Natto: A Delicious Journey into Japanese Fermented Soybeans

Authentic Natto Recipe: How to Make Japanese Fermented Soybeans at Home

Embark on a culinary adventure with homemade natto, Japan’s famous fermented soybean delicacy. This unique dish, known for its subtle coffee aroma and distinctive slimy texture, offers endless possibilities for customization and a flavor profile that will intrigue even the most adventurous food lovers.

While natto is readily available in Japanese markets, creating your own allows you to control the fermentation process and unlock a world of flavors beyond the store-bought varieties. From selecting your preferred soybean type to fine-tuning the fermentation time, homemade natto puts you in the driver’s seat of this fascinating food journey.

The Magic of Natto

Natto’s signature sticky strands are actually a bacterial biofilm produced by probiotic cultures. This process not only creates natto’s unique texture but also enhances its nutritional profile. Many enthusiasts, including Ann Yonetani of NYrture New York Natto, believe that homemade natto retains more health benefits compared to mass-produced frozen versions.

By making natto at home, you can experiment with different soybean varieties. For example, black soybeans yield a milder, more toothsome natto that might appeal to beginners, while smaller brown soybeans produce a more traditional flavor and texture.

Natto-Making Essentials

Creating natto involves boiling soybeans, inoculating them with Bacillus subtilis (commonly known as nattokin or natto bacteria), and allowing them to ferment. Follow these key guidelines for natto success:

  1. Soak the beans for 12 hours to ensure even hydration and cooking.
  2. Add the bacteria starter while the beans are still hot to activate the culture.
  3. Use sterile utensils and containers to prevent unwanted contamination.
  4. Ferment in shallow containers for even heat distribution and better oxygen exposure.
  5. Allow 20-24 hours for fermentation, followed by 12 hours of chilling before consuming.

Choosing Your Soybeans

The beauty of homemade natto lies in the freedom to choose your preferred soybean variety. Whether you opt for large soybeans, black soybeans, or traditional small varieties, each will ferment similarly when properly prepared. Some excellent soybean options include:

  • Shiloh black soybeans
  • Hunza organic soybeans
  • Signature Soy Non-GMO Soybeans for Natto

Signs of Successful Natto

Look for white strands coating the beans as a visual indicator of proper fermentation. If you’ve incubated at temperatures above 100°F, these strands might not appear within 24 hours. In this case, trust your nose – a funky cheese aroma indicates successful fermentation. If in doubt, refrigerate for an additional 12 hours to develop the flavors further.

Savoring Your Natto Creation

While natto over rice with tare (a sweet and salty sauce) is a classic serving method, don’t be afraid to get creative! Try these exciting natto combinations:

  • Refreshing Natto Salad: Mix with diced tomatoes, cucumbers, and shiso leaves for a cooling summer dish.
  • Natto Soba: Top cold soba noodles with natto, blanched okra, and a sprinkle of shiso for a texturally exciting meal.
  • Kimchi Natto Fusion: Combine natto with spicy kimchi for a fermentation flavor explosion.
  • Natto Pasta: Toss hot spaghetti with natto, olive oil, soy sauce, and nori for a Japanese-Italian fusion delight.

Natto Recipe


  • 2 cups dried soybeans (10 1/2 ounces; 300g)
  • Half of 1/8 teaspoon natto starter spores, such as Nattomoto


  1. Soak the dried beans in a large pot of water for 8-12 hours. This crucial step ensures even hydration for perfect natto.
  2. Stovetop Method: Rinse the soaked beans thoroughly. Cover with fresh water and bring to a boil. Reduce heat and simmer until beans are tender but whole, about 4 hours. Prepare a sanitized mixing bowl with boiling water, then drain. Transfer cooked beans to this bowl, discarding cooking liquid.
  3. Pressure Cooker Method: Rinse soaked beans in 3 changes of water. Cover with fresh water and cook at high pressure for 10 minutes, allowing natural release. Prepare a sanitized mixing bowl as above, transfer cooked beans, and discard cooking liquid.
  4. Sterilize all utensils and fermentation containers with boiling water. Mix natto starter with 1 tablespoon water and immediately add to the hot beans. Thoroughly combine to ensure even distribution of the starter.
  5. Divide beans among sanitized containers, ensuring layers are no deeper than 2cm. Cover with cheesecloth and seal with lids.
  6. Place containers in a warm environment (about 100ºF/38ºC) for 20-24 hours. Rotate positions halfway through and check hourly after the 20-hour mark. Look for a thin white film and a cheesy, nutty aroma.
  7. Transfer to the refrigerator for a final 12-hour fermentation. Your homemade natto is now ready to enjoy!

Recipe Notes

Customize your natto by adjusting the cooking time of the beans for your preferred texture. Remember, natto can ferment unevenly – if you see uneven white film, give it a good stir before refrigerating. If beans fail to turn white or develop a scent, you may need to start over with more starter or a warmer environment. Over-fermented beans will become stiff but remain edible.

Storage Tips

Your homemade natto will keep in the refrigerator for 2-3 weeks, developing a stronger flavor over time. Use caution when consuming natto that has been stored for extended periods, as the aroma can become quite potent!

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