Yeasts consume those sugars during fermentation and excrete alcohol, so fermenting sweeter berries leads to higher wine alcohol content – and, indeed, wines in warm regions such as southern France are growing boozier. That's an undesirable trend for the region's consumers, especially since it's accompanied by a drop in acidity, says Cécile Ha, a spokesperson for the Bordeaux Wine Council. Acidity affords a fresh fruitiness and ensures that wines last for years in the cellar.
