Soy sauce is one of the most important ingredients in Japanese cuisine and part of the golden ratio for creating distinctive Japanese sauces and seasonings.

In nearly every American restaurant, you’ll find some basic condiments already on the table ready for your use in seasoning a dish. Typically, salt and pepper will be prevalent, and quite often ketchup and mustard as well. In a Japanese restaurant, you’ll find a bottle of soy sauce waiting for you. The dark liquid serves as the most popular all-purpose seasoning in the cuisine.

You only need a little bit of soy sauce to impart a deep, earthy, salty, umami flavor to many dishes, from simple rice to more complex foods. It is also one of the main components of the Japanese golden ratio to create many different Japanese sauces and seasonings.

What Is Soy Sauce?

Originally developed in China, the use of soy sauce spread throughout Asia approximately 2,200 years ago. Chinese Buddhist monks introduced shoyu, soy sauce, to Japan in the 7th century. The sauce is made primarily from fermented soybeans and wheat, and today there are quite a few types, each with its purpose in Japanese cuisine.

How to Make It?

Soybeans are soaked in water and boiled, and wheat is roasted and crushed. A live mix of fungus spores called Koji is then added to the mix of cooked soybeans and wheat, which helps the fermenting process. Salt brine is also added to the mix. It often takes several months for the soy sauce to develop fully.

Nutrition and Health Benefits

You’ve probably heard that soy sauce is bad for you. This belief stems primarily from the fact that it has a very high sodium content: 900-1,000 milligrams in a tablespoon. As such, recommendation is to limit soy sauce consumption for individuals who need to be careful about their salt intake.

Additionally, there have been several studies about soy sauce being bad for digestion. However, this may stem from the fact that it contains wheat and gluten, and the growing recognition of gluten intolerance in many people may explain these results. More recent studies suggest that soy sauce may be good for digestion (in individuals without gluten intolerance), as the fermentation process creates enzymes that are beneficial to the digestive tract.

Other nutritional qualities include good amounts of protein, vitamin B3, and beneficial minerals like manganese. It is also low in calories and carbohydrates and contains a large number of antioxidants.

As for the health benefits, the antioxidants play a large role. In addition to the possible digestive tract benefits, soy sauce also helps to improve your immune system and inflammatory system. The presence of polysaccharides might also help to reduce the symptoms of allergies. Lastly, the presence of vitamin K, which develops during the fermentation process, supports bone health.

Many studies regarding the health benefits of soy sauce are still ongoing. However, as with anything, consumption in moderation is key. Nowadays, you can even purchase gluten-free or low-sodium version easily in store and online.

Dark and light soy sauce? What's the difference?

How to Store Soy Sauce

Because of the high sodium content of soy sauce, it is difficult for any bacteria or microorganisms to develop, so an unopened bottle can technically be fine for several years. However, the soy sauce may tend to lose some of its flavors over such an extended period.

Unopened, the bottle can be stored in the pantry or any cool and dry area. You can continue to keep the bottle in the pantry after opening, as long as you seal it tightly. It will remain fine for up to six months. You can also keep it in the refrigerator, which won’t affect it. However, either way, the flavor may deteriorate over long periods. Regardless of the loss of flavor, the soy sauce remains fine for use years after the “best by” date.

Different Kinds of Soy Sauce

Today, there are several varieties available for purchase, each with its culinary use.


This is the type of soy sauce you will see on the table in Japanese restaurants, and most commonly on the shelves in supermarkets. It is often labeled simply as “Soy Sauce” on the bottle. When a recipe calls for soy sauce without any other specifics, it usually means to use koikuchi. Koikuchi is ideal for making dipping sauces, marinades, stir-fries, and basting.

Usukuchi Shoyu

Usukuchi Shoyu contains a stronger balance of salty and sweet flavors due to the addition of mirin. It’s lighter in color, so it’s perfect for adding flavoring to ingredients without turning the food a darker color. The flavor is also more intense and saltier than dark soy sauce, and so you should be careful when using.

Tamari Shoyu

Tamari is a great substitute for those with gluten intolerance because it is made primarily with soybeans, and very little to no wheat. A true tamari with no wheat will often say gluten-free on the bottle. However, it’s always safe to check the label for a detailed list of ingredients. Tamari has a strong flavor and is mostly used as a dipping sauce.

Genen Shoyu (Less Sodium)

Reduced-salt soy sauce still contains salt, but only about 50% of what regular one contains. Use it in place of Koikuchi for any recipes that call for soy sauce if you want less salt intake in your diet.

Learn which Japanese foods are gluten-free here.