The influence of selected yeast strains by the production of a low calorie beer.
A comparative test of the suitability of four yeast strains for the production of low calorie beer (of the type where as much as possible of the carbohydrate content of the wort is removed by fermenting to the maximum achievable degree of attenuation) is described. Two worts were used, one all malt and the other containing 35% dextrose to dilute its nonfermentable malt derived constituents. Yeast budding activity was used as a measure of vitality. Viable cell levels were determined by counting after nonviable cells had been stained with methylene blue. The course of fermentation was followed by making periodic measurements of wort gravity. The time taken to complete fermentation was recorded together with the flocculation and settling behaviour of the yeast, the results of analysis of the green beer, the length of maturation needed to bring the diacetyl content down below taste threshold level and the volatile compounds composition of the finished beer. Two of the four strains (L34/70 and L360, both from the Doemens culture collection at Graefelfing in Germany) proved suitable.
Keywords : attenuation beer brewers' yeast comparative test composition fermentation low calorie performance yeast strain