M-77: Implementation of real-time PCR to ensure bacteria-free yeast propagations in a mid-sized craft brewery

B. BAILEY (1); (1) Troegs Brewing Company, Hershey, PA, U.S.A.


Yeast propagation is one of the most sensitive steps in fermentation management due to the fact that the yeast and any possible infections are subsequently used in multiple fermenters and the short time available during propagation for microbiological analysis. An infection of beer-spoiling bacteria during propagation is especially problematic for those breweries that do not stabilize their beers by pasteurization or sterile filtration. Traditional microbiological techniques cannot confirm the presence of beer-spoiling bacteria in less than 5–7 days, although our brewery requires yeast from propagation to be released for fermentation within 3 days. By adding real-time PCR to our microbiological tools, we are able to screen every yeast propagation for beer-spoiling bacteria prior to its release for fermentation, while gaining the ability to identify bacteria found at other process points in the brewery. For many breweries, the costs incurred by a single undetected infection in propagation could justify the investment in a real-time PCR testing program.

Benjamin Bailey as been a member of MBAA since 2010. His paper “The Influence of Hop Harvest Date on Hop Aroma in Dry-Hopped Beers” received the Inge Russell Best Paper Award from MBAA in 2010. He received a B.A. degree in German from the University of Texas at Austin in 2000. After a three year apprenticeship at Live Oak Brewing Co., in Austin, TX, he enrolled at the University of Munich at Weihenstephan, graduating as a diploma brewmaster in 2008. He then worked as a quality assurance engineer for MillerCoors in Trenton, OH, before taking on his current role in 2010 as quality assurance team leader at Troegs Brewing Co. in Hershey, PA.

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