Yeast extract is the common name for various forms of processe yeast products that are used as food additives or flavourings. They are often used in the same way that monosodium glutamate (MSG) is used, and, like MSG, often contain free glutamic acids. The texture ranges from liquid to a light paste. (Herbst p.681) Glutamic acid in yeast extracts are produced from an acid-base fermentation cycle, only found in some yeasts, typically ones bred for use in baking.