Instructions

1. Rinse the soybeans under cool water and put them in a glass bowl. Cover the soybeans with water and stir them with your hands for 20 seconds to clear any debris.

2. Drain the water and clean the soybeans once more. Rinse the soybeans under cool running water and place them in a bowl.

3. Cover the soybeans with 3 times as much water and let them stand overnight, or for 12 hours.

4. Drain the beans in a stainless steel colander and put it in the pressure cooker. Pour 1 cup of water into the pressure cooker.

5. Put the lid on the pressure cooker and place it on the stove. Set the heat to high and lower it to low when the pressure cooker hisses.

6. Cook the soybeans on low for 45 minutes, then remove the cooker from the stove. Place the pressure cooker in the sink and run cold water over it until the lid unlocks.

7. Add 1 cup of natto-kin for every 1 cup of soybeans and quickly mix them together using a spoon. Remove the air-hole cover from the pressure-cooker lid and cover the cooker with it.

8. Put the cooker in a picnic ice-chest and cover it with an electric heating pad. Turn the heating pad on and allow the natto to ferment for two days.

9. Move the natto to the refrigerator and allow it to age for 3 days. You can eat natto after a few hours in the fridge, but it tastes best after aging.