Research of improving the ratio of alcohol ester of high gravity brewing

Response surface methodology was applied to optimize the ratio of alcohol ester in high gravity fermentation beer.Based on single factor experiment,dissolved oxygen,pitching yeast,fermentation temperature were chosen as influencing factors,the ratio of alcohol ester was selected as response value. The mathematical model was established by Box- Behnken central composite design. The results showed that the optimal fermentation conditions were as follows: dissolved oxygen 11.92 mg / L,pitching yeast 2.59 × 107 cells / m L,fermentation temperature 10.9 ℃.Under this condition,the ratio of alcohol ester was 4.35.Analysis of variance results showed that the dissolved oxygen played significantly role in increasing the ratio of alcohol ester for high gravity fermentation beer.