T. Krivenki (1), B. TAUBMAN (1); (1) Appalachian State University, Boone, NC, U.S.A.
Poster
With 84 breweries now open in North Carolina, there is an increasing
demand for locally produced hops. Currently, the vast majority of U.S.
hop production occurs in the Pacific Northwest due to appropriate soil
composition and climate. For this study, the major aroma active
compounds in essential oils were compared in the hop cultivars Cascade,
Zeus, Magnum, and Chinook produced in both North Carolina and the
Pacific Northwest. A headspace gas chromatography-mass spectrometry
(GC-MS) method was developed for the determination of essential oil
aroma compounds in hop samples, specifically myrcene,
beta-caryophyllene, caryophyllene oxide, farnesene, beta-pinene,
alpha-humulene, geraniol, and linalool. A set of multicomponent
standards was prepared in ethyl acetate to increase the limits of
detection. Each sample was allowed to age in the freezer and distilled
every 30 days to observe potential oxidation of the compounds within the
essential oils. The hop essential oil was extracted via steam
distillation according to ASBC Method Hops-13. The essential oil from
each sample was combined with a 5% ethanol solution to imitate the
volatility of the aroma compounds in a beer matrix. In the North
Carolina grown hops, the aroma active compounds were well below the
range expected in the Magnum and Zeus cultivars, possibly the result of
harvesting too early, whereas Cascade and Chinook had concentrations in
the range expected for those cultivars. This method of essential oil
analysis is fast, reproducible, and requires little sample quantity or
preparation. The results of this study will help determine any
differences in hop essential oil compositions among the same varieties
grown in North Carolina and the Pacific Northwest, as well as the
optimum times to harvest North Carolina grown hops to maximize essential
oil production and potential oxidation of the compounds during storage.
Brett Taubman is a faculty member of the A. R. Smith Department of
Chemistry at Appalachian State University (ASU), where he is engaged in
instruction and academic research within the chemistry and fermentation
sciences. He has earned B.S. degrees in both finance and chemistry from
the Pennsylvania State University and Montana State University,
respectively, and a Ph.D. degree in analytical and environmental
chemistry from the University of Maryland (2004). Following his graduate
studies, he worked as a post-doctoral research associate at the
Pennsylvania State University before joining the chemistry faculty at
ASU in 2007. Brett has successfully developed a pilot instructional
brewing facility on the ASU campus and currently serves as president of
Ivory Tower, Inc., a 501(c)(3) nonprofit corporation with the mission of
supporting research and education within the fermentation sciences. He
helped to develop the four-year degree program in fermentation sciences
and shares time between that program and the Chemistry Department. He
has been brewing and teaching brewing sciences and technology for more
than 10 years and is a member of the American Society of Brewing
Chemists, Master Brewers Association of the Americas, and Institute of
Brewing and Distilling.
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