Sixpack Sez

Sept. 25, 2009 | Better drinking through chemistry

CHEMISTRY - perhaps the most-feared course in the college curriculum - has taken on an approachably sudsy look this semester at West Chester University.

"The Chemistry of Beer" is a new elective science class for students who don't wear pocket protectors.

"It seems most students are interested in two things," said associate professor Roger Barth, who created the course to attract nonscience majors to his classroom, "so I thought we'd go with the second one."

The course examines the complexities of chemistry, from acids and bases to hydrophilic molecules, through a beaker full of brew.

Using beer to study chemistry is not really a stretch, Barth pointed out, because "brewing technology has been one of the things that led to many of the advances in chemistry."

Indeed, Louis Pasteur studied bacteria by examining beer through a microscope. Søren Sorensen developed the Ph scale while working in the lab at the Carlsberg Brewery.

Barth, who wrote the course's textbook, leads the class from the very basics of beer, the chemistry of water, through the entire brewing process: milling, mashing, boiling, hopping, fermentation, sterilization, bottling and quality evaluation.

The course also includes a class trip to the Victory brewery in nearby Downingtown, where they'll meet Tim Wadkins, the brewery's director of quality assurance, who has a doctorate in biochemistry.

Though Barth and at least three of his colleagues in West Chester's chemistry department are homebrewers, the course is not designed to teach students how to make their own beer.

After paging through the textbook, I'd guess that even most professional brewers aren't conversant in the chemistry behind, say, sugars and starches. (Quick: What's the difference between D-glucose and L-glucose?)

During the class I visited this week, Barth looked suitably rumpled, with chalk dust covering his wool jacket and a loosened tie decorated with beer mugs. Lecturing on ion exchanges and osmosis, he quickly scribbled chemical formulas, explaining how adding O2 to water can remove unwanted iron.

I was completely lost in less than 10 minutes.

Other students furiously jotted notes, then polished off a surprise quiz in less than five minutes.

Because West Chester's campus is dry, Barth is prohibited from bringing beer into his classroom. Instead, he uses photographs and those hieroglyphic diagrams of chemical reactions.

The lack of beer doesn't seem to hinder Barth's teaching. Presumably most of his students already have a working knowledge with the bubbly liquid.

After class, I buttonholed the kid wearing a T-shirt that proclaimed, "Part-Time Student - Full-Time Partier."

"I never knew most of this stuff about beer," Zach Jameson, 23, a creative writing and theater major, told me.

Why'd you take the class? I asked his friend Brian Malloy, also 23.

"We're homebrewers," he said. "This will definitely help us out."

Last question: What year are you in?

"We're fifth-year seniors," said Jameson.

Jameson and Malloy are exactly the type of students Barth hoped to attract to his class.

"I kind of feel like the students are learning about alcohol one way or the other," Barth said, "so without preaching to them, maybe this class will give them a thoughtful attitude toward alcoholic beverages."

Meanwhile, he added, "Chemistry has a reputation for being a real bear, partly because it is. There's all this chemical bookkeeping and numerical ideas like how many atoms in a molecule and how much a molecule weighs. . . . So maybe beer gets students interested in chemistry."

Indeed, for liberal arts types, it may be their only brush with the periodic table.

The course certainly worked for me: I finally learned the science of why beer comes in brown bottles.

Energy from light is absorbed by riboflavin in beer and transferred to the iso-alpha acids from hops. The process creates an unstable free radical that reacts with sulfur proteins, which produce 3-methylbut-2-ene-1-thiol, the active ingredient in skunk spray.

According to Barth's text, brown bottles let in very little light at the wavelength that can "lightstrike" beer.

And, yes, this will be on the final exam.

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