Where home brewing and microbiology intersect – La Salle University

A non-traditional project in professor Brian DeHavens course calls attention to the practical applications of laboratory microbiology.

For two hours, Brian DeHavens kitchen became his classroom. His countertop acted as a makeshift lab table.

On this September day, DeHaven guided his students through a detailed step-by-step process that called for steeping, boiling, and ice-bathing various materials. His students monitored the color and consistency of their concoctions. They noted mixed resultsOne student had sediment firmly stuck to the bottom of her container. Another referred to the material as slime-like.

Remember, we want to be drinking this stuff next week, not chewing on it, said DeHaven, Ph.D., assistant professor of biology at La Salle University.

For 22 students in DeHavens upper-level microbiology course, this was not a standard laboratory experiment. Its actually a semester-long, beer-brewing project that requires precision and attention to detail.

A broader move in the biology discipline is seeing instructors across the country convert traditional textbook learning and components of classroom instruction into hands-on laboratory experiments. Popularly, in recent years, professors like DeHaven rely on beer-brewing to call students attention to the practical applications of laboratory microbiology.

For DeHavens course, students scheduled times to visit La Salles campus and retrieve beer-brewing kits from Holroyd Hall. (Only one student needed DeHaven to ship the kit by mail.) Under DeHavens watchthrough a synchronous Zoom sessionthe students boiled water before adding material from their kits, like a sugar source (dried malt extract) and hop pellets, which are actually antimicrobial. Hops are in beer, he said, to keep out other elements that will get you sick. The addition of yeast represented the final step. The concoction, DeHaven said, needed to cool before yeast is introduced to preventamong other outcomeskilling the cells before they can make any alcohol.

Once they get the basics down, students capture wild yeast by placing a petri dish filled with agar outside of their homes.

Wild yeast is pervasive. Its literally everywhere. Its in the air. You could swab bark or leaves, for example, as a way to capture it, said DeHaven, who introduced this project and has overseen it for three years. (This years project is a bit different, as La Salle is delivering a majority of its fall courses through remote instruction.)

Upon adding yeast, DeHavens students used a hydrometer to measure the materials specific gravity. This calculation helps brewmasters determine the alcohol by volume (ABV) and the calorie count of a beer. The projects objective, DeHaven said, is for students to question their recipes, procedures, and scientific methods to improve the taste of their beer each time the process is repeated.

Two of DeHavens students are not of legal drinking age. That doesnt take away from the projects value, he said, because their calculations will tell the story.

In past years, DeHavens students have presented their brewed beverages as a competition at La Salles Holroyd Symposiumduring which students across the STEM disciplines showcase their work from the fall semester. While that is unlikely to transpire this year, DeHaven said he is working behind the scenes to highlight his students accomplishments. He is in discussions with a local brewery to position his amateur brewers for internships. Hes also detailed the project in an article he has submitted for journal publication.

I developed this lab to show students that what they learn in lecture has real-life, practical applications, DeHaven said. Being able to teach a lab virtually has been a wonderful bonus.

Christopher A. Vito

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Where home brewing and microbiology intersect - La Salle University