Joseph Spearot (1), Jacob Lahne (2); (1) Yards Brewing Company and Dogfish Head Craft Brewery, Philadelphia, PA, U.S.A.; (2) Drexel University, Philadelphia, PA, U.S.A.
Technical Session 19: Beer Bitterness
Wednesday, August 17 • 8:15–9:30 a.m.
Tower Building, Second Level, Grand Ballroom
In general, beer is composed of malted barley, hops, water, and yeast. The color of beer is derived in large part from malted barley, which also provides sugars for alcoholic fermentation by yeast. Meanwhile, bitterness in beer is derived almost entirely from the main flavoring agent: hops, which also gives the product fruity, woody, herbal, and spicy flavor notes. Thus, flavor and color in beer, particularly bitter taste, are not connected. Nevertheless, the idea that beer color predicts flavor intensity is common among consumers. This is probably due to sociohistorical factors. For example, in the 19th century companies like Miller and Anheuser-Busch began to, and still do, dominate the brewing market, producing German-style lagers with low alcohol, low bitterness, and light colors. Perhaps because of this, there is a common misconception that a dark-colored beer will be more bitter than a lighter colored beer. The current research was designed to investigate whether this common misperception will result in measurable differences in consumer sensory perception. All of the research below was approved by the Drexel University IRB. First, a discrimination study on methods for creating dark color in beers was completed to determine whether these adjuncts created perceptible differences in beers when consumers were blind to color. Three batches of the same basic American pale ale recipe were brewed: one batch was darkened with black malt (~4% total grain bill); one was darkened with Sinamar, a malt-based dye (120 mL per 19 L of wort); and the third was unaltered. A series of triangle tests (n = 24) was carried out between the samples with color concealed; in addition, bitterness (IBU) and color (SRM) were quantified instrumentally. Tests confirmed that the only difference between samples was color. From these results, Sinamar was chosen as a darkening method for the main test; a triple batch of the same recipe was brewed, split into three, and colored to three levels: yellow (13.0 SRM ), brown (30.7 SRM), and black (55.1 SRM). A second set of triangles tests (n = 21) found no differences between these beers. A consumer sensory test (n = 85) collected data on the beers’ flavors with color unobscured. Data were analyzed using repeated-measures ANOVA, with consumers as between-variables and beer color as within-variables. This analysis showed that consumers rated the yellow beer samples as significantly (F (2,164) = 5.15; P < 0.05) more bitter than the black beer samples, although the same samples are not readily discriminable when color is obscured. This is evidence of a significant color–taste interaction in beers. The direction of this interaction, however, was unexpected and may be due to the rise in popularity of India pale ale styles: light yellow beers with intense hop bitterness. To examine this hypothesis further, a posthoc investigation was conducted to explore demographic trends in color–bitterness interactions; the results are presented here.
Joe Spearot received an M.S. degree in food science from Drexel University in Philadelphia, PA, in March 2016. Previously, he completed an undergraduate B.A. degree in biology and chemistry at Arcadia University, where he was able to study in countries such as Scotland and Australia. While in Australia he developed a passion for food and beverage science while working on an organic, biodynamic vineyard. Currently Joe works as the quality control chemist for Yards Brewing Company, also in Philadelphia. Here he is responsible for tests ranging from raw ingredients to shelf stability. His first paper, “Microscale and Macroscale Effect of the Early Pitching Method on Beer Composition During the Brewing Process,” based on his undergraduate research, was published in the Technical Quarterly and presented at the MBAA Brewing Summit meeting in 2014. As a current member of both the MBAA and ASBC Joe looks forward to future participation within both organizations.