Like HowStuffWorks on Facebook!

How Chocolate Works

You've come a long way, chocolate. See pictures of unusual chocolate products.
Michael Rosenfeld/FoodPix/Getty Images




Although chocolate has been eaten since at least 1400 B.C., the way we eat it is a relatively recent invention. Ever taken a bite of unsweetened baking chocolate? Gross. Just try to imagine sipping a hot, frothy drink made of the stuff, maybe with some ground chili peppers for flavor. It's not something I'd look forward to as a treat, but that's how the Mesoamericans were enjoying it.

Europeans later added sugar and milk, but they were still drinking chocolate instead of eating it until the Industrial Revolution. If entrepreneurs hadn't figured out how to process it further to make it easier to eat (and less expensive), chocolate may not be as universal as it is today. Can you imagine? Americans eat up to 12 pounds of chocolate every year, but we aren't the winners by far when it comes to chocolate consumption -- that honor goes to the Swiss, who wolf down 22 pounds a year [source: World Atlas of Chocolate].

Elixir of the Gods: Some Things Don't Change

The cacao tree in all its quirky glory.
The cacao tree in all its quirky glory.

Nobody knows when the first person looked at the cacao tree and decided to eat its seeds. The earliest record of chocolate comes from Mesoamerica, a region that stretches from central Mexico south through Costa Rica. The Mayans were drinking it by about 300 A.D., with the Aztecs taking on the tradition a few hundred years later (when they conquered the Mayan empire). Both cultures considered chocolate sacred and included it in ceremonies and offerings to their gods. The Aztecs believed that it actually came from a god; specifically Quetzalcoatl, who was apparently cast out of heaven for sharing chocolate with us lowly humans.

The Aztecs called chocolate xocoatl (thought to mean "bitter water") and often added spices like chili and vanilla for flavoring before mixing it with water into a frothy beverage. Royalty sucked it down because they believed chocolate could fill them with power and good health. Chocolate wasn't just a food, though; the beans were currency. An Aztec document from the 1500s states that you could buy a turkey for 100 cacao beans and a tamale for one. Definitely more valuable as currency than food!

Europeans got their first taste of chocolate when Spanish explorer Hernando Cortes showed up at the court of Aztec ruler Montezuma II in 1519. The great ruler supposedly downed 50 cups of chocolate a day. Adding sugar soon became the norm for Europeans when cacao started getting shipped back home in 1585. Guess what? They loved the drink once it was sweetened, and sadly for the Aztecs, that soon meant enslaving them to keep up with demand overseas. Wealthy Europeans had to pay dearly for the import all the way from Central America, but eventually, prices fell as more countries planted cacao trees in their own territories around the Equator.

Remember, this was still a drink -- and a gritty, unrefined one at that -- but a series of inventions during the Industrial Revolution changed chocolate forever. In 1828, a Dutch entrepreneur named Coenraad Johannes van Houten learned how to press the cacao beans to separate dry cocoa from the cocoa butter. He also treated the cocoa with alkali, making it smoother and less bitter. This Dutch cocoa was taken by Joseph Fry, an Englishman, and mixed with sugar and additional cocoa butter to make the first solid chocolate bar about twenty years later. Rodolphe Lindt invented conching in 1879. This process consistently created a smooth bar of chocolate and made chocolate even more affordable to mass-produce. By the early 1900s, people like Henri Nestle, Milton Hershey and other big names in chocolate were churning out tons of chocolate candy.

Our beloved confection starts out very humbly as a seed (which we call a "bean") growing in pods on a tree. Looking at it, you'd wonder how anybody would think of turning it into food, but the cacao bean is more complicated than it first appears. Let's start with learning the basics of the bean.

From Jungle to Factory

The delicate cacao tree grows no taller than 25 feet (8 meters) and will only grow close to the Equator in rainforest conditions, where it can get lots of shade. It's a strange-looking thing with pink flowers that grow directly on its trunk. The tree's fruit is a hefty, 6-to-12-inch pod shaped like a football. Although originally from Mesoamerica, today most of the world's supply of cacao comes from West Africa. The Cote d'Ivoire alone produces more than one million metric tons of cacao per year [source: FAOSTAT]. (By the way, we'll use "cacao" to distinguish the tree and the bean from cocoa, the finished product, but they mean the same thing.)

