摘要：Fermentation indices of a bottom-fermented lager brew from high gravity wort (15.5 °P) were analysed using the response surface methodology (RSM, Box-Behnken design). Fermentation parameters like pitching rates (6–10 mln cells mL –1 ), wort aeration (8–12 mg O2 mL –1 ), different times (4.5–13.5 h) of filling CCTs (cylindroconical fermentation tanks; 3 850 hL) and fermentation temperatures (8.5–11.5 °C) were modulated to assess their impact on the fermentation indices. Within the studied ranges of fermentation parameters the experimental factors had a significant influence (R 2 for the model 73%) on alcohol content, pH (83%), extract drop (86%), FAN consumption (70%), bitterness loss (73%) and sensory analysis (71%). Based on the multiple response optimisation analysis, the values of independent factors that optimised alcohol content at the level of 6.94% (v/v), extract drop at 1.77 °P per day with maximization of FAN consumption (ca. 128 mg L –1 ) and pH drop to the level of 4.69 with minimized bitter substances losses (6.2 BU) were as follows: pitching rate 6 mln cells mL –1 ; fermentation temperature 11.2 °C; aeration level 10.5 mg L –1 ; and CCTs filling time 13.5 h.
关键词：bottom fermentation; fermentation indices; production scale; response surface methodology
