The harvest in the middle of August and other traces of climate change in the wine

Tempranillo, Garnacha, Cabernet, Albariño, Graciano, Monastrell or Verdejo. These are some of the grape varieties available in Spanish vineyards and, consequently, in the wines that arrive from the wineries to the shops and supermarkets. Now, we must add new names such as Cinderella, Moneu, Forcada, Querol or verdoncho.

It is estimated that there are about 10,000 varieties of vines, many of which have been forgotten. In Spain, almost fifty grapes are not harvested, although now the lack of rain and the increase in temperatures have changed the discourse and, also, the way of working. “It is probably the crop most affected by climate change,” replies Vicente Sotés, Professor of Viticulture at the Polytechnic University of Madrid.

“You can see it in the cattle, in the flowers that bloom earlier and also in the vineyards,” says Javier Sanz, a Castilian and Leonese viticulturist and head of the DO Rueda winery in La Seca. “The budding, the flowering of the veraison… everything has been brought forward,” adds Iñaki García de Cortázar, director of the Agroclim laboratory of the French National Institute for Agricultural, Food and Environmental Research (INRAE).

Rising temperatures have changed the cycle of the vine. However, “this is not from now,” warns García de Cortázar. “In the last 50 years, all the vineyards in France have harvested one month earlier,” he clarifies. “Last year we finished the harvest on August 25 and it is normal for it to be at the beginning of November,” says Sanz.

An advance of the collection affected by the increase in temperatures that the planet is experiencing in recent decades. “In the period from 1950 to 2014, the average temperature in our Denomination of Origin has risen between 0.9ºC and 2ºC,” warns Pablo Franco, technical director at the Rioja Qualified Denomination of Origin Regulatory Council. “This situation can be extrapolated to any other region,” he says. Forecasts point to an additional degree rise in the 50s of this millennium.

This increase in prices impacts the growing season of the grape, which will define what the wine will be like and what its flavor will be. “If there is more heat during the maturation process, times are shortened and it is key for production,” warns Ignacio Morales Castilla, Professor of Ecology at the University of Alcalá de Henares (UAH).

A hot climate with many hours of light causes the fruits of the vines to be sweeter and less acidic. “This modifies the perception we have of wine” warns Sanz. The amount of sugar is key in the natural fermentation of the wine that comes out of the cellars. Every 17.5 grams of sugar contained in a liter of must, fluid from the grape, will give 1% by volume of alcohol. “This problem was born 20 or 30 years ago and every decade we have increased one degree of alcohol,” reveals García de Cortázar. “This is enough.”

But heat is not only the enemy of crops, the lack of water is also essential for irrigation. “Without water, there is no photosynthesis,” warns Sotés. Water resources in vineyards are important and climate change, according to expert forecasts, suggest that in the coming decades there will be 17% less water availability in the Mediterranean area. “To get an idea, a bottle of wine needs between 800 and 900 liters of water,” reveals the Professor of Viticulture at the Polytechnic University of Madrid. “It’s a problem,” he adds.

“Correct the imbalance”

The increase in temperatures and “also the lack of rain” – Franco recalls – has produced a “decoupling between the alcoholic and phenolic maturation of the grape”. When the degrees of alcohol, arising from the first, and the aromas, born from the second, are optimal, “the harvest occurs,” says Sanz.

The prompt alcoholic maturation produces a gap with the phenolic and this can cause “a different aromatic”, explains the technical director at the Rioja Qualified Designation of Origin Regulatory Council. This reduction in the life cycle of the vine has led to “greater work in the winery,” reveals Sanz.

The techniques implemented by winegrowers in the field are focused on mitigating the high temperatures suffered by the vineyards. “Doing a late pruning delays maturation,” Franco replies. “Also, there are more aggressive techniques such as cutting the shoots to force new buds in June and thus delay their maturation,” he explains.

Despite these mitigation measures to save crops, with a temperature of two degrees, and without taking any measures to avoid it, it is estimated that 56% of the areas in which wine is produced in the world will not be viable. “Vineyards are being seen in areas where 30 or 40 years ago it was unthinkable,” says Morales.

In the LIFE MIDMACC project, researchers from the Institute of Agrifood Research and Technology (IRTA) have studied how to adapt viticulture in the middle mountains. Viticulturists flee from hot temperatures in search of cooler areas to slow down the ripening of their fruit.

An initiative that other wineries are already launching, such as Familia Torres, from Penedés, which has moved part of its vineyards to the Catalan Pyrenees to compensate for the rise in temperatures and thus be able to maintain the quality of its wines at higher altitudes.

“It can be a solution, but that area is limited,” warns Pablo Franco. “We cannot go crazy and uproot 65,000 hectares that have this denomination of origin and take them to the mountains, that cannot be done.”

return to origin

Discarded the transfer, the focus is on the recovery of native varieties to adjust the maturation process to high temperatures and lack of water. “In the same year we can have drought, frost, heat waves or floods,” says Iñaki García de Cortázar. “The solution is to make resilient vineyards that can withstand these weather events,” he says.

Since 2019, 16 research centers in Spain have come together to develop Minorvin, a project that wants to value the existing biodiversity in minority vine varieties recovered in Spain by evaluating their potential to mitigate the effects of climate change on viticulture.

This working group evaluates 51 minority varieties from all over Spain to diversify wine production. “Now I work with two varieties that were in disuse,” reveals Sanz. “One is a Verdejo type that was late ripening and is now perfect and then another red type grape that is ideal,” he adds.

Climate change affects wine and the way winegrowers work, but this change in the care and harvesting of grapes brings to its maximum expression the quote by the French chemist Louis Pasteur who said “there is more philosophy and wisdom in a bottle of came, than in all the books».