Meghan Peltz (1), Thomas Shellhammer (2); (1) Sierra Nevada Brewing Co., Chico, CA, U.S.A.; (2) Oregon State University, Corvallis, OR, U.S.A.
Only a fraction of the hundreds of chemical compounds found in hop oil contribute to beer flavor. Best estimate thresholds of 10 hop compounds were quantified in unhopped pale ale beer with ethanol contents of 5% and 10% alcohol by volume using ASTM E679 threshold methodology. While the solvating properties of ethanol had the potential to impact solubility, this study concluded that variation in the ethanol content had little effect on the sensory orthonasal aroma detection thresholds of hop compounds in beer. Seven of the compounds were not influenced by ethanol concentration. Ethanol had a statistically significant effect on the threshold concentrations of beta-damascenone (195 µg/L in 5% ABV to 74 µg/L in 10% ABV), but the practical significance of the 36 ppb difference between the two ethanol contents is uncertain. The threshold concentrations of geraniol and linalool significantly increased when more ethanol was present, from 141 µg/L to 305 µg/L and 83 µg/L to 205 µg/L, respectively. The potential ethanol suppression of terpene alcohols was relatively small, 2.5-fold, and would likely have little impact on their odor activity values. The results of this study can be used for OAV calculations across a wide range of ethanol concentrations in beer.
Meghan Peltz is presenting the work of her master’s thesis from Oregon State University, under the direction of Thomas Shellhammer, specializing in the areas of sensory and hop chemistry. Post-graduation Meghan was hired at Sierra Nevada Brewing Co. as a sensory manager working with the Chico, CA, and Mills River, NC, breweries. Meghan continues to be an active member of the ASBC Sensory Subcommittee and MBAA in her new role. She is enjoying settling into the northern California lifestyle, hiking and skiing in the Sierra mountain range on the weekends.