Come to the Liberty Well Social Club to check out these four poster presentations.
The Barrel Project, Matt Hulihan, Aaron Wittman
This poster presentation provides a collection of considerations, hints, and other helpful information learned by seven brewers during the brewing, fermenting, and aging phases of their ‘Barrel Project’. The Barrel Project was their first foray into brewing and aging on a 55 gallon scale. It is intended to serve as a foundational quick-reference for other groups who might attempt a similar project.
Engineering a Biosensor to Detect a Secreted Yeast Protease in Beer, Matt Farber
Proteases are responsible for the cleavage and breakdown of other proteins. Previous studies have demonstrated that the yeast protease, Proteinase A (PrA), also called Saccharopepsin, is secreted into beer during fermentation. This protease degrades foam-promoting proteins, thus decreasing head retention of the beer. Because the concentration of secreted PrA during fermentation has been correlated with yeast viability and proper nutrition, the precise measurement of PrA activity is an important readout for quality control. Previous assays to measure PrA activity have demonstrated non-specificity, low sensitivity, and high cost. Therefore, we have developed a novel, genetically encoded PrA sensor using engineered antibodies which fluoresce after cleavage by PrA. Using less than a drop of beer as the source of PrA, we can measure PrA activity over time. In the future, we hope to use our PrA sensor to measure PrA activity induced by brewing variables such as different yeast strains, high gravity fermentation, and yeast re-pitching. By presenting this poster at the AHA conference, I hope to find fellow homebrewers who would be interested in contributing to this project by providing samples to test.
Effects of N-acetylcysteine on Glutahtione Levels During Fermentation, Jake Ocque
In beer, glutathione (GSH) is the main antioxidant and has an effect in prolonging the stability of beer flavor. GSH is produced by all living cells and in the case of beer is produced by the yeast during fermentation. N-acetylcysteine (NAC) has been used clinically to increase the amount of GSH production in humans. The aim of this study was to monitor the effects of treating beer yeast with NAC on the levels of GSH during fermentation and in finished beer. Three pale ales were brewed with the different condition of no yeast starter, with a yeast starter, and with a yeast starter containing 1 gram of NAC. Samples were taken from the moment of pitching yeast to throughout yeast fermentation and finally after packaging. Levels of NAC and GSH were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). After 24 hours from pitching of yeast into the fresh wort, levels of GSH began to double every day for the four days of active fermentation. The effect on flavor was noticeable with the NAC beer having a fresher hop aroma and flavor as compared to the identical beer without NAC. Implementation of NAC into fermentation may lead to a longer shelf life for beer. The added benefits of having NAC and elevated GSH in beer may be beneficial to the beer drinker as well.
From Phenotype to Genotype or What Makes Your Favorite Brewer’s Yeast Tick?, Loren Miraglia, Chris White
Have you ever wondered why one yeast strain performs better than another? I have, ever since I started brewing in 1992. Many experiments with identical wort and different strains convinced me that the Duvel strain my brew partner Mark Graham and I isolated in 1994 was the best we’d ever seen. A chance meeting with an old colleague who now works at Illumina, One of the Next-gen DNA sequencing company, created this collaboration to sequence that strain alongside several others. The collaboration between, Yonder Biology, White Labs and Illumina, enabled the isolation, sequencing and comparison 96 different brewers yeast strains. This is still a project in progress but here I will present the preliminary work done on those strains. White Labs ale and lager strains sourced from multiple countries have been analyzed with the resulting phylogenetic trees, k-mer based, giving us some insight into their evolutionary origins. To be sure, this is only a starting point, as we have only begun to compare deletions/insertions and specific brewing related genes between these strains. With the brainpower of many passionate beer lovers/scientists we hope to answer many questions about what makes each strain unique.
