Heterolactic fermentation

Heterolactic fermentation is a process in which certain microorganisms convert sugars into lactic acid. Unlike homolactic fermentation, it produces other by-products in addition to lactic acid. This fermentation mainly yields lactic acid together with ethanol (alcohol) and carbon dioxide. In sake brewing, heterolactic fermentation plays an important role in bringing out diversity in aroma and flavor. The lactic acid produced softens the character of the sake, and the increased microbial activity promotes fermentation, which also contributes to improving the sake's flavor.