D. W. HERB (1), R. C. Graebner (1), S. Fisk (1), T. Nielsen (2), D. Carey (3), T. Shellhammer (4), P. M. Hayes (1);
(1) Oregon State University, Corvallis, OR, U.S.A.; (2) Sierra Nevada Brewing Co., Chico, CA, U.S.A.; (3) New Glarus Brewing Co., New Glarus, WI, U.S.A.; (4) Oregon State University, Corvallis, OR, U.S.A.
Technical Session 7 - Malt and Grain
Tuesday, June 16
8:30–10:15 a.m.
Fiesta 3,4,6,8
Barley contains significant amounts of positive flavor compounds that are contributed to malt and beer; however the impact of variety and environment on barley flavor is not well understood. In this study we evaluated the beer flavor potential of three barley varieties (Full Pint; AC Metcalfe; Klages) grown in replication in three environments (Corvallis, OR, USA; St. Paul, MN, USA; Saskatoon, SK, Canada). The resulting grain was micromalted by Rahr Malting. Sierra Nevada Brewing Co. and New Glarus Brewing Co. both conducted Congress wort sensory assessments. The controls were AC Metcalfe high- and low-color malts. Gas chromatography coupled with mass spectrometry (CG-MS) at Sierra Nevada revealed that the principal volatile compounds present across samples were dimethylsulfide (759164.8 m/z), 3-methyl butanal (72583.2 m/z), 2-methyl butanal (144753.2 m/z), hexanol (129991.8 m/z), phenylacetaldehyde (393667.1 m/z), and methyl mercaptan (835.5 m/z) and contributed flavors such as fruity, floral, cooked corn, nutty, potato chips, biscuit, malty, and cereal. There were off-odors as well. Concentrations of dimethylsulfide and trans-2-hexanal were highest in Full Pint, while 2- and 3-methyl butanal and methyl mercaptan was highest in AC Metcalfe, and hexanal in Klages. Principal component analysis (PCA) indicated that variety and environment account for 34% and 12%, respectively, of the variation in mass-spec abundance analyte concentrations across samples. In a blind sensory assessment, panelists distinguished unique flavors and preferences across the different varieties and environments, suggesting that barley variety and production environment play a significant role in beer flavor.
Dustin Herb is a Ph.D. student of plant breeding and genetics in the Crop and Soil Science Department at Oregon State University (OSU). His research is currently focused on barley under the instruction of Patrick Hayes. Dustin’s primary areas of study include genome sequencing and genomic selection, genetic mapping for low temperature tolerance, disease resistance, malt quality, and flavor compounds. Prior to starting his doctorate program at OSU, Dustin received his B.S. degree in agronomy from OSU and M.S. degree in plant breeding from Texas A&M University and was the assistant director for research at Oregro Seeds, Inc., working with forage grass, cereals, and legumes. Post studies Dustin intends to return to academia and pursue a position in malting and crop improvement, with a particular focus on brewing and distilling raw materials.
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