have a soil moisture regime that borders on xeric (very dry).
Typic Xerofluvent - is a Fluvent that has a xeric moisture regime (i.e. very dry) and a frigid (very cold), mesic (adapted to moisture), or thermic soil temperature regime. As a "typic" it must be different from all other types of Xerofluvent, and as such represents a kind of standard or "pure" version of that soil type.
The above soil descriptors (e.g. Typic Xerofluvent) are often tagged with "USDA Soil Taxonomy", but there is an alternative set of soil descriptors according to the WRB/FAO.
The US Soil Survey Manual provides the major principles and practices needed for making and using "soil surveys", which encompass the process of soil maping, describing, classifying, and interpreting natural three-dimensional bodies of soil on the landscape. Alongside the US manual there is also a World Reference Base for Soil Resources, an international soil classification system edited by the International Union of Soil Sciences. In 1981 the United Nations Food and Agriculture Organisation (FAO) published the Soil Map of the World (scale 1 to 5 million). In this map it used as a legend a very simple soil classification system which was the first truly international system. Despite having 152 soil units forming 28 major soil groupings, it was intended for mapping soil at a continental scale and not local scale. The names they gave to the different soils were as "traditional" as possible, with a focus on those in general use. However, other names, such as "desert" or "Mediterranean", were not retained because different countries used different definitions.
In 1998 the FAO classification system was replaced by the World Reference Base for Soil Resources (which included a few revisions to the original classification schema). It introduced 30 soil reference groups accommodating more than 200 different type of "soil units", and it also aggregated the 30 reference groups into 10 "super-sets" based upon the differences such as organic or mineral soils, "typical" types of red and yellow soils, permafrost regions, etc. They also adopted the concept of a measurable and observable "diagnostic horizon" defined as a combination of soil properties and soil materials.
The most important point is that whatever soil classification system you adopt it has to describe the different lithologies, landforms, climates and types of vegetation (i.e. the main soil forming factors) that have produced the variety of soils found in both in the valley area and in the mountainous area of the Rioja growing area. According to the WRB/FAO classification, the following soil reference groups are present in the Rioja area:-
Regosols (Calcaric and Eutric) - very weakly developed mineral soil in unconsolidated materials (everything that is not in another soil group), and often found in arid, semi-arid or mountainous regions that have been heavily eroded
These reference soil types are often associated with qualifiers, such as:-
Haplic - having no specific characteristics, thus typical of the soil reference group
Luvic - having a base saturation of 50% or more throughout to a depth of 100 cm from the soil surface
Petric - strongly cemented or indurate (hard) within 100 cm from the soil surface
The reference to "base saturation" is important and needs an explanation (see the Wikipedia article on Base-Cation Saturation Ratio). It has long been recognised that great wine regions in France, Italy and Spain are rich with limestone. Or, more precisely, these soils are rich in plant-accessible calcium carbonate, the main chemical component of limestone, typically from decayed limestone outcroppings (limestone itself being too hard for plants' roots to penetrate). It turns out that there are several reasons why calcium-based soils (calcareous) improve wine quality. They have water-retention properties that are ideal for growing grapevines, and water is essential for cation exchange, i.e. the process by which plants take up nutrients through their roots. But grapevines do poorly in waterlogged soils, which increase the likelihood of root disease. Calcium-rich clay soils have a chemical structure composed of sheets of molecules held together in layers by ionic attraction. This structure permits the soil to retain moisture in periods of dry weather but allows for good drainage during heavy rains. This feature is the main reason why irrigation in some French vineyards is prohibited. The reason is that drip-type irrigation only affects the topsoil, and the vine would only take up nutrients from within the dripper zone, and not from the deeper subsoil (i.e. the vines would not be able to express the terroir). Experts are now convinced that dry farming is perhaps the most important aspect when producing wines characteristic of a particular place, despite the lack of rain during the summer months.
Calcium-based soils tend to be more basic than soils derived from other nutrients. The soil pH of the calcareous layers can be as high as 8, much higher than the typical topsoil pH of between 5.5 and 6.0. Research has shown that cation exchange is greater at higher levels of base saturation, perhaps because most of the minerals that grapevines require are at their most accessible when soils are more basic. The nutrients a grapevine needs to thrive, i.e. magnesium (Mg), potassium (K), calcium (Ca), and sodium (Na), are taken up at certain specific sites on the root hairs through this process of cation exchange. Negatively charged compounds in plant roots attract cations (i.e. positively charged ions). Calcium helps soil particles aggregate through a process called flocculation, which helps make available more cation exchange sites to a plant's roots. In low-pH soil, hydrogen ions start to displace the ions of the four main nutrients. Only above a pH of 6.0 are all four nutrients readily available. So, calcium carbonate acts as a buffer (it has been used for centuries as an antacid) and counteracts the acid created in the breakdown of organic matter in topsoil. The end result is a soil pH level at which nutrient availability is at its highest. Finally, there is increasing evidence that soils rich in calcium help maintain acidity in grapes later in the growing season. There appears to be a link between cation exchange processes in soils rich in calcium and (with enough water) higher grape acidity and lower wine pH.
More generally soil sampling is a critical tool for any farming operation, since it helps determine fertilisation plans for the following growing season, and in the longer term points to how to build sustained soil health. Three key parameters are soil pH, cation exchange capacity and base saturation. Usually the soil samples will also be tested for primary macronutrients, including nitrogen (N), phosphorus (P) and potassium (K), and secondary nutrients.
Firstly the effects of a changing soil pH are far-reaching, since most nutrients will become either more or less available according to the pH level. Take phosphorous (P), at a pH of 6 to 6.5, it is easily available to plants when there is a sufficient level of it in the soil, however, as the pH moves higher (becoming more basic) it becomes less available, and near a pH of 8.0 it becomes almost completely unavailable to plants. More generally nitrogen (N), calcium (Ca), magnesium (Mg), phosphorous (P), and potassium (K) only become fully available at a pH of near 5.5 to 6. Fortunately the pH can be easily adjusted, e.g. in acidic soils with low pH, adding lime is a quick and easy way to adjust pH upward. Basic, or high pH soils are a little more difficult to adjust. It’s common in soils with pH near 8 for growers to add acids, such as sulphuric, or phosphoric acid, to irrigation water. Adding elemental sulphur is another means of lowering soil pH. So the aim is to try to keep the soil pH in the slightly acidic range (5.6-6.9) or natural (pH 7.0), but knowing how much lime to add will depend upon the soil's buffer capacity, i.e. with a high cation exchange capacity, more lime will be need to raise the pH level, than for soil with a low cation exchange capacity.
The cation exchange capacity is effectively a relative measure of the soil’s negative charge and thus its ability to hold certain nutrients that are cations (positively charged in nature). There are only a few components that give soil a negative charge, and the two most common are clay and organic matter. Elements such as calcium (Ca), potassium (K), magnesium (Mg) and others, are cations and have positive charge. Cation exchange capacity levels give a grower a good idea of the overall nutrient capacity as well as soil texture. High results represent clay dominated or fine soils, and low results are for sandy or course natured soils. Fine, or clay soils, retain nutrients better than sandy soils, so they can be fertilised less often. Fine soils hold a great deal more water than course soils, so need less irrigation. It is possible to add gypsum to create better porosity, thereby creating better drainage. In sandy soils, the annual addition of organic matter in the form of manures and composts can help build better charge, better water-retention and increases microbial numbers in the soil.
Base saturations is perhaps the most important parameter since it refers to the level of permeation of soil surfaces by the five cations, calcium (Ca), magnesium (Mg), potassium (K), hydrogen (H) and sodium (Na). What is important is how these percentages relate to one another, and Ca should be 60 to 65%, K 4-6%, Mg 12-25%, H 10% or less, and Na less than 1%. If any of these cations are out of range the grower must try to alter the percentages. The addition of a host of mineral nutrients to the soil to aid in plant nutrition is of little use if the base saturation percentages have not been addressed beforehand. Maintaining good levels of base saturation is important, for example, in strongly acidic soils free amounts of aluminium and iron precipitate phosphorous (P) out of the soil, making it unavailable to the vine. In addition, soil microorganisms, which improve soil fertility through the breakdown of organic matter and the metabolism of nitrogen, can be inhibited in acidic soils. This may appear over-technical, but, as an example, it is known that phosphorous (P) nutrient status can be manipulated by the grower across different soil types, and nutrient status significantly affects vine bud fertility, photosynthesis, dry matter and fruit production, and grape and wine chemical parameters, which can change the sensory attributes of the wine.
Reducing the Rioja growing region soils, as described in the World Reference Base for Soil Resources, leaves us with three key soil profiles, as shown below, i.e. from left to right Calcisol, Cambisol and Fluvisol.
Calcisol is a calcareous soil (i.e. mostly calcium carbonate or chalk) with a substantial secondary accumulation of lime, found often in Mediterranean-type semi-arid environments. Often the qualifier "haplic" is used (i.e. haplic calcisol) to mean "not out of the ordinary", i.e. not hypercalcic, aridic (arid), takyric (barren land), sodic (i.e. containing soluble sodium salts), etc. Calcisols are quite common in northern Spain, and in fact cover more than 6% of the Earth's land surface. Soil profiles often start with the term "O" for a humus or organic top layer (e.g. decomposed leaves, etc.), which can be quite thin or even non-existent. Then follows A, B, C, …, where "A" is topsoil good for plants, etc, "B" is subsoil rich in minerals leached from upper layers, and "C" is the so-called parent material on the Earth's surface from which the soil developed (below that there is "R" or bedrock). The term "soil horizon" is often used to mean soil layers, e.g. "B horizon". So Rioja calcisol has a surface layer that is pale and ochric (i.e. low in organic matter). The subsoil (B) horizon is cambic (i.e. containing gypsum) or argic (i.e. clay), and may even present vertic properties (i.e. having, within 100 cm from the soil surface a vertic horizon), and a "vertic horizon" means a high clay content which is sticky when wet (expanded) and hard when dry, and may produce a groves surface or even broad cracks when dried out. And there is always an accumulation of carbonates in the C horizon.
Cambisol (the FAO has a detailed definition of cambisols), in this context, cambisol a soil with a calcareous content over 25% (i.e. composed of calcium carbonate meaning containing lime or being chalky). It is very poor in organic matter, with little accumulation of clay in the subsoil "B" and lower horizons, and under which there is a marly rock that allows easy penetration of the roots (i.e. marl is a kind of mud containing clays and silt). It is yellowish-brown in colour, drains well and is very suitable for growing vines, but is not particularly fertile (it is nevertheless considered good agricultural land). In terms of the profile (ABC), the subsoil "B" horizon is characterised by a weak to moderate alteration of the original material, and by the absence of significant quantities of clay, organic matter and iron and aluminium compounds. It is an illuvial horizon, i.e. deposited by rainwater.
