Adventures in Fermentation: What is Natto?

Natto over Rice by An Unrefined Vegan

Ten years ago – hell – 5 years ago, I never would have believed that I’d be routinely baking my own bread, brewing my own kombucha, creating non-dairy cheeses, or making fresh tofu. Now those things are all familiar and “normal” to me. But recently I crossed into some virgin food territory.

But first, let’s talk about that kombucha. Stick with me here. It’ll make sense in a sec. I’ve heard that some people think that the taste and smell of kombucha is akin to the odor wafting out of a pair of Nikes after a long run on a hot day. Fair enough. But I’ve come to appreciate this mild form of funk and it’s why I pretty much always have a batch of the stuff doing its “mother” thing in a big jar on top of my refrigerator. Which brings me to another digression – this one in the form of the undisputed King of stink: limburger cheese.

For some reason I can no longer recall, in the 9th grade I thought it would be a good idea to join the marching band. Me and my badly-played cornet (imagine a stubby trumpet) had dreams of lock-stepping in glorious union with my fellow bandmates during half-time at football games. Ahhh, think of it: clear fall nights with a slight nip in the air; the warm coriander smell of steaming hotdogs over at the concession stand, the neon green blaze of the field under bright buzzing lights. Romantic, no? And there I am amidst it all, wearing a tall hat with a plume and a graceless, shapeless blue and red wool tunic and flared floodwater pants (with stripes), tooting out the heroic, if overwrought Fight Song when the team needs support; cheering from the lower bleachers when they score a touchdown or field goal. Cheering on our Wolverines.

But before I could take my rightful spot amongst the shiny golden trumpets and trombones, I had to endure Band Camp. One long, hot weekend in August in a sleepy town named Hiram. Band Camp was known to be hell on freshmen. But not for the long, hot days learning how to decipher the choreography of marching while reading music while playing an instrument. No. The climax of Band Camp was when older bandmates had free reign during one terrifying afternoon. They could legally tap into their inner sadist. For a shy, myopic, brace-faced and knock-kneed girl, there wasn’t a scarier proposition. Turns out this “hazing” really wasn’t TOO bad. Sure, the yelling in our ears sucked, the taunts, the baked beans poured into our hair that dripped down our necks and backs; the honey drying and sticking to the sun-burned backs of our knees was uncomfortable, yes, especially in the relentless heat and humidity. But it was all endurable. Until the limburger cheese…the limburger cheese broke many a freshman. Big gobs of the stinky stuff were smeared under and into our nostrils. There was no avoiding the rank, dank, moldy, musty stench of it. Even now on certain August afternoons when the sun is slanting just right through the trees, and the cicadas scratch out their tuneless drone, I can summon up that smell.

Which brings us – finally – to natto. The odor of natto is one of those things that brings back that long ago late summer day as the sun beat down, drying and cracking the smears of limburger on my upper lip. The odor of natto makes kombucha seem like a freshly-picked bunch of spring flowers. 

So what the heck is natto? Well, you take soybeans, cook them, sprinkle them with magical white powder, let the mixture sit for 24 hours and – voila! – natto! In Japan, natto is often served for breakfast and is thought to give one a manly form of er, strength, if you get my drift. It’s loaded with protein, of course, and it serves up vitamin E and B2. But its real draw is vitamin K – a vitamin also found in greens, broccoli, Brussels sprouts, and blueberries, among other foods (including animal products). Vitamin K is important to keep our blood clotting normally and for regulating calcium. It also may be a benefit for those with heart disease by clearing plaque from arteries.

One other little thing you should know about natto. Full disclosure. It’s slimy as heck. Slug-trail kind of slimy. Three-year old kid with a cold kind of slimy. So why the Sam Hill and tarnation am I making natto? Because my loved one recently got some not-so-good news regarding his heart. So we are doing everything we can think of to keep him healthy and to possibly reverse whatever damage has been done. Thankfully that loved one is rather getting to like natto. He eats it with a touch of soy sauce, pickled ginger (or kimchi), steamed rice, and chopped scallions.

Natto over Rice by An Unrefined Vegan

Just in case this post hasn’t completely thrown you off of natto and you want to try your hand at it. Read on for general directions. For more specific directions, go here or here.

Natto Equipment An Unrefined Vegan

To make natto at home, you’re going to need a few things:

  • Dried soybeans
  • natto spores (I purchased mine here.)
  • cheesecloth
  • several oven-safe glass/ceramic dishes
  • an oven (or other spot) capable of sustaining a 100-103F temperature for 24 hours
  • metal spoon, metal tongs, strainer

Number one most important thing to know before embarking on your own natto adventure is that you want to make sure your dishes, utensils, cheesecloth and hands are as clean as possible. I sterilized everything (even the cheesecloth, but not my hands; simple washing will do) in boiling water (for 5-10 minutes). The temperature that encourages the good spores to grow are also ideal for bad spores to grow. So – you want to start out as clean as you can. 

