With the effects of climate change, especially in the vineyards along the river, the trend in the wine sector is clearly shifting to high-altitude vineyards. The condition of a plot affects the way it works, the dates on which to perform the various tasks it requires, and the result obtained by the grapes, which also affects the qualities of the wines. The heterogeneity of the DO Ribera del Duero territory means that, from east to west, the altitude increases. Therefore, the area of Valladolid is the lowest and the Soriana area is the highest, with the area of Burgos on average more than 800 meters above sea level.
In viticulture, there is a parameter called the thermal integral, which is measured between April and October with an effective average daily temperature above 10 oC and which is used to decide when to do what to do in the vineyard. Its historical evolution shows how it has improved, from an index of 1,295 in 1996 to 1,713 last year. That is, between April and October, a considerable increase in the average temperature suffered by the countryside in general and the vineyards in particular is recorded every year.
The consequences of this warming in the vineyard are clear. “At higher average temperatures, the grapes grow faster than the seeds; the two ripenings are already separated, but the ripening of the seed is what marks the beginning of the harvest,” said Alex González, technical director of DO Ribera del Duero, who clarified that “if the grape is more ripe, it goes to get more alcohol, and we have already seen wines with 15 degrees.
A trend that, if not working in the field, will continue to develop in it. That’s what slows down the vineyard at altitudes where “there are fewer hours of the sun, lower temperatures suitable for ripening, and greater air favors health.” González listed the advantages of having the vineyard along the highest terrain.
These particular conditions are well known to María Burgos, a young wine grower who has his vineyards at an average of 920 meters. “I always remember that the harvest is done at the bridge of Pilar, and last year I started to harvest the white grapes on September 9 and the red grapes on September 13.gives proof of the changes in the vineyard with global warming from his experience.
In addition to spending five years picking grapes in September, other tasks were delayed, such as pruning. “We started later than before to delay germination; you get four or five days on the vine and avoid the dangers of frost at the end of April, beginning of May,” explained María, who knows that the grapes, which are grown at altitude, are “ripe.” “They are slower and healthier because there is less humidity around.”
When the grapes arrive at the winery, or at the time of deciding when to harvest, the winemakers also want more balanced grapes like those obtained from a height. “The higher the level of alcohol, which is the reason for the high temperature, the less acidity, so the wine is less balanced and does not come out of aging,” summarizes José Manuel Pérez Ovejas, from Dominio de Cacología. He committed to “more civilized wines with more parameters” and achieved this by preventing the grapes from roasting in the sun and reducing the removal of leaves to a minimum to increase the protection of the cluster.