Koji basics
How to Make Shio Koji (Room Temperature / Yogurt Maker)
Shio koji is a Japanese seasoning made by fermenting rice koji with salt and water. Use it in place of salt for a soft, rounded umami — it also keeps meat and fish moist. About 1–2 weeks at room temperature, or about 6 hours in a yogurt maker at 60°C.
- Serves
- Makes about 500 g
- Time
- 10 minutes to prepare (1–2 weeks at room temperature, or 6 hours in a yogurt maker)
Ingredients
- Rice koji (fresh or dried)200 g
- Salt (natural sea salt)60 g
- Water250–300 ml
Method
- If the koji is in clumps, break it up with your hands in a bowl. Add the salt and mix well, rubbing the koji between your palms.
- Add the water and mix. The koji absorbs water, so add enough that a little water shows on the surface (use a little more water with dried koji).
At room temperature
- Transfer to a clean jar and rest the lid on loosely (do not seal it). Keep it at room temperature out of direct sunlight, and stir from the bottom once a day with a clean spoon. If the water level drops and koji shows above the surface, add a little more water.
- It is ready in about a week in summer, or about two weeks in winter — when the grains are soft enough to crush between your fingers and it smells sweet.
In a yogurt maker
- Put everything in the container, close the lid and set it to 60°C for 6 hours. Stir once halfway.
When it is ready (both methods)
- Close the lid and keep it in the fridge. For a smooth paste, blend it with a hand blender.
Tips
- Rice koji is steamed rice grown with koji mould (Aspergillus oryzae). Look for it, fresh or dried, at Japanese grocery stores or online.
- Shio koji is about 10–12% salt. As a guide, use about 2 tbsp shio koji in place of 1 tsp (about 5 g) salt.
- Coat meat or fish with shio koji before cooking: the koji enzymes work on the protein, so it stays moist and does not toughen as easily.
- Shio koji burns easily, so cook with slightly lower heat than usual.
- In a yogurt maker, do not go above 60°C. If it gets too hot, the koji enzymes stop working.
- Keeps for about 3 months in the fridge. If coloured mould appears on the surface, throw it away.
Shio koji is the most basic koji seasoning. Simply use it instead of salt and your cooking gains a soft, rounded umami. We use it in many &LAB TOKYO recipes, such as Shio Koji Acqua Pazza, Shio Koji Veggie Fried Rice and Kabocha Potage with Shio Koji. For soy sauce koji, see How to Make Shoyu Koji.
In UMAMI & KOJI LAB in Tokyo, you learn how koji works and make koji seasonings like this by hand to take home.
