The word alcohol comes from the Arabic al-kuhl , a word used to name a powder used to paint eyelids kohl , a term that in those times was also applied to fluids that represented the essence or spirit of something, that is, the product of distillation. According to the Oxford Wine Dictionary it was “the fine impalpable powder that represents the essence of whatever raw material involved".
This brings us to what interests us most: wine. In its fermentation process, alcohol appears as one of its essences, and both enologists and viticulturists have to ensure that it is in harmony with other qualities such as aromas, tannins, acidity, and terroir. Although year after year they get to know their vineyards better and understand their rhythms, things are getting ever more complicated as the climate changes in unpredictable ways. To achieve balance in the final product is no longer easy.
Let's go back to some points I've mentioned in other blogs because they are important to understand what I'm talking about. The grapevine is a plant and its life depends on a more or less stable environment. Photosynthesis (the combination of oxygen, carbon, and hydrogen catalyzed by sunlight to produce fructose) determines how ripe the sugar in the wine will be. The amount of sugar the vine produces directly corresponds to the heat and amount of sun in its microclimate. The more heat, the more sugar and the more alcohol. But sugar is not the only thing that ripens, there are also phenolics that develop like color, aromas, tannin, acidity and also the concentration of indigenous yeasts on the skin of the grape. Sugar and phenolics have to ripen in tandem or the wine will not be of good quality, and as temperatures have now increased in vineyards around the world, viticulturists and winemakers have to work harder to ensure proper ripening in all these aspects. For example, more heat lowers acidity in the fruit. If the fruit is too concentrated in sugar due to heat, you can try to correct the acidity in the winery, but sometimes there are textural differences when we add acids and the result can be a wine with a high alcohol content and an acidity that does not complement it. This is not always the case, but it does happen. When it does, the wine will not age well.
I want to be clear: too much alcohol in a wine is not desirable. It is not just a question of how you like your wine – more potent, full-bodied or more delicate – it has nothing to do with preference. Yeasts – indigenous or colonized in a laboratory – have a range of sugars within which fermentation begins and ends, which sometimes does not end if there is too much sugar, producing a wine with excess residual sugar making it sweet. This doesn't happen very often, but it does happen and it is the nightmare of any winemaker. A truncated fermentation often happens with grapes with too high a concentration of sugar though it can happen if the yeasts aren't strong enough - Something desirable for a dessert wine, but not for a table wine.
Source : https://www.wineswithattitude.co.uk/alcohol-levels-in-wine-or-abv/
Do you remember the summers of your youth? Do you remember the summers of 15 years ago? How does it compare to today? To eight years ago? Is it warmer now? I think there is no doubt. The world and the climate is changing, and fast. Many of the plants (and even animals) we consume are suffering from the problems of climate change and the vineyards aren't any different. The big alarm is that the best areas for producing high-quality wines are few, which is why there is concern that vineyards are in danger.
Since 2005 we have seen the hottest years in global history. Not only are we experiencing hotter summers, but winters are also colder. In Europe, vineyards are experiencing early bud break, coinciding with hail damage, which significantly reduces yields. Similarly, the amount of rain is causing more erosion, droughts are dehydrating grapes and soils, and fires are burning hectares of vineyards. And if that's weren't enough, diseases and pests are more problematic with the heat.
Dehydrated vineyards. Source: https://www.ctvnews.ca/climate-and-environment
So how do we mitigate this problem? What do we do with this new situation? One solution is to plant the vineyards further north where the climate is still not as hot or to grow them at higher altitudes so that they maintain the necessary acidity. Although these two solutions are already being implemented, it's not a viable option for many. You cannot call a moving company and move a vineyard. Planting a new one takes years before you recover the investment. That obviously depends on the location, but vineyards don't have a quick return on investment.
Not everything is worrying though. Through leaf canopy management and creating more shade on the grapes themselves, we can control sunburn, dehydration and some slowing of sugar absorption. Pruning, which happens annually, is the way to balance how the vines absorb and reroute fructose to the fruit or to the leaves. However, since the climate cannot be controlled, we have to be aware that it doesn't protect the vine 100% from the risks of climate change. Irrigating to ensure that the vineyard has enough water for the transpiration process (when the stomata of the leaf open so that the water vapor escapes and cools the vine) is another way that helps keep vineyards cool, but water is an important resource to be protected and there are places in Europe where a vineyard can only be irrigated for the first 3-4 years to establish itself. After that, it is not legal to irrigate, exactly for the reason that water is a finite resource.
To whatever extent these things work (or don't), the truth is that there are surprises every year. Before, each season in the vineyards was different but within normal parameters. Now we are facing things that we've never seen before which forces us to pay much more attention to the vineyards in order to achieve good quality wines.
The great work that a winemaker and viticulturist do is to bring out the best characteristics and to subtly express the complexity of the terroir of their land. It's an art. We say in English: “you have to know the rules to break them.” In the case of wine, I would say: “you have to know about science to achieve the art of making good wine.” Today, it is essential to study the environment, biology, botany, etc., to understand what is happening in the vineyard and thus ensure that the wine fully expresses the spirit and the essence of its raw material - its land.
