How to Make Doubanjiang
Doubanjiang (豆瓣酱) is a spicy, fermented chili bean paste that's fundamental to Sichuan cuisine. Made from fermented broad beans (or soybeans) and chilies, it develops intense umami, heat, and complexity over months of aging. This 'soul of Sichuan cooking' transforms dishes with its deep, savory-spicy flavor.
Category: Legumes & Soy · Method: Fungal/Mold · Time: 3-12mo · Difficulty: 3/5 · Yield: varies · Temp: 18-22°C
History
Doubanjiang originated in Pixian, Sichuan Province, China, with a history of over 300 years. The region's climate is ideal for fermentation, and Pixian doubanjiang remains the gold standard. The paste evolved alongside Sichuan's famous spicy cuisine, becoming inseparable from regional cooking identity.
Ingredients
- 400g Dried broad beans (fava beans) — Peeled and split broad beans are traditional for Pixian style.
- 100g Wheat flour — Essential substrate for the koji mold to colonize the beans.
- 180-200g Sea salt — Non-iodized. Aim for 15-20% total weight to ensure shelf stability.
- 400g Dried red chilies — Er Jing Tiaos or Facing Heaven chilies, coarsely chopped.
- 2g Koji starter (Koji-kin) — Aspergillus oryzae spores.
Equipment
- Fermentation crock or jar
- Large pot for cooking beans
- Grinding equipment
- Incubation setup
- Wooden spoon for stirring
Instructions
Prepare beans and inoculate
Soak broad beans until hydrated, then steam until tender but firm. Drain and cool to 30°C. Toss the damp beans in wheat flour and koji starter until each bean is thoroughly coated in a dry-ish layer. This flour provides the starch necessary for the mold to thrive.
Time: 24 hours
Tip: The flour coating prevents the beans from clumping and provides the primary food source for the Aspergillus oryzae.
Koji Incubation
Spread the flour-coated beans on bamboo trays. Incubate at 28-30°C with high humidity for 48-72 hours. The beans are ready when they are completely covered in a yellow-green fungal mat (the 'douban-qu').
Time: 2-3 days
Tip: Turn the beans halfway through to ensure even airflow and prevent overheating.
Brine and Chili Mix
Mix the chopped chilies with the salt. Combine the mold-covered beans with the salted chilies. If the mixture is too dry to incorporate, add a very small amount of 20% salt-water brine. The consistency should be a thick, heavy paste, not a liquid mash.
Time: 1 hour
Tip: Avoid excess water; the moisture should primarily come from the chilies to prevent lactic acid souring.
Fermentation and Sunning
Place in a ceramic crock. Traditionally, the crock is left outdoors: 'Exposed to the sun by day, and the dew by night.' Stir daily to ensure even fermentation and evaporation. The high salt content (15%+) and solar heat are critical for safety and flavor development.
Time: 3-12 months
Tip: The temperature will fluctuate with the sun, often reaching 35°C, which accelerates enzymatic breakdown.
Fermentation Timeline
- Week 1: Koji on beans — Beans develop koji mold. Nutty, sweet aroma.
- Month 1-2: Initial fermentation — Beans and chilies melding. Active bubbling. Strong aroma.
- Month 3-6: Flavor development — Deep red color. Complex heat. Umami building.
- Month 6-12+: Maturation — Flavors mellow and deepen. Restaurant-quality paste.
Signs of Success & Spoilage
Good signs
- Deep mahogany or dark reddish-brown color
- Rich, savory, miso-like aroma with chili heat
- Thick, jam-like consistency
- Salt crystals may be visible
- pH level below 4.6
Warning signs
- Black or fuzzy mold on surface
- Putrid or ammonia-like odors
- Sour, vinegary taste (indicates too much water/low salt)
- Active bubbling (indicates unwanted yeast fermentation)
Troubleshooting
- Souring or bubbling
- Cause: Salt ratio too low or moisture too high Solution: Increase salt concentration immediately to 18-20%. Ensure the vessel is in a sunny, warm spot to encourage evaporation.
- White film on top
- Cause: Kahm yeast from lack of stirring Solution: Scrape off the film and stir the paste thoroughly. Ensure the surface is pressed flat after stirring.
Storage
Ceramic crock or glass jar Keeps Years at room temperature; indefinitely refrigerated. Ages beautifully. Clean utensils prevent contamination.
Health Benefits
- Capsaicin (metabolism, pain relief)
- Protein from beans
- Probiotics (if unpasteurized)
- Vitamins A and C from chilies
- Iron
- Antioxidants
Serving Suggestions
- Mapo tofu (essential ingredient)
- Dan dan noodles
- Twice-cooked pork
- Stir-fry base
- Hot pot dipping sauce
- Fried rice seasoning
Related Legumes & Soy Ferments
Other Fungal/Mold Ferments
- Miso — Condiment
- Furu (tofu cubes) — Legumes & Soy
- Tempeh gembus — Legumes & Soy
- Stinky tofu — Legumes & Soy
- Blue cheese — Dairy
- Brie — Dairy
- Camembert — Dairy
- Roquefort — Dairy