Natto - Homemade

My mother-in-law has been making natto for over fifty years and hasn't poisoned anyone yet. She uses old plastic buckets that sit out back, multipurpose strainers, wooden utensils that cannot be sterilized even if you wanted to sterilize them, newspapers and dirty blankets. Maybe I should warn people: do not try this at home, please follow usual sterile processes for making any fermented food product to avoid contaminating the product with unwanted bacteria. So I leave it to you dear reader, to determine if you would ever want to follow our methods.

I searched for various "recipes" and most call for a cup of soybeans...here in the village, the smallest measure is "i-sho" the equivalent of 1.8 liters (the size of a big sake bottle in photo). This amount is roughly 8 cups of dry beans. We are making heaps of natto today.

How to make natto: First you want to discard any wormy beans or debris, then soak the beans overnight and rinse them well. Next, figure out how you will cook them. In a pressure cooker, you need to plan 15 minutes per cup of beans or 3 hours in a pot or over a fire outdoors. Then you drain the cooked beans.

Pause: do not throw out the cooking water! One of the benefits of cooking your own soybeans is to have the slippery water to add to the laundry to brighten your load. We store it in empty PET bottles and use half a cup per load.

For perfect control and predictable outcome, you would want to add some natto bacteria powder at this point, obtainable here at the agricultural store or elsewhere in a health market. But obachan usually just adds a bit of the last batch or a commercial batch of natto, much like you would add yogurt to milk. We add half a pack of purchased natto (about 3 Tb to the 1.8 liters of beans) and eat the other half. After mixing it together with the wooden paddle that was laying on the less than clean counter top (I'm telling you, it must be a bacteria war), we scoop it into little cones made from paper thin wood and wrap these in two sheets of the daily newspaper. We prefer the Kumanichi but I'm sure any newspaper would suffice!

The newspaper wrapped beans are packed into a box or just piled neatly onto some more newspaper and bundled up, tied securely with the remnants of an old tatami mat, although I'm sure string would work just. My favorite part of natto making is keeping it warm for the next 12 hours. You could fire up the oven or set it near a water heater, place the bundle under the kotatsu table, or wrap it in an electric blanket. My mother-in-law went nuts with the blankets, piling them on and tucking those beans in like a baby on a sled in a snowstorm.

The aroma (I'm told) will wake the household in the morning; it is pungent and earthy. If there is an ammonia smell, something has gone wrong. The natto is done when a sticky web develops throughout the beans. We take the beans out of the warm place after 12 hours and let them sit, wrapped for another half day before eating them.To slow down the fermentation, store the wrapped beans in the refrigerator for up to a week or in the freezer for longer storage.

I like to eat natto with a drizzle of a 50-50 mixture of vinegar and soy sauce and a dab of hot yellow mustard as a side dish to rice. My daughter prefers just plain soy sauce. I may have to come up with more creative ways of consuming it because we have plenty for the days to come.