The science of chocolate

A Fremont shop will show you how chocolate goes from bean to bar.
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Confections from Theo Chocolate in Fremont.

A Fremont shop will show you how chocolate goes from bean to bar.

As "the food of the gods," chocolate embodies mystery: It is rich but sweet, solid yet melts in your mouth, whimsical but seriously satisfying. Can this indulgence possibly coexist with the rigors of science?

Theo Chocolate in Fremont thinks so, taking its name from Theobroma cacao, the scientific name of the tree providing cacao beans, the raw ingredient of chocolate. It turns out that the complex, if somewhat magical, transformation of these outrageously bitter beans into our beloved chocolate bars has plenty of science behind it, and Theo's shows it off each day with tours open to the public.

Art and science mingle at Theo's, the nation's first and only organic, fair-trade chocolate producer. In the artsy storefront, peer at bonbons in glass cases, sample inviting piles of chocolate pieces, and browse the brightly wrapped chocolate bars. Then leave all that to don a decidedly inelegant blue hairnet, and venture below to view the guts behind their "bean-to-bar" operation. Among the maze of tanks and pipes, the heady chocolate aroma reminds you of the final goal.

Learn that the cacao fruit grows on trees. Discover that the unassuming beans (or seeds) inside are fermented as the fruit surrounding them rots away in the tropical sun. See the difference between good cacao beans and bad; marvel at the bulbous roaster built in 1937; and grasp that the key transformation from cacao nib to chocolate means to grind, grind, grind.

In fact, grinding the cacao nibs down to very fine particle sizes not only allows chocolate to melt in your mouth, but it can also influence the taste, says Andy McShea, chief scientist at Theo's. Although the human palate can only detect particles down to 50 microns (half the width of a single human hair), Theo's grinds them down even further, to give the chocolate a particular mouthfeel, that peculiar quality somewhere between texture and taste.

Next comes conching, a process that warms and mixes the chocolate for hours, sometimes days. Some molecules break down, new ones are made, and the chocolate gets a milder flavor. The trick (and art) is not to go too far, says McShea, which would leech out too many of the tasty molecules, leaving a bland, sad substance in the tank.

But science is catching up to art: Recent research identifies the many molecules behind certain tastes in chocolate, notes McShea. Theobromine gives chocolate its bitterness. L-alanine contributes to sweetness. Epicatechin imparts a sharp, astringent flavor. These and about 30 other molecules all pitch in to give chocolate its complex yumminess.

Epicatechin also bestows — surprise! — health benefits to chocolate, acting as a powerful antioxidant. As we age, our cells accumulate damage from molecules called free radicals. Antioxidants quench these free radicals, keeping them from running amok, and certain foods, like blueberries, are rich natural sources of antioxidants. McShea did the experiment and finds that half a Theo's chocolate bar has antioxidant levels similar to a cup of blueberries.

Think it's all good? It's not. Most chocolate at a 7-Eleven candy counter (described by McShea as "mockolate") has processed the antioxidant properties — not to mention the flavor — out of the chocolate, he says. Not only are mockolate manufacturers inattentive to their cacao processing, but they add cheap sweeteners and fillers like soy lecithin or corn syrup solids to the final product.

He likens it to broccoli, where the potential health benefits depend on how it's cooked. Is the broccoli lightly steamed, preserving the vitamins? Or is it boiled down to a mush and slathered with butter? The same goes for chocolate, he argues.

Despite this chocolate enlightenment, your science correspondent continues to pilfer (and enjoy) the mockolate in her child's Halloween stash. But a flash of limp broccoli now appears consistently before the first bite.


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