There can be some ferrous clay soils’ area (petric calcisols or calcareous regosols) that are formed on sandstones, limonites, clays and marls. They contain less than 25% of limestone and a high proportion of clays, resulting in reddish-coloured soils, usually with an excess of aluminium in their composition. Petric calcisols means a calcisol which is strongly cemented within 100 cm of the soil surface, and regosols are calcaric soils with more than 40% calcium carbonate equivalent, but unconsolidated, so having only a superficial profile development.
Fluvisol derives from the Latin word "fluvius" (river), referring to the fact that these soils are found on top of alluvial deposits (i.e. loose clay, silt and sand). The original material is made up of deposits, predominantly recent ones, of fluvial, lacustrine, or marine origins. The profile is AC, with a very notable topsoil (A horizon) enriched with organic matter. Alluvial soils (fluvisols) are present in the terraces formed by the Ebro River, and are the most fertile and the most suitable for light wines.
Much is written about the ideal habitat for a vine, but if you have to just remember one soil mineral nutrient, focus on the calcium cycle. It has a great influence on other nutrients, and so it is more directly related to the wine grape quality and the wine obtained. Calcium has a significant influence on the plant’s health, both in the root system and in the shoot system, and it is related to the formation of the rhizosphere and the microbiota of the soil.
In addition, calcium defines the soil’s structure and its capacity to supply water to the plant, especially at veraison (ripening), the moment of greatest water consumption. It is the only way to eliminate clays, by helping to combat toxicity due to aluminium excess in the soil, and it is the only element capable of eliminating excess sodium from the root bulb.
Calcium is also crucial for meristem growth and for the growth and proper functioning of leaves, i.e. a lack or shortage of calcium in leaf tissue can cause the disorder "tip burn", as well as "bitter pit" in apples. It is a middle layer component, with a cementitious function as a calcium pectate. It prevents cell membrane damage by stabilising cell walls and providing rigidity. It also appears to act by modulating the action of plant hormones, regulating germination, growth and ageing.
Above we have developed a reasonable science-based view of the soil found in the Rioja wine region, including both soils intrinsic properties (depth, texture, etc.) and extrinsic properties (i.e. topography, climate, hydrology, vegetation and use). However increasingly people look less at just the soil and more at land as a socio-economic and political system, including the size and location of the parcels, costs and capital investment needed, the workers and machinery available, markets and local distribution networks, and even official agricultural policies in place including grants, etc. The problem is that soil evaluation is a scientific discipline (as is the acquisition of biophysical data), whereas land evaluation can produce confusing results that are also highly dependent on market demand (customers).
However, another totally different way of viewing the Rioja wines is through the metaphor of the "Seven Valleys of Rioja". It's just a nice way to integrate a little knowledge about Rioja wines, Rioja soils, and Rioja traditions.
Valle de Oja, Rioja Alta
The Oja (and Tirón) rivers connect to the Ebro River at the hill town of Haro. According to a disputed theory, the Oja gives its name to the entire region. The vineyards in the Oja/Tirón watershed are known as the highest elevation vineyards in Rioja Alta and are sometimes referred to as "Alta Alta". The vineyards close to Oja have clay and sandy alluvial soils that are often covered with white river stones (similar to parts of Châteauneuf-du-Pape). The wines are highly aromatic with richer, more plump (less acidity) plum flavours with earthy notes of forest floor and cigar. The vineyards on the north side towards the Obarenes Mountains (which separate Rioja from the Bay of Biscay) have calcareous clay soils which look very chalky and dry on the surface. These wines are said to have a "lean minerality", when scientific research has established that we cannot "taste" flint or chalk in wines. What we can taste are the red-fruit flavours with heightened acidity and marked tannin, meaning that these wines tend to taste better after long-term ageing. The valley is home to some of the best vineyards in the region, e.g. Bodegas de Ollauri (ex-Paternina from 1896) and Berberana. Check out this review of the old Paternina wines by Spanish Wine Lover. Generally this valley is a traditional area for the cultivation of Tempranillo and its wines are balanced, with a lively acidity, and largely define the character of the reds of Rioja Alta.
Valle de Najerilla, Rioja Alta
Considered by many as the central valley of the Rioja this valley has the greatest number of hectares dedicated to vineyards. The region also contains a great number of very old vineyards with Tempranillo and Garnacha vines some more than 100 years old. There are also ancient terraces carved out of the hillside higher up in the valley. Besides a patch of calcareous clay soils where the Najerilla River meets the Ebro River, the majority soils here are ferrous-clay in nature with a ruddy orange colour. Wines often have a smoky tobacco note along with rustic red-fruit flavours with heightened acidity and tannin. It is said that Garnacha was traditionally grown in the highest part of the valley, and produced the classic Rioja "claretes" with its pale red colour, lowish alcohol content, and pleasant spicy taste (those of Cordovín, San Asensio and Badarán rival in prestige). The lower area, more open and which could be considered as the Ebro River valley rather than its tributary, is one of the areas with the highest density of vineyard plantations in the region, with a clear predominance of the Tempranillo variety.
Valle de Iregua, Rioja Alta and Rioja Oriental
The Iregua River is the dividing line between Rioja Alta and Rioja Oriental (some even advocated the creation of a "Rioja Media"). The Iregua River connects with the Ebro River in La Rioja's largest city, Logroño, and the region is more populated than the rest. The valley also contains many orchards with other crops like olives, almonds and walnuts as well as vineyards. Vineyards in this region appear to be divided between ferrous-clay soils and alluvial sandy clay soils. Because of the warmer temperatures the wines have medium acidity and, if grown in the alluvial sandy soils, also have less tannin, with flavours of candied black cherry and black plums. The great producers in the region focus on fruit selection during grape harvesting which greatly increases the quality. The historic Marqués de Murrieta is found here. Above we can see the famous El Mirador de Peñueco which sits on the Iregua River.
Valle de Leza, Rioja Oriental
The Leza River is the most obvious climate divide between Rioja Alta and Rioja Oriental, and the landscape acquires reddish tones due to the ferrous-clay soil. The Rioja Alta tends to be cooler, greener and more lush than the Rioja Oriental due to the influence of the cool air from the Bay of Biscay. The Rioja Oriental has a gentler relief and the cultivation of the vine, although abundant, does not have the overwhelming predominance seen in the western valleys. The Rioja Oriental region is noticeably drier and the Leza Valley contains steep canyons that are reminiscent of what might be found in a desert. Wines grown in predominantly ferrous-clay soils have a taste of fresh red fruit as well as a touch vanilla from being aged a year or more in oak.
Valle de Jubera, Rioja Oriental
A stream that flows into the Río Leza has more alluvial soils that contain a higher prevalence of limestone (that white chalky stuff). Vineyards here are old and typically hand harvested, with wines having slightly more complexity with higher acidity than from the Leza Valley.
Valle del Cidacos, Rioja Oriental
Cidacos is a wide valley, with a smooth orography, and some say it is mostly too hot to produce wines of great quality. It is an area of abundant fruit trees and horticultural production, however further up the valley the wines can be quite distinctive. Here the vines are spread out because of limited water and the soils are a mix of clay-limestone and ferrous-clay. Wines from this region often will be lighter in colour but have bold dried fruit (like fig) and tobacco flavours. It’s also pretty common to find organic wines in this area due to a limited numbers of pests. The valley is home to Viñedos de Aldeanueva with its 13 million bottles annually, Bodegas Ontañón with its unique collection of small vineyards, and the "village wine" of La Pedriza in Tudelilla with its 100-year-old Garnacha.
Even more intriguing is the village of Arnedillo which is famous for its hot springs.
Valle de Alhama, Rioja Oriental
The southernmost valley of La Rioja borders the wine region of Navarra and is also close to Campo de Borja wine region in Aragon. The best vineyards in this area can be found high up in the mountains, is a biosphere reserve recognised by UNESCO for its rich diversity of flora and fauna. When well-made, the wines have rich black raspberry flavours with subtle notes of cigar and vanilla. Because the region is almost unknown, you can often find wines of outstanding value. The Basilica de la Virgen Del Monte in Cervera del Río Alhama is said to house one of the most beautiful Romanesque images of the Virgin and Child to be found in La Rioja.
The Valles de Sadacia comprises four of the "seven rivers" (Iregua, Leza, Cidacos and Alhama), and is the area that receives the lowest rainfall and most hours of sunlight in La Rioja. Since 2003 it is a Vino de la Tierra for white wines called Valles de Sadacia. The allowed varieties include also Muscatels, Chardonnay, Sauvignon Blanc, and even Riesling and Gewürztraminer.
Precision viticulture is a special case of precision farming, and the idea is to use detailed information about the biophysical characteristics and performance of a vineyard, at high spatial resolution, as the basis for viticultural management and decision making. A decade ago, wineries managed at the vineyard level, but today it's possible to manage individual vines. It's an increasingly important tool, because there are more than 7 million hectares planted with vines across the globe, and grapevines are particularly disease-prone and sensitive to weather and soil conditions.
Among the many approaches, the phytogeomorphological approach stems from the fact that the geomorphology component typically dictates the hydrology of the vineyard. The starting point is that landforms significantly affect how vines grow, and with GPS (and GNSS) it is now possible to map a variety of measured variables, e.g. topography, climate, hydrology, yield, soil profiles, organic matter content, moisture levels, nitrogen levels, pH, cation exchange capacity, base saturation, magnesium (Mg), potassium (K), etc. Real-time sensors mounted on farm equipment can measure using multispectral imagery everything from chlorophyll levels, leaf anthocyanin content, net photosynthesis to plant water status.
Data can be acquired using drones and electric vineyard robots, and then merged to provide an integrate view of the vineyard.
You start by defining areas of the vineyards based upon climate, lithology, geomorphology and soil profiles, and then overlay more precise elements that allow a discrimination based on grapevine development and grape composition, which is usually linked to the water status of the plants. The idea is that you can infer foliage density and leaf area, plant water status, vine yields, and wine grape quality, composition and yields.
As a simple example, you can use small drones to localise dead, damaged or simply missing vines (red is missing). Usually the resolution will be better than 10 cm. You can then also integrate ground sensors measuring temperature, soil moisture or nitrogen content. Below we can see the analysis of the vine canopy (the small box is the "training" box for the algorithm).
Knowing the vine canopy and the location of missing vines, etc. it's possible to create a map (below) of vine vigour. The colour zones help identify where vine vigour is too low or too high.
Below we can see the detection algorithms at work for vine diseases and canopy water content.
The ultimate goal of precision technologies, including remote sensing, is the zoning of a vineyard so as to:-
Optimise vineyard sampling for the planning of phytosanitary treatments, harvest, etc.
Better management resources, both fertilisers, phytosanitary products, etc. and human resources.
Maximising yields and better differentiating quality, while minimising environmental impact and risks.
Precision viticulture will continue to evolve along with precision farming. Above we have an example from 2020 where trellis wire, tree trunks and support poles have been manually labelled (a), harvest points for individual apple locations are identified (b), and how individual apple trees are identified (c).
