Soy Sauce Guide: The Types and How Shoyu Is Brewed

October 12, 2026

Soy sauce is soybeans, wheat, salt and water, brewed for months until a mold, yeasts and bacteria have turned them into a dark, salty liquid with a deep savory taste that none of the four has on its own. The different kinds of soy sauce come from changing that recipe or that wait. This guide follows that process from the first steamed bean to the pressed sauce, then sorts the bottles that come out of it: the five types Japan recognizes, the grades printed on Japanese labels, the light and dark sauces of Chinese cooking, and tamari, a word that has meant more than one thing. It ends with which bottle to reach for, by job. For keeping an open bottle fresh, sodium and gluten, the soy sauce storage and questions guide has the answers.

Four ingredients, two jobs

The Japan Soy Sauce Brewers' Association, the trade body for Japan's soy sauce makers, lists the raw materials as soybeans, wheat and salt. Its notes describe defatted soybeans, meaning soybeans with the fat removed beforehand while the protein stays. Each ingredient has a job.

Soybeans bring protein. An enzyme called protease, a protein that cuts other proteins apart, breaks the soy protein down into amino acids, the small building blocks of protein. The association calls those amino acids the umami parts of soy sauce. Umami is the savory taste, and glutamic acid is one of the amino acids behind it; the umami guide explains the chemistry.
Wheat brings starch. A second enzyme, amylase, turns the starch in the wheat into glucose, a simple sugar. The association credits that sugar with sweetness and depth, and the microbes feed on it: lactic acid bacteria turn part of it into organic acids that soften the saltiness, and yeasts turn part of it into alcohol that adds aroma.
Salt keeps the mash safe. The association notes that salt, dissolved in water, is the base of the salty taste and holds back the putrefactive bacteria (the kind that rot food), so the useful microbes can work for months without the batch spoiling.

How shoyu is brewed, step by step

Shoyu is the Japanese word for soy sauce. The traditional Japanese method is called honjozo, which the association translates as the regular fermenting method. Fermenting means letting microbes change a food by feeding on it. Here is the method in order.

Cook the grain. The soybeans are steamed and the wheat is toasted. The association describes the two being mixed in roughly equal proportions.
Make the koji. Spores of koji mold are added to the mix. The Umami Information Center names the mold as Aspergillus oryzae. As it grows over the grain, the mold makes the protease and amylase described above. The moldy grain is called koji, and it is the engine of the whole process.
Make the moromi. The koji goes into a tank with brine, which is salt dissolved in water. The thick, wet mash that results is called moromi.
Wait and stir. The association says the moromi rests for around six to eight months, with repeated stirring. During that time koji mold, natural yeast, lactobacillus (a lactic acid bacterium) and other microorganisms break it down, ferment it and mature it. The Umami Information Center gives a wider range: anywhere from half a year to three years per batch.
Press, age, heat. A production chart in an article from the Kikkoman Institute for International Food Culture lists the later steps as pressing, aging, fining (clearing out fine solids), heat treatment, inspection and packaging. Pressing squeezes the liquid sauce out of the mash.

Most of the types in the next sections change one of two settings in this list: what goes into the tank, or how long it stays there.

Brewed and non-brewed soy sauce

Not all soy sauce is made by the months-long route above. The Brewers' Association names three methods:

Honjozo, the traditional way of making soy sauce, with koji and moromi. The association says it accounts for approximately 80 percent of production.
Kongo jozo, which it translates as the semi-fermenting method: amino acid fluid and other ingredients are used in the brewing to produce a distinctive savory taste.
Kongo, the mixing method: amino acids and similar ingredients are mixed in to shorten the manufacturing time.

A faster route skips the koji's slow work altogether. In their history of soy sauce, the soyfoods researchers William Shurtleff and Akiko Aoyagi of the SoyInfo Center describe soy sauce made by quick acid hydrolysis, using acid to break the protein apart, instead of the traditional slow breakdown by enzymes. Scientists called the result HVP soy sauce (hydrolyzed vegetable protein), chemical soy sauce, or nonfermented soy sauce. The soy sauce storage and questions guide covers how to tell the two apart on an ingredient list.

The five Japanese types

Japan's agricultural standard, called JAS (Japanese Agricultural Standard), sorts soy sauce into five types. All five start from the same idea. Most of what separates them is one change in the brewing: more salt, less wheat, or finished soy sauce used in place of brine. The table puts the difference beside each type.

