Fungal/Mold Fermentation

Fungal fermentation uses molds like Aspergillus and Rhizopus to transform foods through enzymatic action.

Overview

Fungal fermentation employs molds to produce enzymes that break down complex proteins and starches. Koji (Aspergillus oryzae) is essential to Asian fermentation, while Rhizopus molds create tempeh. These fungi don't directly produce flavors but create conditions for other transformations.

The Science

Mold fermentation works through enzyme production rather than metabolic byproducts. Aspergillus oryzae produces amylases (which break down starches into sugars), proteases (which break down proteins into amino acids), and lipases (which break down fats). These enzymes do the actual work of transformation. The mold itself provides the enzyme factory.

Common Foods

  • Koji (for sake, miso, soy sauce)
  • Tempeh (Rhizopus molds)
  • Blue cheese (Penicillium molds)
  • Miso and soy sauce (koji-based)
  • Amazake (koji-fermented rice)

Tips

Mold cultivation requires specific conditions - high humidity (80-95%), controlled temperature (85-95°F for koji), and clean environment. Mold sporulation (visible as green or white fuzz) is normal. Work with food-safe mold strains only.

Temperature Guide

  • Koji incubation (start): 86-90°F (30-32°C) — Initial spore germination period
  • Koji incubation (peak): 95-104°F (35-40°C) — Mold generates heat; monitor closely
  • Tempeh incubation: 85-90°F (29-32°C) — Rhizopus requires consistent warmth
  • Cheese mold ripening: 50-55°F (10-13°C) — Slower, controlled mold development

Troubleshooting

Mold not growing
Check temperature and humidity; spores may not be viable
Black or green contamination
Wrong mold species; discard and sterilize equipment
Koji too dry
Increase humidity; mist lightly or cover with damp cloth
Tempeh has black spots
Spore formation - normal if rest of tempeh is white
Ammonia smell from tempeh
Over-fermented; use sooner next time

Required Starters

  • Aspergillus oryzae spores (koji-kin) for koji
  • Rhizopus oligosporus spores for tempeh
  • Penicillium roqueforti for blue cheese
  • Penicillium camemberti for soft-ripened cheese
  • Purchase from reputable suppliers - wild molds can be dangerous

Ferments Using This Method (49)