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The sweet science of chocolate

Editor's note: The script below is not intended as a print feature - it is a transcript of the accompanying video, produced by KQED's QUEST. The script is derived directly from the spoken word/on-camera interviews and as a result, contains many fragmented sentences.

Ahhhh, Chocolate.  For some connoisseurs it's a delightfully sweet treat. for others, a sinful obsession. 

Either way, fanatical devotion is not a recent phenomenon. Chocolate's universal appeal dates back 2000 years to the ancient civilizations of the maya and aztec people.

Both cultures believed that cacao, the tropical plant that produces chocolate, was imbued with divine powers And used it as a religious offering to the gods.   Cacao seeds were also used as currency, as a general health tonic, and even as an aphrodisiac.

But that was a long time ago.  nowadays we recognize chocolate only for its guilty pleasure.  or do we?

The exciting news with our study is we found that small daily doses of dark chocolate could actually improve vascular function.

In 2004, Mary Engler, a professor in the School of Nursing at the University of California San Francisco, conducted a clinical trial.  her purpose was to investigate the effects of the antioxidants found in dark chocolate.

Dark chocolate is within the one category of flavonoids called flavonols. Within that group are a number of compounds that have catechin or epicatechin within the product.

Those two compounds, catechin and epicatechin, are naturally occurring chemicals that can increase the levels of nitric oxide in your bloodstream. and it's the nitric oxide level that makes your arteries dilate and relax, promoting better blood flow.

We know that heart disease, you have narrowing of the arteries and blood flow can't get through. So blood flow's very important to help prevent any kind of cardiac event.

But not just any chocolate is good for your heart ...

When you're looking at the differences between dark, milk and white, dark chocolate is much better because of the high content of the cocoa flavonol.

And how does dark chocolate compare with other flavonol-rich foods?

Dark chocolate is immediately the highest. Even in comparison to say, cherries, red wine and tea, dark chocolate is the highest.

And that's just one chocolate's potential health benefits.

There are a number of compounds that are also in dark chocolate, besides the heart healthy cocoa flavonols. And they include many minerals, so magnesium, even potassium, copper, calcium. And they found, too, that you can raise your serotonin levels, and that's why you get the good feeling that you do after having dark chocolate.

Usually when you think about chocolate, health isn't the first thing that comes to mind. It's all about taste -  extremely refined taste.

So, that's what the final chocolate looks like.

And finding and perfecting that taste is Timothy Childs' mission. He's the chief chocolate officer at San Francisco's designer chocolatier TCHO. As a former software developer on the space shuttle orbiter program, Childs is just the guy to meld Silicon Valley know-how with Willy Wonka whimsy.

Chocolate's an incredibly complex system. It goes beyond just hard science. You also have to integrate art and a lot of intuition, too, at the same time. So it's a really interesting combo.

Any delicious bar of fine chocolate begins with the cacao tree. A mature tree produces about 20 fruits, or pods, each of which contains about 40 beans. about 500 beans are needed to produce a pound of chocolate so an average tree produces about two pounds a year. After the beans are extracted from the pods, they need to be fermented.

One of the big mysteries of chocolate is a lot of people don't realize that you actually have to ferment the beans, right?  You have to do it with coffee as well as beer, all sorts of stuff gets fermented. 

Fermentation halts the seed's growth and it also develops the cacao's complex flavors. 

The traditional style of fermentation is in big piles. And that doesn't have proper kind of even cooking of the beans, and so we try to encourage our farmers to go to a more of a box method.

Instead of a big pile that on the outside, it's cold and in the center it's warm, you can mix them as they go from one box to another. You actually can control it a lot better so consistency is really important.

After fermenting, the beans need to be dried. traditionally, growers would dry their beans on concrete, but that simply won't do for today's high-tech chocolatiers.

