Name(s) of Faculty Adviser/Mentor
Bruce C. Hamper
Lupulones and humulones are two families of compounds derived from the hop flower (Humulus lupulus), utilized in brewing beer. Isohumulones are produced during the boiling process by isomerization reactions of humulones and are the primary bittering compounds in beer. The concentration in parts per million (ppm) of isohumulone is reported as IBU (International Bittering Units). Measurement of these compounds is valuable to brewers, but is confounded by other constituents in beer which may also absorb at the 275nm wavelength in UV-Vis spectrometry, the industry standard method. 25 samples were measured using UV-Vis, then analyzed by High Precision Liquid Chromatography (HPLC) and HPLC-Mass Spectrometry (LC-MS). Results were varied with respect to reported IBU. Of note, a sample containing an adjunct had much higher 275nm absorbance than expected, absent when eluted through HPLC, suggesting a falsely higher reading than actual due to interference by the adjunct.