Beer is an ancient alcoholic beverage just like wine. It is the term generally applied to the fermentation of barley malt. Terms like ale, stout, lager and porter is used for beer with the difference in the method of production. The ingredients generally used for the preparation of beer are barley, malt, cereal adjuncts, hops, water and yeast. The principal operations in the production of beer are malting, mashing and fermentation.

The starting material used in the production of beer is barley malt. Starchy materials that are cheaper than malt are used as adjuncts to replace some malt. The most common cereal adjuncts are maize, broken rice, raw barley, sorghum, tapioca and barley. The entire starch of the adjuncts is converted into sugar. Beer is being flavored by hops. Hops help sterilize the brew before fermentation. The yeast used depends on the type of beer prepared. For preparation of ale, top fermentation system is used and for the production of lager, bottom fermentation technique is used. Variation in the quality of beer such as strength of alcohol, color and extractives depends on the quality of the malt, malt adjuncts, mashing methods and the condition of fermentation.