When the beans are drying, they're out gassing what we call volatiles, which are pretty much acidic acids and other undesirable flavors. But if you're out-gassing on plastic or concrete, it bounces right back into the bean. If you actually dry on bamboo racks or anything that's got air moving underneath it, those acidic acids combine with the oxygen and blow away.

But how do you maintain quality control if your beans are a 12-hour flight away? Childs came up with an innovative device to bridge this physical gap with his growers in Peru.

We've pretty much took an off-the-shelf weather system and did some custom modifications to it. This weather system sends weather data wirelessly to a laptop, and that laptop's hooked up to a cellular modem that sends it up to the internet.

Childs correlates this weather with the fermentation data to track how each batch of beans was grown and processes. Then, when he gets a superior batch of beans from his growers, he knows exactly what conditions produced it.

Over 90% of the people that actually grow beans, which are mostly small family farms, they've never tried chocolate or cocoa mass from their beans before. And you kind of go huh? So, there's no feedback loop there.  We're educating our partners about coming up with common language of sensory analysis. Basically, what does it taste like as well as methodologies on how to measure how well it's fermented.

When they arrive, Childs does a cut test of his beans that helps him grade the cacao by size, shape, color and texture - all indicators of the quality of the fermentation. 

I'm just going to take it and cut. Isn't that a great sound? Cuts 50 beans at a time.

So, basically there's a couple of things to look at. Look at this right here. See this great definition? How really well-formed it is, it starts breaking apart. That's a really great-tasting bean. And let's find one that's little under fermented. Like, look at this one right here. This one's a little what I call slatey. See it? Doesn't have a lot of definition to it. That's under fermented. Look at the difference in the texture. See how's it doesn't have a lot of definition to it? This tastes good, this does not taste good.

Childs evaluates beans in the flavor lab, which simulates the production process of a chocolate factory. it's equipped with a modified turkey oven that roasts raw cacao beans. childs then cracks the beans and uses another homemade contraption to separate the nibs, or the meat of the bean, from the shell. He then grinds the nibs with a repurposed Indian curry dal maker. 

It'll turn into a paste like this, which is cocoa mass, ok? 

TCHO roasts, winnows, and grinds its beans off-site, but refining happens at its factory in San Francisco. This is the stage that influences the chocolate's texture and creates the smooth "mouth-feel" that aficionados savor.  Then the chocolate is conched, or heated and cooled repeatedly, to fine-tune its most subtle flavors. Still, for childs, the real magic happens during the tempering stage.

You temper chocolate just like making tempered glass or tempered steel. You start with a molten fluid. You seed it with a piece of already crystallized material. You're actually creating this molten lattice crystal structure that's flowing, and then if you mold it and you cool it just right, what ends up happening is all these little fat molecules kind of line up and they get  tighter and tighter and tighter, till it goes "Whoosh!" and it fuses in this crystal. And that's what gives chocolate its snap. 

Crystallization is key, so if you don't have it well-tempered, it doesn't melt in the same rate and all the flavors get all mashed together. 

Every step of the way, TCHO works to change the game with their silicon-valley approach to "chocolate science." their first batch of chocolate in 2007 was even dubbed a "beta" release.

We do a beta and we get friends and family feedback. We slightly tweak the formulations based upon that feedback. And then once we're done with that, we ship 1.0.

So what will chocolate 2.0 look like?  For starters, TCHO is in the process of creating a virtual chocolate tour for curious consumers. also being perfected is ‘satchel,' a database that stores tcho's research information.

And more high-tech help is on the way. In 2008, the U.S. Department of Agriculture partnered with IBM and the chocolate company MARS to sequence and analyze the entire cocoa genome in the hopes of breeding a more disease-resistant cacao tree. The research will be freely available as the 5-year project progresses.

But in the mean time, some food for thought...

Well, since our study, I've changed. I've switched from milk chocolate to dark chocolate. And I feel that when I do have a treat on occasion that I'm eating a more heart-healthy product. And I can feel my arteries dilate. I think we're seeing everyone switching over to the dark side.