N. MADER (1); (1) Fremont Brewing Company, Seattle, WA, U.S.A.
Yeast, Fermentation, and Microbiology I
Friday, October 9
As more breweries continue to develop wild yeast and barrel aging programs, the risk for cross-contamination increases substantially. This project dissects common methods used to prevent cross-contamination by compiling information from a number of breweries and suppliers. Overall, 16 breweries that produce both clean (S. cerevisiae or S. pastorianus) and wild beers (Brettanomyces spp. or mixed cultures) participated in a survey. The survey first evaluated specific measures for equipment separation in the brewery, as well as changes to sterilization practices in regard to CIP procedures and chemical quantities. Next, differences in yeast handling methods for clean versus wild beers were examined, from propagation to pitching and/or inoculation. Among the breweries surveyed there were inconsistencies in cleaning and sanitation methods, especially treatment to barrels and foeders used for wild fermentations. From a quality control standpoint it is clear that specific carbonation, filtration, and packaging methods are advantageous for clean versus wild beers and need to be treated as critical control points for breweries to mitigate cross-contamination. Moreover, quality control measures taken before and after packaging, such as ATP swabbing, air monitoring, and pasteurization are discussed in more depth. The feedback provided by brewery-focused chemical and hygiene suppliers details various sterilization techniques and misconceptions of killing beer spoilage (or enhancement) organisms like Brettanomyces. Results from the survey not only suggest methods of best practice to prevent cross-contamination, but also propose new technologies available to aid quality-driven breweries.
Nick Mader is a brewer/cellarman at Fremont Brewing Company, with previous industry experience at Crooked Stave Artisan Beer Project and Boulevard Brewing Company. He is currently an M.S. degree candidate in brewing and distilling at the International Centre for Brewing and Distilling through Heriot-Watt University. His research and interests include brewery sterilization practices, the integration of fermentation techniques from the wine and spirits industries, and bioflavoring through the use of secondary fermentations.