Lacto-fermentation — the anaerobic fermentation of vegetables, fruits, or other foods in a salt solution by naturally occurring Lactobacillus bacteria — is the oldest and most universal food preservation technique in the world. The Noma Guide's contribution is the systematic, laboratory-level documentation of the process: the bacterial ecology, the salt percentage curve, the pH progression, and the specific fermentation conditions for different substrates. Where traditional recipes say "ferment until sour," the Noma Guide gives pH targets, temperature ranges, and bacterial succession maps.
**The salt percentage:** - 2–3% salt by weight of the water (not the total weight) is the standard range for most lacto-fermentations. - Below 1.5%: too low to suppress pathogenic bacteria — the fermentation is unsafe. - 3–5%: slower fermentation, longer shelf life, saltier result. - Above 5%: inhibits even Lactobacillus — the fermentation stalls. - [VERIFY] Noma's specific salt percentage ranges for different substrates. **The bacterial succession:** - The fermentation proceeds through a succession of bacterial populations, each creating the conditions for the next: - Initial aerobic bacteria deplete oxygen - Leuconostoc and Weissella establish the initial lactic acid environment - Lactobacillus brevis (heterofermentative) produces CO₂ and lactic acid - Lactobacillus plantarum (homofermentative) dominates the later stages, producing a stable, consistently sour environment - The pH progression: starting at 6.5–7.0, falling to 3.5–4.0 by the end of active fermentation **The temperature:** - 18–22°C: optimal for most vegetable lacto-fermentations - Higher temperature: faster fermentation, less complex flavour development - Lower temperature: slower, more complex, better for long fermentations **The seal:** - Anaerobic conditions required: the fermentation vessel must exclude oxygen. Traditional: brine covering the vegetables. Modern: vacuum sealing or airlocks.
Noma Fermentation