Soya sauce is made from fermented soya beans, wheat flour, water, and salt. It is used to add colour and flavour to soups, sauces, marinades, meat, fish and vegetables, as well as for a table condiment. The two main types of soy sauce are light and dark. As the name implies, light soy sauce is lighter in color, and also sweeter than dark soy sauce. Dark soya sauce is more often used in Chinese cooking. Dark soya sauce is thicker and less salty than light soya sauce. Soya sauce should always be kept refrigerated and out of direct light. An opened bottle of soya sauce that has been left unrefrigerated could become slightly bitter.