Some people might still doubt that our planet is getting warmer, but growers and winemakers in Rioja aren't among them. In a recent study 90% of the 481 growers and winemakers surveyed believe that climate change was a reality. 65% felt that its effects will be negative or very negative and 46% thought that Rioja will have to adapt to new circumstances.
These opinions were based upon the day-to-day realities they face in their vineyards and wineries. They have detected more climate variability (>88% of wineries), an increase in temperature (>86%), a decrease in rainfall (>67%), and a change in grape harvesting in the last 5 years or more (>70%). For nearly 65% the result has been an increase in costs caused directly by weather changes. These are costs associated with adaptation measures (irrigation systems, pest control, vine diseases, etc.), insurance payments and mitigation of unexpected phenomena such as droughts and rain storms (changes in the dates of collection and regulation of the grape load). However, so far the impact of climate change has been less evident in the actual production of wine.
Global warming is not a new phenomena, one analysis has shown that in 17 out of the world's 27 major wine growing regions, the growing season average temperature has increased by nearly 1.3°C between 1950-1999. Most noticeable was the increase of more than 4°C in the growing season temperature in the Rhône Valley (and about +3.8°C in the winter period). While the observed warming of the late 20th century appears to have been mostly beneficial for high-quality wine production worldwide, the impact of future climate change will be highly heterogeneous across grape varieties and growing regions. Critically, in some regions, warming may exceed the varietally specific optimum temperature threshold such that the ability to ripen balanced fruit from the existing varieties grown and the production of current wine styles will be severely challenging if not made impracticable.
Certainly one of the most important challenges facing the La Rioja region, and Rioja wine production, in the near future is climate change. Global forecasts show an increase in temperature, longer summers and a more heterogeneous distribution of rainfall. Droughts are expected to be more frequent and prolonged and there will be more anomalous weather phenomena. In addition, the risk of soil erosion and desertification has increased.
The Rioja wine region is located in the western sector of the Ebro valley, and is an area that, from the geographical point of view, has a particular combination of climatic, geomorphological and topographic characteristics that are (or were) eminently suitable for wine-growing. So the question is how will climate change affect wine production in the region?
Such generic statements as warmer/drier or cooler/wetter might have been sufficient 50 years ago, but today everyone, and in particular those involved in viticulture and winemaking, are interested in climate change and the impact it is having and will continue to have on wine production. Generally, across many wine growing regions, climate change has mostly led to regional warming and greater variability in seasonal rainfall. However, despite the global extent of climate change, disregarding regional variations can lead to erroneous generalisations. This is why both the Winkler Index (classification of growing regions based upon growing degree-days) and the Huglin Index (a bioclimatic heat index for vineyards) can be used to more objectively understand climatic variables such as temperature, rainfall, insolation or frost frequency and timing.
A word of warning, what we are discussing in this section is climate change in the growing area of Rioja, and not in La Rioja the autonomous community. The conclusions are often the same, but the data provided is only for the growing area. As an example, in the southern part of La Rioja there is a mountainous region that forms part of the so-called Sistema Ibérico (Sierra de Moncalvillo, Sierra Cebollera, Los Camerso, Sierra de la Demanda, etc.), with numerous peaks in the range 1500-2200 metres. Discussing temperatures and rainfall in the Rioja growing region, ignores the fact that in this mountainous region temperatures will easily drop below 5°C in winter (peaks will usually be snow covered) and annual rainfall can easily exceed 1000 mm, whereas in the growing area it is usually well below 400 mm for the growing season (April-September).
Above we can see a comparison between two sub-periods, 1983-2014 against 1950-1982 for the Rioja wine growing region. Most of the region saw a moderate temperature increase of between 0.3°C and 0.7°C for the so-called "growing season temperature". However, in a few areas the temperature increase was more substantial, between 0.7°C and 1.1°C. The nominal growing season is April 1 to October 31, but given that a growing day is a day where the temperature is above 10°C, the season can start earlier or later. Traditionally the season closes in the Rioja region with the Wine Harvest Festival in Logroño, i.e. Fiestas de San Mateo is when people come to town to watch the grape-crushing ceremonies starting on the Saturday before 21 September.
In order to understand better the significance of this temperature increase the Winkler Index is used to classify a region in terms of growing degree-days, i.e. based upon the fact that the development rate of a plant depends upon the daily air temperature above a "zero growth" temperature (10°C for vines). Growing degrees are the number of degrees above 10°C (for vines), and are accumulated as the season progresses, so in some way they represent a measure of heat accumulation by a plant, which is related to its development rate. The index is just the accumulation of the growing degrees (measured as total °C's) and there are several ranges or classes that correspond to a grapes general ripening capabilities and final wine styles. For example, Bordeaux is classed as Region II (1389-1667°C), an early and mid-season good quality wine, whereas Rioja is now increasingly classified as Region III (1668-1944°C), an area of high production for standard to good quality wine.
As a word of warning, the Winkler Index essentially describes the mean daily temperature, but many other important factors contribute to a region's suitability for viticulture (and its terroir) are excluded, e.g. sun exposure, latitude, precipitation, soil conditions, and the risk of extreme weather which might damage grapevines (winter freezes, spring and fall frosts, hail, etc.).
Above we have the Winkler Index for 1950-1982 (a) and 1983-2014 (b) for the Rioja region. We can see the Region II index (orange) and the Region III index (red), which shows a significant warming in the region during the last 60 years. This has important implications for the viticulture of the region, as the grapevine growth cycle has been advanced, leading to earlier phenological stages and changes in ripening dynamics.
The starting point for the DOCa Rioja is the presumption that growing, harvesting, yields, vinification and ageing follows a set of rules designed for winemakers in Region II (the same as for Bordeaux wines). The yellow area corresponds to between 850-1111 °C, and is best adapted to hybrid grape varieties that achieve a high quality but ripen very early. We can see above that increasingly the Rioja growing region is moving from Region II index to Region III index. The future evolution will depend upon what mitigation measures are put in place. If nothing is done, within the next 20 years, one-third of DOCa Rioja will fall under a Region III index, i.e. sub-optimal for producing high-quality wines from the grape varieties presently used. And slowly but surely the Rioja growing region will shift from Region II to Region III, and then on to Region IV (favourable for the high production of acceptable table wines). If effective mitigation measures are implemented, then it's possible that the worse case scenario will peak around 2040, and then start regressing.
The Huglin Index appears to be more widely used in Europe, since it gives more weight to maximum temperatures and uses an adjustment for longer days found in higher latitudes, but the index remains functionally similar to a "growing season average temperature". In Europe, vineyards are found in areas where the average temperature during the ripening season (April-October) is between 12 and 22°C. The optimal temperature is different for each grape variety, e.g. 15.0°C for Pinot Noir, 15.5°C for Chardonnay, 17.5°C for Tempranillo, 18.0°C for Merlot, 18.2°C for Grenache, etc.
Above we can see that in the period 1950-1982 (a), the Rioja wine region had an Huglin Index of 1800-2100, ideally suited to the grape varieties such as Cabernet Sauvignon, Merlot and Syrah, whereas for the period 1983-2014 (b), the region appears more suited to grape varieties such as Grenache (Garnacha Tinta), Carginan (Mazuelo), and Mourvèdre.
On the surface this may not appear too surprising since the varieties authorised for red Rioja are Tempranillo, Garnacha Tinta, Graciano, Mazuelo, and Maturana Tinta (Trousseau). However, there are variations in the reporting of the Huglin Index for different grape varieties, and in particular Tempranillo is often associated with a lower index.
Interestingly the growing season precipitation in the Rioja wine region over the entire period 1950 to 2012 did not change significantly, even if the area associated with a slightly lower rainfall did grow over time.
One important additional topic associated with rainfall in the Rioja region is the problem of water erosion. One of the most important causes of soil degradation is water erosion. Erosion tends to be more intense in plots with lower vegetation cover, and for this reason, vineyards are one of the crops most susceptible to this phenomenon. This happens because, in general, the vineyard soils are kept free of vegetation, either through conventional tillage or through the application of herbicides, and the protection of the vine cover against the impact of rain drops is not enough. On a larger scale, the expansion of vineyards to areas with steeper slopes, the arrangement of the vine rows slopping downhill, the fine texture of the soils and the nature of precipitation in the Mediterranean regions favour erosion. Terraces on steep slopes can lose between 20% and 40% of the annual rainwater. A lot of things can affect soil loss on terraces (e.g. terraces that are not flat topped, collapsed walls, the formation of channels, rills, gullies, underground piping, etc.), and those losses can add up to anything between 3 tons/hectare/year to over 100 tons/hectare/year (but will always be worse if there is no terracing).
The adoption of cover cropping with different species is one of the alternatives to face the problem of soil degradation, but in Mediterranean environments its use is not very widespread, due to the risk of an unfavourable competition for water with the vine. Also there are indications that cover crops in Mediterranean environments have contributed to a smaller canopy size reducing the consumption of water by the vine and have resulted in decreases of yields. However a reduction in water consumption has been associated with an improvement in the quality of grapes, so these changes can also be positive in that it can help winegrowers reduce their production to the limit established for DOCa Rioja (i.e. in the latest set of regulations maximum yields have been reduced).
One way to adapt to bioclimatic changes is to increase the vineyard surface towards higher and colder altitudes. However, moving a vineyard or implanting a new one involves considerable effort and a significant investment for winegrowers. The use of other varieties more adapted to the new climatic conditions and some new vineyard management practices are also possible.
On the other hand, precipitation shows a decreasing trend in a large area of the DOCa Rioja wine-growing territory. However, the high inter-annual variability makes it difficult to isolate a statistically significant decreases in rainfall, except for a narrow strip along the course of the Ebro that runs from Rioja Alta to the town of Agoncillo.
From the viticultural point of view, these changes affect the phenological development of the vine. In this way, the different stages of development of the plant are advanced, from sprouting to harvesting, generating imbalances in the composition of the grape due to an advance in maturation (sugars and acidity) with respect to phenolic maturity in red varieties. This has a direct impact on the wines. By increasing the sugar content, wines with a higher alcohol content are obtained. In the case of reds, the perception in the mouth (mouthfeel) can change due to the later maturation of the phenolic compounds that give them their organoleptic properties. What this means in practice is that warmer temperatures create a problem in determining the optimal time to harvest since there is will be an imbalance between the sugar/acidity level and the phenolic compounds responsible for colour and texture in the finished wine. Picking when the potential alcohol in the grapes is 12% to 13%, could mean that the level of phenolic compounds that produce colour and texture will be too low, but waiting until this phenolic compounds at optimal could mean the potential alcohol in the grapes would be 15% or even 16%.
Temperature is the major driver of vine phenology. Harvest dates have been used to reconstruct temperature series spanning several centuries. As an example, in Alsace, over a 70-year timespan, budbreak has advanced by 10 days, flowering by 23 days, véraison by 39 days, and harvest by 25 days. Harvest in Alsace for Riesling used to occur in the first two weeks of October, but today, harvests more frequently occur in the first week of September and sometimes even at the end of August. This evolution can be detrimental for the quality potential of the grapes, which are increasingly high in sugar content and may eventually become less aromatic. In addition, advanced budbreak exposed vines more frequently to spring frost. Similar trends are observed in many winegrowing regions around the world.
