Term for the conversion of malic acid into the milder-tasting lactic acid (Latin malum = apple, lac = milk), which plays an alternative role in the production of fruit juice, wine and sparkling wine(champagne, sparkling wine). The process is also called biological acid degradation (BSA), bacterial malic acid degradation, microbial acid degradation or apple-lactic acid fermentation, because carbon dioxide is also released. However, it is not actually a real fermentation, but was once thought to be. Around 1890, Dr. Hermann Müller-Thurgau (1850-1927), who was working in Geisenheim at the time, correctly suspected bacteria as the cause. Dr. Wenzel Seifert (1862-1942) was then able to identify the acid-degrading bacterium in 1903 at the Klosterneuburger Weinbauinstitut and named it "Micrococcus malolacticus". Today, BSA is almost always used in red wine, but generally before barrique ageing. The advantages are a reduction of malic acid, more fullness due to the lactic acid, less need for sulphur dioxide and better microbiological stability.