how to make nattō in an instant pot

(Due to the popularity of our post on DIY homemade nattō, there have been requests for us to share detailed instructions on how we make nattō in our Instant Pot.)


5 from 1 vote
diy homemade natto - how to make natto in an instant pot
Instant Pot Nattō
Prep Time
18 hrs
Cook Time
22 hrs
Total Time
1 d 16 hrs

Healthy, homemade nattō made using an instant pot .

Course: Side Dish
Cuisine: Japanese
Keyword: instant pot, natto
Servings: 12
Author: Holly White -
  1. Rinse and drain two cups of soybeans and place in a large bowl.    
  2. Fill the bowl with water, covering the beans by about an inch (3 parts water : 1 part beans).
  3. Cover with a clean cloth or dish towel to keep out dust and soak overnight (approximately 12 to 18 hours).
  4. Drain and rinse the beans again with fresh water.
  1. Place the beans into the Instant Pot and add in about 3 cups of water (enough to cover the beans).
  2. Set the pressure vent to “seal.” Cook the beans on “Manual” for 20 minutes, then allow the pressure to come down naturally for 10 minutes.
  1. While the beans cook, lay out anything that will come in contact with the beans on a cooling rack and slowly pour boiling water over them.
  2. Don’t dump out the remaining water, you’ll need about two teaspoons to activate the nattō cultures in the next step.
  1. Just before releasing the remaining pressure from the pot (after the 10 minute natural release), add one spoonful of the nattō spores to the small glass mixing bowl using the small spoon that comes with the spores.
  2. Add two teaspoons of sterilized water and mix with a sterile spoon..
  3. Open the pressure release valve. (I recommend covering it with a cloth to keep the hot water from splashing).
  4. Then remove one bean for testing. It should be soft in the center and able to be smashed between your fingers with gentle pressure. If it's too mushy, the beans are overdone and will not be usable for nattō.
  5. Carefully remove the soybeans (without touching them), and add them to the large mixing bowl.
  6. Add the nattō starter culture mixture to the beans and gently but thoroughly mix.
  7. Remove the remaining water from the Instant Pot, replace the steamer basket, and then add the beans back into the basket. The beans should only be piled about 3 beans high to allow for maximum surface area exposure during fermentation.
  1. Cover the beans with the sterilized cheesecloth (or dishtowel) and then put on the glass lid. This will keep the beans moist, but prevent condensation from dropping on the beans.
  2. Set the Instant Pot to the "YOGT" setting for 20 to 24 hours. The temperature should remain between 90 and 104 F (30 - 40 C). Even though the Instant Pot does a good job of maintaining the temperature, I like to keep the thermometer in the pot and check it every so often.
  1. Once the cycle is finished, let the beans cool for a few hours.
  2. Then place the beans in the refrigerator to “age” for one to three days. This will slow down fermentation and enhance the flavor.
Recipe Notes

We usually put the nattō in two separate containers before aging so that once complete, we can keep one in the fridge to eat within the week and then store the other in the freezer for later.

Also, if you notice your nattō is not very sticky, you may need to get a fresh batch of spores.  Good luck and enjoy!

how to make nattō in an instant pot

As you read and try out our recipe please keep in mind this is a work in progress.  We are still experimenting and trying new tweaks.  Please share your findings in the comments below to help us all in the never ending quest to make that perfect batch of delicious homemade nattō!

One thought on “how to make nattō in an instant pot”

  1. David says:

    testing review feature…

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