Homemade Nattō

Tender soybeans bound by characteristic elastic white strings from successful fermentation. A powerful earthy, cheese-like aroma with a deep umami flavor.

• Prep time: 30 min
• Cook time: 60 min
• Difficulty: Medium
• Calories: 565
• Protein: 47 g
• Carbs: 27 g
• Fat: 25 g

Ingredients

• 500 g Whole soybean ( dry )
• 2 L Mineral water ( for soaking )
• 10 g natto ( for inoculation )
• 2 tbsp soy sauce optional ( for final seasoning )
• 1 tsp Mustard optional ( as a side )
• 1 piece Spring onion, sauté/poêlé sans matière grasse optional ( finely sliced )
• 1 pinch Bacillus subtilis natto culture optional ( diluted in a teaspoon of lukewarm sterile water )

Instructions

1. Soaking the beans

   Wash the soybeans thoroughly. Let them soak in mineral water for at least 12 hours: the beans should double in size and lose their round shape to become oval.

2. Steam cooking

   Steam the beans. The bean is ready when it crushes without resistance between the thumb and pinky finger. Sterilize all your fermentation equipment with boiling water during this time.

3. Inoculation

   While the beans are still piping hot, mix them with a small amount of nattō or the diluted bacillus-subtilis-natto culture. The heat helps the bacteria spread quickly.

4. Controlled fermentation

   Place the beans in a clean dish, cover with a sterile cloth, and maintain at a constant 40°C for 24 hours. A thin white film should appear and the smell should become distinct.

5. Cold maturation

   Place the nattō in the refrigerator for an additional 24 hours. This rest stabilizes the fermentation and allows the filaments to become more elastic and long.

Chef's tips

• Hygiene is critical: boil every container and spoon to prevent mold growth.
• Mix vigorously before eating: the more you stir, the whiter and creamier the strings become.

Storage

Store in an airtight container in the refrigerator for up to 7 days. Freezes well to stop the fermentation process.