How is Soy Sauce Made?

Soy sauce is a valuable part of much of the food at our Bellevue Japanese restaurant.  You dip your sushi in it, you sprinkle it on your rice, and it’s even a chief ingredient in teriyaki sauce.  But where does soy sauce come from?


  • The first part of the process is to soak and steam the soybeans, then mix these beans with roasted grains of wheat.

  • After this, the manufacturer wants to encourage koji mold to grow in the mix.  This breaks down the soy’s proteins and the wheat’s carbohydrates into a substance they call shoyu koji.  This process takes about three days.

  • This shoyu koji is then mixed with salt water to ferment and age for a few months.

  • After the fermentation process, the shoyu koji has turned into a thick mash.  This mash is pressed and strained through a cloth to remove the fluid.  This fluid is called “raw” soy sauce.

  • Finally, the raw soy sauce is cooked so as to pasteurize the mixture and bring an end to the chemical reactions, stabilizing the soy sauce.  Now it is ready to be bottled, sold, and enjoyed!