IMPROVEMENT OF BREWER’S YEAST VIABILITY BY ADJUSTING WORT COMPOSITION

Along with necessary substances for yeast, wort also contains extraneous impurities and technologically important components that affect the cells adversely. The effect of these compounds on yeast can be mitigated by adding adsorbents and stabilizers into a fermentation medium. In this article, methods of improving brewer's yeast viability by removing phenols and high-molecular-weight proteins from wort are considered to accelerate the fermentation process and improve the final product quality. Both traditional materials (natural zeolite-containing tuffs from different fields of Siberia) and new ones (carbon-containing fibers and cyclodextrins) were suggested to transform wort composition. It has been revealed that introduction of 5% of zeolites into a mash at 70°C, or filtration of hopped wort through a mineral or carbon fiber layer at 0.10 l/min reduces haze-forming components content by 12-25%. Without significant effect on other characteristics of wort, polyphenols tend to be absorbed more than proteins. Addition of cyclodextrins in amount of 0.1-5.0% (w/v) into wort before fermentation contributes to clathrate formation with proteins and phenolic compounds. The materials used provide favorable conditions for yeast: biomass increases by an average 20%, yeast growth and extract fermentation intensify, and by-products formation decreases. This allowed us to shorten the fermentation process by 1-1.5 days, produce beer with desired organoleptic parameters, and increase its resistance to colloidal hazes formation