What You Need to Know
Lactic acid bacteria (LAB) including Lactococcus lactis subsp. lactis/cremoris convert lactose into lactic acid at 20-30°C, lowering pH to 4.5-4.8 while producing diacetyl and acetaldehyde.
Creates thickened, tangy cultured dairy products with superior flavor complexity compared to thermophilic fermentation.
Key Parameters
Temperature
24°C
20°C - 30°C
Time
18-24 hours
12 hours - 48 hours
Equipment
Non-reactive container (glass/ceramic)Cheesecloth/muslin coverDigital pH meter
Steps
- 1.
Crème fraîche (Normandy): Develops characteristic nutty aroma and spoonable viscosity
- 2.
Filmjölk (Sweden): Creates drinkable texture while preserving live cultures
The Science
Primary Reaction
C12H22O11 (lactose) + H2O → 4 C3H6O3 (lactic acid)