One option is to delay ripening by planting new vineyards at higher altitudes (a very expensive option). Another option is planting wine grapes with longer growth cycles, such as Graciano and Garnacha. A 4°C temperature increase, an increase in carbon dioxide emissions, and a decrease in relative humidity to 12%, would result in wines with less colour and a higher pH. This would give a cheap looking pale wine, lacking crispness and texture. Already with Tempranillo winemakers add acid to lower the pH, so it would be especially affected. In addition Tempranillo has a shorter growth cycle, and would be disproportionally hit by higher daytime temperatures without the benefits of cooler nighttimes. The upside for Rioja is that part of the production is already at higher altitudes, so they will profit from an increase in daytime temperatures.
So one way to adapt to higher temperatures is to change the vines (e.g. new drought resistant rootstocks and cultivars, and late-ripening clones). Another way is to modify viticultural techniques (e.g. increasing trunk height, reducing leaf area to fruit weight ratio, late pruning) such that harvest dates are maintained in the optimal period at the end of September or early October. Vineyards can be made more resilient to drought by planting drought resistant vines, modifying training systems (e.g. favouring goblet or bush vines, or trellised vineyards at wider row spacing), or by selecting soils with greater soil water holding capacity. While most vineyards in Europe are currently dry-farmed, irrigation may also be an option to grow sustainable yields under increasingly dry conditions but the result might be wines with different organoleptic properties. In addition, even with fine-tuned irrigation management, the blue water footprint of an irrigated vineyard is generally at least 100 times higher compared to a dry-farmed vineyard.
On top of everything else, the increase in temperature can alter the cycle and development of pests and diseases, a fact that represents an added challenge for the winegrower.
Few growers expect things to re-stabilise, with >70% of them planning for new irrigation systems, nearly 75% expecting changes in harvesting dates, and >70% expecting more diseases and pests. Nearly 40% indicated that they are looking at new wine grape varieties and/or planting at higher altitudes.
If we extend our view from the Rioja wine growing region to the rest of Europe, we first note that Europe produces about 70% of the world's wine, and is home to more than 40% of the world's total vine cultivation area. European vineyards are predominantly in the Mediterranean region, particularly in Spain, France, and Italy. We have already mentioned that the grapevine is one of the most sensitive crops to climate changes, since it needs a basal temperature of 10°C for its growing cycle, and vineyards are traditionally situated in areas where the average temperature during the ripening season (April–October) is between 12°C and 22°C. We have also mentioned that each grape variety has an optimum temperature, from 15.0°C for Pinot Noir through to 18.2°C for Garnacha. In addition, the thermal optimum for the development of the fruit in summer is within the 20°C to 30°C range. But a plants photosynthetic system can be negatively affected by a prolonged exposure to extremely hot temperatures (e.g. above 40°C), so high temperatures can compromise grapevine productivity and quality.
Projected changes over Europe under high emission scenarios indicate an average warming between 2.5°C and 5.5°C by the end of the 21st century, with higher warming rates in southern regions and towards the north-east. Additionally, temperature extremes are also projected to increase. Mean annual precipitation is also expected to decrease in most of southern Europe and to increase in northern regions. Grapevines are relatively resistant to drought thanks to their deep roots, but they can be adversely affected by severe dryness. Therefore, the projected future climate change will certainly modify the conditions favourable for the growth of vines in the current winemaking regions, and lead to the appearance of new wine producing areas.
A wide range of bioclimatic indices has been proposed to assess the suitability of a given region for growing wine grapes, which include different climate variables that affect the plant growth and development, e.g. the average growing season temperature index (GST) measures the average temperature during the ripening season. The vulnerability of vineyards to severe thermal stress makes it also necessary to consider maximum temperatures during spring and summer. Additionally, enhanced plant evapotranspiration due to higher temperatures results in increased water demand. We have already mentioned that an increase in maximum temperatures would negatively affect the growing cycle of the European grapevines, especially in summer, when the development of the fruit occurs. It is quite likely that vines will be exposed during longer periods to temperatures that exceed the correct maturation threshold (e.g., more than 30°C in southern France, Spain, Portugal, and Italy). Therefore, vines will grow in sub-optimal conditions, and the resulting fruit will have less aromas and a loss of pigments. This will be coupled with a reduction in vine yields due severe thermal stress conditions.
Mediterranean vineyards are projected to suffer a reduction in both vine yields and overall grape and wine quality. However, countries of central Europe that currently have a growing season temperature of less than 16°C (Germany, North France, and the Czech Republic) could reach favourable thermal conditions also for new grape varieties (notably Merlot and Chardonnay). So traditional wine growing areas will suffer both in terms of volume and quality, but a warmer climate could create more favourable conditions for vineyards in some countries of central Europe (Germany, Belgium, Poland, southern England, etc.). The reality is that some Southern European wine producing regions that have traditionally focused on producing higher quality grapes for higher price wines, might have to shift to lower quality wines selling at lower prices, and turn their focus to optimising yields and reducing production costs (i.e. increasing mechanisation).
One finally point concerning climate change, is the fact that wine tourism is often seen as an important component in sustainable rural development, with "a good climate" considered a core feature for tourists deciding to visit a wine region. Data appears to show that tourism in the La Rioja region is actually already quite high all year round, but is quite sustained in the period July-October. Climate change predictions suggest that tourism in La Rioja in the next decades will become almost totally deseasonalised, with an increased presence of tourists all year round. By 2050 it is suggested that Rioja-regional tourism could increase year around, to an almost constant level in excess of that seen today even in August. This of course begs the question that by 2050 the economic consequences of global warming could be such that the number of tourists able and willing to travel to the La Rioja might have dropped considerably.
Rioja - the grapes
|Tempranillo||Black||231,000 ha worldwide||Grown in 17 countries, but 88% of area is in Spain|
|Garnacha Tinta/Grenache Noir||Black||163,000||Spain and France|
Historical Cultivation and Usage
Vitis vinifera is thought to be native to the area near the Caspian Sea in southwestern Asia. The Phoenicians carried wine cultivars to Greece, Rome and southern France, and the Romans spread the grape throughout Europe. Spanish missionaries brought Vinifera grapes to California in the 1700s and found that they grew very well there. The medicinal and nutritional value of grapes has been known for thousands of years. Egyptians consumed grapes at least 6000 years ago, and several ancient Greek philosophers praised their healing power. European folk used an ointment from the sap of grapevines to cure skin and eye diseases. Grape leaves were used to stop bleeding, inflammation and pain. Unripe grapes were used to treat sore throats and dried grapes were used to heal consumption, constipation, and thirst. The round, ripe, sweet grapes were used to treat a range of health problems including cancer, cholera, smallpox, nausea, eye infections, and skin, kidney and liver diseases.
Vitis vinifera has been the hallmark of French viticulture. It is very likely that many traditional cultivars such as Chardonnay, Cabernet Sauvignon and many others were deliberate crosses rather than chance seedlings. For example, the cultivar Petite Sirah (widely believed to be Durif) popular in California is likely to be a seedling of Peloursin × Syrah made around 1880 (Bowers et al., 1993; Meredith et al., 1999). Cabernet Sauvignon originated in the seventeenth century as a cross (likely intentional) between Sauvignon blanc × Cabernet franc (Bowers and Meredith, 1997). Numerous Burgundian cultivars can be traced back to the Middle Ages or before and are hybrids between Gouais blanc (Aligoté, Auxerrois, Chardonnay, Gamay noir, Melon), and many could potentially have Pinot noir as a parent (Bowers et al., 1999). Whether any of these cultivars were the results of deliberate crosses or chance hybridization is a matter of speculation. Myles et al. (2011) provided evidence showing that Pinot noir may be a parent of Chardonnay, Gamay and Muscat blanc. Traminer may be a parent to cultivars as diverse as Petit Manseng, Tinta Madeira and Verdelho, and Chenin blanc and Sauvignon blanc are likely siblings for which the parents are Traminer and Colombard. Further afield, we are now aware that Albillo Mayor × Benedicto is the cross that produced Tempranillo, the main red wine cultivar of Rioja and Ribera del Duero in Spain (Ibanez et al., 2012).
However, the talents of French grape breeders were put to a great test in the late nineteenth century (Cattell and Stauffer, 1978; Wagner, 1955). European viticulture was faced with three major devastating crises beginning in the 1870s. First came phylloxera, and thereafter powdery and downy mildew. There was every indication that European viticulture could be irreparably harmed unless a solution was quickly found. French breeders eventually settled on two distinct approaches: use of rootstocks resistant to phylloxera to preserve those cultivars already being grown, and establishment of grape breeding programmes to combine natural resistance to phylloxera, powdery mildew, downy mildew and perhaps other diseases with oenological qualities of V. vinifera. Tens of thousands of hectares of French–American hybrids were planted throughout France starting in the late nineteenth century, and many hectares remained up until the latter part of the twentieth century. A summary of land devoted to cultivation of these hybrids in France, New York State and Ontario is found in Table 4.1 (Galet, 1998). Detailed descriptions of most of the significant French–American hybrids can be found in Galet (1956, 1979, 1998).
Vitis vinifera is the most important grape species in cultivation. Its cultivars constitute the principal grapes grown worldwide. Varieties solely or partially derived from other Vitis spp. are grown in parts of the Pacific Northwestern and Eastern regions of North America, Brazil, Uruguay, Japan, and northern China. In these latter regions, the cultivars may be hybrids between two or more North American Vitis species (American hybrids), hybrids between North American species and V. vinifera (French–American hybrids), or occasionally selections or crossing with indigenous Vitis species. American hybrids are primary selections from Vitis labrusca, Vitis aestivalis, Vitis riparia, and Vitis cinerea, whereas French–American hybrids are often complex derivatives of Vitis rupestris, V. riparia, and V. aestivalis, repeatedly backcrossed with one, but typically several, different V. vinifera cultivars. The initial intent in producing French–American cultivars was to generate cultivars containing the disease and pest resistance of American Vitis spp., but possessing the winemaking characteristics of European cultivars. In the latter part of the nineteenth century, several disease and pest agents, endemic to the Americans, were accidentally brought to Europe, with devastating effects. Hybridization has also been used more recently to incorporate cold tolerance from Vitis amurensis into V. vinifera cultivars, to produce cultivars capable of growing in regions of China experiencing frigid winter conditions. In a similar vein, hybridization is being studied to supply tolerance to cultivars grown in warm to hot humid climates of the southern United States, Mexico, Central and South America, and tropical parts of India, Thailand, and China. In the southeastern regions of the United States, most cultivars are derivatives of Vitis rotundifolia, the muscadine grape. It is tolerant to Pierce's disease that limits significant commercial production of V. vinifera cultivars.
