What You Need to Know
During fermentation, lactic acid bacteria metabolize lactose to lactic acid and CO₂, while yeasts convert sugars to ethanol and trace gases. The polysaccharide kefiran is secreted by the bacteria, forming the grain matrix and contributing to the beverage’s viscosity. The combined metabolic activities lower the pH to 3.8–4.5, creating a tangy, slightly effervescent drink.
The Science
Primary Reaction
lactose → lactic acid + CO₂ (by LAB) + ethanol (by yeasts)