Dr. Tom Carr’s chemistry students recently enjoyed a guest speaker, Dr. Malcolm D. E. Forbes, who helped them explore the art and science of beer. Thank you to Dr. Carr for submitting the following write-up on the experience.
NSCC promotes STEM education, in part, by exposing its students to practitioners. One example is a field trip made to Bowling Green State University’s Center for Photochemical Sciences earlier in 2017. There, we made the acquaintance of the Center’s director, Dr. Malcolm D. E. Forbes, who has expertise in the art and science of beer. Besides brewing beer on the side, Dr. Forbes has a history of characterizing chemical processes that affect beer flavor. He spoke about his work to NSCC chemistry students on October 3, 2017.
“Beer is proof God loves us and wants us to be happy” – Benjamin Franklin.
Dr. Forbes began by describing beer’s history. Obtaining beer likely drove the transition from hunting and gathering to agriculture. Sumerian beer goddess, Ninkasi, relates how beer has been a feature of civilization since its earliest days. Beer’s continuing importance to human existence led to the first consumer protection law, the German Reinheitsgebot, which stipulated beer could only contain water, malted barley, hops and yeast.
“In wine there is wisdom, in beer there is freedom, in water there is bacteria.” – Benjamin Franklin
Health benefits for beer consumption were cited. Historically, boiling steps made beer healthier to drink than just water. Beer also provides vitamins, helps to prevent cancer, and contributes to stronger bones via elevated levels of silica.
Dr. Forbes continued with various aspects of the beer making process. He discussed how malting and roasting processes affect the color, flavor and alcohol content of beer. He detailed the role of hops in beer. Besides adding a bitter flavor, hops provide antibacterial, antioxidant and head foam stability properties.
He then segued into his research into causes of off-flavors in light-struck, also known as “skunky,” beer. UV light-initiated chemical reactions of hops compounds leads to formation of “skunky thiols.” These are sulfur-containing compounds; chemically related to disagreeable components found in skunk perfume and cat urine. This explains why so many beers are sold in brown and green bottles. He also mentioned how addition of lime wedges improves flavor of “skunky” beers, as the acidity will change thiols into more agreeable species.
Dr. Forbes concluded with discussion about craft beers. He described technical and business aspects of what distinguishes craft beers from mass-produced beers, as well as the brewing industry’s technical contributions to microbiology, characterizing genomes, and standards for green industries. Overall, our students found that while he may not have been the “most interesting man in the world,” he was clearly a close second.