Step 1

Rinse the rice until the water runs clear (to remove all the starch).

Step 2

Soak the rice in water for 8-12 hours.

Step 3

Steam (not boil) the rice until it’s softened, but still sticky (see notes for advice).

Step 4

Cool the rice to room temperature.

Step 5

Thoroughly mix the koji-kin culture into the rice.

Step 6

Spread the rice out on a baking dish. Cover with a damp cloth (to keep it moist but not wet) and maintain at 90 F (30 C) for 48 hours.

Step 7

Stir every 12 hours to break up the clumps and evenly distribute moisture. After 48 hours, white mold fibres should have started to develop. Stop at this point or it will spore.

Step 8

Store koji rice in the freezer until you are ready to use it.

Step 9

See below for incubation options and to learn how to save your own koji-kin mold spores for future batches.