Authentic soy sauces are made by mixing the grain and/or soybeans with yeast or ''kōji'' and other related microorganisms. Traditionally soy sauces were fermented under natural conditions, such as in giant urns and under the sun, which was believed to contribute to additional flavours. Today, most of the commercially-produced counterparts are fermented under machine-controlled environments instead.
Although there are many types of soy sauce, all are salty and earthy-tasting brownish liquids used to season food while cooking or at the table. Soy sauce has a distinct basic taste called umami by the Japanese . Umami was first identified as a basic taste in 1908 by Kikunae Ikeda of the Tokyo Imperial University. The which naturally occur in soy sauce are what give it this taste quality.
Soy sauce should be stored away from direct sunlight.
Many cheaper brands of soy sauces are made from soy protein instead of brewed from natural bacterial and fungal cultures. These soy sauces do not have the natural color of authentic soy sauces and are typically colored with caramel coloring. Similar products are also sold as "liquid aminos" in the US and Canada.
Some artificial soy sauces posed potential health risks due to their content of the chloropropanols 3-MCDP and 1,3-DCP which are minor byproducts of the hydrochloric acid hydrolysis .
Soy sauce has been integrated into the traditional cuisines of many East Asian and South East Asian cultures. Soy sauce is widely used as a particularly important flavoring in , , and Chinese cuisine. However, it is important to note that despite its rather similar appearance, soy sauces produced in different cultures and regions are very different in taste, consistency, fragrance and saltiness. As such, it may not be appropriate to substitute soy sauces of one culture or region for another.
Chinese soy sauce
Chinese soy sauce is primarily made from soybeans, with relatively low amounts of other grains. There are two main varieties:
*Light or fresh soy sauce : A thin , opaque, dark brown soy sauce. It is the main soy sauce used for seasoning, since it is saltier, but it also adds flavour. Since it is lighter in color, it does not greatly affect the color of the dish. The light soy sauce made from the first pressing of the soybeans is called tóuchōu , which can be loosely translated as first soy sauce or referred to as premium light soy sauce. Touchōu is sold at a premium because, like extra virgin olive oil, the flavor of the first pressing is considered superior. An additional classification of light soy sauce, shuānghuáng , is double-fermented to add further complexity to the flavour. These latter two more delicate types are usually for dipping.
*Dark/old soy sauce : A darker and slightly thicker soy sauce that is aged longer and contains added molasses to give it its distinctive appearance. This variety is mainly used during cooking since its flavour develops under heating. It has a richer, slightly sweeter, and less salty flavour than light soy sauce. Dark soy sauce is partly used to add color and flavour to a dish.
In traditional Chinese cooking, one of the two types, or a mixture of both, is employed to achieve a particular flavour and colour for the dish.
*Thick soy sauce : Dark soy sauce that has been thickened with starch and sugar. It is also occasionally flavored with . This sauce is not usually used directly in cooking but more often as a dipping sauce or poured on food as a flavorful addition.
* : Although not really a soy sauce, it is another salty soy product. It is one of the main ingredients in a dish called ''zhajiang mian'' .
Japanese soy sauce
Buddhist monks introduced soy sauce into Japan in the 7th century, where it is known as "shoyu". The Japanese word "tamari" is derived from the verb "tamaru" that signifies "to accumulate," referring to the fact that tamari was traditionally from the liquid byproduct produced during the fermentation of . Japan is the leading producer of tamari.
Japanese soy sauce or ''shō-yu'' , is traditionally divided into 5 main categories depending on differences in their ingredients and method of production. Japanese soy sauces include wheat as a primary ingredient and this tends to give them a slightly sweeter taste than their Chinese counterparts. They also have an alcoholic sherry-like flavor. Not all soy sauces are interchangeable.
; Koikuchi : Originating in the Kantō region, its usage eventually spread all over Japan. Over 80% of the Japanese domestic soy sauce production is of koikuchi, and can be considered the typical Japanese soy sauce. It is produced from roughly equal quantities of soybean and wheat. This variety is also called ''kijōyu'' or ''namashōyu'' when it is not .
; Usukuchi : Particularly popular in the Kansai region of Japan, it is both saltier and lighter in color than ''koikuchi''. The lighter color arises from the usage of amazake, a sweet liquid made from fermented rice, that is used in its production.
; Tamari : Produced mainly in the Chūbu region of Japan, tamari is darker in appearance and richer in flavour than ''koikuchi''. It contains little or no wheat; wheat-free tamari is popular among people eating a . It is the "original" Japanese soy sauce, as its recipe is closest to the soy sauce originally introduced to Japan from China. Technically, this variety is known as ''miso-damari'' , as this is the liquid that runs off miso as it .
; Shiro : A very light colored soy sauce. In contrast to "tamari" soy sauce, "shiro" soy sauce uses mostly wheat and very little soybean, lending it a light appearance and sweet taste. It is more commonly used in the Kansai region to highlight the appearances of food, for example sashimi.
; Saishikomi : This variety substitutes previously-made koikuchi for the brine normally used in the process. Consequently, it is much darker and more strongly flavored. This type is also known as ''kanro shoyu'' or "sweet shoyu".
Newer varieties of Japanese soy sauce include:
; Gen'en : Low-salt soy sauces also exist, but are not considered to be a separate variety of soy sauce, since the reduction in salt content is a process performed outside of the standard manufacture of soy sauce.
; Amakuchi : Called "Hawaiian soy sauce" in those few parts of the US familiar with it, this is a variant of "koikuchi" soy sauce.