Some people compare the cacao bean to a wine grape -- there can be huge differences between beans depending on where they're grown, although it's simpler because there are just three main varieties. Forastero is the most commonly grown bean by far because it's the hardiest tree and yields the most beans. Its beans also have the strongest chocolate flavor. Criollo falls on the other end of the spectrum. It's known for a more complex flavor, but it's also the most delicate and difficult to grow, so it's just a tiny percentage of all cacao grown. Trinitario falls in between -- it's a hybrid of the two that occurred when Forastero was brought to Trinidad, which then primarily grew Criollo. But a Forastero bean from the Ivory Coast will produce a chocolate that tastes different from a Forastero bean from Cameroon.

Usually, the bean is grown on small family-owned farms of less than 10 acres (4 hectares). Mass production just isn't possible because cacao farming is a really intense process. The pods are harvested by hand -- there's no other way to remove them without damaging the bud from which additional pods will grow. Cacao pods don't ripen all at the same time, either; the pods, which turn from green to orange, have to be monitored carefully and harvested individually using knives on long poles. After the ripened pods are cut, the beans and pulp are removed and left to ferment either in piles covered in banana leaves or in wooden boxes (depending on where the cacao is grown).The moisture seeps out and the whole mass is mixed periodically to ensure even fermentation.

OK, fermentation sounds nasty, but hey -- beer, wine and cheese all ferment, too, and we love them. In cacao beans, organisms and bacteria like yeast produce acids and gases that partially break down proteins and sugars in the bean. After about a week, the beans are dark brown. The family then packs the bags and takes them to buyers, who grade the beans before paying for them. Next, they're off to the factory.

From Bean to Paste

The low-tech way of turning chocolate nibs into chocolate paste.
Tom Eckerle/FoodPix/Getty Images

Making chocolate is a complicated process, and it varies depending on the company and how the chocolate will be used. But it always starts with the beans. Some companies rely on a single source for their beans or only buy them from a certain region. Others may use up to 12 different sub-varieties of bean to create a single chocolate blend. The mix of cacao beans is usually a big company secret, and no two brands use the same one.

When the beans show up at the factory (usually in huge, jute bags), it's time to roast them. Roasting is a necessary step for a couple of reasons. First, it kills any bacteria or mold that may be lingering. While the traditional method is to roast the whole bean, some manufacturers follow an alternative method because they're concerned about uneven roasting when using beans of different sizes, or they just think that roasting in the hull makes the chocolate bitter. They may pre-treat the bean with just enough heat (via steam or infrared radiation) to kill the bacteria and crack the hull. Then the nibs are actually roasted or even ground first into chocolate liquor before roasting.

The roasting process both removes bitterness and develops flavor. The bean gets mellower when some of the acids, such as ethanoic acid, evaporate. Roasting also creates a chemical reaction called non-enzymatic browning, or the Maillard reaction (which is responsible for flavors in lots of other foods, too). It's a complex process that happens when the sugars and amino acids in cacao react with each other in the presence of heat, creating that distinctive chocolaty flavor and smell. It's different with each roasting method and with each type of cacao bean.

The grinding process is done by a machine called a melangeur, which has huge granite rollers that mash the cacao nibs into a paste called mass. The mass goes into a powerful press, which splits the cacao into its two components: powder and butter. The powder is a dry circle called presscake, and if it's going to be used to make drinking chocolate or cocoa powder, that's pulverized into a fine powder. If the company is making solid chocolate, they may make it straight from the mass or start with cocoa powder and add back in cocoa butter (plus some extra if it's really good chocolate or vegetable oil if it's not). Now's the time they'll also add in sugar, an emulsifier like lecithin and other flavorings.

The next two steps, conching and tempering, are so complicated and mysterious that they deserve their own section. And you thought that the roasting process was science-y ...

The Science of Chocolate

Unless you're really into chocolate making, you've probably never heard the term conching. Yet if our eating chocolate wasn't conched, you'd definitely be able to tell the difference because it would be gritty and uneven.

