Decomposition of L ‐malic acid by wine yeasts

Abstract 46 yeasts from 5 genera were examined for ability to decompose L‐malic acid in grape juice. Saccharomyces yeasts decomposed between 3 and 45%, the amount decomposed being somewhat greater in highly acid juice. Schizosaccharomyces malidevorans brought about complete decomposition with stoicheiometric yield of ethanol. Pichia and Candida growing as oxidative films also brought about some decomposition. Mixed cultures of Saccharomyces and Schizosuccharomyces were examined quantitatively. The difference between yeast and bacterial decomposition of L‐malic acid is discussed, as well as the possible selection of yeast cultures for controlled deacidification in wine‐making.