Fermentation
The use of microbes such as yeasts, bacteria and moulds to change food, adding flavour and helping it keep.
Also: fermenting
In fermentation, tiny living things feed on the sugars and other parts of a food and turn them into acids, alcohol, gas and many flavour compounds. People have used it for thousands of years to preserve food and make it tastier or easier to digest. Bread, yogurt, cheese, beer, wine, vinegar, soy sauce, miso, kimchi, idli and chocolate all depend on it. The acid or alcohol produced also stops harmful microbes from growing.