Put cooked black rice and water in a large bowl and mix. The amount of water is just enough for the rice to soak.
Put 100 g of rice koji to the mixture in step 1, stir well. Add more water to make it warm.
Put in a container (fermentor or yogurt maker) and set the settings. Incubate at 55-60 ° C for 6-8 hours.
When the texture is gloopy and have sweet flavor, the black rice amazake is ready to serve.
Notes
You can cook the amazake using the mix of cooked black rice with brown rice, too.The nutrition of brown rice is the same, and the fermentation power from rice koji will boost the nutrients. It is sweet and easy to drink.