2017 Master Brewers Conference
 
22. Results of co-fermentation trials with S. cerevisiae and B. bruxellensis, and the organoleptic benefits from mixed culture fermentations

Nicholas Mader, Fremont Brewing Company, Seattle, WA, U.S.A.

Yeast, Fermentation, and Microbiology II
Thursday, October 12
3:30–5:15 p.m.
M301–M302

Mixed culture fermentations conducted with multiple yeast strains and often bacteria are frequently used amongst breweries looking to display distinct flavor and aroma profiles in beer. As these techniques gain popularity in the brewing industry, there remain gaps in knowledge about how different yeast species interact with one another in the course of fermentation. This exploratory research project evaluates S. cerevisiae (BSI-565) and B. bruxellensis (BSI-Drei) by conducting both pure and mixed culture (without bacteria) fermentations. The pure culture fermentations of both S. cerevisiae and B. bruxellensis will be used in this research project as baselines for comparison against the results from mixed culture fermentations. Mixed culture fermentations were simultaneously inoculated with S. cerevisiae (BSI-565) and B. bruxellensis (BSI-Drei) at a rate of 1 million cells/mL/degree Plato in three different blends (25/75, 50/50, and 75/25). The results from this project showcase the potential of co-fermentation techniques in regard to creating beers with unique, and perhaps novel, organoleptic properties. Additionally, the parameters of selecting yeast strains/species to be used together in mixed culture fermentations will be elaborated upon.

Nick Mader leads the pilot brewing and mixed fermentation programs at Fremont Brewing Company and has previous industry experience at the Crooked Stave Artisan Beer Project and Boulevard Brewing Company. He is currently finishing his M.S. in brewing and distilling at the International Centre for Brewing and Distilling through Heriot-Watt University. His research and interests include the integration of fermentation techniques from the wine and spirits industries, brewery sterilization practices, and mixed culture fermentations.

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