Nattō Recipe

Making nattō at home feels like conducting a science experiment in your kitchen. The first time I tried it, I was convinced I’d messed something up – until that characteristic stringy texture started forming right on schedule.

If you’ve ever been curious about fermentation but felt intimidated, nattō is surprisingly forgiving. Yes, it takes time, but most of that is just waiting while bacteria do their thing.

The key to success? Temperature control and patience. That’s really it. No fancy equipment required – just your oven light can provide enough warmth for the fermentation magic to happen.

What You’ll Need

• 2 cups dried soybeans (300g)
• 1/16 teaspoon nattō starter spores
• Clean cheesecloth
• Sterilized containers
• Thermometer (optional but helpful)

Steps

1. Start by soaking the soybeans in plenty of water for 8-12 hours. They’ll expand significantly, so use a large container.
2. Drain and rinse the soaked beans thoroughly. Cook using either method:

• Stovetop: Simmer for about 4 hours until tender but whole
• Pressure cooker: 10 minutes at high pressure, natural release

1. Sterilize all your tools by boiling them for 5 minutes. This includes spoons, bowls, and fermentation containers.
2. Mix the nattō starter with 1 tablespoon water in a sterilized bowl. Add this to the hot beans immediately and mix thoroughly.
3. Transfer to sterilized containers, keeping bean layer under 2cm deep. Cover with cheesecloth and seal.
4. Maintain at 100°F (38°C) for 20-24 hours. Use your oven with just the light on, or a yogurt maker.
5. Check after 20 hours – look for white film and a nutty, cheesy smell.
6. Move to refrigerator for final 12-hour fermentation.

Substitutions That Actually Work

• Can’t find nattō starter? Use 2 tablespoons of store-bought nattō mixed with 2 tablespoons warm water
• Black soybeans work perfectly 1:1 for regular soybeans
• Any heat-safe container can replace specialized fermentation vessels

Making It Diabetes-Friendly

This recipe is naturally diabetes-friendly with only 11g net carbs per 100g serving. The fermentation process actually helps reduce the glycemic impact. Keep portions to about 1/2 cup per serving.

Tips & Storage

• Store finished nattō in airtight containers for up to 1 week in the fridge
• Freeze individual portions wrapped in parchment paper for up to 2 months
• If white film doesn’t appear after 24 hours, your temperature might be too low – try increasing by 2-3 degrees
• Small batches work better than large ones for even fermentation