WHAT’S REALLY IN SOY SAUCE?

Authentic soy sauce is made from only four ingredients: soybeans, wheat, water, and salt, and the way it’s produced makes a big difference in flavor and texture. Traditionally the soybeans are soaked in water, the wheat is roasted and crushed, and then Aspergillus mold is added to the mixture, which develops for several days. After the addition of water and salt the mixture ferments in a tank for five to eight months or even longer. When the aging process is finished, the mixture is pressed to obtain the liquid soy sauce, which is pasteurized and bottled. Cheap soy sauces are produced by a chemical method called acid hydrolysis, which results in “soy sauce” in days instead of months. This product is less flavorful because it lacks the substances yielded during traditional fermentation and has to be “improved” with extra flavoring, coloring, and sugar. The method can also create carcinogens that are not present in traditional soy sauce. In Japan only a product made by the traditional method may be labeled as soy sauce, but the rules are not as strict in the United States. To be sure you’re getting the real thing, read the label: It should list only the four standard ingredients, say “traditionally brewed,” and indicate a high protein content (10% or more).