(PRESS RELEASE) CINCINNATI, OH (November 22, 2024) – In a major advancement for the craft brewing industry with big implications for smaller craft breweries, new research led by Rhinegeist and the University of Idaho reveals that “killer yeasts” can offer a natural solution to a persistent problem: secondary fermentation. This process, when it occurs in packaged beer, often results in unintended consequences such as off-flavors, unpredictable alcohol levels, and, in severe cases, exploding bottles and cans. However, this innovative research demonstrates that killer yeasts drastically reduce the likelihood of contamination, offering craft brewers an effective, eco-friendly alternative to costly pasteurization.
The team’s findings, recently published in the American Society for Microbiology (ASM) Journals, highlight the potential for killer yeasts to safeguard craft beer from spoilage due to diastatic yeast contamination. The study found that killer toxins produced by wine yeast strains were able to inhibit up to 95% of harmful diastatic yeasts. This discovery could mark a transformative shift in brewing practices, allowing brewers to protect the quality of their beer without compromising flavor or incurring high costs.
Diastatic Yeasts: A Craft Brewer’s Nemesis
Diastatic strains of Saccharomyces cerevisiae (brewer’s yeast) can wreak havoc if they contaminate finished beer, leading to hyperattenuation that not only alters flavor but also raises alcohol content to unsafe levels. Larger breweries often avoid this risk by pasteurizing their beer, but for small craft brewers, this process remains prohibitively expensive and can impact the taste of the final product.
“For the vast majority of small craft breweries, pasteurization and filtration costs are steep,” explains Nicholas Ketchum, Quality Assurance Manager at Rhinegeist and co-author of the study. “Once fully developed, this killer yeast technology could save many small breweries from having to discard beer due to spoilage. Larger breweries would also benefit by avoiding investments in extensive pasteurization equipment. This research combines Rhinegeist’s practical brewing expertise with Dr. Paul Rowley’s decades-long experience with killer yeast, bringing a practical solution to craft brewers across the country.”
Environmental and Economic Implications
The study also highlights the broader environmental benefits of using killer yeasts as an alternative to pasteurization. If widely adopted, this approach could significantly reduce the brewing industry’s energy and water consumption. For instance, pasteurization in brewing requires between 14-20 kBtu per barrel of energy. Extrapolated to the total output of the U.S. craft beer industry, a 20% increase in the use of tunnel pasteurizers would require approximately 1 billion cubic feet of natural gas per year. Furthermore, tunnel pasteurizers consume significant volumes of freshwater, which is increasingly precious in regions like California, Colorado, Texas, and Oregon. The research suggests that a shift to killer yeasts could yield substantial water and energy savings, helping brewers meet sustainability goals while maintaining product quality.
“Beer has been central to human society for thousands of years, largely in part to its simplicity in processing giving it close ties to agriculture,” adds Cole Hackbarth, VP of Brewery Operations at Rhinegeist. “As we face increasing climate change and global food insecurity, it behooves us to look inward at the basic ingredients in beer for answers. Water, malt, hops and yeast continue to be the building blocks of beer and it’s in these natural ingredients that we can innovate for the future.”
Nicholas Ketchum, who recently attended the prestigious Cold Spring Harbor Labs Yeast Genetics and Genomics Course, credits the experience with equipping him with advanced genetic tools that will support further research into killer yeast strains.
For further details, read the full study in ASM Journals.
Nicholas Ketchum appeared on NPR’s Cincinnati Edition on November 19th to summarize the research.
About Rhinegeist Brewery
Founded in 2013 in the heart of Cincinnati, Ohio, Rhinegeist Brewery is rooted in the historic Over-the-Rhine Brewery District. The brewery, whose name means “Ghost of the Rhine,” is known for its commitment to quality and creativity, making it the 22nd largest craft brewery by volume in the U.S. as of 2023. With an unwavering focus on innovation and sustainability, Rhinegeist continues to pioneer solutions that benefit the broader brewing community. Learn more about Rhinegeist at www.rhinegeist.com or follow @rhinegeist on social media.