Malic acid is one of the primary contributors of acidity in the grape. Its concentration tends to decrease as the grape ripens.

Malic acid is very important in wine. If there is not enough, the wine will taste “flat,” and will be more susceptible to spoilage. If there is too much, the wine will taste “green,” or “sour.” Thus it is important for the winemaker to control the amount of Malic acid present.

One of Malic acid's defining characteristics is the strength of its taste. Some would describe it as harsh. Because of this, many winemakers choose to replace Malic acid with Lactic acid through Malo-lactic fermentation. Lactic acid is the primary acid in milk and is much “softer” than Malic acid.