📝 About This Recipe
Embark on a culinary journey into the heart of Japanese probiotics with this traditional recipe for homemade Natto. These fermented soybeans are prized for their unique nutty savoriness, a distinctive 'stringy' texture known as neba-neba, and an incredible profile of Vitamin K2 and Nattokinase. While the aroma is bold and earthy, the flavor is deeply umami, offering a buttery richness that transforms a simple bowl of rice into a nutritional powerhouse.
🥗 Ingredients
The Culturing Base
- 2 cups Small dried soybeans (specifically 'natto-mame' or small organic soybeans for better texture)
- 6-8 cups Filtered water (for soaking)
- 0.1 grams Natto spores (Bacillus subtilis natto) (or 1 small spoonful of the starter culture)
- 2 teaspoons Sterilized warm water (to dissolve the spores)
Traditional Seasonings (For Serving)
- 2 tablespoons Japanese Soy Sauce (Shoyu) (high quality, naturally brewed)
- 1 teaspoon Karashi (Japanese hot yellow mustard)
- 1 tablespoon Dashi (kombu or bonito stock to loosen the texture)
- 1 teaspoon Mirin (for a hint of sweetness)
Garnish & Accompaniments
- 3 stalks Green onions (finely sliced)
- 1 packet Katsuobushi (dried bonito flakes)
- 2 sheets Nori seaweed (shredded or cut into strips)
- 2 pieces Pickled Umeboshi (optional, for tart contrast)
- 3 cups Short-grain Japanese rice (steamed and hot)
👨🍳 Instructions
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1
Thoroughly wash the soybeans in a large bowl, rubbing them together to remove any dust or loose skins. Rinse until the water runs clear.
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2
Soak the beans in 6-8 cups of filtered water for 12 to 24 hours. The beans should triple in size and become oval. In colder climates, aim for the full 24 hours.
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3
Drain the soaking water. Steam or boil the beans until they are very soft. If using a pressure cooker, cook on high for 45 minutes; if boiling, it may take 3-4 hours. The beans are ready when they can be easily crushed between your thumb and pinky finger.
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4
While the beans cook, sterilize all equipment (bowls, spoons, fermentation containers) with boiling water. This is crucial to prevent the growth of unwanted bacteria.
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5
Dissolve the natto spores into 2 teaspoons of sterilized warm water. If using a 'starter' batch of store-bought natto instead of spores, mix 1 tablespoon of it with a little warm water.
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6
Drain the cooked beans and place them in a wide, shallow sterilized container while they are still very hot (at least 180°F/82°C). The heat helps kill surface bacteria and activates the spores.
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7
Immediately pour the spore solution over the hot beans and stir gently with a sterilized spoon to ensure every bean is coated.
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8
Spread the beans in a thin layer (about 1-2 inches deep) to ensure oxygen can reach the bacteria, which is essential for fermentation.
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9
Cover the container with a piece of sterilized cheesecloth or a paper towel, then place a loose-fitting lid on top. This allows the beans to breathe while retaining moisture.
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10
Place the container in a fermentation chamber (like a yogurt maker, oven with the light on, or a dehydrator) set to 100°F (38°C) to 104°F (40°C). Ferment for 22 to 24 hours.
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11
Check the beans after 22 hours. A white, thin film should cover the beans, and they should produce long, sticky strings when stirred. A faint ammonia smell is normal, but it shouldn't be overwhelming.
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12
Remove from the heat and let the natto cool. Transfer to the refrigerator for at least 24 hours (and up to 3 days) to 'age.' This stops the fermentation and allows the flavors to mellow and the strings to become more resilient.
💡 Chef's Tips
Cleanliness is paramount: ensure every utensil is scalded with boiling water to avoid mold. Use small soybeans if possible; they have a higher surface-area-to-volume ratio, which results in more 'sticky' surface area. If you don't have a fermentation chamber, an Instant Pot on the 'Yogurt' setting (Low or Medium) works perfectly. Don't skip the refrigeration step; aging the natto for 24-48 hours significantly improves the taste and reduces the harshness of the aroma.
🍽️ Serving Suggestions
Serve over a bowl of steaming hot Koshihikari rice with a raw egg yolk (Tsukimi style) for ultimate creaminess. Mix with chopped kimchi and a drizzle of sesame oil for a spicy, probiotic-rich snack. Fold into an omelet (Natto Omuritsu) for a savory, high-protein breakfast. Pair with a cup of hot Genmaicha (brown rice green tea) to complement the nutty notes of the beans.