🍷 Malic acid

Malic acid is a sharp acid, like that in a green apple. It is present in grapes and wine, and partly determines how sour the wine tastes. The name comes from the Latin malum, apple, because it was first found in apple juice.

Unripe grapes have a lot of malic acid. As they ripen, there is less, especially in a warm climate. That is why wine from cold areas is often sharper. Malic acid can be softened. For this, malolactic fermentation is carried out: bacteria turn it into lactic acid, which is softer and closer in taste to milk. After this fermentation the wine becomes rounder and softer.

This fermentation is usually done in red wines and in some whites, such as Chardonnay. In light, fresh whites it is often avoided to keep the sharpness. Malic acid is part of the acidity of wine along with tartaric and citric acids. The balance of acids matters for the freshness of wine and its ability to age.