Lactic fermentation is a biological process in which lactic acid bacteria convert available sugars into lactic acid and, depending on the microorganisms and conditions, other flavour compounds and gases. The acid lowers the pH of the food and contributes the tangy flavour associated with many fermented vegetables, dairy products and cured foods.
Lactic acid bacteria use sugars as an energy source and produce lactic acid. As acidity increases, the flavour changes and the environment becomes less favourable to many spoilage organisms. The organisms present, salt level, temperature, oxygen exposure and ingredient composition influence the speed and character of fermentation.
Fermentation is not automatically safe because a food tastes sour or contains salt. Use a tested recipe, appropriate ingredients and clean equipment; control salt concentration, temperature, time, pH and oxygen exposure as specified by the process. Keep vegetables submerged when the recipe requires it, use suitable fermentation vessels and follow validated storage and refrigeration instructions. Do not rely on a generic salt percentage as a universal safety guarantee.
Chef’s tip: Record the batch formula, fermentation temperature, time and pH where required. A consistent process is more reliable than judging readiness by smell or taste alone.
Key distinction: Lactic fermentation produces lactic acid through bacterial activity; alcoholic fermentation converts sugars primarily into ethanol and carbon dioxide through yeast activity.
This term is one of hundreds covered in depth across OCS courses, learning paths, and 1-on-1 coaching with Chef Eric.