All of these varieties are sold in the marketplace in three different grades according to how they were produced:
; Honjōzō hōshiki : Contains 100% naturally fermented product.
; Shinshiki hōshiki : Contains 30-50% naturally fermented product.
; Tennen jōzō : Means no added ingredients except alcohol.
All the varieties and grades may be sold according to three official levels of quality:
; Hyōjun : Standard pasteurized.
; Tokkyū : Special quality, not pasteurized.
; Tokusen : Premium quality, usually implies limited quantity.
Other terms unrelated to the three official levels of quality:
; Hatsuakane : Refers to industrial grade used for flavoring, powder.
; Chōtokusen : Used by marketers to imply the best.
Perhaps the most well-known producer of Japanese soy sauce is the Kikkoman Corporation.
Taiwanese soy sauce
The history of soy sauce making in Taiwan can be traced back to southeastern China, in the provinces of Fujian and Guangdong. Later, the cultural and political separation between Taiwan and China since the end of the First Sino-Japanese War in 1895, when China ceded Taiwan to Japan, brought changes to traditional Chinese soy sauce making in Taiwan. Some of the top Taiwanese makers, such as Wan Ja Shan, Wei-Wong and Ve-Chung have adopted the more sophisticated Japanese technology in making soy sauce for the domestic market and more recently foreign markets as well.
Korean soy sauce
, is a byproduct of the production of ''doenjang'' . ''Joseon ganjang'', thin and dark brown in color, is made entirely of soy and brine, and has a saltiness that varies according to the producer. Wide scale use of ''Joseon ganjang'' has been somewhat superseded by cheaper factory-made Japanese style soy sauce, called ''waeganjang'' . According to the 2001 national food consumption survey in Korea, traditional fermented ''ganjang'' comprised only 1.4% of soy sauce purchases.
Vietnamese soy sauce
Vietnamese soy sauce is called ''xì d?u'', ''n??c t??ng'', or sometimes simply ''t??ng''.
Indonesian soy sauce
In Indonesia, soy sauce is known as ''kecap'' from which according to one theory the English word "ketchup" is derived. Two main varieties exist:
; Kecap asin : Salty soy sauce, which is very similar to Chinese light soy sauce, but usually somewhat thicker and has a stronger flavor; it can be replaced by light Chinese soy sauce in recipes.
; Kecap manis : Sweet soy sauce, which has a thick, almost syrupy consistency and a pronounced sweet, -like flavor due to generous addition of palm sugar. It is a unique variety; in a pinch, it may be replaced by molasses with a little vegetable stock stirred in.
''Kecap inggris'' , or ''saus inggris'' is the name for Worcestershire sauce. ''Kecap Ikan'' is Indonesian fish sauce.
Malaysian soy sauce
In Singapore and Malaysia, soy sauce in general is dòuyóu ; dark soy sauce is called jiàngyóu and light soy sauce is jiàngqīng . ''Angmoh tauyew'' is the name for Worcestershire sauce.
Malaysia, which has cultural links with Indonesia, uses the word 'kicap' for soy sauce. Kicap is traditionally of two types: kicap lemak and kicap cair. Kicap lemak is similar to kecap manis but with very much less sugar while kicap cair is the Malaysian equivalent of kecap asin.
A popular condiment in the Philippines, it is called ''toyo'' , and is usually found beside other sauces such as '' '' and '''' . The flavor of Filipino soy sauce, made from soybeans, wheat, salt, and caramel, is interestingly milder compared to its Asian counterparts--possibly an adaptation to the demands of the Filipino palate and its cuisine. It is thinner in texture and has a saltier taste compared to its Southeast Asian counterparts, much more similar to the Japanese ''shōyu''. It is used as a staple condiment to flavor many cooked dishes and as a marinade during cooking, it is also a table condiment, and is usually mixed and served with '''' . Popular Philippine brands are Marca Pi?a, Silver Swan, Lauriat, Datu Puti, Toyomansi and UFC.
A unique type of soy sauce produced by Aloha Shoyu Company since 1946 is a special blend of soybeans, wheat, and salt, historically common among local Hawaii residents. Hawaii residents rarely use the term "soy sauce," opting to use the Japanese loanword "shoyu" instead. However, while the Japanese word ''shōyu'' is pronounced like ''show you'', Hawaii residents prounounce the word like ''shoi-yu''.
A study by National University of Singapore shows that Chinese dark soy sauce contains 10 times the antioxidants of red wine, and can help prevent cardiovascular diseases. Soy sauce is rich in lactic acid bacteria and of excellent anti-allergic potential.
Soy sauce does not contain the beneficial isoflavones associated with other soy products such as tofu or edamame. It can also be very y, so it may not be a suitable condiment for people on a low sodium diet. Low-sodium soy sauces are produced, but it is impossible to make soy sauce without using some quantity of salt.
In 2001 the United Kingdom Food Standards Agency found in tests of various low-grade soy sauces that some 22% of samples contained a chemical called 3-MCPD at levels considerably higher than those deemed safe by the European Union. About two-thirds of these samples also contained a second chemical called 1,3-DCP which experts advise should not be present at any levels in food. Both chemicals have the potential to cause cancer and the Agency recommended that the affected products be withdrawn from shelves and avoided.
In order to evade conscription in Japan during World War II, people were known to drink large quantities of soy sauce to damage their kidneys.
Soy sauce and allergies
Most varieties of soy sauce also contain wheat. Individuals with a wheat allergy, Celiac disease, or a gluten intolerance should avoid this condiment and dishes seasoned with soy sauce.