The Beer is defined as a drink obtained by the alcoholic fermentation of an aqueous extract of germinated cereals with the addition of hops. The principle distraction between beer and other drinks is the persistent heat formed by evolution of carbon -di -oxide. Fermentation is the process by which fermentable carbohydrates like sugars are converted by the yeast into alcohol, carbon – dioxide and numerous by products. Beer is a fermented beverage made from barley malt, hops, water, yeast and sometimes other ingredients. Wort is a sweet liquid derived from mashing, or mixing malted barley with water. At this stage, it is regarded “Sweet wort” later as brewed wort and finally beer. Fermentation is dependent on the composition of the wort, the yeast and fermentation conditions, only two strains are used for brewing: Sacchromyces cervisiae (ale yeast) and Sacchromyces uvarum (layer yeast). Sacchromyces cervisiae is the most thoroughly investigated Eukaryotic microorganism, which aids our understanding of the biology of the Eukaryotic cell. For several centuries, Sacchromyces cervisiae has been used in the production of food and alcoholic beverage.