This is an essential component for the life, vitality, and balance of all wines. Acids form the basis of a wine’s tartness. Too little acidity results in wines which can be described as being flabby. Young wines which display too much acidity will often benefit from time in the cellar to even out the acid levels. In champagne, relatively high degrees of acidity are required to carry the flavor through the tactile sensation of the mousse. Acids also contribute to the longevity of a wine in the bottle (the ability of the wine to survive extended periods of bottle aging).
There are two basic acids in young wines: tartaric and malic. Through the process of Malolactic fermentation, harsher tasting malic acids are transformed into their softer cousin, lactic acid. Tartaric acids, unlike tannins, are not affected by either the fermentation process or bottle aging. Tartaric acids can be reduced by chilling wine until tartaric crystals form (an indicator that wine has been chilled during storage can be found when tartaric crystals are present from either on the cork or in the bottle).