Place rice koji and all other ingredients in a clean yogurt maker container. *2
Stir well to mix all ingredients.
Place the yogurt maker container in the yogurt maker.
Set the yoghurt maker at 58°C for 8 hours and press start.
After 8 hours, transfer the koji seasoning into a clean container to store in a fridge. *3
Notes
*1 amount of salt is 13% of weight of rice koji and water.*2 I used a yogurt maker. It can be also just left in room temperature for a week to ferment. If you use this method, you need to stir them daily. *3 If you prefer smooth texture, it can be blitzed by a hand held blender. *Nutrition Fact is for Salt Koji Seasoning.