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 . Low molecular weight polyphenols, as well as elagitannins, are susceptible to be extracted from cork stoppers into the wine. The identified polyphenols are gallic, protocatechuic, vanillic, caffeic, ferulic, and ellagic acids; protocatechuic, vanillic, coniferyl, and sinapic aldehydes; the coumarins aesculetin and scopoletin; the ellagitannins are roburins A and E, grandinin, vescalagin and castalagin. Guaiacol is one of the molecules responsible for the cork taint wine fault. Flash release is a technique used in wine pressing. The technique allows for a better extraction of phenolic compounds. The exposure of wine to oxygen in limited quantities affects phenolic content. Depending on