M-80: Effect of the early-pitching method on beer composition during the brewing process

J. W. SPEAROT (1); (1) Arcadia University, Glenside, PA, U.S.A.


Esters are flavor and aroma compounds of huge importance in foods and beverages. In brewing these naturally occurring chemicals often give beers a desirable fruity flavor. With this in mind an increase in these desirable flavors while decreasing undesirable fusel alcohols should result in a better overall end-product. At the 2012 World Brewing Congress Koizumi and Nakamura proposed an early pitching method in which yeast is pitched into wort at a faster rate than in conventional brewing. From their research a microscale brewing experiment was designed and completed at Arcadia University. The experiment was completed using two standard 6.5 gal plastic fermenters modified with four sample spigots installed along the side. Using a standard pale ale recipe with Citra hops and Whites Labs English Ale yeast, three trials of homebrew were brewed and tested. Within these trials a control, uniformly pitched batch was brewed alongside an experimental, early pitched batch. During fermentation temperature, pH, yeast cell counts, and amine content were tracked at each spigot in both the control and experimental beers. After aging, fusel alcohols were extracted, and esters were analyzed using headspace gas chromatography. Results indicated a decrease in the level of fusel alcohols and an increase in ester levels using the early pitching method. Currently a taste test is pending before the Institutional Review Board; if allowed it will determine if differences between methods are detectable within human flavor thresholds.

Joseph Spearot is a student at Arcadia University double majoring in biology and chemistry. Upon graduation in May he will be attending Drexel University, Philadelphia, PA, as a graduate student in the food science program. After an internship at Lowe Wines in Mudgee, NSW, Australia, during 2012, Joseph’s interest in food and beverage chemistry increased. During the summer of 2013 he secured an internship in the quality assurance lab of Yards Brewing Company in Philadelphia, where his current research was planned. It is his hope to continue participation in MBAA and research into brewing.

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