Arigato NattoーHow to Make Natto at Home Even in Africa

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Once you touch it, it will stick to you without leaving you. Usually people hate it at the first sight , but some people gradually start loving it and cannot even stand without it as it can be a great supporter of your life.

What is it? Is it what is so called a love?

No, it is Natto, fermented soy beans which is one of the cheapest and healthiest foods in Japan (you can buy 3 packs of Natto for 100 JPYーless than 1 USDーin most markets. In this article, let me share the importance of Natto and how to make it at home, which was successful even in Africa.

Why Natto

According to an article “Why Natto Is Super Healthy and Nutritious“, Natto is rich in protein, vitamins and minerals. The fermentation process it undergoes reduces its antinutrients, increases its beneficial plant compounds and helps your body absorb the nutrients that it contains.

In addition to the nutrition, I personally likes the taste and texture.

Homemade natto for whom

Natto making at home can be money, time and effort consuming, so if you can have access to it, it is much better to go to a market.

Homemade natto is meaningful for people who:
ーlike to create something badly
ーhave no access to Natto despite your affection, especially those who ive abroad
ーdo not mind spending 3 days to take care of making process

And as I met all of those 3 conditions, I gave it a try.

The summary of how to make Natto with cooler box

Steps Time Remarks
0. Prepare ingredients and tools Japan visit You don’t need pressured pot, yogurt maker nor rice cooker
1. Soak soy into the water 16 h put it into the fridge
2. Cook beans and prep for fermentation 1-8 h 1h if you have pressured pot
3. Fermentation 24h This is the core part of natto making
4. Cool down 24h You did your best, so forget the rest.
Total 3 days  Eat, freeze and make another one if you liked

*In fact, the summary is also shown in the drawing above.

0. Prepare ingredients (visit to Japan and shopping)

(1) Soy beans (300 g)
(2) Bacillus Natto (0.2g and 6-7 ml (or 6-7 g) of disinfected water)
(3) Coolerbox
(4) Petbottle or stenless pot (to keep the temperature for fermentation)
(5) Pot (better if you have pressured pot but not obligatory)
(6) Thermometer (if you have)
(7) Alcohol spray
(8) disinfected spoon, container, strainer  and towel
(9) plastic wrap and kitchen paper
(10) Patience and time (3 days)

1. Soak soy beans into the water (16h)

After washing soy beans, soak them (300 g) into the water of around 3 times of soy (900g). Put it into the fridge and wait for 16 hours. It is good to caclualate time depending on you schedule. if you wish to use a weekend, it is better to prepare on Friday afternoon.

2. Cook beans and prep for fermentation (1-8h)

In just one night, soy beans abrosrbe lots of water and it makes 3 times bigger and 2 times heavier (I hope my learning will be that easy and simple…).

If you have pressured pot, you can make it in 1 hour (if boiling with normal pot which was my case, it takes 5-9 hours).

While you cook soy beans, it is better to prepare for fermentation, as the transition of the both steps has to be done very quickly). The prep includes disinfecting all the material (a cup, strainer, container and spoon), setting up the environement of 40℃, and making fermentation liquid (1kg of soy / 10g of boiled water + 2-3 tiny spoon of Bacillus Natto or real Natto, if you have).

3. Fermentation (24h)

This was the most difficult but interesting part for me. The point here is keeping the temperature around 40℃ (I even tried to buy a rice cooker just because it has a function of keeping temperature). For that, I used water bottles and stainless pot filled with hot water, in the coolerbox.

Once soy beans are ready for fermentation, put them onto disinfected strainer, and move in a disinfected bowl to mix with fermentation liquid while beans are still hot.

Put beans into the container, then cover with kitchen paper (to avoid natto getting wet out of evaporation) and put plastic wrap with tiny whole (with tooth stick) as fermentation needs oxygen. Then cover it with disinfected towel. All of these have to be done while cooked soy beans are still hot.

Every once in a while you have to check the temprature (I had to change hot water 3 times, and the process was such an interesting part, as if you were taking care of baby).

24 hours later, if they have something white surrounding, it means they are fermented.

If you have a doubt, you can check with spoon, and if it’s slimy and sticky with string, you made it!

4. Cool down (24h)

After 24 hours of taking care of your work, it is quite normal to want to eat immediately, but you have to cool down and let it sleep another 24 hours in the fridge. To preserve, you can use new plastic wrap (this time without hole)

24 hours later…

Voila! Very sticky!

You can keep in the freezer. Overall, it took me 72 hours (and even more if including shopping).

The result and taste?



I think it is just sticky, slimy and delicious, even more than the one you find at the market!!

At the moment I tasted, I was really excited. All the efforts for these 3 days (whole weekend) for Natto making was totally worth and I realized it destressed me and made happier. It also reminded me that things we have exist thanks to many processes and people’s hands. For all the experience…

Arigato Natto!

Continuation of this blog: Arigato Natto 2ーHow to Make Natto Sustainablly Even in Africa

The learning of this time 

I learned that the process of natto making was quite tough but possible, which reminded me of the fact that many things we have are made through others’ efforts, and sometimes it is good to experience the process to feel the sense of satisfaction and appreciation. 

Thank you for reading. If you like it, please don’t forget to subscribe. If you have any comment/question, please feel free to leave. Have a great learning!



4 thoughts on “Arigato NattoーHow to Make Natto at Home Even in Africa

  1. Monika F

    Bonjour, MD san. Je suis une hongkongaise fan de natto residant en France. Je souhaite confectionner du natto d’une manière durable pour éviter les bacs polystyrène ainsi que l’empreinte carbone d’importation des petits boites de natto depuis Japon. Je vous remercie de votre recherche inspirante sur ce sujet. Savez vous si je peux utiliser des graines de soja déjà Graines de soja dépelliculé comme ceci pour faire du natto ? Sinon je ne trouve que des tres grosses graines ici est ce n’est pas vraiment mon truc. Merci infiniment de votre conseil !

    1. MD Post author

      Bonjour Monika F-san, merci pour votre message.
      Pour répondre à votre question, je suis tout à fait certain que vous pouvez le faire avec de nombreux des haricots différents, y compris ce que vous venez de partager (veuillez essayer et me le faire savoir). Avez-vous lu la version 2 de mon article du Natto? (pour faire du natto de manière durable)?ーhow-to-make-natto-sustainablly-even-in-africa/?lang=fr
      Une fois que vous avez du natto, vous pouvez le congeler et l’utiliser pour en fermenter de nouveaux (bien que je trouve que la fermentation devienne un peu plus faible si vous en utilisez une congelée)

    1. MD Post author

      Salut Pierre, c’est vrai que Le fameux Bacillus Natto est difficile de trouver, mais tu peux utiliser Natto pour la fermentation (s’il y en a dans supermarche).


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