he basic ingredients of a completed wine are water and alcohol, though other components present in minuscule quantities account for quality and character. A list follows:
Water (80 to 85 percent)
The water in wine derives entirely from grape juice, so it is biologically pure. It is the base for all the complex biochemical phenomena that occur as wine is made and aged.
Alcohols (10 to 17 percent)
Alcohols in wine are attained by yeast-converting sugars. Besides adding their own characteristic flavors and odors, alcohols are the main carriers of aroma or bouquet. The most important alcohol in quantity is ethyl, a monoalcohol. Then comes glycerol, a polyalcohol that adds a degree of sweetness. Butylene glycol is among other polyalcohols and cyclic alcohols present. In some fortified wines, alcohol attained by distillation may be added.
Acids (0.4 to 1 percent)
Acids give wine the sour or sharp aspect that enhances flavor when in balance with other components. Of the three organic acids that originate in grapes, tartaric is prevalent as the base measure of total acidity in wine, followed by malic and citric. Three other acids - succinic, lactic and acetic (source of volatile acidity) - are produced by fermentation.