In contrast to the shoot (scion) system of most grapevines, North American Vitis species have been used primarily in the development of grapevine rootstocks. Most are a cross between different species, often including a V. vinifera parent. It often facilitates graft union between the rootstock and scion. Though the choice of rootstock, the vineyardist can limit the damage caused by a broad range of soil-based problems, such as enhancing drought tolerance, donating resistance or tolerance to various root pests and soilborne viruses, or greater acceptance of chalky or saline conditions. In most regions, viticulture would not be commercially viable without grafting to an appropriate rootstock.
Over the centuries, selection, if not specific breeding, has generated the incredible range of fruit shapes, sizes, and colors, as well as cluster form (Plate 1) that exist today. There are an estimated 15 000 named cultivars. Most of these are wine grapes, reflecting the major use to which grapes are put. According to Anderson (2013), the most extensively grown cultivars are, in order Cabernet Sauvignon, Merlot, Airen, Tempranillo, Chardonnay, and Syrah (Shiraz), with Tempranillo, Syrah, Cabernet Sauvignon, Merlot, and Sauvignon blanc being those cultivars that have increased their vineyard coverage the most between 2000 and 2010. With the exception of three of these cultivars (Airen, Chardonnay, and Sauvignon blanc) all are red cultivars. Nonetheless, despite the dominance of red wines in commerce, the plantings of white cultivars have increased, whereas that of red cultivars has declined in the past decade or so. These changes reflect greater sophistication and varietal knowledge by consumers, and thereby, mentioning the cultivar(s) used in a wine's production on the label. Thus, varieties with poor consumer recognition, that were used principally in blends (e.g., Airen, Mazuelo, Trebbiano, Garnacha, Rkátsiteli, and País), have seen their coverage drastically shrink. Surprisingly, the most well-known grapevine cultivars constitute only a small fraction of the vines grown, even in the country of origin. Some of the most highly prized wine cultivars at the moment are Cabernet Sauvignon, Chardonnay, Pinot noir, Riesling, and Syrah (Shiraz).
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Plate 1. Grapevine heterogeneity as illustrated by the diversity in morphology, structure, and coloration in grapes and grape clusters.
Photo courtesy of Kühn-Institute, Institute for Grapevine Breeding Geilweilerhof, Siebeldingen, Germany.
For wine grapes, relatively small berries, providing a high skin to volume ratio is usually optimal. The skin and underlying hypodermis contain most of a variety's distinctive aromatic compounds, and in red grapes, the pigments. Equally preferable is the hydrolysis of the flesh (mesocarp) of the fruit during ripening. This greatly eases juice extraction and limits the development of pectin-induced cloudiness in wine. High sugar contents (22–25%), and comparatively acidic juice (pH 3.1–3.5; 0.55–0.85 g l−1 titratable acidity) are also desirable at maturity. The best cultivars possess a distinctive, but subtle aroma, sufficient to generate, but not overly dominate, the development of a complex wine fragrance.
Of all grape cultivars, table grapes are thought to be the most ancient, due to their possessing the largest number of mutations. Because grape cultivars are propagated by vegetative means, the longer a variety has been in existence, the greater the period during which mutations can occur and accumulate. Most table grape varieties are unpigmented and partially to completely seedless (both recessive mutations), large fruited, low in acidity (0.3–0.6 g l−1), and moderate in sugar accumulation (18–20%). Additional desirable traits include retention of a pulpy flesh, strong adherence to the stalk, and relatively strong skin – facilitating transport to market in pristine condition. Most long-established varieties are thought to have originated in the Caucasus and adjacent northern section of the Near East (Levadoux, 1956; Negrul, 1938), and are adapted to hot, arid climates. Several hundred table grape varieties are grown worldwide, but the most extensively cultivated are Almeria, Calmeria, Dattier, Emperor, Malaga, Perlette, Ribier (Alphonse Lavallée), Flame Tokay, and Thompson Seedless (Sultana).
Theoretically, any seedless cultivar could be used for raisin production, but in practice only a few are. Thompson Seedless (Sultana) is the most extensively used for raisin production worldwide. Nonetheless, Muscat of Alexandria is the dominant raisin cultivar grown in a few countries. For currant production, Black Corinth (Zante Currant) is the dominant cultivar.
There are at least two aspects to vines and wine grapes used in the rioja growing region, firstly which ones are allowed, and secondly how should they be treated?
Unfortunately, the oldest references to vineyards in the Rioja region have no details on the varieties grown. They always speak of vineyards in general, without specifying varieties. It was not until the 17th century (1622) that the first reference that can have some relation with a grape variety is found (it was Ribadavia, now known as Robeiro). From that time on, the references continue uninterrupted to the present day.
The grape-growing tradition of Rioja has solid roots in history and certainly dates back at least two thousand years. The writings of some Latin authors mention the existence of a flourishing wine-making activity under Roman rule. There are also numerous remains of terra sigillata earthenware (ancient Roman pottery) from that time, decorated with grape growing motifs, found in the Najerilla area (Tritium Megallum), so very much in the Rioja region. Unfortunately, there is no reliable testimony about pre-Roman times. But even if viticulture existed before that time, it is plausible to hypothesise a Romanisation of the territory, also from an ampelographic and viticultural point of view, although there is no information on the type of plant material they cultivated.
During and after the Roman Empire, viticulture in general was repeatedly abandoned. Domitian is known to have prohibited vineyards and wine itself in the year 81 AD. And then there were the barbarian invasions (5th century AD and beyond) and that of the Saracens (8th-9th centuries AD).
What happened then with the already old varietal heritage during the subsequent periods of depopulation of the cultivated areas? What is almost certain is that some of the varieties grown in Roman times would have naturalised and survived in a wild state. That remaining genetic makeup would have been inherited by new settlers of arable land, and the medieval grape grower was born. A painstaking selection process was started again, and perpetuated for centuries to the present day.
Firstly, it should be noted that a cultivated grape vine consists of two distinct parts joined by a graft: the bottom is called a rootstock and the top is known as variety, vinifera, graft or scion. The need for grafting arises as a consequence of a pest of the vine, phylloxe- ra, which destroys the root system of cultivated varieties and affects vineyards across world since the mid-nineteenth century. This pest forces growers to graft the variety they want to grow on a resistant rootstock, which belongs to a species other than Vitis vinifera (the only species whose fruit is of sufficient quality). These include Vitis riparia, Vitis rupestris or Vitis berlandieri, fruitless vine species that vegetate spontaneously in North America.
The root comes from the rootstock.
It is formed by main roots that ramify successively until they form very fine rootlets that constitute the feeder root system; They are the most active part of the root system. At the end of each rootlet there is a pilliferous layer which is the area that absorbs practically all the water and mineral nutrients.
Figure 1. Grapevine with different types of buds. Illustrations: Valle Camacho
Normal cane Old wood
Figure 2. Detail of a green shoot with its different organs
Main green shoot
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Although the genotype exerts a small influence, the development of the root system depends, fundamentally, on the characteristics of the soil and never goes far from the surface. So, most of the root system and its most active part is between about fifteen and a eighty centimetres deep. In the colonisation of the surface horizon of the soil (the first twenty or thirty centimetres) the particular soil main- tenance technique applied is a major influence: tillage, herbicides or ground cover.
2.2. The aerial part
The aerial part is mainly the grafted variety.There are three types of el- ements or structures: trunk, arms and shoots. The latter can be shoots, suckers and secondary shoots (figure 1).
The trunk and arms consist of old wood (more than two years old). The spurs and canes grow from the wood of the previous year, when pruning is carried out. A spur is the portion of wood from the pre- vious year with a number of buds not greater than two. A cane has more than two, normally six or eight.
Traditional grape growing uses a type of training called gobelet or bush and consists of three arms with two spurs in each arm. As each spur carries two buds, for a total of twelve buds, which will give rise to twelve shoots.
In the case of trellised grapevines, the vine is trained with a ver- tical trunk and two horizontal arms or cordons, in the direction of the rows, with three spurs per arm, thus giving twelve shoots, which grow supported on wires.
The buds that come out each year are the shoots, suckers and secondary shoots.
The green shoots show a number of bumps, the knots, in which the rest of the organs are located: leaves, buds, inflorescences or clusters and ten- drils (figure 2). Towards the month of August, there is a hardening of the green shoots, lose water and turn brown, a process called ‘lignification’, and they are renamed ‘canes’. This process progresses from the base to the apex of the shoot and accumulates starch as a reserve material.
The leaves are located in the nodes of the shoot, one per node alternat- ing sides. Its functions are photosynthesis, transpiration, respiration and photorespiration. They have between five and seven lobes, more or less pronounced, with their corresponding sinuses. The leaf is the main organ used to identify varieties and rootstocks.
Figure 3. Detail of the different types of buds that grow from the shoot
The buds of the vine are mixed, ‘wood and flower’. At each node of the shoot, in the axillary position of the leaf, there are two distinct buds. The larger one sprouts the year after its formation and is called latent bud or dormant bud and the smaller is the lateral bud.
In the insertion of the green shoots or canes in the previous year’s wood, there are a number of little-developed buds called base or basal buds. None of these buds are taken into account in pruning. Only latent buds are considered (figure 3).
The internal structure of a latent bud consists of a primary bud, which is the one that normally grows, and secondary and tertiary buds, which make a reserve. Less fertile than the primary bud, they only sprout when the primary bud is affected by some issue (figure 4).
2.2.2 Inflorescence and flowers
The flowers are grouped in inflorescences. The tendril is an inflores- cence that is sterile (i.e., without flowers). The vine uses it to climb, as it actually is a liana.
The inflorescences and tendrils are arranged on the knots on the side opposite the point of insertion of the leaves; But not all knots carry tendril or inflorescence. Generally, cultivated vines have one to three inflorescences per branch; The average is two inflorescences. In the three or four first knots of the shoot there are neither inflorescenc- es nor tendrils, then two consecutive knots appear with inflorescences; Then another knot with nothing, other two consecutive knots with tendrils, another with nothing and so on until the end of the shoot.
The flower is pentameric, that is to say it has five pieces in each ver- ticil: calyx, formed by five fused sepals; corolla, consisting of five fused petals welded and forming a cap; androecium, a male organ consisting of five stamens; gynoecium, a female organ consisting two fused car- pels and with two ovules in each carpel (figure 5).
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2.2.3 Cluster and berries
It consists of a rachis, stem or stalk on which the berries or grapes are inserted. The stem represents 5% of the cluster weight (figure 6). The berry has the following structure:
• Skin. Layers of outermost cells of the berry; corresponds to the epicarp. It can account for 7% of the weight of the berry. It is the ‘richest’ part of the berry as it has the highest concentrations of anthocyanins and aromatic precursors. On this outer part, a waxy layer is formed that is called cuticle.
• Pulp. It makes up most of the berry. It is formed by large cells. It corresponds to the mesocarp of the fruit. It can account for 84% of the weight of the berry.
