M-37: Bottle finish design and its effect on sheared finish package failure

C. BAUGH (1), T. Nielsen (1), G. Sanchez (1); (1) Sierra Nevada Brewing Company, Chico, CA, U.S.A.

Packaging (Bottles, Draft and Cans)
Saturday, June 7 - 1:00 p.m.-2:45 p.m.
Level 4, State Ballroom

Sheared finish is a common consumer complaint concerning beer packaged in glass containers. Sheared finishes occur when a portion of the bottle opener contacts the bottle finish and, during the opening process, exerts a force upon the glass that results in the chipping of the finish or a catastrophic failure of the bottle. This type of package damage not only poses an injury risk to the consumer, but also negatively affects the perception of the quality of the product within the failed package. Here we report the results of a collaborative effort between brewers and glass-packaging manufacturers to minimize this type of package failure. Two independent finish designs with differences in the radius of the locking bead at the top of the finish (R1 dimension) were evaluated for both seal integrity and propensity for sheared finish damage. We show that not only the finish design, specifically the roundedness of the R1 dimension, is important but that the hardness of the crown liner and the type of opener used also affect the frequency of sheared finish, as well as closure integrity. Our data indicate that an R1 dimension with a larger radius of curvature reduces sheared finish failures, but this larger radius must be combined with a soft crown liner material to counteract the inherent loss of seal integrity associated with this finish alteration. Resistance to crown damage is also discussed as a critical point of analysis when designing the optimal package closure to ensure consumer safety, package integrity, and product stability.

Chris Baugh graduated with a B.A. degree in microbiology from UC San Diego in 1991. Following undergrad school, Chris worked as a research technician at Scripps Research Institute, San Diego, studying mouse hepatitis virus coat proteins and mouse models of diabetes in the Buchmeier and Sarvetnick laboratories, respectively. Chris returned to school and earned a doctorate in molecular, cellular, and developmental biology in 2000 from UC Santa Cruz with the thesis “The Structure Function Relationship in RNA Molecules; Studies of the Signal Recognition Particle and Malachite Green Aptamer.” After graduate school Chris worked as a scientist for Anadys Pharmaceuticals in San Diego designing high-throughput drug-screening assays in search of a drug to treat hepatitis C. Following this stint in the pharmaceutical industry, Chris returned to school, enrolling in the UC Davis Extension master brewer program and earning a diploma in brewing in 2007. The Sierra Nevada Brewing Company hired Chris on after completion of this degree as a production brewer. After two and a half years of brewing, Chris moved to the research and development laboratory and is currently senior research analyst. Chris is a member of ASBC.

Brewing Resources

Ask the Brewmasters Technical Quarterly MBAA Webinars MBAA Podcasts Food Safety Brewery Safety Vendor Search