The total acidity of a grape must is normally 6.5-7.5 g / l for white wines and 5-6 g / l for red wines. It is composed of tartaric acid, malic acid and lactic acid and succinic acid. Tartaric acid is the "backbone" of a wine. It shapes its taste and is a determining factor in its storage life. The relationship of acidity and alcohol content, among other factors, is an integral part of the wine's harmony. The proportion of tartaric acid also depends on the grape variety. In immature wines, the malic acid predominates. In some years, the acid must be reduced with calcium or potassium. This can also be initiated by means of special bacterial cultures by biological means (BSA). Over the years, the acid breaks down naturally.