Soy sauce is a staple condiment and ingredient throughout all of Asia. Produced for thousands of years, soy sauce is a salty, brown liquid made from fermented soy beans mixed with some type of roasted grain (wheat, barley, or rice are common), injected with a special yeast mold, and liberally flavored with salt. After being left to age for several months, the mixture is strained and bottled. The sauce's consistency can range from very thin to very thick. Flavors, too, vary by type and have very subtle differences. Light soy sauce from Japan has a thinner consistency and a saltier flavor than the darker varieties. It is preferred when a darker sauce will ruin the appearance of a dish, or when a lighter flavor is sought, especially when serving seafood. Dark soy sauce is used throughout Asia and is a bit richer and thicker than the lighter varieties. It tends to have a chocolate brown color, and a pungent, rather than overly salty, flavor. Mushroom soy sauce is a dark soy sauce from China which adds straw mushroom essence to the sauce's brew. It has a deep, rich flavor and can be used in place of other types of soy sauce in most recipes. It is especially nice as a table condiment where its unusual flavor can come through. Tamari is a deeply colored Japanese soy sauce which has a rich texture and intense flavor. It can be used anywhere regular soy sauce is called for, and is especially good to use as a table condiment and dipping sauce. Wheat-free varieties of soy sauce are available in some markets.