Soy sauce or soya sauce is just one of the many functions of soya bean. In order to make soy sauce, the soy beans are first boiled and then mixed with roasted grain, brine, and Aspergillus oryzae or Aspergillus sojae molds. This mixture is then fermented. After fermentation, the mixture is made into a paste, which is then pressed to produce a liquid. This liquid is what is called soy sauce. The leftover mixture is used as animal feed.
There are now a variety of different soy sauces produced, such as light soy and dark soy, which are just the tip of the ice berg. The variations in taste and texture are achieved via different methods and durations of fermentation and through
different ratios of water, salt, and fermented soy. Sometimes other ingredients are also added either to the mixture or to the sauce to give it a different taste. Some types of soy sauce are also aged for different times to give it a stronger flavor. This is especially true for dark soy sauces. Dark soy sauces also tend to be richer and slightly sweeter than light soy sauces. Some other varieties of soy sauce include thick soy sauce, mushroom soy sauce, shrimp soy sauce, etc.