Natto 3: Ann’s Pressure Cooker Method

This is a guest recipe from Ann who was commenting on the post Natto 2: Fermentation Boogaloo.



What You Need

  • Natto culture (see picture of Raffy showing packet)
  • 250 g of ORGANIC soybeans
  • 1 container with lid. I used a plastic one with clip on lid. 20 x 14 x 7 cms – wall of beans should not be more than three high.
  • A piece of cheese cloth that is draped over box of beans before pushing lid on. A bit of a struggle and that is why you need something like a fine muslin.
  • I am extremely fortunate enough to have an up market dehydrator (given by rich friend) and so keeping a constant heat of 100 degrees was easy. However, any form will do as long as you can keep that heat constant for between -22-24 hrs. I got so neurotic, I bought an oven thermometer just to check every now and again.

natto culture

Natto culture


  1. Soak the beans for 24 hrs.
  2. Drain and pressure cook for approx 8 mins. Try a little less like 7 mins first of all, just in case your pressure cooker is better than mine. The beans should still be whole, but if pressed between finger and thumb, they should be soft. You do not want them mushy.
  3. While all that is going on take the tiny spoon that comes with culture and put it in a small container with 10-20 ml of already boiled water. WATER MUST BE TEPID. All of your utensils including cheese cloth, must be sterilized with scalding water to avoid contamination of the culture.
  4. When the beans are cooked, lift out of pressure cooker and tip them into your sterilized container and after the steam has left (3-4 mins) stir in the mixed culture and water. Be sure to mix thoroughly but don’t bash the beans about too much. A nice slow mix and turn is good.
  5. Place the fine cloth over the top and push down the press on lid. Place this in whichever method, apparatus you have chosen and ferment for 22-24 hrs. At the end you are looking for something that is covered with what looks like a mild frost.

I have now cooked by this method a couple of times and it works beautifully. I hope you find this easy to follow and you have success.


Add yours

  1. Where can I get that dog?! He’s precious AND a healthy eater!

  2. Why thank you. His name is Rafferty but you can call him Raffy. He hasn’t tried the natto yet, but I am working on it.


  3. Johan Lindén

    Aug 12, 2015 — 2:52 pm

    What do you do with the natto?

  4. @Johan – Eat it over rice with hot sauce.

  5. As MAS has said, eat it and over rice is a good way.
    For those who maybe interested, Natto is high in K2-MK7. There is a MK4 but it is very very expensive. You can buy the natto in supplement form as Nattokinase, but many people suffer with palpitations (as I do) and can’t take it. I have hashimotos, and most hashi people are severely depleted of Vit D. If you take vit D you need K2 to avoid or slow down arterial calcification. Natto has a huge 775mcg per 100gram serving. Worth persevering with Natto!

  6. Sorry, foggy hashimoto brain. The Vit D is Vit D3, which I am certain you knew but ……,


  7. Cute dog. How old?

  8. Hi Thomas – Raffy is nearly twelve. Not bad for a little dog with an autoimmune disease! He has a sister Ruby, and if I can find a good excuse to include her on the Natto project, I will.

  9. Anita Pandolfi

    Jul 26, 2022 — 12:01 pm

    Hi I’m excited about making natto and I love love love my pressure cooker. Kuhn Ricko I think its called. I got the fancy double-walled one with brass handles and a trivit and double-walled top for serving.
    I bought the expensive Koncentrate K which has 5mg of MK7. It gave me wicked palpitations. I called the guy that puts it out he says no way. Now I’m afraid to take it. So I thought I would make Natto. Will Natto give me palpitations?
    Please help me with this. And, thanks.

  10. @Anita – No idea.

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