M. L. PELTZ (1), T. H. Shellhammer (1); (1) Oregon State University, Corvallis, OR, U.S.A.
Poster
Hops are the spice of beer, contributing substantial impact per weight
in the brewing recipe. Many approaches have been taken over the years to
identify “hoppy” character in beer. The identification of compounds
that significantly contribute to the aroma of beer is commonly
accomplished by the determination of odor activity values (OAV), which
are defined as the concentration of a particular compound relative to
its sensory threshold in the same beer/matrix. Historically, published
thresholds have been measured in water or light lagers. In many cases
thresholds for individual hop compounds are not found in the published
literature. Furthermore, the effects of different beer matrices,
specifically alcohol concentration and beer style, on the sensory
thresholds of hop compounds have not been quantified. This study
evaluated the effect of ethanol content on a selection of important
aromatic hop compounds; beta-damascenone, carophyllene, citronellol,
geraniol, geranyl acetate, humulene, linalool, myrcene, and nerol.
Sensory aroma detection thresholds were determined using the forced
choice ascending series of limits methodology in model systems of 5, 10,
and 15% ethanol and water mixtures. The range of ABV (alcohol by
volume) tested reflects the range available in beer styles up to barley
wine. Results indicated that the effect of ethanol content on aroma
thresholds varies depending on the hop compound. Beta-damascenone,
carophyllene, and humulene aroma thresholds were significantly affected
by ethanol content, while other compounds were not. Chemical properties
of the compounds were analyzed to look for correlations to sensory
results. Sensory testing in various beer styles was also carried out to
determine if similar ethanol effects on detection threshold were
observed in increasingly complex bases. This information can be used by
brewing scientists to define correct odor activity values for a range of
different beer styles.
Meghan Peltz is a new member of ASBC and MBAA. She is currently a
master’s student at Oregon State University, studying under Thomas
Shellhammer. Prior to pursuing a graduate degree Meghan worked at Kalsec
Inc. as a sensory scientist from 2009 to 2013. There she became
interested in the study of hop chemistry and sensory science as a result
of her specialization in Kalsec’s hop extracts product line as sensory
panel leader, analyst, and technical sales representative. Meghan holds a
graduate certificate in applied statistics from the Penn State
University World Campus and graduated with a B.S. degree in food science
from Michigan State University.
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