Then winemakers often use calcium carbonates to reduce the acid content of juice before fermentation. This material is occasionally used to reduce the acid content of finished wines by small amounts. However, when carbonates are used to reduce the acidity of a finished wine, they can change wine flavors, raise pH and cause other problems. Grapes grown in warm climates are usually low in acid, so carbonates are seldom used with warm climate fruit. Citric Acid Citric acid is one of the work horse materials in the winery, and it is used for several different purposes.
Citric acid is mixed with sulfite powder and water to prepare sulfur dioxide solutions.
Sulfur dioxide solutions are used to sterilize winery pumps, hoses, filters and other winery equipment. Sulfur dioxide solutions are also used for wet barrel storage. Sometimes, citric acid is added to finished wines specifically to increase acidity and improve acid balance. In small quantities, it provides a fresh, citric characteristic, and the citric quality is often appreciated in white table wines. Nevertheless, bench trials should always be done before making any large additions of citric acid.