Fermentation

Thu, 09 Apr 2026 00:00:00 +0100

Fermentation

Fermentation is the transformation of food by microorganisms — yeasts, bacteria, and molds. It is one of the oldest and most consequential food technologies: bread, cheese, yogurt, wine, beer, soy sauce, vinegar, chocolate, coffee, and kimchi are all fermented foods. In every case, microbes do work that humans cannot — breaking down complex molecules into simpler, more flavorful, more digestible, or more preserved forms.

The basic mechanism

Fermentation in the strict biochemical sense is anaerobic metabolism — organisms extracting energy from sugars without oxygen, producing alcohol or organic acids as byproducts. In culinary use, the term is broader, encompassing any microbial transformation of food.

Yogurt and Fermented Dairy

Thu, 09 Apr 2026 00:00:00 +0100

Yogurt and Fermented Dairy

Fermented dairy products — yogurt, sour cream, crème fraîche, kefir — are milk or cream transformed by lactic acid bacteria. The bacteria convert lactose to lactic acid, which drops the pH, coagulates casein proteins, thickens the liquid, and generates tangy flavor. The result is more digestible (lower lactose), longer-lasting (acid inhibits pathogens), and more flavorful than the starting milk.

The fundamental reaction

Lactic acid bacteria (LAB) — primarily Lactobacillus and Streptococcus species — consume lactose and excrete lactic acid. As pH drops from milk’s neutral 6.6 toward 4.5, casein micelles lose their electrical charge, clump together, and form a gel that traps water. This is the same acid coagulation used in fresh cheese making, just stopped at a different point.

Bacteria on Kvalifood

Fermentation

Fermentation

The basic mechanism

Yogurt and Fermented Dairy

Yogurt and Fermented Dairy

The fundamental reaction