Make Your Own Koji
Known in eastern Asia for over 2000 years, koji is a fungus from the genus Aspergillus that is essential for making things such as sake, miso, amazake, and soy sauce.
Material:
- Incubation chamber of your choice kept between the temperatures of 27 - 35°C. (Ex. an oven with the light on with the door slightly ajar)
- Large glass or stainless-steel dish
- Steamer
- Strainer
- Thin cloth
- Plastic wrap or aluminum foil
- Thermometer
- Spray bottle (optional)
Note: All utensils must be sanitised with boiling water or alcohol prior to use.
Ingredients:
- 2 2/3 cups (525 g) long-grain rice (ex. basmati)
- 2 tablespoons (20 g) all-purpose or rice flour
- ½ teaspoon (1 g) koji spores
Instructions:
- Rinse rice until water runs clear. Soak in water for 8-12 hours. Drain for 2 hours.
- Envelope rice in cloth and steam for 45-60 minutes on medium heat. Starting at 45 minutes, check the rice for doneness. It should be al dente.
- While the rice is cooking, toast flour on low heat until it changes color. Remove from heat, cover and let cool. Mix koji spores with the flour.
- Once ready, immediately transfer cooked rice to your tray, spread to achieve a maximum thickness of 4 cm, cover, and let cool to 43°C.
- Distribute koji flour evenly over the rice and mix well. Cover tray with film and poke just a few holes throughout.
- Place in incubation chamber along with a bowl of warm water inside to maintain humidity.
- After 12 hours, check the internal temperature of the koji. If it’s getting close to 35°C, mix koji to cool it down and lower the heat in your incubation chamber. If it’s under 27°C, warm up your incubation chamber. If it’s too wet, remove the covering. If it’s too dry, spray with filtered water and mix. Continue checking koji every 12 hours.
- Koji will be ready after about 40 hours of incubation. The rice should be covered in white fluffy mycelium. It should smell like brie cheese. It should not smell sour or bad. Do not leave it long enough that it starts to sporulate and become yellow or green.
- Mix it up to break up the clumps.
Storage:
- Place in the fridge for use within the next 10 days.
- Place in the freezer for use within 2 months.
- Dehydrate at 30°C for about 7 hours. Can be kept in the refrigerator for up to 6 months.
Buy koji spores HERE
Adapted from Miso, Tempeh Natto & Other Tasty Ferments by Kirsten K Shockey & Christopher Shockey
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