lactic acid, one of the milder acids in wine, present in much lower concentrations than either malic acid or tartaric acid. Lactic acid, named after lactis, Latin for milk, is most frequently encountered as the principal acid in yoghurt, sour milk, pickled cucumbers, and sauerkraut. Lactic acid is a common participant in both plant and animal metabolic processes. It is the end-product of intense muscular activity in animals (see acids); a by-product of the alcoholic fermentation process in wines and beers; and the end-product of the metabolic action of the many lactic acid bacteria.