• Seeds or pips. They average two per berry and they correspond to the endocarp of the fruit. They can account for 4% of the weight of the berry.
The vegetative cycle of the vine consists of a period of rest, during the winter, called ‘winter dormancy’, in which the only visible manifestation that occurs is bleeding, which occurs in the month of February. In April, the budburst, which marks the beginning of canopy development which continues until August, when it slows down or stops altogether. At this point the ligni!cation period begins, which lasts until the leaves fall off. During ligni!cation, the green shoots turn into canes.
The reproductive cycle, however, occurs during the warmest season, starting in June, with "owering and setting until the end of grape ripening in autumn (!gure 7).
3.1 Vegetative cycle
During winter dormancy, in mid-February or early March, when the soil reaches a temperature of about 10 °C, bleeding occurs. This is due to the beginning of root absorption, which produces pressure on xylem vessels so that the ascend- ing of xylem sap seeps out of the pruning wounds. Bleeding can mean a loss of 0.5 to 5 litres per vine but it does not weaken the plant as the loss of dry matter is negligible. It usually lasts from ten to !fteen days.
The winter dormancy ends with the budburst or bud break, which takes place in April. During budburst, the buds begin to swell and the bud down becomes visible.
3.2 Reproductive cycle
The reproductive cycle requires two consecutive years. In the !rst, "oral initia- tion takes place in the buds and, in the second, when these buds develop, "ow- ering and transformation occur in fruit. That is, the clusters that are harvested a year have been initiated to "ower in the previous year, inside the buds.
Flowering, when the "oral buttons open into "owers, takes place by mid- June and, just after, fertilization takes place and, in consequence, the "ower turns into fruit. This is called ‘setting’. When the number of "owers that be- come fruit is abnormally small, the fruit set is considered defective and termed “shatter”.
Berry growth goes through three distinct periods:
1. Period of herbaceous growth, that begins with the setting and lasts until the veraison. In its !rst !fteen days all the cellular multiplication that is going to take place in the berry takes place. From there, the berry only grows by cellular elongation, without any mitosis. In those few initial days, the number of cells in the berry is determined and this conditions its !nal size.
2. Veraison, is a brief period that marks the boundary between herbaceous growth and ripening. The berry stops growing for a few days, and sugars start to be transported to it. It becomes more elastic and the skins changes colour, especially in the red varieties in which the synthesis of anthocyanins begins.
3. Ripening period, which begins at the end of veraison and continues until the berries are fully ripe. This period is the most important in determining the !nal characteristics of the fruit and, therefore, the quality of the wine produced with it. Within the berry, in its different parts, it is possible to distinguish between two types of ripening: the ripening of the pulp, which refers to the accumulation of sugars and the decrease in the concentration of tartaric and malic acids, and phenolic ripening, which includes the evolution of phenolic compounds, particu- larly anthocyanins and tannins.
Until 2008, there were only four red varieties employed by Rioja, i.e. Tempranillo, covering about 80% of the productive vineyards, Garnacha, Mazuelo (known as Cariñena or Carignan in other regions) and Graciano. As a word of warning, many lesser known varieties have many local synonyms, and even a few of them are in fact mistaken synonyms.
In March 2008, another three red varieties (and six white) were authorised, i.e. Maturana Tinta, Maturana Parda (both old, recovered varieties), and Monastel (not to be confused with Monastrell or Mourvèdre). Monastel from Rioja is the same grape grown in Somontano as Moristel, which is also called juan ibáñez in the south of aragón. ???
In addition there are also“international” varieties such as Cabernet Sauvignon, which is in some ways more indigenous to Rioja than is Garnacha, since Marqués de Riscal planted it almost 150 years ago, whereas Garnacha only made its appearance after phylloxera, some 50 years later.
A wine grape is any grape that can be crushed or pressed using normal winery procedures and that it is capable of undergoing a spontaneous alcoholic fermentation.
Grape must is a liquid obtained from crushed or pressed fresh grapes, whereas preserved grape must is when the fermentation process has been prevented by either sulphating, or by carbonation (i.e. the addition of carbon dioxide). It is possible to concentrate un-fermented grape must by partial dehydration, and equally a caramelised non-fermented grape must can be obtained by partial dehydration and direct heating.
The basic definition of a wine is that it is the partial or complete alcoholic fermentation of fresh grapes, whether crushed or not, or of grape must. And the actual alcohol content shall not be less than 8.5%.
A dry wine is a wine that contains maximum of 4 g/l sugar or 9 g/l when the level of total acidity (expressed as g/t tartaric acid) is no more than 2 g/l less than the sugar content.
A still wine is when the carbon dioxide concentration is less than 4 g/l at 20°C.
We are told that this variety prefers cool areas, as in situations of water stress it can lose its leaf. Quality wines usually result from low yields. It produces structured wines, with remarkable tannins, intense colour, high alcohol content, ph tending to increase and low acidity level that improves in fresh areas; in these areas the wines are very balanced, with structure and length. In warm areas, their tannins are exacerbated and the wines are shorter and unbalanced.
The above-mentioned characteristics may reveal the growing success of this variety in Rioja. It is very balanced in all respects and tolerates high yields well. It is like the average. It blends in very well and welcomes what the other varieties can bring to it.
In our opinion, its treatment as a varietal requires careful control of production. Better still, the higher clayey soils – preferably facing the sun to the east or north -, which guarantee freshness, and consequently acidity, the presence of red fruits, and more delicate and expressive tannins. It goes without saying that the yield cannot be forced. On the contrary, we measure the load of grapes very carefully, thus controlling water stress, depending on the power of the vine itself.
To do this we use old vines – old age is also a guarantee of a suitable biotype, as we explained earlier – which we look for in high areas throughout the designation of origin. In cold years, it is possible to blend with those from lower areas to provide balance. We pay special attention to the organic control of production and processing. Staying in large barrels guarantees that their natural properties are not disfigured.
Tempranillo has traveled to many different places within Spain (and to a few other countries), and has done so under a variety of names. In fact, it is only in Rioja and Navarra that the grape is called Tempranillo with relative regularity. In Valdepeñas it is known as Cencibel. In Penedes it is called Ojo de Liebre (in Spanish), and Ull de Llebre (in Catalan). Within the region of Castile-León alone, it travels under at least three different names: Tinto (or Tinta) del País in Cigales, Tinta de Toro in Toro, and Tinto Fino in Ribera del Duero. Here and there, one also hears it called Tinto Madrid or Tinto de la Rioja. It is known as Tinta Roriz in Portugal, and as Tempranilla in Argentina, but since the nomenclature is already sufficiently confusing just within Spain, we'll keep our focus there.
This hodgepodge of names wouldn't necessarily pose grave difficulties for understanding if the grape produced strongly similar wines from these various places. But it doesn't. For example, Rioja, surely the world's most famous rendition of Tempranillo, has traditionally been characterized as a light- or medium-bodied wine, prized for complexity and prettiness much more than power. At the other end of the spectrum, wines from Toro tend to be massive and very intense, packing a wicked wallop of alcohol and lots of gutsy tannin.
These differences in profile indicate that Tempranillo is sensitive to different climatic conditions from region to region. Yet, that shouldn't prove too confusing, right? We should expect lighter, leaner wines from cool climates and richer, more robust renditions from warmer regions. That much is certainly true, but the complexities don't end there, because the variations we see in finished wines aren't simply the result of different climates having different effects on a single grape variety. In fact, the different climates in which Tempranillo is grown have actually gotten into the variety itself, in the sense that the vines have adapted to different growing conditions over many centuries.
Localized adaptations complicate our effort to get a grip on Tempranillo, since they create sub-types within the variety. However, the adaptation process itself is easy enough to understand. It has two key elements, a spontaneous one arising from nature, and a deliberate one stemming from human viticulture.
The natural element is genetic mutation, which occurs randomly in all sorts of organisms including grape vines. Most mutations aren't advantageous to a vine, but some are. For example, some mutations will enable a vine to resist drought or mildew, or to produce more fruit or ripen it earlier. When growers notice such advantages in a mutant vine, they can use cuttings to replace other vines, or even propagate many new plants to establish entire vineyards with vines that are clones of a single parent.
Use of clones for large commercial vineyards didn't begin until the 1920s, but replacement of vines with cuttings from plants altered by adaptive mutations has been practiced for centuries. Over time, particular regions have ended up with quite distinctive strains of particular vine varieties, and Toro provides an important case in point.
The Toro region near Zamora is very dry during the growing season, with sandy soils and wide temperature swings from day to night, largely due to vineyard altitudes between 2,000 and 2,400 feet. These are very challenging conditions for Tempranillo vines, but, over hundreds of years, Tempranillo has adapted to meet these challenges. After centuries of mutations and selective replantings, Tinta de Toro vines have unusually deep-running roots to help them seek water, as well as leaves that grow in a way that helps the plants retain moisture. And, perhaps most importantly, Tinta de Toro grapes are extremely small. Since the components holding color, aroma and flavor in wine grapes reside principally in the skins, the low ratio of juice to skins in the Tinto de Toro gives it the potential to yield wines of great depth and intensity.
This is of course great news for wine lovers, but not such great news for those hoping to get a grip on Tempranillo. It means that we must not only track it to many different places under different names, but must also recognize that our elusive quarry has transformed itself into several sub-types wherever it has settled. Moreover, our search for Tempranillo's essential nature is complicated by the fact that, in all of these different places, the human beings who grow the grapes and turn them into wine do so differently, further muddying the waters.
For example, if asked whether Tempranillo produces light or heavy wines, we would really need to respond with multiple answers. Based on the factors we've already considered, we'd need to say that a Tempranillo-based wine will be heavier if grown in a hot climate, but lighter if grown in a cool one, and heavier if it is Tinta de Toro being grown, but lighter if the vines are high-yielding commercial clones. And after considering the influence of the viticulturalist, we'd also need to add that the wine will be heavier if yields are restricted by pruning and crop-thinning, but lighter if yields are increased by fertilizers and irrigation.
For this reason, it is no longer possible to say flatly that Rioja, for example, is a relatively light wine. Yes, it can be as light as cool-climate Pinot Noir, but it can also be as syrupy as Shiraz. A significant number of producers in Rioja have severely cut the crop loads from their vineyards to make 'high expression' wines that can compete with the world's richest, meatiest reds. Winemakers have gotten into the act as well, replacing many big old casks with barrels that are much smaller and replaced much more frequently, adding spice and tannin to their wines.
On top of all this, many wines from regions traditionally associated with Tempranillo actually incorporate significant proportions of other grapes. Sticking with Rioja as our example for a moment, many producers seeking richer wines are not only decreasing yields but also blending in larger percentages of Graciano. And in Ribera del Duero, where Tinto Fino makes rather muscular wine on its own, some producers are seeking even bulkier bottlings by adding Cabernet Sauvignon to their blends.
* * *
It is important to acknowledge all of these intricacies and complications, yet we can nevertheless identify some red threads of continuity that help us get a fix on this great grape. By comparison to other red varieties, Tempranillo ripens relatively early. Indeed, its name derives from early, which means early in Spanish.
