Abstract:The remnant proteinase A in draft beer seriously affects its foam stability,which restricts the improving of draft beer quality.In order to explore the effect factors of proteinase A secretion in beer fermentation process,this paper examined the impact of the strain,physiological state of yeast,yeast generation,wort concentration and fermentation stage on the secretion of proteinase A.It was found that strain with high proteinase A secretion,yeast after stable phase,high yeast generation,high original wort concentration,late fermentation stage would result in high proteinase A activity in fermentation broth.Therefore,in the actual production,the introduction of few proteinase A secretion strains,adjusting the physiological state of yeast,using yeast less than 3 generations,fermenting with less than 18° P wort,ending the fermentation as soon as possible would play an active role in reducing the secretion of proteinase A.
