Wort sugars, yeast sugar uptake and beer quality

Abstract

The uptake of different sugars under brewing conditions in chemically defined media and in worts with different sugar adjuncts was studied. The brewer's yeasts grew equally rapidly on glucose and fructose. However, when both sugars were present in the same medium glucose inhibited the utilization of fructose. Growth on maltose and especially on maltotriose was slower than on glucose or fructose. In the chemically defined media the uptake of galactose, maltose and maltotriose was clearly repressed by glucose, although in wort the repression was less marked. The use of glucose or invert sugar in pilot scale production of beer increased yeast growth, the fermentation rate and to some extent the amount of fusel oils, but did not affect the quality of finished beer.