Sugars in wine Sugars in wine Sugars in wine are at the heart of what makes winemaking possible. During the process of fermentation, sugars from wine grapes are broken down and converted by yeast into alcohol (ethanol) and carbon dioxide. Grapes accumulate sugars as they grow on the grapevine through the translocation of sucrose molecules that are produced by photosynthesis from the leaves. During ripening the sucrose molecules are hydrolyzed (separated) by the enzyme invertase into glucose and fructose. By the time of harvest, between 15 and 25% of the grape will be composed of simple sugars. Both glucose and fructose are six-carbon
Wine in China "materia medica" compiled in the late Han, states that grapes could be used to produce wine. In the Three Kingdoms era (220–280 AD), Wei emperor Cao Pi noted that grape wine "is sweeter than the wine made [from cereals] using ferments and sprouted grain. One recovers from it more easily when one has taken too much." Grapes continued to be grown in the following centuries, notably in the northwestern region of Gansu, but were not used to produce wine on a large scale. Wine thus remained an exotic product known by few people. Not until the Tang dynasty (618–907) did