(213b) Beer Experiments - a Hopping Success

In the Biochemical Engineering Laboratory (CHE 194) course, students learn bioprocess engineering experimental techniques for eight weeks including microbial fermentation, protein purification, ultrafiltration, chromatography and enzyme kinetics.

Following the modular labs, a true inquiry lab experience is had by the students. Student teams submit a proposal for an experiment of their choice, using a previously published rubric for design of experiments. Five weeks is allotted for the inquiry experiment so they have sufficient time to repeat parts of the experiment that didn’t work the first time. Students rate the experience highly on the end-of-semester evaluations.

Beer is a popular subject for many chemical engineering students. An experiment has been added into the chromatography module giving the students the opportunity to calibrate the high pressure liquid chromatograph (HPLC) instrument using a standard for alpha acids and then they can bring their favorite beers and test them for alpha acid content. Beer hops confer alpha acids into the beverage that have some health benefits, such as antioxidant activity, as well as anti-microbial activity for preserving the beer early during the fermentation when the alcohol level is low. Hops are added during the boil because the solubility of the alpha acids is higher in hot water than cold. Popular now is also the dry-hopping process whereby hops are added after the boil and the ethanol produced during the fermentation enables the solubilization of the alpha acids. Students have done several experiments related to beer over the years. The alpha acid HPLC module will be presented here as well as the inquiry experiment design and two of the most interesting beer experiments designed and executed by students over the years.