User:Derf/Natto

Natto and stringy goodness.

Natto is a traditional Japanese food that is made of cooked soybeans cultured with natto bacteria (Bacillus subtilis variant natto). The result is a slimy and stringy mass of beans that is beneficial for gut health. The enzyme responsible for the stringiness is nattokinase — an enzyme with studies indicating a reduction in heart diseases.

Natto is traditionally eaten for breakfast, stirred vigorously to make it extra stringy, optionally with a few drops of soy sauce or mustard for flavor. Personally, I like it mixed into rice dishes (after cooking to preserve probiotics) or just on its own as a snack. Some people make natto fried rice and some sushi restaurants even sell natto rolls — although natto is hard to find at restaurants in Japan in my experience.

Materials

• Instant Pot (pressure cooking + adjustable temperature "yogurt" mode)
• Instant Pot steamer basket OR a colander small enough to fit in the instant pot
• Packet of frozen natto to use as a starter (can be gotten in Asian market). Powdered spores can be used, but avoid using freeze dried natto as I had multiple failures with it.
• Soybeans (Laura Soybeans recommmended, Soymerica requires longer pressure cook and are bigger than average).
• Sealable glass bowl large enough to hold beans.

Soaking the Beans

The beans must be soaked to hydrate them before cooking. The beans should double in size, so choose an appropriately sized bowl.

1. Pour two cups of uncooked beans into large bowl.
2. Remove any oddly colored beans.
3. Add twice as much water as beans to completely cover them with extra.
4. Cover with plastic wrap and allow it to soak overnight.

Cooking the Beans

Now you will cook the beans. While you can cook them without a basket, it will be sitting in the water and take on a more bitter flavor. The beans should change to a darker color after cooking.

1. Wash the beans with water until the water runs clear and there's not much bubbly foam on top.
2. Add water to the instant pot until it is an inch deep.
3. Put the beans in the steamer basket. If needed, put a ramekin under the basket so the beans are not touching the water.
4. Pressure cook the beans with these settings:
   • Pressure: High
   • Time:
     • Soymerica beans: 45 minutes
     • Laura beans: 30 minutes?
   • Keep warm: On
   • Pressure slider: Closed
5. Allow it to naturally release the pressure (~20 minutes) until it says you can open the lid. Do not do a manual release.
6. When it finishes, remove the lid and try not to drip water into it. You may want to immediately rinse the lid as the bean juice tends to be very hard to remove when dry.

Culturing the Beans

This is the point that you culture the beans using the natto starter.

1. If using frozen natto, cut the frozen natto into either 6 or 9 pieces. You may have a higher success rate with 6 pieces, but it's not necessary. If using powder, follow the instructions on the bottle.
2. While the beans are still hot (hotter the better), add the natto starter.
3. Pour two small spoonfuls of the brown cooking water over the natto starter. Heat is apparently important to activate the starter.
4. Stir it to ensure all the beans touch the starter.
5. If you have a second steamer basket, put half the beans in each to maximize the amount of oxygen the beans have access to.
6. Press the yogurt button on the instant pot and set it to these settings:
   • Temperature: Custom (set to 108°F / 42.2°C)
   • Time: 24 hours
   • Pressure slider: Closed (to retain moisture)
7. Allow it to culture. You can occasionally open it to check on it, which will give it fresh oxygen. There won't be much noticeable activity until it's near the end.

Fermenting the Beans

At this stage, if everything went well, the beans should be stringy. If they aren't, it's still edible soybeans (good to mix into rice bowls) but just a failure in terms of making natto. It may smell a little like ammonia and more like soybeans than natto, but this will clear up after fermenting in the fridge.

1. Rinse the sealable glass bowl and put the glass into the microwave for 1 minute on high to sterilize it.
2. Pour the beans into the bowl, seal it, and allow it to sit in the fridge for 3 days. You can eat it in the meantime, but it will have the best flavor after 3 days.
3. Freeze what you won't eat in a week. It can last a little longer than a week in the fridge. You can also save some to use as a starter, though people recommend only doing this a couple times, as it will get weaker and new starter is cheap.