Exactly how Swiss chocolate maker Rodolphe Lindt figured out the process is a legend -- some sources claim that he accidentally left chocolate mixing for a few days in a melangeur, a sort of "happy accident." The result was a smooth liquid that was much easier to pour into molds and that also made chocolate customers very happy.

The crazy thing is that even after more than 100 years, we still aren't sure of everything that happens during conching. (The name, by the way, comes from the shell-shaped machine that Lindt eventually designed just for this process.) We just know that it makes chocolate delicious. Like most other things about the chocolate-making process, it's different depending on the type of chocolate and the company making it.

It is universal, though, that a few basic things happen to the chocolate during conching. The constant grinding action evenly distributes the cocoa butter within the chocolate mass, creating a smoother mixture. The friction polishes the cocoa particles and makes them smoother. It also generates heat in the cocoa mass, releasing volatile oils and flavor compounds. If the mass contains milk powder (which is often the case when making milk chocolate), heat will also encourage the Maillard reaction. Finally, the rotation introduces air into the mass, removing more bitter acids and compounds.

Tempering is another "science is magic" step in the process of making chocolate to eat. You might be familiar with this one if you've made candy. In factories, there are machines that do it automatically to take out the possibility of error. Without tempering, candy wouldn't be shiny and snappy, plus it wouldn't last as long. Basically, it involves getting the crystals of cocoa butter to the perfect size. Left to their own devices, the crystals cool into irregular, jagged shapes. Not pretty.

Chocolate scientists (what a job!) have discovered that there are six different stages of crystals depending on the temperature. Only type V, at about 93 degrees Fahrenheit (34 degrees Celsius) makes for the perfect eating chocolate. So the chocolate is heated to melt all of the crystals, cooled to the temperature that induces type IV and V crystallization, agitated to create tiny type V crystals and finally, heated again to get rid of all the type IV crystals. Done correctly, you end up with type V. Perfect. Screw it up and you have to start over -- unless you've burned it.

Chocolate isn't just a food -- it's a part of human culture.

Chocolate, Chocolate Everywhere

In Japan, bathing in chocolate has become another Valentine's Day tradition.
Koichi Kamoshida/Getty Images News/Getty Images

People like Milton Hershey helped make chocolate a relatively inexpensive snack for the masses -- a candy bar could be bought for a few cents around the turn of the century. Today chocolate can be far pricier, but there are also lots of other sweet options available. Yet it's still present at nearly every holiday -- and some holidays, like Easter, Valentine's Day and Christmas, seem to practically require it.

This isn't limited to Western holidays, either. The Japanese, for example, have two festive days for chocolate exchange: Valentine's Day on February 14, when women give chocolate to men, and White Day on March 14 (blatantly invented by a candy maker), when men return the favor. This includes people you don't even love -- there's something called "obligation chocolate," or giri-choco.

Hanukkah wouldn't be the same without chocolate gelt, or coins. Diwali, a five-day-long Hindu festival celebrated in India and other predominantly Hindu countries, includes highly decorated chocolates shaped like the traditional oil lamps called diya. The Day of the Dead, a Mexican holiday celebrating ancestors, features chocolate skulls, drinking chocolate and dishes made with mole (a savory sauce incorporating chocolate with tons of other ingredients). Chocolate is everywhere!

For decades, we were satisfied with the "normal" chocolate fillings and flavorings. But as I mentioned earlier, chocolate is the new platform for all different kinds of flavor combinations these days. It's hard to say who first came up with the idea of dipping bacon in chocolate (bacon has also become a Thing), or putting potato chips and spices in it. All of this seems to have come about in the past 10 years or so, though. It probably has to do with the fact that cuisines and ingredients that were once considered exotic and unusual are becoming less expensive and easier to find. If I wanted to make chocolate candy with green tea or wasabi, for example, I could find everything at my chain grocery store to do it. That wasn't always the case.

But why does chocolate have such a stranglehold on our collective psyche? Of course, it tastes good -- humans are naturally wired to enjoy foods high in fat and sugar. Some of us might just be wired to enjoy that special mix in chocolate more than others. That perfect cocoa butter crystallization temperature is just below body temperature, so that melt-in-the-mouth sensation is unlike anything else. Some people describe it as sexy. Aside from its culinary credentials, we may simply love chocolate because it makes us feel good.

