Chocolate Aromas and Taste Development
by constantine jan 2nd, 2020
What remains an ongoing, simmering battle in the chocolate industry: the roasting of the cocoa beans. So what's better: computerized roasters or hands-on roasting on an open fire?
Machine vs. human. An ongoing question of which method is superior to the outcome.
Flavor formation and character in cocoa and chocolate.
Let's look at academic research on the science of roasting.
Chocolate characters not only originate in flavor precursors present in cocoa beans but are generated during post-harvest treatments and transformed into desirable odor notes in the manufacturing processes. In addition, complex biochemical modifications of bean constituents are further altered by thermal reactions in roasting and conching and in alkalization [reducing acidity, which is good for ridding your body of free radicals*].
However, the extent to which the inherent bean constituents from the cocoa genotype, environmental factors, post-harvest treatment, and processing technologies influence chocolate flavor formation and relationships with final flavor quality has not been clear. (in other words: not settled science.)
Sensory properties of chocolate and their development
According to the NIH: "Sensory attributes of eating chocolate are determined by processing variables and inherent characteristics of the cocoa bean. Flavor precursors develop during fermentation and primarily interact at roasting temperatures. Complex browning reactions occur during roasting. Numerous heterocyclic flavor compounds produced then contribute to the characteristic chocolate flavor. The feel of chocolate in the mouth (mouth feel) and the unique properties of cocoa butter determine textural properties. Careful processing and selection of ingredients are necessary to produce desirable attributes.'
Adulteration
[When science and poor-quality cocoa beans meet, the outcome is not in the consumer's favor.]
"The different treatments were evaluated by chemical analysis (hydrolysis efficiency) and sensory analysis of the treated material compared to good-quality cocoa almonds [beans]. The results show that it is possible, through the use of microbial enzymes**, to generate the mixture of compounds that will release, after roasting, the characteristic chocolate flavor in poor-quality almonds [beans]."
* Oxidative stress is an imbalance of free radicals and antioxidants in the body, which can lead to cell and tissue damage. Oxidative stress occurs naturally and plays a role in the aging process.
** Microorganisms such as bacteria, yeast, and fungi and their enzymes are widely used in several food preparations to improve taste and texture. They offer substantial economic benefits to industries.
Conclusion
Chocolate taste and aromas in roasting play an integral part in the process of making chocolate products. However, reliance on a computer's program does not take into account: the age of the beans, moisture content, the humidity of the environment of the facility, outside temperature, and moisture.
The Talk of the Town May 13, 1972 Issue
The Conching Rooms By John McPhee May 5, 1972
Pools and pools and pools of chocolate—fifty-thousand-pound, ninety-thousand-pound, Olympic-length pools of chocolate—in the conching rooms in the chocolate factory in Hershey, Pennsylvania.
Big, aromatic rooms. Chocolate, far as the eye can see. Viscous, undulating, lukewarm chocolate, viscidized, undulated by the slurping friction of granite rollers rolling through the chocolate over crenellated granite beds at the bottoms of the pools. The chocolate moves. It stands up in brown creamy dunes. Chocolate eddies. Chocolate currents. Gulfs of chocolate. Chocolate deeps. Mares’ tails on the deeps. The world record for the fifty-yard free-style would be two hours and ten minutes. Slip a little spatula in there and see how it tastes. Waxy? Claggy? Gritty? Mild? Taste it soft. That is the way to get the flavor.
Conching—granite on granite, deep in the chocolate—ordinarily continues for seventy-two hours, but if Bill Wagner thinks the flavor is not right he will conch for hours extra, or even an extra day. Milky? Coarse? Astringent? Caramely? For forty-five years, Mr. Wagner has been tasting the chocolate. His taste buds magnified a hundred times would probably look like Hershey’s kisses. He is aging now, and is bent slightly forward—a slender man, with gray hair and some white hair. His eyeglasses have metal rims and dark plastic brows. He wears thin white socks and brown shoes, black trousers, a white shirt with the company’s name on it in modest letters.
Everyone wears a hat near the chocolate. Most are white paper caps. Wagner’s hat is dapper, white, visored: a chocolate-making supervisor’s linen hat. A man in a paper hat comes up and asks Wagner, “Are we still running tests on that kiss paste?” “Yes. You keep testing.”
Wagner began in cocoa, in 1924. The dust was too much for him. After a few weeks, he transferred to conching. He has been conching ever since, working out the taste and texture. Conching is the alchemy of the art, the transmutation of brown paste into liquid Hershey bars. Harsh? Smooth? Fine? Bland? There are viscosimeters and other scientific instruments to aid the pursuit of uniformity, but the ultimate instrument is Wagner. “You do it by feel, and by taste,” he says. “You taste for flavor and for fineness—whether it’s gritty. There’s one area of your tongue you’re more confident in than others. I use the front end of my tongue and the roof of my mouth.” He once ate some Nestlé’s; he can’t remember when. He lays some chocolate on the tip of his tongue and presses it upward.
