The oxidation process of beer will produce a variety of adverse factors，including the following points，which intensifies the formation of cold turbidity and oxidative turbidity, affects the abiotic stability of beer, and shortens the storage period of beer.the flavor changes, resulting in bad tastes

As we known, the beer basic materials are water, beer hops, yeast, and malt. In this one, yeast decides to beer fermentation type, and in meantime decide beer types. The beer fermentation has two types, one is Top-fermented beers, and another is Bottom-fermented beers.

Fermentation is the process by which fermentable carbohydrates are converted by yeast into alcohol, carbon dioxide, and numerous other byproducts. It is these byproducts that have a considerable effect on the taste, aroma, and other properties that characterize the style of beer.