Fig. A: Your materials (minus the pot). Fig. B: Wash the
beans and soak fully submerged in water for up to 24 hours.
Fig. C: Steam until the beans are soft. Some recipes
demand that the beans be inoculated immediately while
still hot, but I know one fanatic fermenter who finds this
unnecessary. Fig. D: Mix the commercial natto with your
beans and spread in a glass dish. Mail-order spores will
have their own instructions.
» 2 cups dried soybeans
» 1 package commercial natto or
appropriate dose of spores Japan’s
organic produce seal bears the green
letters “JAS” and a leaf in a triple circle.
» Large pot with lid
» Metal steamer basket
» Glass baking dish
» Aluminum foil
» Incandescent work light
Fresh natto is hard to come by in the U.S. “I’m the
only kid on the block,” explains Charles Kendall of
the Kendall Food Company in Worthington, Mass.,
which is likely the country’s only commercial
producer. If you don’t live in the Northeast and don’t
plan on visiting Japan, you’ll just have to pick up a
frozen package at a specialty grocery store or order
the bacteria from GEM Cultures (
and grow your own.
Wash dust and dirt from the beans and remove any
that are discolored. Soak fully submerged in water
for 12 to 24 hours until they’re swollen (Figure B).
Drain the beans and give them another rinse for
good measure. Fill the pot with water to just below
the steamer bed. Put in the beans, cover, and steam
until they are soft enough to crush easily but are
not yet bursting on their own (Figure C). In a regular
pot, this can take 5 or 6 hours. Replenish with ½ cup
boiling water every hour. A pressure cooker shortens
this time to 45 minutes.
When the beans are ready, sterilize the baking dish
and the spoon with boiling water, vodka, or another