How to Make Soy Sauce

Soy sauce has been used to flavor foods for over two thousand years.[1] It's a common ingredient in Asian cuisine. If you make Japanese, Chinese, or Korean food often, it may be worthwhile to learn how to make your own soy sauce, rather than buying it by the bottle, especially if you're concerned about the origin of the ingredients. This recipe is basic and straightforward. Yet, while the ingredients are simple, beware, for making soy sauce is both a long and somewhat smelly process! Nevertheless, it's gratifying to work on for 3-6 months, then serve it at your dinner table. Keep reading for a detailed recipe.


  • 16 ounces / 453g soybeans, (organic if desired) cooked until they're crumbly, removed from pods
  • 12 ounces / 340g flour of choice (all purpose, organic if desired)
  • 8 ounces / 226g salt
  • 1 gallon / 3.7 litres water


  1. Image titled Soy Bean 1
    Finely chop the cooked soybeans that have been removed from their pods. You can chop with a knife, but using a food processor is much easier.
  2. 2
    Transfer the soybean 'paste' to a large mixing bowl. Add flour, and mix until combined.
  3. 3
    Knead the mixture well. Turn it out onto a flat surface and form it into a log shape.
  4. 4
    Cut the log into 1/4 inch / 6.2mm thick slices. A serrated knife will make this easier.
  5. 5
    Grow some mold.
    • Moisten paper towels with water. Lay them all out flat.
    • Layer the 'dough disks' between the damp paper towels. Start with a towel layer, and end with a towel layer.
    • Wrap the stack of disks in plastic wrap. Make sure it's wrapped tightly.
    • Place the entire wrapped package on the baking sheet. Place it in an inconspicuous area, and leave it until the whole thing is completely saturated in mold. This can take a week or more.
  6. 6
    Now comes the fun part. Unwrap the whole package, and place the disks, an inch or two (2 to 5cms) apart, on clean baking sheets. Leave them to dry completely, until they turn brown. It is best to leave them in direct sunlight if possible.
  7. 7
    Mix the salt and water in the large pot. Add all of the disks, and cover the pot loosely with plastic wrap.
  8. 8
    Allow the mixture to ferment. Stir it once a day with the wooden spoon.
    • When the disks are completely dissolved, the fermentation is complete. This can take anywhere from a few weeks to several months.
  9. 9
    Strain. When the dissolving is completed, strain the liquid through cheesecloth into a 'easy to pour' container, like a large measuring cup.
  10. 10
    Transfer to bottles. It's now ready to serve.
    • Add a label with name, date, and bragging rights.


  • This soy sauce can be used anywhere you'd use store bought soy sauce, so enjoy it often.
  • The proportion of salt to water in the above recipe results in a 6% brine solution (226g of salt to 3700ml of water). While a recipe can be modified to fit individual tastes, the use of a brine solution with a concentration between 15% (~600g of salt to 3700ml of water) and 25% (~900g of salt to 3700ml of water) is recommended. The use of a stronger brine results in an environment that is hospitable to the desired molds, and inhospitable to the undesirable ones.
  • Experiment. Try using different types of stock (vegetable, beef or chicken) in place of the water for different flavors.


  • If you can't handle your home having a bit of an unpleasant odor, you might want to stick with the supermarket variety of soy sauce.
  • If you get bored easily, or you're impatient, this project might not be the best for you. It can take up to six months to see the finished product.

Things You'll Need

  • Paper towels
  • Plastic wrap
  • A food processor
  • Mixing bowl
  • Serrated Knife
  • Wooden spoon
  • Large pot
  • Two or three baking sheets
  • Cheesecloth
  • Bottles for storage
  • An 'easy pour' container, like a measuring cup.

Sources and Citations

  1. Wisegeek, What is soy sauce?,

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