The negative effect of high gravity brewing on yeast quality and performance is still in concern. We have applied flow cytometry as a rapid measuring method. Measurements of cell size distribution, cell granularity, glycogen and DNA content of Saccharomyces cerevisiae yeast strain in high- concentrated 16 and 20 °P wort and conventional 12 °P wort fermentation were made. The yeast activity was determined by acidification power test and by consequent fluorescent staining techniques. Results showed that activity of yeast, cell cycle and current growth level of the yeast population depended on wort gravity. Experience from measurements can be use for prediction and control of the individual phases of fermentation and characterization of pitching yeast. By means of these measurements fermentation can be run in optimum condition and saved process time.
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