Natto 納豆


I made natto from scratch!!!! AND IT WAS NOT THAT HARD!


So, what is natto? It’s a fermented soy bean dish commonly eaten in Japan, often for breakfast. Recently, it’s been getting some attention as a health food because it contains nattokinase, a natural blood thinner.

I’m 26, so I don’t have to worry about that! What I love about it is that it’s delicious, gentle on the stomach, low calorie, high protein, high fiber, and full of probiotics! And unlike other high fiber foods, since the probiotics have already broken down a lot of it, it shouldn’t make you too gassy (yeah, I know, gross, but this is important when planning what to eat for breakfast)!

If you’ve never tried it before, it’s REALLY funky smelling. Don’t worry! After you’ve had it a few times, all you’ll notice is a pleasant earthiness! I think the best comparison is getting used to blue cheeses.

For first-timers, I recommend dousing it in a ton of soy sauce and a small bit of spicy mustard.

I’ve always been intimidated by the idea of making natto, but there really is no need. Despite the long description below, the process is actually very simple: Cook beans, add natto, and keep warm until gooey.


One package store-bought natto

1/3 cup water (80 ml) (use bottled water if you have anything in your water that will kill probiotics)

2 cups (400 grams) (or as much as you want!) dried soy beans

Soak beans overnight or until doubled to tripled in size.

Steam or boil beans until they are soft and easily smashed between your fingers (or basically, a creamy texture you would enjoy eating).

With a pressure cooker, it takes 30 minutes to steam or boil them. Without a pressure cooker, expect them to boil for 6-7 hours. I don’t know how long it would take to steam them without a pressure cooker, estimates online say at least an hour. Steaming preserves more nutrients, but there’s no other reason to choose one method over the other. Remove beans from heat and strain.

Allow soy beans to cool until they are warm to the touch, but will not burn your mouth or fingers.

Combine store-bought natto and water in a bowl.

It looks so gross, right?! This step allows you to spread the probiotics more effectively into the beans. And yes, I accidentally used more than 1/3 cup water…oops!

Leave the freshly cooked beans in the strainer, and pour the natto and water mixture over them. Mix it in, allowing the natto and the water to coat all the beans, and excess water to drain out the bottom of the strainer.

Put the beans in something without holes in the bottom (ie. Not a strainer!). And place plastic wrap directly on top of the beans. Poke a ton of holes in the plastic wrap with a toothpick (I did 20 for a large jar).

Cover with plastic wrap and poke the plastic wrap with a toothpick

Place the beans somewhere hot and humid for 20 hours. The temperature should ideally be between 37-40 degrees Celsius (98.6-104 Fahrenheit), but don’t stress too much over exact temperatures.

My rule of thumb is “crappy hot day” level of heat 🙂 Again, this should be warm to the touch, but not burning hot. This could be a turned off oven with a pan of boiling water inside it (replace the water periodically), a yogurt maker, or even outdoors if the weather is hot enough. If choosing the last option, make sure the beans are protected from direct sunlight by draping a towel over them.

Check the beans after 20 hours. When they are ready, they should have a light white coating.

White coating on fermented natto

When you stir the beans, gooey “strings” will come off of them. Taste to see if the flavor is strong enough for you. If not, allow to ferment longer until you like it. Store in the fridge or freezer for as long as you like 🙂

Natto becomes gooey and stringy when stirred.

Note: If you are using more than 2 cups of dried beans, expect it to take longer than 20 hours. This is because the starter has to “grow” itself through more of the beans. I started with a 1 kilo (2.2 lbs) bag of dried soy beans, and the same amount of starter (the store-bought natto). It took between 26-30 hours to get it as strong as I wanted. Less time will yield a milder, subtler natto.

To serve: Spoon a small portion of natto (1/4 cup or more) in a cup with spicy mustard and soy sauce or natto sauce. Stir it vigorously with chopsticks until it becomes foamy and stringy. Pour on top of freshly steamed rice and add kimchi, green onions, or any other desired toppings.

To make natto sauce: Combine 1 teaspoon soy sauce, pinch of dashi powder, pinch of brown sugar, 1/8 tsp apple cider vinegar.

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