Shoyu

Shoyu is a thin, salty brown sauce made from nearly equal parts of soy bean and wheat flour. To preserve freshness, alcohol is often added and contributes to taste changes if used in cooking (because the alcohol burns off). Although this is typically very high in sodium, there is a low-sodium form of shoyu available as well. Also known as soy sauce, there are light and dark forms. Dark soy is generally used in cooking and more often it is Japanese. Chinese soy sauce is often lighter in color and saltier. Lighter soy is opted for when used with brightly colored vegetables, as not to change their color. Light soy tends to have a shorter life than dark soy and should be used soon after opening.