A Class on Chocolate? Sign Us Up!


From Top: David Schiraldi, Jon Pokorski, Michael J. A. Hore and LaShanda Korley

First-year student Jacob Rosales Chase watched the classroom experiment with anticipation last fall, as liquid nitrogen cascaded into a shallow bowl filled with chocolate pieces, enveloping them in a cloud of white gas.

"It was really cool—the chocolate froze instantly and then they smashed it on a desk and gave everybody pieces to taste," said Rosales Chase.

And that's where the real lesson came in.

"When chocolate isn't treated with the care it deserves and freezes too quickly, the crystal structure within it changes," said Rosales Chase, a native of Guadalajara, Mexico. And the result, as he and fellow students quickly learned, "tastes bitter and even abrasive."

Welcome to "The Chemistry, Physics and Engineering of Chocolate," a SAGES (Seminar Approach to General Education and Scholarship) class for first-year students at Case Western Reserve that took deep dives into the science, history and, of course, taste of a substance that has been savored for more than 4,000 years.

"Yeah, I'm going for that!" Roshni Bhatt, a self-described "chocoholic" from suburban Chicago, remembers thinking last summer as she selected the first five classes of her college career.

Bhatt said that, in addition to "learning more about chocolate than I ever thought possible," she got to make her very own flavor using botanicals and extracts. While classmates opted for coffee, orange peel and even peanut butter and jelly to customize their blends, Bhatt went with fresh ginger, a favorite staple in the Indian food she grew up eating.

David Schiraldi, PhD, the Peter A. Asseff Professor and chair of the Department of Macromolecular Science and Engineering, led the class, teaching it with three others from his department: Climo Associate Professor LaShanda Korley, PhD; Assistant Professor Michael J.A. Hore, PhD; and Assistant Professor Jon Pokorski, PhD.

Why a class on chocolate? Schiraldi, an accomplished researcher in the field of complex polymer systems, said the subject matter meshes perfectly with his areas of expertise.

"We found out that there are six different crystal structures that chocolate can have, making it more complex than most of the polymers we work with," he said.

In addition to having regular taste tests—including a sample of chocolate from Florence, Italy—students designed and printed a mold for molten chocolate using a 3-D printer at the Larry Sears and Sally Zlotnick Sears think[box] innovation center at the Richey Mixon Building.

On a chilly November evening—and in a "worlds colliding" moment—Schiraldi brought together students from both the chocolate class and another SAGES class he taught on fire science with the evocative moniker "Burn, Baby, Burn!" The students huddled around a bonfire and made—what else?— chocolate s'mores.

Chocolate Fast Facts

A food to claim as our own: Starting in the 1500s, chocolate began migrating from Mesoamerica (that is, Central and North America) to Spain, then to Italy and then in the 1800s to the rest of Europe.

A solid change: Thanks to Italian confectioners in the 1700s, chocolate evolved from primarily being a beverage to a sweet candy.

Crystals in every bite: Chocolate is one of the few crystalline materials we eat. Other foods with a crystal-like microscopic structure include butter, sugar and salt.

Stimulating—or toxic: Chocolate contains theobromine, a chemical compound that can serve as a mild aphrodisiac, diuretic or blood-vessel widener in humans. But in dogs and cats, it can be toxic.

Sources: David Schiraldi and Michael J.A. Hore