Mixed Fermentation

Many ferments involve some combination of alcoholic, lactic, and acetic fermentations. Until Louis Pasteur’s 1860s research isolating yeast and other fermentation organisms, microorganisms always existed in communities, and many—arguably all—traditional ferments have involved more than a single type of fermentation. For instance, sourdough breads (and all bread until the isolation of yeast) are risen by a combination of yeasts and lactic acid bacteria. Similarly, in traditional fermented alcoholic beverages that rely on wild yeasts rather than isolated pure strains, the yeasts are always accompanied by lactic acid bacteria, and the products include not only alcohol but also lactic acid.