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 grapes known as teinturiers, such as Alicante Bouschet, which have a small amount of anthocyanins in the pulp that produces pigmented juice. There are several types of anthocyanins (as the glycoside) found in wine grapes which are responsible for the vast range of coloring from ruby red through to dark black found in wine grapes. Ampelographers can use this observation to assist in the identification of different grape varieties. The European vine family "Vitis vinifera" is characterized by anthocyanins that are composed of only one molecule of glucose while non-"vinifera" vines such as hybrids and the American "Vitis labrusca" will