When you squee a slice of lemon in your tea to improve its taste, in fact you increase the acid content of the drink. The same happens for wine. All wines contain a variety of basic natural acids, especially tartaric acid, malic acid, lactic acid and citric acid. These, in addition to preventing wine from being damaged during fermentation and aging, add acidity to the same opposing its sweetness and giving to it both balance and a fresh and refreshing taste. A wine is defined acidic if it is a not balanced wine because the acidity level is too high. Instead, wines lacking in acidity may seem weak or flat.