The conversion of organic matter to methane, carbon dioxide and other molecules by anaerobic bacteria. The fermentation process has about three primary forms:

  • Acetic acid fermentation - converts grains, fruit or starches into bitter tasting condiments or vinegar. This process is the reason for the differences between regular apple cider and apple cider with vinegar
  • Ethanol fermentation - occurs when the molecules in sugars or starches are dissolved by the yeasts into carbon dioxide molecules and alcohol to produce beer or wine
  • Lactic acid fermentation - converts sugars and starches through the workings of bacteria and yeasts to produce yoghurt, pickles, sourdough bread and other foods with metabolite lactate yeasts and bacteria convert starches or sugars into lactic acid in foods like sauerkraut, kimchi, pickles, yoghurt and sourdough bread.

These fermentations are specialized in producing their own products through specific substances through the workings of microbes.