Natto: Make-It-Yourself Recipe

Vegans and Vegetarians (and omnivores!) rejoice! Here is a simple way to make your own natto!
It does require a little sneaky trick for the first batch (like for yoghurt) but from the second batch it will all yours and only yours!
As usual, as this is a basic recipe, I willl explain step by step, and mentioning the quantities on the way!

Firts the soy beans (daizu/大豆 in Japanese).
Use a large vessel as you will need 2 to 3 times as much water: 1 volume of soy beans + 2~3 volumes of water.
Make an effort touse clean cold water!
Let the the soy beans soak overnight.

You will discover that after a night of soaking the soy beans will have changes in shape from round to elongated!

Next you must steam the soy beans (preferably the slow way) for three hours to get them soft, otherwise they will not ferment. You may use a pressure cooker, but you will have to expperiment!

Important point: From now on, especially, make sure that all vessels and utensils you use are properly boiled in hot water first to kill all germs, or you will end with a yeast/germ/mold battlefield!
Use a large metal shallow vessel for even wieght and spread.
Transfer the steamed soybeans on eat as shown in above picture.
Be aware that the smell will be strong, so choose your room!

Now, for the all-important “sneaky” trick!
The beauty of it is that from the second batch you will use your own batto! Friends with some knowledge in yoghurt or Japanese sake fermentation will easily understand!
Drop a few grains of natto bought at the market in half a cup of water/ 100~cc/ml. (use high quality non-gaseous mineral water!)
After stirring 2 or 3 times, the water should start turning whitish. This is your yeast/fermentation starter!

Carefully pour the fermentation starter (with the natto beans) evenly all over the steamed soy beans.

Cover/wrap the whole with cellophane paper. Punch small holes (about 20) with a toothpick to allow ventilation.

Tap the cellophane paper so as to keep it close in contact with the soybeans. Do not press.

Now, the whole important thing: the temperature!
Like for Japanese Rice fermentation, it must stay between 30 and 40 degrees Celsius. There are many ways to do it if you do not have the right room for it: use a hot water bottle (above) put nearby and cover it with a blanket, or put it under a heated blanket….

keep checking the temperature!

Let ferment for 20 hours.
Upon lifting the cellophane paper, the natto should show white filaments.

Here is the finished product!
True to tell, home-made natto might not as “sticky” as natto bought in markets, but this is still true natto.
Actually, the lack of “stickiness” might be be a blessing for some!

Keep in mind this is a true food, especially for vegans and vegetarians who are in more need of nutrients than omnivores!

21 thoughts on “Natto: Make-It-Yourself Recipe”

  1. Ah, I wish it were so…I stirred and stirred, and not a thread appeared. I think the beans were not soft enough after pressure cooking. I already have my next batch soaking. I’ll change up a few things and maybe the next batch will be better. *sigh*


  2. Thanks for your quick reply!
    Please allow me to clarify: if I make a large amount of beans, but do not use them all at once to make natto, say I use only half of them – the extra beans NOT mixed with the natto starter, just soaked and steamed – if I freeze these BEFORE mixing with natto starter, and use them some time in the future, (defrost, heat up, mix with natto starter, ferment) will that be OK? Thanks for your patience!


    1. Dear Jackie!
      No, actually, you have to make the whole natto first and freeze it all. Frozen cooked beans will not work well because of the water inside the beans breaking the texture!
      best regards,


  3. If I make a large amount of beans, but don’t want to use all of them for a batch of natto, can I freeze them? Then when ready, defrost, heat them up and then add natto starter and make a batch to ferment? I’m planning on using a natto maker machine, which only holds 1 liter (about 1 quart). It’s a lot of work and time to process the beans to get them to the point of adding natto starter, so I thought freezing the excess and using them later might work. What is your opinion?

    Also, OK to substitute regular black beans or garbanzo beans instead of soy beans? Thanks!


    1. Dear Jackie!
      Freezing natto is no problem. Make sure the packagng is as airtight as possible.
      I’m afraid only soy beans can be made into real natto, but you never know. It all depends on taste, texture, etc.!


      1. Just completed my first batch of “not quite” natto. Tastes good, but strings are so few as to be nonexistent. Not sure where I went wrong. Followed all steps, saw white stuff growing on the beans in the incubator, but no “neba neba” to be found.
        Even bought the smaller, round, organic non GMO beans! Used starter culture from Gem Cultures (no local Asian market for 1.5 hour radius), sterilized everything, had a constant 107 degrees incubator…
        any suggestions?

        Liked by 1 person

  4. I used to eat this food from time to time when I was on the JET programme as an ALT in Japan. Since coming back to Australia & reading some negative things about soy foods (in relation to women who have PCOS) I cut all soy foods from my diet. However I have just read an article by a very credible source on natto being the highest known food in vitamin K2, known as the ‘anti-wrinkle’ vitamin. The fermentation process reduces the phytic acid content of the beans & does something magic to the proteins & amino acids basically unlocking the nutritional potential of the beans. Ancient China & Japan can’t be wrong… & look at the beautiful skin many people have there! There is a world of difference between the processed foods & oils that have become ubiquitous in the modern diet & are derived from gmo soybeans & natto made from the non gmo organic Australian grown soybeans I have just bought. I plan to give this a go & have acquired some frozen imported natto to get started (thanks for the thawing info above). I have been making my own kombucha & keffir for a while now so I thought I’d be able to innoculate a batch with a starter from a commercially bought product.
    One detail I wanted to ask about: do the beans really have to be laid out singularly like in your photo. I ask because I was hoping or thinking I could resuse the polystyrene containers that the store bought natto came in as well as the cellophane sheets that lie on top (of course they will be squeeky clean). Do you think that will work?


  5. Here in Australia, cellophane is a gift wrapping paper….could you mean cling wrap (elastic like plastic that stretches)


  6. A great and very important recipe for me, i need to ferment soy beans to make them healthy otherwise they are not. But i have a few questions:

    “Carefully pour the fermentation starter (with the natto beans) evenly all over the steamed soy beans.”

    Do the soy beans need to lay in this fermentation starter water? or hardly need to be touched by the water? i dont toss down the fermentation starter water right? but does the water surface need to be as high as the soy beans in the vessel?
    Many thanks for this article.


    1. Dear Dennis!
      You are most welcome!
      “does the water surface need to be as high as the soy beans “: Yes!
      Don’t hesitate if you need more information!
      Best regards,


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