Phenolic content in wine - quercetin. Like other flavonoids, the concentration of flavonols in the grape berries increases as they are exposed to sunlight. Some viticulturalists will use measurement of flavonols such as quercetin as an indication of a vineyard's sun exposure and the effectiveness of canopy management techniques. Anthocyanins are phenolic compounds found throughout the plant kingdom, being frequently responsible for the blue to red colors found in flowers, fruits and leaves. In wine grapes, they develop during the stage of "veraison" when the skin of red wine grapes changes color from green to red to black. As the sugars in the grape
Classification of wine a bottle of cooking wine, which may be opened and used occasionally over a long period of time. In other countries sherry wine is used for cooking. Fortified wines resist spoilage, as their alcohol content is too high to permit bacterial growth. A vintage wine is one made from grapes that were all, or primarily, grown in a single specified year, and are accordingly dated as such. Consequently, it is not uncommon for wine enthusiasts and traders to save bottles of an especially good vintage wine for future consumption. However, there is some disagreement and research about the significance of