How To Make Soy Sauce

Name: How To Make Soy Sauce
Prep time: PT-491404H4M5S
Total time: PT-491404H4M5S
Cuisine: Korean
Ingredients: 6 cups dried soybeans; 4 cups good salt (Himalayan or sea salt); Filtered or spring water; A few pieces of charcoal; Optional: dried Korean chilies, dried jujubes; 1 raw egg (for salinity testing)

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If you’ve ever wondered how soy sauce is made the old-fashioned way, this guide walks you through the authentic Korean process using only soybeans, salt, and water. It’s slow and intentional—months instead of days—but the result is a deeply savory, aromatic sauce you can’t replicate from a store bottle.

Collage of homemade soy sauce being poured from a spoon into a glass bowl, and glass jars of soy sauce with soybeans on a rustic wooden surface. Text overlay says “How To Make Soy Sauce.”

You don’t need special equipment or rare ingredients; just a few traditional touches and plenty of patience. It’s less a recipe and more a meaningful kitchen project that connects you to generations of home cooks.

Why Make Your Own Soy Sauce?

You’re basically crafting one of the world’s most essential seasonings from scratch. You control every ingredient. The process is pure kitchen alchemy: just beans, salt, water, sun, and time become a powerful umami elixir.

What You’ll Need

Dried soybeans
Good-quality salt
Filtered or spring water
Small pieces of charcoal
Dried Korean chilies (optional)
Dried jujubes (optional)
Lukewarm filtered water (for brine)
Extra water for soaking and cooking
Large glass jars or earthenware crocks
Cheesecloth and string
A raw egg (for testing salinity)
Time, patience, and commitment

For precise amounts, check the recipe card at the end of the post.

A glass of water, a scoop of pink salt, and scattered soybeans on a wooden board, the essential ingredients for making soy sauce from scratch.

Step-By-Step Instructions

1. Soak and Cook the Soybeans

Pick over, wash, and soak soybeans overnight in filtered water.
Drain, rinse, and cover again with fresh water.
Boil, then simmer until beans are very soft (can take hours). Add more water as needed.
Strain and cool beans.

2. Form and Dry the Bean Blocks

Mash cooled beans with a mortar & pestle or food processor.
Divide into 4 portions, shape into blocks, and lay them on a parchment-lined tray.
Dry near a heater for several days, flipping as needed. Fungi/mold are normal—they help fermentation!

Four finished meju blocks resting in a rustic bowl on a small wooden table, ready to be used for homemade soy sauce.

3. Hang and Cure the Blocks

Tie string around the blocks and hang them (in a well-ventilated place) for several weeks, until hard and covered with white/gray fungi.
Gently rinse off fungi under running water, then let blocks dry near a heater again.

Several meju blocks tied with twine, hanging by a sunny window to air dry and cure before the soy sauce fermentation process.

4. Ferment in Brine

Dissolve salt in 16 cups lukewarm filtered water. Test salinity: drop in a raw egg; if it floats, the brine is ready.
Place 2 bean blocks in each glass jar. Add a few pieces of charcoal, dried chilies, and jujubes.
Pour in brine. Cover jars with cheesecloth.
Set jars somewhere sunny, letting them ferment for 5+ months. Occasionally let them soak up sunshine uncovered.

Glass jars filled with large chunks of meju blocks and dried fruits, steeping in brine to age and infuse flavor for traditional soy sauce.

5. Strain and Age

After 5–6 months, remove the blocks. Discard charcoal, chilies, jujubes, and excess fungi.
Strain the sauce and bring to a boil on the stove. Let cool.
Transfer to smaller glass jars and age in a cool pantry for at least a few more months for best flavor.

Close-up of glass jars filled with homemade soy sauce and surrounded by soybeans, highlighting the traditional Korean fermentation method.

6. Enjoy!

Once your soy sauce has darkened and the flavor is deep, it’s ready to use.
Pour into small bottles for daily use. Use as a dipping sauce, seasoning, or marinade—this stuff is gold!

Close-up of a spoon drizzling thick, homemade soy sauce into a glass bowl, with jars of soybeans and brine in the background.

Tips & Troubleshooting

Salt is essential: Don’t reduce the salt below the “egg floats” threshold—salt is what keeps bad bacteria away.
Fermentation takes time: Let nature do the work. Soy sauce gets better the longer it ages.
Don’t worry about the fungi: It’s a natural part of the process and safe for this traditional method.

FAQ

Why use charcoal and dried fruits?

Charcoal purifies the brine; jujubes add mild sweetness and depth.

Is homemade soy sauce always this salty?

Yes, but the finished sauce has a rich, balanced flavor. If you need lower-salt, dilute finished soy sauce with broth when using.

Can I skip the jujubes or chilies?

Yes! They’re traditional, but the essential process works without them.