Welcome to Natto Land

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This English page has been opened 981009
revised 1st. June 2003
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Please write in plain English. (Japanese is preferable :-p )

Do you know what natto is?
Have you ever tried it before?

Natto is a Japanese original and traditional food.
Natto is a fermented food made of soybeans and is rich in vegetable protein.
It is usually eaten with rice. Natto has a certain characteristic flavor, therefore some people do not like it.
Also natto has sticky paste on its surface, and once it is stirred, the sticky paste increases its volume and becomes more sticky.
When you get natto with spoon or chopstick, you will find that the paste pulls a part of as if a spider web. This is another case why some do not like natto.

But, of course these features attract other people including me.
If you like blue cheese, then you'll surely love natto.
If natto is available near you, please try once.

How to eat natto
Nowadays, the natto product is packed in small plastic packages with soy sauce and mustard..
One pack is about 50grams.

Most popular way to prepare natto is as follows.

  1. Please put natto into a suitable porcelain bowl.
  2. Stir the natto with chopsticks or other suitable tool. Do not mash. Stir fast and well. (Not 1 hour, 60 seconds is enough:-p)
  3. Pour the soy sauce and mix mustard.
  4. If spring onions are available, it is recommended to finely chop these and mix in. Then put a spoon of natto on steamed rice and eat them together.

Miso soup matches well with natto.
There are various ways of cooking with natto on my Japanese web page.

Natto open sandwich
1 Prepare natto (30 to 50grams) mixing with mayonnaise (5 to 20grams).
(mix shoyu a little if you like)
2. Prepare sliced (1 to 1.1.5cm thickness) bread toasted.
3. Put mayonnaise natto on the toasted bread.
4. Put several pieces of sliced (very thin) onion on the natto.
5. Put cheese (pizza type) on top.
6. Cook in an oven.
(mix mustard in natto or paste on the bread if you like)

Natto spaghetti
Natto omelet
Natto fried rice
Natto curry

If you have your original natto cuisine, please send me your recipe by mail: ny@ynest.com@

Received mails
from hiroko-san in Spain

Prepare boiled water in big pan and cook followings in the pan.

-Dashi (soysauce, dried bonito flakes soup, mirin;sweetened sake )
-any vegetables you feel like (hakusai, enoki, shiitake, leeks, etc.)
-Udon(Japanese wheat noodles)

Dip sauce
-flaked tuna
-raw egg
-chopped onion
-soy sauce

Cook the udon and vegetables as for an ordinary nabe. While they are
bubbling, mix all the other ingredients in small bowls. As the udon
and vegetables cook, dip them in the Dip sauce.

How to make natto


  1. soybean
  2. dried rice straw (usually natto bacillus is living on it)


  1. Soybeans shall be soaked in the water, until the bean stop swelling. It takes one night in summer. It may take one full day in winter.
  2. Steam or boil the soybeans until the beans become soft. (Recommend to steam., if boiled, the taste of the soybean flow out to water and the thin skin of the bean peels off, and also recommend to use a pressure cooker, otherwise it takes several hours to cook.)
  3. Put the dried straw into boiling water several minuts to sterilize (Natto bacillus survive in 100C(=212F) hot water more than 10 minuts)
  4. Prepare the straw as a package. Probably one package for 50g(=1.75oz) of bean (use enough straw)
  5. Put the cooked beans on the straw and cover up with the straw and tie
  6. Keep the package at about 42C(=108F) degree. Usually I put it in the cooler chest with hot water petbottle.Temperature changes 45C(=113F) to 35C(=95F) and then replace the hot water in the pet bottle (plastic transparent bottle such as for Coca-Cola ) Please be careful that natto fermentation requires enough oxygen
  7. Fermentation will proceed enough in one or two days. Then keep it in refrigerator.

If you have cultured natto bacillus, straw is not required. Add hot water to the bacillus powder and add onto the cooked soybeans and keep in a suitable package (beans shall be open for enough air)

Another way, is to get Japanese natto product once, and use the several pieces as mother bacillus.


What shall be the temperature and humidity conditions?
According to Dr. Toshio Hara (Prof. of Kyushu university), natto bacillus live between 10C(=50F) to 65C(149F) degree, and most suitable temperature is 40C(=104F) to 45C(=113F) degree. ( It will turn to seed under 10C degrees or over 65C degrees) Humidity is necessary. But, I don't make any special treatment for fermentation. Inside my Styrofoam box has very high humidity during the fermentation process. Humidity comes out from the soybeans and water used for mixing bacillus powder.

If box is enclosed without oxygen, are there any results and/or problems?

If itherfe is not enough oxygen, then the fermentation doesn't proceed well. I'm not sure of the necessary air volume. It seems 10 litter of air is good enough for 500g(=17.5oz) dry soybean.(=before water soaking)

Sour flavor occurring in natto. Is It normal?

It sounds bad, There might be contaminated bacillus.

White film is made around of bean. Is It normal?

Yes, it is OK.
Probably the white coloring looks like it is frosted. It is the sign of successful fermentation.

Ammonia flavor is made after the end of natto fermentation. It seems fermentation is too long. If you keep the Japanese natto product 5 to 10 days out of refrigerator, then you smell ammonia flavor. How long will natto last?
One of Japanese product, near me now, shows 7 days after manufacturing on condition that it is stored under 10 degree. Usually it should be kept in the refrigerator.

How to get the seed -Natto powder ?


Ask your friend who visit Japan to buy it at "Tokyu Hands" the famous "do it yourself shop", located in Sinjuku, Shibuya, Yokohama, Hiroshima, etc.
Dried cultured natto bacillus is "Natto Kin" in Japanese.

Where can I buy natto in USA?

My friends told me that natto should be very good helpful to your body,but they couldn't tell me the real effects in detail,would you like to teach me the real function of it to the health?

There are various nutrients in the soybean, such as saponin, protein, oligosaccharide, vitamin B1, food fiber and vitamin E.
Lecithin reduces bad ball cholesterol, and remove the cholesterol which stuck to the blood vessel, and that prevents high blood pressure.
Saponin controls a cancer.
Isoflabon spelling not found prevents aging of the blood vessel, breast cancer and prostatic cancer.
There is an enzyme of nattokinaze in the natto.This enzyme has the effect which melts a thrombus. There is a vitamin k2 in the natto. When that is not in the body, calcium can't become bone. A vitamin k2 is produced at the intestines. If it is not enough in body, nattokinaze helps. Vitamin k2 doesn't exist in other food. There is a research that regional natto consumption and fracture is inversely proportional.

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