History of Natto and Its Relatives (1405-2012 - SoyInfo Center

pressurized steamer. Steam at 14.7 pounds pressure for 25
to 30 minutes, then release the pressure, open the cooker,
tilt it forward, and scoop the beans into a large aluminum
bowl (4 ft. diameter, 14 inches deep). Allow to stand for 5
to 10 minutes, then thoroughly mix in the inoculant. Discard
any excess liquid that settles to the bottom. Run or spoon
the beans into a tray, cover them with a sheet of perforated
plastic (1/8-inch-diameter holes every 1½ inches), and cover
the tray loosely with a plastic lid and put it in the incubation
room. Keep at 40-43ºC (104º to 108ºF) for 14 to 15 hours.
Actually the temperature is regulated as follows: It starts at
40ºC (104ºF) and is gradually increased to 50ºC (122ºF) at
8 hours; it remains the same until 13 hours. At that time it
is gradually reduced to 35ºC (95ºF) at 15-16 hours. Do not
allow the temperature to rise above 55ºC (131ºF). Once this
process is fi nished, put the tray into a cold storage room and
cool for 1 night. The cooling reduces the moisture content
through evaporation. Now with plastic boxes the natto cools
more slowly.
The traditional natto process: Soak as above then boil at
atmospheric pressure for 7 hours. Inoculate as above or (a)
mix in natto from a previous fermentation [but it gets bad
after 2 to 3 generations since undesirable microorganisms
propagate], or (b) use bacteria naturally occurring on rice
straw [except that when pesticides and herbicides are used on
the rice, the number of bacteria is reduced to about 15% of
the natural count]. Wrap hot natto in rice straw and put in the
kotatsu (charcoal heater under a table covered by a blanket)
to get 40ºC temperature, then wrap it in a blanket and keep it
at this temperature for 2 to 3 days and nights. In the West, a
yogurt incubator works well.
It is said that a longer incubation produces better
fl avored natto. Perhaps short fermentation tastes milder with
a subtle vanilla or chocolate fl avor, whereas long-incubated
natto has a stronger, more distinctive fl avor, and more of
an alcoholic aroma. Address: c/o Aoyagi, 278-28 Higashi
Oizumi, Nerima-ku, Tokyo 177, Japan. Phone: (03) 925-
4974.
718. Shurtleff, William. 1977. Report with color slides on
trip to Ose Noboru natto factory in Tokyo, Japan. Nerimaku,
Tokyo, Japan: New-Age Foods Study Center. 1 p.
Unpublished manuscript. Nov. 10.
• Summary: Shurtleff took some color slides of the nattomaking
process on this one-day trip to this small-scale,
modern natto factory in Suginami-ku, Tokyo, with Alfred
Birnbaum and James Udesky. We study, photograph, and
write up the process. Mr. Ose is head of the Japanese Natto
Assoc. Met Alfred Birnbaum for the fi rst time.
The slides / photos are now in a numbered set as
follows:
1. Natto or fermented whole soybeans is a traditional
food that originated in the northeast part of Japan over one
thousand years ago. The dark brown natto beans have a
© Copyright Soyinfo Center 2012
HISTORY OF NATTO AND ITS RELATIVES 243
sticky-slippery surface so that lifted from a bowl, they form
gossamer threads. Natto’s fl avor and aroma are strong and
distinctive, with not-so-subtle ammonia overtones–some
people love them, other people don’t. Traditionally natto was
made and sold wrapped in rice straw as you see to the left.
Now it is sold in shallow polystyrene trays.
2. Here you see the beans inside the traditional rice-
straw wrapper; in some farmhouses they are still prepared in
this way. Bacteria on the rice straw naturally inoculate the
beans.
3. Here are various types of natto packaging used in
Japan. Some natto is made with cracked soybeans (hikiwari
natto), some contains pieces of kombu. Most types are
served with a little shoyu (natural soy sauce) and mustard.
4. A typical Japanese supermarket carries a large