Soak the soybeans overnight, rinse and drain. Then cook the soybeans until soft. I use a pressure cooker and it takes about 20 minutes. It’ll take longer on the stovetop.

While the beans are still warm and after you’ve sterilized your tools, mix some of the natto spores with some sterilized water and then pour this mixture over the beans. Stir well, but gently because the beans should be very soft. Divide the mixture between dishes (you want a fairly thin layer of beans, not a big mass of them in one container), cover with cheesecloth and then with a lid or tightly with foil. Place the dishes where you can maintain a temperature range of between 100-103F. I did one batch in my oven, keeping the light on. Turns out the oven stays between 100-102F. Perfect. I also did a batch in my dehydrator. This worked pretty well, too, but some of the beans dried out* just a bit. Not a big deal because they later plumped back up. Just something to keep in mind.

After 24 hours at this temperature, place the beans (still in their respective dishes) in the refrigerator overnight. After that, your beans are ready to eat! Beans are freezable for later consumption – just in case you made yourself a gigantic batch.

*For a crunchy snack, I may dehydrate some natto. Dried natto beans are actually quite tasty, but they are very expensive to buy.


22 thoughts on “Adventures in Fermentation: What is Natto?

  1. Pingback: Adventures in Fermentation: What is Natto? | Harvey Diamond Fan Page

  2. allysia

    It’s not every day you come across a blog post on homemade Natto, that’s for sure! We used it in culinary school a couple times, and I really tried to get into it…but that stringy sliminess, man. I have just not acquired that taste (yet…I’ll keep trying). It definitely does make the fermentiness of kombucha seem like no big deal though!

  3. Jane

    Thanks for this interesting post! I don’t think i could ever manage this process – too complicated and time consuming – but we can purchase at my health food shop a product called natto miso – which is barley and seaweed and a few other things presumable fermented with the natto…. a dessert spoonful mixed with noodles and some steamed greens, possibly some braised tofu if you have it on hand, is a wonderful healthy dinner when you are rushed! I love the flavour – very ‘umami’ (hope that’s right) but to me, not at all like stinky cheese!
    All the best for your partner’s heart health!

    1. An Unrefined Vegan Post author

      I would love to find that product, Jane! It sounds like something even I could stomach. The pure natto beans (and yes, you are right – it’s a pain-in-the-butt process) are just too hardcore for me, but that miso version sounds pretty good!

  4. Christine Baker

    I have had natto in Japan and yes it is very slimy, even my daughter in law, who is Japanese doesn’t like it. I must admit to pushing it to the side.

  5. Virginia

    HI Annie, This is awesome! I usually get natto in an Asian store. I bet this homemade recipe beats the prepacked ones. Thank you also for providing links for the ingredients.

  6. Cathy

    Sadly I cannot take in anything “soy”, BUT what I do want to say is take care of that “loved one”. I know if anyones food can help, it WILL BE yours. <3
    Oh yeah, and a 😉

  7. lemonandcoconut

    Thank you for reminding me about natto. I don’t eat soya either (as above), but can eat fermented soya so I think natto should be okay for me. Only I do also feel apprehensive about it! I’m sure it’s delicious, and certainly super healthy and so fantastic food. Wishing you and your partner all the best 🙂

    1. An Unrefined Vegan Post author

      You might try and find natto in an Asian market to try before making your own, simply because the taste is very strong and I suspect not enjoyable to most people. Thank you for your kind thoughts!

  8. tearoomdelights

    I take my hat off to you, you never seem to be fazed by things like this. Did you ever think of becoming a chemist, I wonder? I think all the test tubes and weighing and measuring would have been right up your street. Mind you, you probably wouldn’t want to eat the end products, and I reckon the noshing is a big motivation. I hope the natto works on your loved one’s heart.

  9. Poppy

    Wow, where to start? Band camp sounds shockingly awful? I don’t understand why they did that to you and why they were allowed to? I’m sorry to hear about Kel’s health, I really hope it’s not too serious and that with your wonderful kitchen magic, you can help it. Also, the slimy natto sounds gross, I won’t be rushing to try it any time soon!!! Hehe! XO

    1. An Unrefined Vegan Post author

      Band camp was pretty awful! But it gave me some good stories! I guess back in the early 80s it was just considered part of the ritual and a rite of marching band passage to do horrible (but ultimately harmless) things to newbies! And I think you are wise to avoid natto…

  10. Mary

    Since glyphosate is used heavily as a desiccant just before harvest on non-gmo soybeans I would strongly recommend going full certified organically grown. To your health! 😉


Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.