Step 1 Place koji in a medium non-reactive bowl or container and add sea sea.
Step 2 Mix thoroughly and vigorously, using your hands.
Step 3Heat water to 140 degrees; add just enough to moisten.
Step 4Knead till fragrant. Mix in rest of hot water.
Step 5Store loosely covered for 1 week at room temperature. When ready, the koji rice grains will be smaller; mixture will have consistency of loose porridge. Refrigerate covered for up to 6 months.