Early ripening helps us understand why Tempranillo is so widely planted. It grows well in rather hot climates like Valdepeñas, but can also thrive in cool zones, ripening before the autumn chill shuts down the growing season in places such as Rioja Alavesa. Similarly, its short growing cycle enables it to deal with the rigors of growing conditions in Ribera del Duero, which has an annual weather pattern that a grower once described to me as 'one month of summer and eleven months of hell.'
Although Tempranillo wards off cold weather problems in autumn by ripening early, it does not avoid spring frost problems by sending out its buds particularly late in spring. This sometimes poses problems for growers, who can suffer serious crop losses if spring frosts kill the young buds or shoots emerging from the vines. Frost damage is a particular problem in north-central Spain. In some cases, however, what growers regard as a problem turns out to be a boon for consumers. Spring frosts reduced crops dramatically in Toro and Ribera del Duero in 2001, and this mandatory yield reduction contributed significantly to the density of wines from this vintage, which many observers and winemakers regard as the greatest in a generation.
Another characteristic that enables Tempranillo to grow in cool climates (where it can produce particularly refined wines) is that the grapes are lower than normal in acidity. This is especially helpful in growing seasons that are lacking in sunshine and warmth, and hence marginal for ripening. Whereas more acidic grapes would produce tart, angular wines in such a year, the more forgiving Tempranillo provides more balanced results.
Relatively low acidity is not a straightforward advantage in warmer regions, but neither is it a clear disadvantage. In hotspots like La Mancha or parts of Castile, Tempranillo's low acidity is not well suited to making ageworthy wines, yet the flip side of this is that bottlings of varietal Tempranillo from these places are wonderfully soft and accessible at a very young age.
Finally, with regard to aromas and flavors, some critics have maintained that Tempranillo is lacking, or that, at a minimum, it lacks a strongly defined identity. One version of this criticism contends that a lack of aroma explains the historical frequency with which Tempranillo has been lavished with oak. (Oak aging directly furnishes notes of spice and vanilla, and indirectly lends leathery notes over time due to oxygen passing through the wood's pores and between the staves.) Another version of the criticism holds that Tempranillo's lack of assertive aromas and flavors explains why it has so often been blended with grapes like Garnacha and Graciano.
In my view, neither of these criticisms stands up to close scrutiny. Both are virtually refuted by the recent rise of wines that are composed entirely of Tempranillo and only minimally oaked. Many of these wines are designated as Vino de la Tierra de Castilla, but Ribera del Duero also produces Roble wines in this style, and Rioja makes Joven wines that fit the profile.
In most cases, these wines are neither lacking nor indefinite in aroma or flavor. On the contrary, many are very expressive, featuring notes of red and black cherries, strawberries, or blackberries, with flavors so appealing that one begins to wonder why so much Tempranillo has been submerged under so much oak over the years.
I believe there are at least two answers to that question. The first points to the influence exerted by winemakers from Bordeaux, who migrated to northern Spain after oidium and phylloxera devastated their vineyards in the second half of the 19th century, and who brought their proclivity for oak aging with them.
Second, the practice of aging Tempranillo in oak had the effect of altering consumer expectations, which in turn constrained producers in how they could vinify Tempranillo. The practice of designating wines by reference to oak aging (Crianza, Reserva and Gran Reserva) contributed to the impression that more time in oak is simply better than less time, and over the decades the notion that Tempranillo needs wood to be interesting hardened from a novelty into a tradition, and ultimately into something like a dogma.
Today, however, the dogma has receded, and we now see a wonderful welter of diverse renditions of Tempranillo from all over Spain. In the absence of a ruling orthodoxy regarding how Tempranillo must be crafted, the little nuances lent by its various genetic strains and far-flung vineyard locations are being revealed more fully with each successive vintage. As this process continues into the future, we are certain to enjoy many years of friendly debate regarding which styles - and which regions - stand as the ultimate expression of Tempranillo.
2. GARNACHA (tinta)
The pattern of this variety given in the reference book seems to make it complementary to the previous one: it is resistant, although sensitive to Botrytis or rot, it bears water stress better, and it is less plastic than Tempranillo, so that the higher yield is followed by the proportional decrease of its attributes and the increase of its oxidative character. Its acidity is also higher than that of Tempranillo, while its pH is lower (it seems that the Rioja Alta or upper and the Rioja Oriental, when it was a Rioja Baja or lower, gave each other a complementary hand).
The wine stands out for the vivacity of its tones and aromatic intensity with very characteristic notes of red fruits. In the mouth it is a soft variety, with little tannin and very pleasant. Globally, the best expression of Garnacha is usually found in cool areas and poor soils, where more structured wines with a lot of personality are produced.
Our Garnacha respects these parameters on principle. It comes from high areas and old vines from all over the designation, they are generally bush-trained vines, which fits in very well with the variety, as it grows very vertically, so that production control is guaranteed and the wine responds to what is expected: red fruits, grassy nuances of scrubland, light, without excess alcohol, good acidity, subtle complexity and elegance. Extremely pleasant because it is transparent as it reflects very well the climate, terroir and work with which it has been developed, and extremely pleasant also for the one who drinks it.
The barrels in which it is kept are also large, 600 litres, so as not to interfere with its natural properties.
Although it is known as “Malvasia de Rioja”, in reality it has little to do with the Malvasia that can be found in many other regions (up to 9 different varieties), as our reference book tells us. The capital name of our variety is Alarije.
Our book goes on to tell us that it is a very productive variety, with very compact bunches, and therefore prone to rot. This is why it tended to be planted in the “headlands” of the plots, where the slope is steeper, the depth of the soil is shallower and the vigour of the vines is very limited. As for its characteristics, he adds that it produces wines with low pH, good acidity and alcohol content suitable for making white wines. When it comes from poor soils, these are fatty, sweet, and balanced by a good acidity, not too aromatic; when it comes from fertile soils, it becomes a very light variety, acid and with herbaceous and citrus aromas, suitable only for the production of young wines for quick consumption.
Our Malvasia comes from vineyards with limestone soils in the higher areas of the designation of origin. It is macerated for 24 hours in its own skins, which allows the must to be impregnated with aromas and tannins and protects the wine from oxidation. It sounds paradoxical, but rapid and controlled oxidation in must protects the wine from oxidation in wine, or, as it is commonly said, better to oxidise the must on the lees in contact with the skins than to oxidise the wine. This is helped by the fact that it is kept in an oval-shaped concrete tank – literally a “concrete egg” – which contributes to better lees circulation and thus combats oxidation. The result is a complex, powerful and extraordinarily gastronomic wine.
As we have already said, our book does not give us a pattern for Viura, as it does not consider it to be a minority grape. José Peñín, in his book published in 1989, “The Great Book of Rioja Wines”, tells us that for a long time wines of this variety used to be subjected to prolonged ageing in oak, given the slowness of their oxidative evolution. However, in line with new trends that call for the presence of fruit, this method of winemaking has been modified and has shown enormous possibilities that translate into considerable aromatic and fruity potential. The wines are pale in colour and have perfect acidity (which allows them to be sometimes added to Tempranillo and even to rosé wines). Incidentally, we mention this book because at some point we will have to dedicate a special instalment to it and observe how much things have changed in thirty or so years.
We can highlight that our varietal avoids the cloying of Verdejo or Sauvignon Blanc. It is born very timidly and its ageing capacity is surprising. Its initial citrus aromas gradually transform in the bottle into aromas of fruit such as pear, apple and peach, gradually gaining in complexity and personality. Extraordinarily pleasant to drink.
Fermented in large barrels in which it is aged on its lees for a year, gaining in body and length, without an excess of wood drowning out the fruit and delicacy of the wine.
EU Wine Legislation
Spain is part of the EU, and as such must apply a set of EU wine legislation composed of basic regulation, delegated regulations, implementing regulations and supplemented by guidelines and legal interpretation.
The rules and regulations can be quite complex, so I've added a few explantation in italics, but I've also tried to focus on only the essentials that touch on making red wines in the Rioja wine growing region.
Firstly, wine is an agricultural product in the EU's Common Agricultural Policy (as per 2013). It was in 2008 that an earlier decision to prohibit planting vines was repealed. That earlier decision was intended to end a long-standing structural surplus of wine production in the EU, and reflect a decreasing demand for wine across the Union. The result had been a marked decrease in vine growing areas, the exit of less competitive producers, and the phasing-out of market support measures that had not been economically viability. However, despite recognising that international demand for wine is on the increase, and that keeping its market share is important, rules were introduce to limit new plantings to 1% of the planted vine area on an annual basis (excluding replanting of existing vine areas). Member States were left to decided on wine grape varieties, oenological practices, quality levels, etc. provided they were in line with those recommended by "Office Internationale de la Vigne et du Vin". Mention was also made to the importance of protected designations of origin and geographical indications, and the need to respect quality policies that apply for all types of foodstuffs (e.g. traceability, etc.).
Secondly, the Common Agricultural Policy references a considerable range of specific allowable support measures, including restructuring and conversion of vineyards, "green harvesting" or reducing yields to zero, harvest insurance, and investment to improved winery infrastructure.
Thirdly, there is a specific reference to the need to regulate coupage of must and wine, including blending.
Fourthly, there is a need to classify which grape varieties can be planted, and oddly the following varieties are specifically excluded from classification, namely Noah, Othello, Isabelle, Jacquez, Clinton and Herbemont.
Fifty, it is here that the designation of origin and geographical indications are defined. We see immediately that "a designations of origin" is for wines that are essentially or exclusively due to a particular geographical environment with its inherent natural and human factors, that the grapes come exclusively from that geographical area, and that the production takes place in that geographical area. Whereas "a geographical indication" means a wine that possesses a specific quality, reputation or other characteristics attributable to that geographical origin, that at least 85% of the grapes used for its production come exclusively from that geographical area, and that its production takes place in that geographical area.
Sixth, labels must indicate the type of protection (i.e. origin or geography), the alcoholic strength by volume, provenance, and the bottler. Optional information includes, vintage, grape varieties, production method, another name or geographic region that is either smaller or larger than the type of protection already applied.
"Coupage" just means the mixing of wines or musts of different origins, different vine varieties, different harvest years or different categories of wine or of must. Naturally the result blend or coupage must still be a wine in the sense of these regulations. Coupage of a red wine with a white wine to try to produce a rosé wine is prohibited, however it can be used to produce a cuvée (i.e. a specific blend or batch).
In addition there is a mention of a number of useful wine-related definitions, namely:-
"Fresh grapes" are those that are picked, crushed or pressed by normal wine-cellar means and spontaneously produce alcoholic fermentation, and "grape juice" means the unfermented but fermentable liquid product with an actual alcoholic strength of not more than 1% by volume
"Grape marc" means the residue from the pressing of fresh grapes, whether or not fermented
"Wine fortified for distillation" means a product having an actual alcoholic strength of between 18% and 24% by volume, and obtained exclusively by the addition to wine a distilled wine having a maximum actual alcoholic strength of 86 % volume
Marc has a general definition of just the solid remains after something like grapes have been pressed, however it is also used to produce grappa and orujo, and even the pomace brandy Marc de Champagne.
