变酸的

The usaul contaminate in beer are bacterium,fungus and wild yeast, most of them are anaerobion causing the muddy, flavor chaging and turning sour, Beer anaerobic culture medium should be found out.

啤酒中常见菌有细菌、霉菌、野酵母菌,但主要存在危害性较大菌是细菌中大部分氧菌,会使啤酒产浑浊、变味、变酸等。