Kotastu nattō

Kotatsu こたつ
n : a low table with a heating lamp under it and often a blanket on top to keep your legs warm. A necessity to live through the Japanese winter.

Nattō 納豆
n : a fermented soy-bean product that smells like a fourteen-year-old boy's sock. A traditional Japanese food that most foreigners cannot stand the sight or smell of.

How do these two seemingly mutually exclusive things come together?

On a visit to the "Nattō Museum" in Ogawa, Ibaraki, I discovered that you can actually make your own nattō using the heat of a kotatsu to speed up the fermentation process.

Warning: unlike other home made foods, homemade nattō does not taste any better than store-bought nattō.

I guess I am being a bit harsh. I know there are some people out there that actually enjoy eating the stuff, but I don't think I will ever be turned to the dark stinky side.

But for the spreading of knowledge, I will explain what I learned about making it in your kotatsu. This is actually very similar to the traditional way that people made nattō hundreds, maybe thousands of years ago, but in their case they didn't have electric kotatsu, but kotatsu with real charcoal fires underneath.

Step 1 - selection

Step 1

Find the largest, cleanest and roundest soy beans you can. The whiter the beans, the brighter the nattō.

Step 2 - washing

Step 2

Wash them well to remove any non-nattō friendly bits of dirt or rubbish like grass or seeds.

Step 3 - soaking

Step 3

Cover the beans in water. Leave them until they swell up to twice their original size.

Step 4 - boiling

Step 4

Boil the beans for 4–5 hours or until they are soft enough to squish between your fingers.

Step 5 - Adding the bacteria

Step 5

Place the beans into a container, and while they are still hot, mix in some store bought nattō to kick start the fermentation process. You can also buy "nattō-kin 納豆菌" or "nattō bacteria" in packets and mix that in instead.

Step 6 - wrapping

Step 6

Place a lid on the container, but leave a gap for air by putting a pair of chopsticks between the lid and the container. Then wrap the whole lot in a "furoshiki" or clean towel. Wrap all this in newspaper.

Step 7 - Kotatsu method

Step 7 - Hot water bottle method

Step 7

Place the parcel in a 40 degree Celsius environment for more than 20 hours. This is where the kotatsu comes in handy. The other method is to place it under a not-too-heavy futon on top of a hot water bottle.

Step 8

Put the finished nattō in the refrigerator to stop it from fermenting again.

Step 9

If you are brave, eat it!