Citric acid is found in small quantities in grapes and larger quantities in other fruits.It is metabolized both during primary alcoholic fermentation and during malolactic fermentation. Excess quantities can produce high levels of diacetyl
during MLF, a condition which can make wine unpleasant tasting. Instead, consider the use of tartaric acid.
Citric acid, in combination with potassium metabisulfite, is used to sanitize equipment and also in a final rinse solution when preparing a barrel for wine.