Ferment II (Natto)

July 10, 2010

I’ve been a little quiet on the blog lately as we have been in the mountains in the Philippines without electricity or roads, let alone internet access. We hit a south east Asian natural farming jackpot in the mountains of Ifugao but you’ll have to wait a bit longer for the reports on that. In the meantime there are some posts that I began in Japan before leaving for the Philippines…

Natto is probably the most notorious of all the Japanese ferments. If you tell a Japanese person you like Japanese cuisine they will inevitably ask “but how about natto?” It seems that westerners particularly struggle to appreciate natto. I have introduced a few people to it and not one of them was willing to try it a second time (unless it was heavily disguised in miso soup). I believe its mostly the texture that people struggle with. The texture of natto is, well, slimey. The smell is also rather strong, comparable in intensity to a very mature blue cheese. Sound appealing? It is absolutely delicious, really.

Natto is made by fermenting soy beans. The nutritional value of many foods is increased with fermentation but it is particularly important with soy beans as the fermentation reduces the mineral binding effects of the phytic acids present in soy beans. Other forms of fermented soy beans include miso, shoyu (soy sauce) and  tempeh. Although natto is usually made with very small soy beans any soy beans can be used. In the step-by-step photographs of the natto making process below we are using large green soy beans.

After the fermentation process is complete natto is prepared for eating by whisking it up with chopsticks and, usually, adding a little mustard and shoyu. The whisking creates a kind of goo resembling melted cheese that sticks to the beans and makes them potentially very messy to eat. It is usually eaten with rice and, just in case the strong smell, strange flavour and slimey texture aren’t enough, it is often eaten for breakfast, when our stomachs are at their most vulnerable!

Natto process, from top to bottom:

1. Rice straw contains the bactria Bacillus subtilis. It is this bacteria that is used to ferment the soy beans in making natto. The rice straw is cut to size to fit in the plastic containers we are using. Traditionally the natto is made in a rice straw ‘package’.

2. The rice straw is pasteurized (heated to about 65 degrees centigrade). Bacillus subtilis can withstand relatively high temperatures so pasteurizing the straw kills off other bacteria and favours the Bacillus subtilis.

3. Cool the pasteurized rice straw.

4. Place half the rice straw on the bottom of a container.

5. Place cooked soy beans on the rice straw. The soy beans should be soaked overnight before cooking. Because Bacillus subtilis can withstand high temperatures it is not necessary to cool the cooked beans although it is probably best to let the cooked beans sit for 10 minutes or so after cooking is finished.

6. Place more of the rice straw on top of the beans.

7. Put a lid on the container and place in an insulated box with a hot water bottle. Let sit over night and the natto should be ready just in time for breakfast.

8. In my eagerness to taste the natto we had made I forgot to take a photograph of it! This photo was found on the web and shows natto made from the smaller brown soy beans that are typically used in commercial natto production.

Coming Soon: Ferment III (Shoyu)


7 Responses to “Ferment II (Natto)”

  1. Jocelyn Says:

    You seem to be in fermentation heaven… I’m happy with my sour dough which gets made every 5 days or so. I can just imagine the race for breakfast the morning the natto was ready. Big hugs to you both

  2. Ralph Says:

    I am an American living in Butuan , I regret not bringing along my natto starter. I’ve never made natto, but always wanted to try it. I eat all kinds of foods here,so I hope I can develop a taste for this great food. Thanks

    • dion Says:

      Ralph, natto is easy to get started if you have access to rice straw – and being in Butuan I expect you do. Bacillus subtilis is usually present on rice leaves/straw. Just follow the directions in the post.

  3. Ralph Says:

    How long do I cook the soy beans?

  4. Loved your natto preparation technique. Is it not necessary to add some sugar and salt to the cooked soybeans before fermenting them with hay?

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