Type	How it differs	Where, and how much	What it gives
Koikuchi (common)	The standard: steamed soybeans and toasted wheat in roughly equal parts, brewed in brine	About 80 percent of domestic production	Deep umami, rounded sweetness, refreshing acidity and a bitterness that brings the tastes together
Usukuchi (light color)	About 10 percent more salt, which makes fermentation and maturing more gradual	Originated in Kansai, the region around Osaka and Kyoto; about 10 percent of production	Reduced color and aroma, so the food's own color and taste stay in front
Tamari	Little or no wheat	Brewed mainly in Chubu, central Japan; about 2 percent of production	Thick, with dense umami and a red tint when heated
Saishikomi (refermented)	Finished soy sauce goes into the tank in place of brine, so the sauce is brewed twice	Western Japan, from the San-in region to Kyushu, centered on Yamaguchi Prefecture; about 1 percent of production	Dense in color, flavor and aroma; also called sweet soy sauce
Shiro (extra light color)	Kept paler than usukuchi, finishing a pale amber	Originated in Hekinan, in Aichi Prefecture	Pale amber, mild, with strong sweetness

The descriptions and regions come from the Brewers' Association. The production shares for tamari and saishikomi come from Yuka Utsunomiya, an associate professor at Gakushuin Women's University, writing in the Kikkoman Institute's journal, where she gives tamari about 2 percent of national production and saishikomi about 1 percent. She also notes saishikomi is matured for 18 months to about two years. The tamari detail comes from Shurtleff and Aoyagi, who describe tamari as a type of shoyu made with little or no wheat.

One name trips up English speakers. Usukuchi means light in color, not light in salt. It uses about 10 percent more salt than koikuchi, so a recipe written for koikuchi wants a lighter pour when usukuchi stands in. The association also draws a line around the family: bottled seasonings built on soy sauce, such as dashi soy sauce (soy sauce blended with dashi, a Japanese soup stock), tsuyu (a noodle dipping sauce), tare (a seasoning base or glaze) and ponzu (a citrus and soy sauce), are not JAS soy sauce.

Saishikomi has its own article. The Yugeta Shoyu producer guide follows one Saitama brewery that makes it in cedar barrels, and traces the style back to the port town of Yanai.

What the grades on a Japanese label measure

A Japanese label can carry a grade as well as a type. For the grade, the Brewers' Association points to total nitrogen, a lab figure it uses to express how much of the umami-carrying amino acids a sauce holds. The JAS standard also sets criteria for color and for salt-free soluble solids (everything dissolved in the sauce apart from salt), and sensory inspectors, who must pass a strict qualifying exam run by the Japan Soy Sauce Technology Center, judge color and aroma by sight and smell.

For brewed koikuchi, the association gives this ladder:

Grade on the label	Meaning	Total nitrogen, at least
Hyojun (標準)	Standard	1.20 percent
Jokyu (上級)	Upper grade	1.35 percent
Tokkyu (特級)	Special grade	1.50 percent
Tokusen (特選)	Specially selected, a label word allowed above special grade	1.65 percent

Read plainly, each step up the ladder means a higher total nitrogen figure, which is a measure of how concentrated the savory amino acids are. Grade does not say which type a bottle is, how long it aged, or what wood it sat in. Those answers sit in the type name, the method on the label (honjozo for fully brewed) and the maker's own description.

Chinese light and dark soy sauce

Shurtleff and Aoyagi trace soy sauce to China, where its two ancestors were jiang, a fermented seasoning paste, and chi, fermented soy nuggets. They date the earliest mention of soy sauce in Japan to AD 775, and they record the sauce traveling south as well, under local names such as kecap in Indonesia and Malaysia and toyo in the Philippines.

Traditional Chinese brewing, as they describe it, was done in large earthenware pots or vats set outdoors in a courtyard, open to the sun during the day and covered at night; the warmth from sunning sped the fermentation and improved the color and aroma. After about three to six months a slender strainer of woven bamboo was pushed into the mash, and the liquid that collected inside was ladled or siphoned off. In plants visited in 1948, a survey they cite found typical fermentation of eight to nine months, with a range of three months to two years.

Chinese cooking uses two main kinds of soy sauce, and the names can mislead in the same way usukuchi does.

Light soy sauce, sheng chou in Shurtleff and Aoyagi's spelling (they also call it thin soy sauce), is the thin one. Historically it was made from the first drawing of liquid from the mash and was considered the best quality, and they note it is preferred for dipping. The phrase "first draw" still appears on bottles today, as on the Hong Kong company Lee Kum Kee's Supreme Authentic First Draw Soy Sauce, which the company describes as naturally brewed and undergoing double fermentation.
Dark soy sauce, lao chou, is the darker, thicker one. Historically it came from the second or later fermentations and drawings and was often mixed with molasses. A modern example: Lee Kum Kee lists water, salt, caramel color, sugar, soybeans and wheat for its Premium Dark Soy Sauce, and pictures a plate of beef chow fun (a Cantonese stir-fry of wide rice noodles and beef) made with it for color.