The mention of "actual alcoholic strength by volume" means the number of volumes of pure alcohol contained at a temperature of 20°C in 100 volumes of the product at that temperature. Whereas "potential alcoholic strength by volume" means the number of volumes of pure alcohol at a temperature of 20°C capable of being produced by total fermentation of the sugars contained in 100 volumes of the product at that temperature, and "total alcoholic strength by volume" just means the sum of the actual and potential alcoholic strengths.
And there are also a series of quite specific definitions concerning "wine", namely:-
Wine must have an actual alcoholic strength of not less than 8.5% by volume provided that the wine derives exclusively from grapes harvested (a minimum of 9% by volume is allowed in some designated wine-growing zones)
Some specific wines can have, if protected by a designation of origin or a protected geographical indication, an actual alcoholic strength of not less than 4.5% volume
Wine must have a total alcoholic strength of not more than 15% by volume, but by way of derogation it can have an upper limit for the total alcoholic strength of up to 20% by volume
The upper limit for the total alcoholic strength may exceed 15% by volume for wines with a protected designation of origin which have been produced without "enrichment"
The term "wine" can be used if accompanied by the name of a fruit other than grapes that have been fermented
"Liqueur wine" means having an actual alcoholic strength of between 15% by volume and 22% by volume, but usually not less than 17.5% by volume, and obtained from grape must in fermentation, and to which has been added alcohol produced from the distillation of dried grapes, having an actual alcoholic strength of not less than 96% by volume, or wine or dried grape distillate, having an actual alcoholic strength of between 52% by volume and 86% by volume, or both
"Sparkling wine" must have a total alcoholic strength of not be less than 8.5% by volume, and be obtained by a first or second alcoholic fermentation from fresh grapes or grape must, or from wine, and which, when the bottle is opened, releases carbon dioxide derived exclusively from fermentation (with an excess pressure of not less than 3 bar)
"Aerated sparkling wine" is for wines where carbon dioxide has been added.
"Enrichment" appears to be another name for "chaptalisation", which is the process of adding sugar to unfermented grape must in order to increase the alcohol content after fermentation.
Concerning the winery itself, there are some other specific requirements, namely:-
Wine should be produced in the wine-growing zone where the fresh grapes were harvested
Acidification and de-acidification of wines must take place in wineries in the wine-growing zone where the grapes were harvested
Quantities of concentrated grape must, rectified concentrated grape must or sucrose used by producers, bottlers, processors and merchants must be kept in the same place as the fresh grapes, grape must, grape must in fermentation or wine in bulk (and quantities must be registered, or at least entered in a goods inwards and stock utilisation register)
Concentration by cooling, and acidification and de-acidification of wines may be practised throughout the year
All oenological practices shall exclude the addition of water
Grape juice and concentrated grape juice can not be made into wine or added to wine
Coupage using a wine originating in a third country is prohibited
The over-pressing of grapes shall be prohibited
Acidification is the process of artificially increasing the acidity of wine with the addition of acid during the process of fermentation. De-acidification is the process of decreasing the total acidity of must and wine, leading to an increase in pH.
"Rectified grape must concentrate" is the liquid, non-caramelised product that is produced from grape must through rectification (i.e. refinement or purification by distillation) and extensive dehydration, as well as other approved treatments to remove the ingredients other than sugar. It is a highly concentrated sugar syrup made from grape must.
I'm not sure what "concentration by cooling" actually refers to. However, the physical and chemical conditions of fermenting must depend upon the content in sugar, temperature, acidity, pH, and the richness in nitrogen sources, and is influenced by the operating conditions such as yeast population, temperature, agitation, oxygenation and the overall fermentation time. The metabolism of residual sugars during the fermentation process releases heat, which is dissipated through the tank walls and by the release of volatiles, and directly impacts on the concentration of ethanol. So I presume "concentration by cooling" refers to cooling the tank wall in order to control the temperature of the fermentation process, in order to increase the concentration of fermentable sugars and resultant total alcohol strength.
Rioja wines are classified in the wine-growing zone C II, which specifically means that the natural alcoholic strength by volume can be increased by, but not exceed, an addition 1.5% by so-called "enrichment processes", by only one of three alternatives, namely:-
Or the partial concentration of wine through cooling.
In addition for Rioja wines:-
Adding sucrose by dry sugaring is excluded
The "enrichment processes" can not exceed a volume increase of 6.5%
The increase obtained through "enrichment processes" can not exceed a total alcoholic strength of 13% by volume
Acidification and de-acidification is permitted, but acidification is only permitted up to the limit of 1.5 g/l (expressed as tartaric acid) for products other than wine, and for wine the limit is 2.5 g/l
De-acidification is permitted up to the limit of 1 g/l (expressed as tartaric acid).
Dry sugaring is the addition of beet sugar (crystal sugar) or sucrose to grapes, grape must, partially fermented grape must or young wine for the purpose of increasing alcohol. The official term for dry sugaring is enrichment, and in some countries also chaptalisation. In contrast, the addition of sugar to the finished wine in order to increase the residual sugar content is called sweetening.
There are additional regulations concerning wine-growing areas, alcoholic strength, oenological practices, etc., some of which I've collected below.
Correcting alcohol content (i.e. reducing excessive levels of ethanol in a wine) in order to improve the balance of flavour is allowed under the following conditions:-
The wines treated must already have no organoleptic faults and must be suitable for direct human consumption
Elimination of alcohol from the wine may not be carried out if it has already undergone an enrichment operation
The alcohol content may be reduced by a maximum of 20%.
Sugar content of musts may be reduced by membrane coupling (i.e. microfiltration or ultrafiltration to nanofiltration or reverse osmosis), provided:-
The processes must allow the content of must constituents other than the sugars to be preserved
It cannot be used in conjunction with an enrichment operation.
The total sulphur dioxide content may not exceed 150 milligrams per litre for red wines.
Pieces of oak wood may be used for winemaking and ageing, but with the following constraints:-
The pieces may be left in their natural state, or heated to a low, medium or high temperature, but they may not have undergone combustion, including surface combustion, nor be carbonaceous or friable to the touch
The pieces may not have undergone any chemical, enzymatic or physical processes other than heating, and no product may be added for the purpose of increasing their natural flavour or the amount of their extractible phenolic compounds
The label must mention the origin of the botanical species of oak and the intensity of any heating, the storage conditions and safety precautions
The dimensions of the particles of wood must be such that at least 95% in weight are retained by a 2 mm mesh filter.
Using oak barrels in wine fermentation and ageing increases a wines aromatic complexity and improves overall quality. The use of oak in wine is and has always been very popular, despite the fact that it costs more money to produce an oaked wine than it is to produce a wine made in stainless steel tanks. A French oak barrel can cost anything between €900 to over €2,000 and an American oak barrel can cost around $500 (remembering that a barrel can be used three to five times). As a result of this cost differential, some wineries look for alternatives to oak barrels that give similar aromatic and quality characteristics to the finished wine without the high costs. An alternative is to use oak chips instead of oak barrels, as it has been shown that using oak chips in wine fermented and/or aged in stainless steel tanks results in finished wines that are said to be aromatically similar to wines that are fermented and/or aged in oak barrels. Oak chips can be added to the wine at any stage during the winemaking process, and will result in varied styles of wine depending upon exactly when the chips were added. Oak chips, oak staves, oak inserts, oak spirals, oak cubes, oak dominoes, oak chains, and oak bags can cost around $4 per 100g, and they are more efficient in imparting oak flavours and tannins than barrels (so also reducing ageing times). It is also possible that the application of oak extract (e.g. "Boisé" has always existed in the brandy industry) to the vines during the growing season may impart oak flavour characteristics into the finished wine, but it not current practice. The reality is that it is almost impossible for a wine costing less than €15 to have been aged in oak barrels. Secondly, some regions mandate oak barrel ageing, for example Rioja. One problem is that there is a risk that oak chips (often called over-oaking) are added to mask the lack of flavour of a wine. On the other hand, using fresh oak chips may be better than using an old recycled oak barrel.
Stefan K. Estreicher, "A Brief History of Wine in Spain"
"La Rioja and Rioja Alavesa Vine and Wine Cultural Landscape", a text for a UNESCO World Heritage Centre
Fernando Martinez de Toda, "Anatomy of the vine. Origin morphology, vegetative and reproductive cycles and varieties"
D.Marín, et. al., "Challenges of viticulture adaptation to global change: tackling the issue from the roots"
An alternative version of the story is that Camilo, when in Bordeaux was commissioned by the Álava Provincial Council to hire a winemaker who could teach the region's harvesters the techniques used in the Médoc, and who could produce wine according to the Bordeaux method.
He contacted Jean Pineau, winemaker at Château Lanessan, who initially helped the winemakers of Álava, and then worked for
It is said that Hurtado immediately sent to Rioja Alavaise, wine of Cabernet Sauvignon, Merlot, Malbec and Pinot Noir, the finest grown in France, to test them in his vineyards, where grapes of the Tempranillo and Graciano varieties were grown.
In 1858, Hurtado who had inherited from his father a few cellars in Elciego, founded the Marqués de Riscal cellars by applying the techniques used in France, he built the first building of his warehouse. It still stands, and inside is La Catedral, a unique collection made up of bottles from all the vintages produced by the winery from its first, in 1862, to the present day. It is an underground treasure hidden under a maze of vines.
Marqués De Riscal From the 1970s, the company decided to diversify its production and bet on the development of other varieties of wine. Thus, after two years of testing, in 1972, it began producing white wine in its new cellar in Rueda (Valladolid) 7. The success of production in this area attracted new investors, and in 1980 it led to the creation of the appellation of Rueda4.
The company's wine production spans a vast extension of vineyards. Marqués De Riscal has 1,500 hectares of vineyards in the Rioja area in Elciego, Leza, Laguardia and Villabuena d'Álava, of which 500 are owned and 985 controlled9. In the Rueda area, it has the largest owned vineyard in the entire D.O., with 205 in the municipality of Rueda. It has 250 more in the rental of Rueda, La Seca, Serrada and Rodilana7. In addition, it has 200 in the municipalities of Zamora de Toro and San Román de Hornija, from which the red of the land of Castile and Leon is produced10.
The Marqués de Riscal winery was created in 1858, and produced it first bottle in 1862. The first extension, El Palomar, was built in 1883 (additions made also in 1968 and 2000).
The soil is poor, being rich in clay-lime.
In the original cellar there is "the cathedral", home to bottles of all the vintages since 1862.
A maximum of 5,500 kilos of grapes collected per hectare go through an elaborate process until they finish on the palate. The leftover grape is used as fertilizer, the leftover from the barrel is sold for the production of pomace or served in the wine therapies of your hotel,