Abstract: The effects of different yeasts(Y1110, Anqi and model yeast)on beer fermentation, the contents of α-AN, pH, diacetyl and high alcohol during the fermentation process and the flavor substance content of three kinds of beers were studied in this article. The results were as follows: Y1110 yeast multiplied most quickly, α-amino nitrogen content and the pH value declined rapidly, reduction speed of diacetyl was fastest, diacetyl content was lowest after secondary fermentation, alcohol content was higher in Y1110 beer sample, and Y1110 was suitable for lager beer brewing; Anqi yeast multiplied slowest, α-amino nitrogen content and the pH value dropped slowest, ester content was higher in Anqi beer sample, and anqi was suitable for light beer brewing. Alcohol and ester contents were both higher in model yeast sample. So it was unsuitable for beer brewing.

Key words: beer, yeast, fermentation, flavor