Production of acetic acid can be reduced by addition of a polypeptide having alpha-glucosidase activity in the fermentation process in the high gravity brewing of beer.In manufacturing beers, starch derived from ingredients including malt is hydrolyzed by hydrolases (e.g., alpha-amylase, beta-amylase) and fermentable sugars such as glucose, maltose, and maltotriose, which a brewer's yeast can meta