What Is Shoyu?

This popular condiment is a type of soy sauce, but it’s not what you’re likely to pour out for your spicy ahi roll.

Soy sauce, a thin, umber liquid that’s popular to use with stir-fries, dipping sauces, and sushi, originated in China centuries ago. There, the condiment was usually 100 percent soy, with no other ingredients. The fermentation process introduces the rich flavor and intense salinity that’s associated with the sauce.

When soy sauce was introduced in Japan, however, the recipe changed to equal parts soybeans and wheat. Brewing the beans with wheat adds a subtly sweet flavor that’s less harsh and more rounded. This Japanese-style soy sauce is called shoyu.

Shoyu has carved out a cadre of intensely loyal fans, people who prefer the full-bodied flavor and delicate sweetness over assertive Chinese soy sauce. Not all shoyus are made the same, however, so it’s smart to learn about the variety you want before you head to the store.

Types of Shoyu

Shoyu can be divided into five main categories:

Koikuchi (regular soy sauce): Known as “dark” shoyu, this popular variety is rich and intense. Koikuchi is the most popular soy sauce in Japan, accounting for a major share of the country’s domestic soy sauce production. It is made from nearly equal quantities of soybeans and wheat, and has been perfected mainly in the Kanto region since the Edo period. Shoyu bottles in most U.S. grocery stores are the koikuchi variety, even if it isn’t labeled as such. Because of its fine balance of color, taste and aroma, koikuchi is a versatile seasoning that can go with just about any ingredient or dish. It lends itself particularly well to teriyaki, nitsuke (simmered dishes) and fish dishes using red fish (bonito, yellowtail, etc.) and blue fish (mackerel, etc.). It can be used in marinades, basting sauces, dips, stir-fries,and more.

Usukuchi (light colored soy sauce): This “light” shoyu is thinner, with a more salty, assertive flavor. However, at the end of the fermentation process, mirin (a sweet rice wine) is added, so usukuchi shoyu is sweeter than koikuchi, though not the sweetest shoyu option. Because of its light color and subdued aroma, it is used to enhance the natural colors of ingredients in cooking. Usukuchi is particularly recommended for simmered vegetable dishes, clear soups and udon noodle soups. It helps retain the color of white root vegetables (taro, lotus root, etc.) and green vegetables. Additionally, usukuchi is an excellent choice if you need to season dishes without adding any color to them, as is the case with chawan-mushi (egg custard) and clear soup. Usukuchi isn’t suitable for use alone as a dipping sauce or a table condiment.

Tamari: Tamari uses little to no wheat, so it’s a great condiment option for people who are eating gluten-free. Tamari tends to be thicker and richer, almost sweet. It is the “original” Japanese soy sauce, as its recipe is closest to the soy sauce originally introduced to Japan from China. Along with the typical use as a sashimi dipping sauce, tamari is also used as coating sauce when baking arare and senbei rice crackers, because it turns a beautiful reddish color when heated. It’s frequently used in stir-fries, salads, and drizzled over light proteins like fish and chicken.

Saishikomi (refermented soy sauce): The word saishikomi (meaning “twice fermented”) is derived from a production process in which the soy sauce is actually fermented twice. Generally, this type has a dark color, a thick texture and a rich flavor. But because saishikomi is expensive, it’s used mostly as a table condiment, particularly as a dipping sauce for sashirni and sushi. In the production process of regular soy sauce, salt water is added to the koji-mold culture. However, in the case of saishikomi, soy sauce is used instead of salt water. You’re unlikely to find this type of shoyu at mainstream grocery stores, but it may be in your local Asian market.

Shiro (extra light-colored soy sauce): In contrast to tamari, shiro primarily uses roasted wheat and only a small amount of steamed soybeans. Its color is even lighter than usukuchi, and its flavor and richness are more subdued.This lighter shoyu variety is a great way to add shoyu flavor but not turn your ingredients or final dish a dark hue. Shiro is used to highlight the appearance of foods, and is used as an addition to soup stock for hot pots, steaming soups, udon noodles and tossed with steamed vegetables. With a higher percentage of wheat, this type of shoyu is also sweeter than the others.

What is Nama Shoyu?

In Japanese, “nama” means raw, so nama shoyu is a raw or unpasteurized shoyu sauce. Because it is cultured or fermented, nama shoyu often contains beneficial living enzymes and organisms, like probiotics. Other shoyu are heated for preservation purposes.

Some tasters claim nama shoyu is more delicate and less assertive, but it still maintains the classic shoyu balance of sweet and salty. It’s also a favorite among “raw” food eaters, but it does contain gluten—almost all shoyu does—so raw purists may not be able to eat it.