Beer-Beer is an alcoholic product, produced by brewing. It is a principal malt beverage where the fermentation of carbohydrates to alcohol takes place. Barley is used in the preparation of beer. Yeasts play a major role in the preparation of beer. Lager beer is produced by Saccharomyces uvarum, which settles at the bottom of the fermenting vat and is known as the 'bottom yeast'.,