Rinse the mixed grains thoroughly.
Soak the rinsed grains for about 30 minutes.
Add the soaked grains and water to a pot or rice cooker.
Bring to a boil over high heat, then reduce to medium heat once it starts boiling.
Simmer for 30–40 minutes until the grains are cooked through.
Place the cooked mixed grains in a bowl to serve.