Black Bean Natto

black bean 1

Note from Shannon: Please welcome Sarah, CFH Customer Service Representative and Cultured Kitchen-Keeper.

Natto is purported to be one of the most healthful forms of fermented soybeans. But, soybeans are not the only legumes you can make natto from.

With just two pounds of rinsed organic, dry black beans ready for an overnight soaking, you too can get started making your own black bean natto. Here’s how.

In the morning, rinse your beans well and place them in a large pot with fresh water. Bring to a boil and cook the beans until just tender. I prefer my natto with some firmness, but if you like really soft natto, keep cooking longer. I boiled mine for about 30-40 minutes, until they were the tenderness I wanted.

While these are cooking, start another large pot of water. Bring to a boil and start adding any utensils, measuring cups or containers you will use to make your natto. If it’s going to touch the beans, boil it.

Drain the cooked beans and place in your large, boiled bowl. Stir the beans occasionally to make sure they cool evenly. You want to bring them down to 110-115° temperature range. Mix one scoop of the natto spores into 2-3 Tbsp of freshly boiled water that has also cooled. Pour over the beans and stir well to make sure the culture is evenly distributed. If your beans are particularly dry, add enough more boiled water to moisten. This is not a dry culture like Tempeh.

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Yes that teeny little scoop is all the nattomoto you need to make a big batch of natto!

Now transfer your beans to shallow pans that will fit in your culturing appliance of choice. If you are using your oven, go big!. I used my small cooler, so I found some small containers that would hold my beans at a depth of 2-3 inches.

To cover your beans, either boil cheesecloth or muslin and wring out, or use unbleached parchment paper. Lay the cloth or paper over the beans, and then seal the container with a layer of foil. Place the beans in your culturing place that you have confirmed maintains a temperature of about 100°F.

A cube dehydrator works very well. Some people have an oven with a light that will maintain the correct temperature. I use a small cooler and heating pad.

A trick I have learned for making natto with lots of strings is to “heat shock” the natto. For the first 2-3 hours that your natto cultures, try to keep the temperature near 110°F. Then drop the temperature down to 100 for the remainder of the time. My batch of black bean natto took 23 hours to culture.

An important consideration, especially if you live with others, is to find an isolated place to culture your natto. It has a very strong smell while culturing! And during a 23-24 hour culturing time, you are bound to have complaints! A garage, sheltered spot outdoors or even a room with a good ventilating fan are all good options. Culturing near an open window next to a fan would also work.

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As soon as your natto is forming lots of stringy gels, transfer it immediatedly to the refrigerator. After 6-8 hours, it is ready to eat.

I ate mine for breakfast with some rice noodles in spicy sauce with lettuce, green onions and a poached egg.

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I have had some questions from customers about their natto not being as stringy as commercial natto. So here is a comparison. The first picture of the finished beans is just plain natto after being refrigerated for 8 hours.

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This one is with some tamari stirred in. Just a little liquid makes a big difference! If you are comparing your natto to commercial natto, keep in mind the ingredients and that the commercial natto has been aged for a while before making it to your bowl.

Natto will keep for about 4-6 weeks in the refrigerator, though the smell will intensify as it ages. For a mild flavor, it is best to consume it within a week. For longer storage, you can freeze natto for several months. But you will need to consume it within 5-7 days of defrosting.

Sarah

Sarah

I live in Oregon with my 4 kids. I hop between my kitchen and sewing room. As the daughter of a ranch-girl turned County Extension Agent, I really believe that with enough ingenuity and know-how, anything can be made. I try to keep some cultured vegetables and condiments on hand, as well as a robust supply of yogurt. What really excites me though is finding old ways of culturing foods from around the world and making it work in my life. “I wonder” is a phrase I utter a lot, and can make my kids nervous! I love to learn and share what I’ve discovered.

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Comments

    • Sarah says

      The Vitamin K levels should be fairly similar. However, I’ve not seen a study yet on the results with different beans and cannot answer that definitively.

  1. Dwight says

    DO YOU KNOW WHAT WOULD HAPPEN IF YOU ADDED THE NATTO CULTURE TO COOKED VEGETABLES? IS THERE SOMETHING INHERENT IN THE BEANS THAT ALLOWS THE CULTURE TO GROW?

    • Sarah says

      While vegetables can be cultured with natto, there is a bit of a trick to getting them cooked enough to remove other bacteria and not cooking so much that the vegetables are mushy. All fermentation will result in vitamin K, so I recommend lacto-fermenting vegetables. They are much more pleasant to eat this way!

  2. aa says

    Great write up. I just finished making Natto out of black beans and they came out really well. I sprouted mine, and cooked them until they were very soft. (at least with sprouting you can be sure the beans are vital, unlike some Adzuki beans I tried to sprout – didn’t work – the were sitting in a warm shop too long.) Anyhow, my previous batch were not nearly as soft and no strings resulted. The bacteria have to be able to penetrate the bean easily, so the outer skin must be broken and the inside should melt in your mouth (just my experience.) Another important thing is humidity when fermenting. It needs to be very humid, and there still needs to be airflow.

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