A Chinese recipe that calls for both is asking each to do a separate job: light for seasoning, dark for color.

The word tamari

Tamari has two meanings in English, and Shurtleff and Aoyagi explain how that happened. In Japanese, tamari is the low-wheat type in the table above, written with characters that mean "the liquid extracted from (soy) beans." In about 1960, George Ohsawa, a teacher of macrobiotics (a diet philosophy built around whole grains), chose "tamari" as his name for the traditional, naturally fermented Japanese shoyu he worked to introduce to the West. Shurtleff and Aoyagi call that a mistake, because the word already named a specific type made with little or no wheat. Because the word has carried both meanings, the ingredient list is the place to check how much wheat a bottle labeled tamari holds. The soy sauce storage and questions guide covers tamari and gluten in detail.

What soy sauce does in a pan

The Brewers' Association lists several effects that explain why the same bottle behaves differently at the stove and at the table.

Heat makes new aromas. Heated with sugars in food, soy sauce takes part in an aminocarbonyl reaction, a browning reaction between amino acids and sugars. The association credits it for the aroma of broiled eel and yakitori (grilled chicken skewers) and for the color and fragrance of teriyaki. The chicken teriyaki recipe shows the glaze in practice.
It removes fishy smells. A quick soy sauce rinse is a Japanese technique the association describes for taking fish and meat odors away.
It brings sweetness forward. The association calls this a contrast effect: a little soy sauce brings out the sweetness of sweet boiled beans.
It multiplies umami. The glutamic acid in soy sauce works with inosinic acid in shaved bonito (dried, smoked fish flakes) to make a deeper umami than either gives alone. The association names the tsuyu dipping sauces for soba (buckwheat noodles) and tempura as examples.

The practical split follows from the first point. Heat turns soy sauce into new, roasted aromas, while a few drops added at the table go on just as they came from the bottle. That is the case for keeping a table bottle apart from the cooking bottle. Raw yolks cured overnight in soy sauce and mirin (a sweet rice seasoning), in the soy-cured egg yolk recipe, show the uncooked side of the sauce.

Which soy sauce for which job

The job	A fitting choice	Why
Everyday cooking and the table	Koikuchi	The association calls it general-purpose, for cooking or the table
Simmered dishes, soups and egg custards that should keep their color	Usukuchi for simmered dishes, shiro for soups and chawanmushi (a steamed egg custard)	The association names usukuchi for dishes that keep the ingredients' color and taste, and shiro for soups and chawanmushi; usukuchi is saltier, so pour less
Sashimi (sliced raw fish), sushi, chilled tofu	Tamari or saishikomi	The association names tamari for the table with sushi and sashimi, and saishikomi as mainly a table sauce for sashimi, sushi and chilled tofu
Grilled glazes and rice crackers	Tamari	The association lists grilling, simmering in soy sauce and senbei (rice crackers) among its uses, with a red tint on heating
Chinese dipping sauces	Chinese light soy sauce	Shurtleff and Aoyagi note light is preferred for dipping
Dishes meant to look deep brown, such as beef chow fun	Chinese dark soy sauce, with light for seasoning	Lee Kum Kee pictures its dark sauce giving beef chow fun its color
Ramen broth	Shoyu as the tare, the seasoning base	The ramen broth guide covers how broth and tare fit together

Two bottles for the table

Yugeta's double-brewed shoyu is a saishikomi from Saitama. Its importer, The Japanese Pantry, lists four ingredients (water, soybeans, wheat and salt), explains that the maker brews a regular first batch and then a second using the first batch in place of salt and water, and describes a richer flavor and more viscous texture than regular soy sauce, aged in cedar barrels called kioke (shop Yugeta double-brewed shoyu). As a saishikomi, it belongs at the table: a few drops over sashimi, sushi or chilled tofu.

Haku's Matsutake Shoyu comes from Kyoto Prefecture and pairs shoyu with matsutake, a mushroom. Its listing suggests it for sushi, sashimi, stir-fry, marinades and as a finishing sauce on rice and noodles (shop Haku Matsutake Shoyu). For more to set beside them, shop the Asian ingredients collection. For heat alongside soy, the chili crisp guide has the pairings.

The shop is at 263 Josephine Street in Cherry Creek, Denver. Visitors can ask staff questions in the shop. Products ship nationwide from theambrosianpantry.com.

Most bottles in this guide start from the same soybeans, wheat, salt and water, moved one setting at a time: more salt for usukuchi, less wheat for tamari, a second batch for saishikomi, a later draw and, historically, molasses for Chinese dark. That makes soy sauce less a single condiment than a range of tools, each set by the brewer for a particular job. The cook's part is to match the setting to the dish.