Achievement of both good haze and flavor stability of beer is a key problem that brewing researchers have been trying to address for years. Polyphenols were the compounds which their hydroxy groups were connected directly with phenyls. Phenolic compounds in beers including phenolic acids, flavonoids, proanthocyans and anthocyans, they take important role in beer non-biological stability, flavor stability, color and soluble oxygen, and so on. In practice, flavor stability can be improved by the choice of bar...