What to Know About Soy Sauce

Reviewed by Jabeen Begum on June 22, 2021

‌Soy sauce is a popular food used both as a cooking ingredient and a condiment. 

The history of soy sauce goes back over 2,000 years in China. It was developed to help keep food from spoiling and add flavor to it, as salt was expensive at the time. It was introduced to Japan in the 7th century and later to Korea and Southeast Asia. It is now popular in many other parts of the world.  

What is Soy Sauce?

‌Soy sauce is known as shoyu and soya sauce. It’s made with soybeans, wheat, salt, and a fermenting agent. 

‌The traditional brewing method to make soy sauce involves soaking soybeans in water for several hours and steaming them. Wheat is then roasted, ground into flour, and mixed into the steamed soybeans. Fungal spores, usually Aspergillus oryzae, A. sojae, and A. tamarii, are added in and left for 3 days. 

The next step is fermentation, where a brine solution is added. This may be left to ferment for from 1 month up to 4 years. For some premium soy sauces such as double-fermented soy sauce (saishikomi-shoyu), a raw soy sauce mix is added. After fermentation, the mixture is pressed to filter the solids, heated to remove molds and yeasts (pasteurized), and packed. 

The acid hydrolysis method is much faster, taking just a few days. This uses soybeans without the oil, wheat gluten, and hydrochloric acid. The mixture is heated for 20 to 35 hours to break down the proteins. 

Some soy sauces are a mixture of both traditional brewing and acid hydrolysis, which makes them cheaper but less tasty. A longer brewing time means better flavor.

Types of Soy Sauce

‌Soy sauces differ according to the country they’re made in. Japanese soy sauces use equal amounts of soybeans and wheat. Chinese soy sauces use a higher ratio of soybeans to wheat.

There are two main types of Chinese soy sauce. The more common one is light soy sauce. It’s light brown with a thin consistency. Dark soy sauce is thick and darker brown in color because of the longer fermentation time. It may also have molasses or sugar added in, making it sweeter, less salty, thicker, and more full-bodied than light soy sauce.

There are five types of Japanese soy sauces. ‌

  • Dark soy sauce or koikuchi-shoyu. This is the most common type found in Japan and overseas. 
  • Light soy sauce or usukuchi-shoyu. Due to a shorter aging time, this type is lighter in color and has a milder taste.
  • Tamari soy sauce or tamari-shoyu has very little (about 10%) or no wheat. As a result, it has a mild aroma and a darker color. 
  • White soy sauce or shiro-shoyu has a much higher ratio of wheat to soybeans. Because of the way it’s fermented, it has a light yellow color.
  • Double-fermented soy sauce or saishikomi-shoyu is more expensive and usually used for sushi and sashimi.

Soy Sauce and Nutrition

‌A 15-milliliter (about 1 tablespoon) serving of soy sauce contains:‌

  • 10 calories
  • 2 grams of proteins
  • 0 grams of fat
  • 0 grams of carbohydrates
  • 920 milligrams of sodium (38% of daily value)

Is Soy Sauce Healthy?

‌Soy sauce tends to be used in small quantities. As such, it’s unlikely to have many health benefits. Soy contains isoflavones, which are compounds said to have benefits such as reducing menopause symptoms and improving cholesterol. If you’re interested in including the benefits of soy in your diet, tofu or other soy products like soy milk may be a better option.

‌‌Antioxidants. A study found that dark soy sauce may be high in antioxidants. Antioxidants may delay or prevent cell damage from free radicals. But as this evidence is limited, we need more studies to be sure. 

High in sodium. Just 1 tablespoon of soy sauce contains nearly 40% of the daily recommended 2,300 milligrams of sodium. Salt is an essential nutrient that our body needs to function. But too much of it can increase blood pressure and lead to heart disease and stroke. The average American takes in more than 3,400 milligrams of sodium a day.

Allergens. Soy is a common cause of allergy, especially in children. Soy sauce also contains wheat, which some people may be allergic to. Others may have celiac disease, an autoimmune disorder caused by eating gluten. 

Most soy sauces contain wheat, but some brands produce gluten-free soy sauces. Tamari is a category of soy sauces that can be made with less or no wheat, so you should check the label for ingredients if you have any allergies. 

How to Use Soy Sauce

‌Soy sauce can be added to dishes such as stir fries, stews, or soups. You can use it as a dip, as with sushi or sashimi. You can put it in a marinade or a glaze for meats. You can also use it to season rice and noodles. Try it as a salad dressing with sesame oil, honey, and rice vinegar. There are even desserts that use soy sauce, such as soy sauce caramel, and soy sauce brown sugar ice cream.

Show Sources


Biomedical Reports: “Soy isoflavone: The multipurpose phytochemical (Review).”

‌Centers for Disease Control and Prevention: “Heart Disease: Sodium.”

Free Radical Research: “The antioxidant activities of seasonings used in Asian cooking. Powerful antioxidant activity of dark soy sauce revealed using the ABTS assay.” 

Journal of Allergy and Clinical Immunology: “The natural history of soy allergy.”

‌Korean Cultural Center: “Food.”

‌National Center for Complementary and Integrative Health: “Antioxidants: In Depth.”

‌‌US Department of Agriculture: “FoodData Central: KIKKOMAN, SOY SAUCE.”

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