Learn how to Make Natto at home three ways with this easy step-by-step recipe!

Ways to Enjoy Natto (COMING SOON!)

  • How to Eat Natto
  • Natto Monjayaki
  • Natto Kimchi Don
  • Natto Bibimbap
  • Natto Mochi
  • Natto Jiru

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How to Make Natto

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5 from 9 reviews


Learn how to Make Natto at home three ways with this easy step-by-step recipe!


Units Scale

Natto from scratch (bacteria starter)

Natto from frozen pack

  • 1 pack of frozen natto (or 60g from previous natto)
  • ~380g dry soy beans
  • 1 tbsp filtered water

Natto from previous batch 

  • ~400g cooked soy beans
  • 60g natto from previous batch


  1. Soak the soy beans overnight– it should expand and look plump. 
  2. Discard the water and then cook the soy beans in an instant pot, pressure cooker or over the stove until tender. 
  3. Lay cling wrap on a tray or shallow tupperware (this step is not essential but helps immensely with the clean up process). Sterilize any utensils and bowl with hot water to remove any bacteria. Drain the soybeans well and then add the soy beans to the tupperware.
  4. Add 1 tbsp of filtered water into the pack of natto and mix to loosen. Then spread the natto over the soy beans and mix well. If using the starter, sprinkle the starter over and mix. If using previous batch, add the natto and mix well. Cover with paper towel, cling wrap and then elastic bands to secure.
  5. Place in a yogurt maker, fermentation box or a warm area at 40 C for 24 hours. The next day, place into the fridge and continue to ferment for another 24 hours.
  6. The natto is complete! Store in the fridge for up to 2 days or transfer to portioned size freezer safe reusable bags or tupperware. When ready to eat, thaw in the fridge and enjoy!
  7. You can repeat this process maximum 3 times with previous natto. Then you must use the frozen store bought natto (because the bacteria is stronger). 


  • Prep Time: 15 minutes
  • Cook Time: 30 minutes
  • Category: basics
  • Method: fermenting
  • Cuisine: japanese


  • Serving Size: 1 serving (60g)
  • Calories: 120


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About Lisa

I'm Lisa, a home cook, recipe developer and founder of Okonomi Kitchen. Here, you'll find a mix of classic and modernized Japanese recipes, and creative, plant-forward meal inspiration using seasonal ingredients. I hope to share more about Japanese cuisine and culture through food and recipes.

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  1. Hi, thanks for sharing how to make natto at home, could you show me how to make video please, many thanks…..

  2. I give this recipe a 10 out of 10.
    I thought I ruined it because my oven on low/warm registered 140F (which is not the 100F or 40C in the recipe) but this is very forgiving. Very much like yogurt making.
    I stirred it after 24 hours, expecting to add another store bought portion of Natto, but NO. It was gooey and had all the consistency and taste of the natto I’ve been loving since living in Japan 20 years ago. I eat it regularly so this will save me quite a bit of money.
    The beans are still cream colored and not the dark brown that you get when you buy the frozen. Not sure if they will change once frozen. But the taste was delicious, same as what I have been eating.
    Can’t wait to try other beans as I saw a Korean black bean version of natto. After 24 hours in the fridge, I’ll make a batch of rice and add Asian mustard, soy sauce and green onions. I perfect lunch with a cup of miso soup.
    I wish I could attach my pictures of the gooey strands that make natto what it is. It will froth up just as expected. A high protein, K2 gut health packed snack or meal.

    1. Meredith,
      Thank you for posting about temps! You’ve given me the courage to try this as I find my yoghurt makers can sometimes run high etc. Like 60C has killed my yoghurt bacteria in the past, so I was worried.

      I think I can actually do this. I’ve never tried natto, but at least I’ll know what’s in it and who made it. Also comforting to know I can freeze it.

  3. Perfect but…I avoid plastic and heat so instead of putting the natto into Tupperware or wrapping in plastic I just kept it in the instapot on yogurt setting after adding frozen natto. Clean up was still extremely easy, it just slid out. It tasted perfect and made me so happy! Wait, one more thing why do you discard the eater after soaking. Is it impurities on the beans? It doesn’t say to add more water to the instapot to make them tender but I assumed that one should so I did and it worked.

  4. hi, I’ve seen other recipes that just call for cooking beans (after soaking etc.) and since I don’t have an instant pot, I usually cook my pinto beans in my crock pot…I could do the same. here right? all you need are cooked beans to go into the recipe right? of course I need water in the crock pot, I can use a minimal amount….but should that water then be drained out as I’ve seen also in other recipes, or just use beans with cooked liquid, does that matter really? wouldn’t one way produce wetter beans than the other….but still fermented the same right? tia

  5. Hi! I made a batch and used more than 0.1 g of natto starter be it’s just hard to measure😅 when the natto came out of the second fermentation period in the fridge, it was very nice & sticky but not yet as flavorful as store-bought natto. Then I ate it the next day after putting it in the fridge again and all the stickiness was gone! The flavor was great but I really miss the stickiness. Did I use too much of the powder? Or did I do sth else wrong? Like maybe my yoghurtmaker does not work well? Another batch I made right after also came out not sticky. Thank you for your wonderful recipes Lisa!

  6. When making this recipe double, do you have to double the starter? In wine I just use yeast of 1 packet and it will grow as needed

  7. “You can repeat this process maximum 3 times with previous natto”

    In most fermented products, we always can use the previous one as yeast. Why 3 times?
    Is it okay if we keep the previous one in the deepfreeze and use it as starter?

    1. I have the same question since you can always use previous starter when making sourdough and ginger bugs. Why only three times with previous natto?

      1. I experimented with this and sometimes i got strange smells, i think when using the previous batch as a starter there is increased probability of catching some undesired bacteria instead of pure bacillus subtilis

  8. Thank you for the recipe . Can I get the same result using cheap peas instead soya beans. ?


    Sergio vinhal

  9. Hi, I got a packet of natto starter from amazon, and it is 0.1 oz. I just noticed that your recipe calls for 0.1 g. I had used the whole packet. Did I use way too much of the starter?? I used the whole packet. 🙁