Evaluation of Saccharomyces cerevisiae strains isolated from non-brewing environments in beer production

This study sought to select novel Saccharomyces cerevisiae strains not previously used in the production of beer. Twelve strains isolated from grape must, bakery, wine and apple stillage were compared through laboratory scale fermentation. Yeast from the grape must exhibited a superior fermentative capability (comparable with that of two commercial strains). Some of the strains produced appreciable concentrations of esters and higher alcohols, suggesting their potential as novel yeasts for beer characterised by distinct flavours. The most suitable strain for beer production, based on fermentative ability and volatile profile, was a baker’s yeast which was subject to pilot plant scale-up. The standard quality attributes, amino acids, volatile and sensory profiles were monitored during the primary fermentation and after bottle conditioning. These were aligned with those of a standard ale, suggesting that the selected yeast strain could be used for beer production. Interestingly, some esters were above the sensory threshold.