Sugars in wine as chaptalization solely in order to boost the alcohol content – chaptalization does not increase the "sweetness" of a wine. Glucose, along with fructose, is one of the primary sugars found in wine grapes. In wine, glucose tastes less sweet than fructose. It is a six-carbon sugar molecule derived from the breakdown of sucrose. At the beginning of the ripening stage there is usually more glucose than fructose present in the grape (as much as five times more) but the rapid development of fructose shifts the ratio to where at harvest there are generally equal amounts. Grapes that are over
Phenolic content in wine concentration in the skins of wine grapes. The accumulation in ripe berries of different concentrations of both bound and free resveratrols depends on the maturity level and is highly variable according to the genotype. Both red and white wine grape varieties contain resveratrol, but more frequent skin contact and maceration leads to red wines normally having ten times more resveratrol than white wines. Resveratrol produced by grape vines provides defense against microbes, and production can be further artificially stimulated by ultraviolet radiation. Grapevines in cool, damp regions with higher risk of grape diseases, such as Bordeaux and Burgundy, tend to