Zymology

Zymology is the science of fermentation, including the microorganisms and biochemical processes that transform sugars and other compounds into alcohol, acids, gases and flavour-active substances. It is relevant to winemaking, brewing, baking, distilling and the production of fermented foods such as yoghurt, vinegar, sauerkraut and sourdough.

Microorganisms and fermentation

Yeasts, bacteria and other microorganisms carry out different fermentation processes. Yeast can convert sugars into ethanol and carbon dioxide during alcoholic fermentation. Lactic acid bacteria convert sugars into lactic acid in cultured foods and can convert malic acid into lactic acid during wine malolactic fermentation. Acetic acid bacteria produce acetic acid under suitable conditions.

Applications in food and beverage

• Winemaking and brewing: yeast converts fermentable sugars into alcohol and carbon dioxide.
• Bread making: yeast produces carbon dioxide that leavens dough; sourdough also involves lactic acid bacteria.
• Fermented vegetables: lactic acid bacteria acidify vegetables and contribute flavour and preservation.
• Vinegar production: acetic acid bacteria convert ethanol into acetic acid in the presence of oxygen.

Example: understanding zymology helps a baker manage sourdough fermentation and a winemaker control yeast activity during alcoholic fermentation.

Zymology versus microbiology

Zymology focuses specifically on fermentation and its processes. Microbiology is the broader study of microorganisms, including those involved in fermentation as well as pathogens, spoilage organisms and environmental microbes.

Chef’s note: fermentation is a controlled biological process. Food-safety, temperature, acidity, salt and time controls are essential when producing fermented foods.