Soy Sauce
The lengthy, resonating flavour that characterises soy sauce is described as "umami" but it comes in two guises, natural and chemical. The former is the result of amino acids developing as the sauce brews naturally; the latter comes through the simple addition of monosodium glutamate. There are three types of soy sauce:
Japanese naturally brewed soy sauce - made using the koji process, similar to wine-making. Aspigillis bacteria are added to soya, wheat and water and the mash exposed to humid heat to grow a mould. The sauce is brewed for up to six months, and amino acids develop. This soy sauce contains no added sugar, colour or flavour, though it does contain salt.
Chinese fermented soy sauce - made with soya and no wheat, and less acidic. Sodium benzoate or potassium sorbate is usually added to preserve it. Japanese soy sauce is extracted by pressing the mash, while Chinese sauce is water that is flushed through the mash, taking on only its flavour. The liquid must then be coloured with caramel, and salt, sugar and sometimes artificial flavourings are added.
Hydrolysed vegetable protein (HVP) soy sauce - a highly processed and disgusting product. Hydrochloric acid is added to the beans, creating flavour-producing amino acids. HVP has been found to contain chloropropanol, which is a carcinogen.