The statement that sends ninety thousand pounds on its way to be eaten is always the same. Wagner’s buds blossom, and he says, “That’s Hershey’s. ”Milton Hershey’s native town was originally called Derry Church, and it was surrounded, as it still is, by rolling milkland. Hershey could not have been born in a better place, for milk is twenty per cent of milk chocolate. Bill Wagner grew up on a farm just south of Derry Church. “It was a rented farm. We didn’t own a farm until 1915. I lived on the farm through the Second World War. I now live in town.” Wagner’s father, just after 1900, had helped Milton Hershey excavate the limestone bedrock under Derry Church to establish the foundations of the chocolate plant.
Derry Church is Hershey now, and its main street, Chocolate Avenue, has street lamps shaped like Hershey’s kisses—tinfoil, tassel, and all. The heart of town is the corner of Chocolate and Cocoa. Other streets (Lagos, Accra, Para) are named for the places the beans come from: quotidian freight trains full of beans that are roasted and, in studied ratios, mixed together—base beans, flavor beans, African beans, American beans—and crushed by granite millstones arranged in cascading tiers, from which flow falls of dark cordovan liquor. This thick chocolate liquor is squeezed mechanically in huge cylindrical accordion compressors. Clear cocoa butter rains down out of the compressors. When the butter has drained off, the compressors open, and out fall dry brown discs the size of manhole covers. These discs are broken into powder. The powder is put into cans and sold. It is Hershey’s Cocoa—straight out of the jungle and off to the A. & P., pure as a driven freak, pure as the purest sunflower seed in a whole-earth boutique.
Concentrate fresh milk and make a paste with sugar. To two parts natural chocolate liquor add one part milk-and-sugar paste and one part pure cocoa butter. Conch for three days and three nights. That more or less is the recipe for a Hershey bar. (Baking chocolate consists of nothing but pure chocolate liquor allowed to stand and harden in molds. White chocolate is not really chocolate. It is made from milk, sugar, and cocoa butter, but without cocoa.)
In the conching rooms, big American flags hang from beams above tin chocolate. “Touch this,” Mr. Wagner says. The cast-iron walls that hold in the chocolate are a hundred and thirty degrees Fahrenheit. “We have no heat under this. It’s only created heat—created by the friction that the granite rollers produce.” “What if the rollers stop?“ The chocolate will freeze. ”When that happens, the result is a brown icecap, a chocolate-coated Nome. Sometimes fittings break or a worker forgets to shut off a valve and thousands of pounds of chocolate spill over, spread out, and solidify on the floor. Workers have to dig their way out, with adzes, crowbars, shovels, picks—chocolate Byrds, chocolate Amundsens.
“The trend today is people want to push buttons,” Wagner says. “They’ll try to find ways to shortcut. It’s a continual struggle to get people to do their share. There’s no shortcut to making Hershey’s. There have been times when I wished I’d stayed on the farm.” Every day, he works from six in the morning until four-thirty in the afternoon, so he can cover parts of all shifts. He walks (twelve minutes) from his home, on Para Avenue. “Para is a bean, I think. It’s a bean or a country, I’m not sure which. We have another street called Ceylon. That’s not a bean. It’s a country.” In the conching rooms Wagner can see subtleties of hue that escape the untrained eye; he can tell where the kiss paste is, and the semisweet, and the chocolate chips, and the bar milk chocolate. Kiss paste has to be a little more dense, so the kisses will sit up.
Wagner has grandchildren in Hershey, Colebrook, and Mechanicsburg. When he goes to see them, he slips them kisses. Within the connoisseurship, there are acknowledged superior chocolates, and, God knows, inferior ones, but undeniably there is no chocolate flavor quite like that of a Hershey bar. No one in Hershey can, or will, say exactly why. There is voodoo in the blending of beans, and even more voodoo in the making of the milk-and-sugar paste. There is magic in Bill Wagner when he decides that a batch is done.
All this, however, does not seem to add up to a satisfactory explanation of the uniqueness of the product. Mystery lingers on. Notice, though, in the conching rooms, what is happening to the granite rollers rolling under the chocolate on the granite beds. Slowly, geologically, the granite is eroding. The granite beds last about thirty years. The granite rollers go somewhat sooner than that. Rolling back and forth, back and forth, they become flat on one side. Over the days, months, years, this wearing down of the granite is uniform, steady, consistent, a little at a time. There seems to be an ingredient that is not listed on the label. Infinitesimal granitic particles have nowhere to go but into the chocolate. A Hershey bar is part granite. Ask management where the granite comes from. The official answer is “New England.” “Where in New England?” “New England. That is all we are saying. Nestlé’s won’t say anything about anything. Mars is the same way. So we don’t say anything, either.”
♦Published in the print edition of the May 13, 1972, issue.
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