Chocolate and You

Wonder if she's tempted to lick off that chocolate face mask?
Wonder if she's tempted to lick off that chocolate face mask?
Ingram Publishing/Thinkstock

Because our love of chocolate is so strong, we've started using it in some unusual ways. Just a few quirky chocolate products on the market include chocolate-flavored toothpaste, chocolate-scented perfume and chocolate facial products. Chocolate toothpaste sounds like a great idea for kids who don't like the strong, minty flavors of adult toothpaste or the other flavors of kids' toothpastes, which seem to be limited to things like fruit and bubblegum. Some studies have shown that cocoa extract may be even better at fighting cavities than fluoride.

Personally, I don't understand wanting to simply smell like chocolate without eating it, but chocolate health and beauty products are a growing trend. Not only do they incorporate the aromatherapy aspect (with the smell of chocolate possibly lifting your mood), but some people believe that the antioxidant properties that might make chocolate healthy could also reduce wrinkles and sun damage. Chocolate does contain vitamins and minerals, and cocoa butter is a moisturizer present in lots of different beauty products already. There's not much proof on whether a chocolate facial is better for you than any other kind, but it just sounds decadent to put chocolate on your body instead of in your belly.

But let's get back to the real reason why you're reading this article -- eating chocolate. Since we love it so much, it shouldn't surprise you that numerous studies have been conducted on chocolate's impact on us. It definitely has some mood-elevating benefits, thanks to the theobromine, caffeine and other compounds (including one that's similar to the high-inducing chemical in marijuana) that make us feel alert, euphoric, and happy. Despite its Valentine's Day association, though, it's not been proven to be an aphrodisiac. There's also evidence indicating that it may be good for us in other ways -- compounds called flavonoids can decrease your risk of heart disease and other illnesses. Here's the catch, though: only if you eat small amounts of very dark chocolate.

I don't know about you, but when I next savor that spicy bite of boutique chocolate or just scarf down a square of milk chocolate, maybe I'll think about it differently -- how it grew on an ugly little tree somewhere near the Equator, the people who may have harvested it and all of the complicated processes it went through before winding up in my greedy little hand.

Related Articles


  • Beckett, T.S. "The Science of Chocolate." Royal Society of Chemistry. 2000.
  • Bensen, Amanda. "A Brief History of Chocolate." March 1, 2008. (Feb. 6, 2012)
  • Cadbury. "Chocolate Making." Kraft Foods Australia. 2012. (Feb. 6, 2012)
  • Donahoo, Daniel. "The Science and Art of Chocolate Making." Wired Magazine. Dec. 19, 2011. (Feb. 6, 2012)
  • Domrose, Caroline. "Sweet Science." NurseWeek. Feb. 14, 2005. (Feb. 6, 2012)
  • Field Museum. "All About Chocolate: From Seed to Sweet." The Field Museum. 2007. (Feb. 6, 2012)
  • Grenada Chocolate. "Tour." Grenada Chocolate. 2011. (Feb. 6, 2012)
  • National Confectioner Association's Chocolate Council. "The Story of Chocolate." 2011. (Feb. 6, 2012)
  • Scharffenberger. "The Artisan Process." Artisan Confections Company. 2012. (Feb. 6, 2012)
  • Scharffenberger, John. "Making Chocolate." All Chocolate. 2012. (Feb. 6, 2012)
  • Silberner, Joanne. "In Search of the Healing Power of Chocolate." NPR. Dec. 15, 2005. (Feb. 6, 2012)
  • Simon Frasier University. "The World Atlas of Chocolate." SFU. 2003. (Feb. 6, 2012)
  • Sowden, Jim. "15 Things You Didn't Know About Chocolate." Ecosalon. Jan. 16, 2009. (Feb. 12, 2012)
  • Spadaccini, Jim. "The Sweet Lure of Chocolate." The Exploratorium. 2011. (Feb. 6, 2012)
  • Swiss World. "Rodolphe Lindt." Federal Department of Foreign Affairs Presence Switzerland. 2011. (Feb. 6, 2012)
  • World Cocoa Federation. "History of Cocoa." WCF. 2012. (Feb. 6, 2012)