Kikkoman Corporation

Our current feature series is taking a closer look at the five internationally recognized flavors—sweet, salty, sour, bitter and umami—and how they reveal themselves in Japanese cuisine. In this second installment of the series, we turn to saltiness.

What makes something taste "salty"? Salt (sodium chloride or NaCl) is the leading source of this flavor. While the body requires sodium ions to function normally, it has no apparatus for storing sodium and thus we must constantly ingest the amount the body requires. Salt plays a crucial role not only in the seasoning of foods, but in our bodies' health.

Simple Salt

In Japan, salt is produced from seawater. Sun-dried salt is often made by evaporating seawater using the heat of the sun and wind power. Japan's climate of high temperature and high humidity, however, does not produce salt from seawater naturally, so seawater is first condensed and then boiled down to produce salt.

Salt is often the defining flavor of dishes, but adding flavor is not its only role in food preparation. Salt plays a major part in the production of dried fish and in the pickling of vegetables. Cooks may add salt to food for many purposes, including, for example, soaking peeled apples to keep them from turning brown; draining water from and wilting vegetables; promoting the coagulation of meat and fish protein during grilling; and extracting water from fish and condensing its umami.

In addition to its use as a seasoning, salt is also used in various purification rituals in Japan. For example, sumo wrestlers scatter salt into the ring before a match as a form of purification. A small dish of salt called teshio (hand salt) may be served with a meal which, while acting as symbolic protection against impurities, also allows diners to adjust the flavor of their dishes according to their own tastes. Even today, tempura is often eaten with teshio.

Savory Soy Sauce

Soy sauce is an all-purpose seasoning that goes well with a wide range of foods—its complex palate comprises not only saltiness, but umami, sweet, sour and bitter flavors. It is graced as well with a distinctive aroma derived from its many ingredients. It is indispensable at the Japanese table.

The origins of soy sauce go back to hishio. Hishio is a general term that encompasses all fermented products, including shishibishio or gyoshou (products made of fish) and kokubishio (products made of grain). Some fish sauce does exist in Japan, but most Japanese sauces are made of grains such as rice, wheat or soybeans; these have been in widespread use here since the seventeenth century.

There are five types of soy sauce in Japan: the two most popular are koikuchi (dark) and usukuchi (light), followed by tamari, saishikomi and shiro soy sauces. Koikuchi is generally made using the traditional "natural brewing" method; that is, equal portions of steamed soybeans and roasted wheat are mixed, to which tane-koji (koji starter) is added and is cultured to form koji. Saltwater is added to make moromi mash. The moromi is allowed to age and the fermented liquid is squeezed out, then heated by a process called hi-ire ("adding the fire"), which halts enzyme activity to create fragrance, smoothness of umami and the unique color characteristic of soy sauce. Koikuchi soy sauce is versatile in its uses from kitchen to table, and accounts for 83 percent of the country's soy sauce consumption.

Usukuchi soy sauce is made with more salt than koikuchi soy sauce, and contains amazake, a traditional sweet drink made from fermented rice, which is added after fermentation. The concentration of salt in usukuchi soy sauce is about 2 percent more than koikuchi soy sauce. The "light" meaning of usukuchi refers not to salt content, but to the lightness of its color. This soy sauce is often used in making dishes to which one usually avoids adding color, or to enhance the natural taste of ingredients, such as stewed vegetables or clear soups.

Classic Miso

Miso is a fermented soybean paste made by adding malted rice and malted wheat to soybeans. Miso soup is the leading Japanese dish made with miso, making its appearance on the average table once a day. Miso is also used as a seasoning for stewed and broiled dishes. The use of miso as a flavoring dates back even further than that of soy sauce—it came into general use during the fourteenth and fifteenth centuries.

Miso production depends on such factors as available ingredients, local climate and water quality, and specific regional tastes. As we can gather from expressions like temae miso (referring to self-praise, originating in the practice of people boasting about their homemade miso), miso was something that, at one time, most households made themselves. There are different flavors and textures of miso, such as shiromiso or white miso, which is light-colored and sweetish and akamiso, which is reddish, darker and saltier.

Salt Substitutes

In Japanese cooking, salt, soy sauce and miso are used in large quantities. Soy sauce and miso have a salt content of 14 percent to 18 percent, but because other elements temper this saltiness, the actual high salt content of this diet might go unnoticed, potentially leading to excessive salt consumption. To avoid too much salt intake, cooks sometimes choose to reduce salty seasonings while adding instead natural dashi stock, or sour ingredients, or such flavorings as sesame seeds, shiso (perilla) and ginger to add spice and flavor to their foods. Low-sodium soy sauce is also used.

Author's Profile

Takashi Yamamoto was born in Fukui Prefecture in 1944. He graduated from the Osaka University School of Dentistry. He taught at the Faculty of Dentistry at the university from 1972 -1991. Since April 1991 he has held a professorship at the Faculty of Human Sciences there. A specialist in brain science and the physiology of taste, Dr. Yamamoto is currently engaged in research on the mechanisms of taste and eating preferences.