Definition of fermentation
1a : the enzyme-catalyzed anaerobic breakdown of an energy-rich compound (such as a carbohydrate to carbon dioxide and alcohol or to an organic acid) by the action of microorganisms (such as bacteria or yeast) that occurs naturally and is commonly used in the production of various products (such as food, alcoholic beverages, and pharmaceuticals) especially by controlling microbial enzymatic activity The wine then undergoes a long fermentation that results in a high alcohol content (15 to 17 percent) and a dry wine.— Kim Marcus The panda is quite unlike most other herbivores, however, whose digestive tracts contain bacteria and protozoans that break down hard-to-digest plant materials through fermentation.— Miriam Levine Helbok During a starter's fermentation, yeast produces alcohol, carbon dioxide, and sulfur compounds, all of which contribute to good bread's unique flavor.— J. Kenji Alt Cultured butter is made from cream in which fermentation—the conversion of milk sugars into lactic acid—has begun to take place.— Ben Mims broadly : any of various enzyme-catalyzed aerobic or anaerobic processes (such as oxidation) involving transformation of organic compounds Most of the catechins are oxidized during the natural fermentation process that converts fresh green tea leaves to black tea. — Food & Fitness Advisor Tobacco fermentation is basically highly controlled composting, and releases many chemicals and impurities that would otherwise ruin the tobacco's flavor. — Tad Gage
b : an instance or occurrence of fermentation The process is simplicity itself—a couple of fermentations, a gradual tilting of the bottle to remove the sediment and a final addition of sugar to make it brut or doux.— Miles Kington The ancient Chinese also stored vegetables in a pickling brine with a vinegar base. Various vinegars, made from fermentations of rice, wheat, grapes, or even peaches, were used.— Nina Simonds
2 : ferment sense 2 Music concerts, poetry readings, and other progressive campus activities can produce intellectual fermentation and thought provoking ideas.— Robert Hoffman
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