Tannins in wines

Tannins are very important for the winemaking and wine quality,because of their multiple characteristics.The tannins from grapes come from different parts,but all of them are the polymers of catechin.The quantity,structures and some properties of these phenolic compounds are specific with the localization (skin,seed and pedicel).Tannins from white and red cultivars are qualitatively the same.Epicatechin is the major unit of grape tannins.The enological tannins can deposit proteins,restructure poor wines,stabilize the pigments,and protect wines from oxygenation,bacteria,the flavor of reduction and the sun flavor.So under the conditions of reasonable utilization,tannins can improve the wine quality and the aging of wines.