How is chocolate made? | BBC Science Magazine
Chocolate is made from beans of Theobroma cacao, a small evergreen tree native to the rainforests of Central and South America. Translated as “food of the gods” in Greek, its elongated pods grow up to 35cm and vary in color from bright yellow to deep purple.
Archaeological evidence – traces of cocoa on ancient pottery – suggests that we have been indulging in cocoa products for 5,300 years (3,300 BC). The Maya, an indigenous people of Central America and Mexico, enjoyed it as a thick, frothy, bitter drink and the beans were even potentially used as currency in the 250s to 900s.
Beans were so revered that the Aztecs (c. 1345 – 1521) believed cocoa was a gift from the god Quetzalcoatl. They continued the Mayan tradition of preparing cacao as a drink, and it was enjoyed by rulers, priests, and nobles. Cocoa was eaten for a variety of purposes, including medicinal and as an aphrodisiac, and was part of the rations provided to Aztec soldiers. On special occasions, such as weddings, even the lower class members of society would be treated to a sip of the divine drink.
Today, cocoa is grown commercially in tropical areas around the equator where climatic conditions are well suited to their capricious nature; high temperatures, abundant rainfall and humid air, while the rainforest canopy provides shade and protection from the wind.
The Theobroma cacao tree bears flowers in small clusters along the trunk and lower main branches. Once pollinated, these flowers turn into berries, called “pods”. The pods take about five or six months to ripen and ripen, taking on a yellow-orange color as they go.
The elongated pods are harvested by hand and split open to reveal between 20 and 60 oval seeds arranged along the longitudinal axis in a soft, white, mucilaginous pulp. This usually happens the same day of harvest, or at least within a few days.
If you want, you can eat the cocoa beans raw, and they have a bitter, earthy flavor.
The pulp and beans are extracted from the pods and the beans are separated from the placenta. Careful fermentation develops flavor through microbial succession.
First, the yeasts react, then the lactic acid bacteria, and finally the acetic acid bacteria. The fermentation process essentially modifies the beans and removes the mucilage, changing the color, taste and smell of the beans.
The beans are dried to remove the moisture content. Traditionally, this is done naturally by the sun, and the drying process continues to develop the flavor. Drying the beans quickly will result in a more bitter taste, but careful moderation will allow volatile acetic acid to evaporate during the drying process, resulting in a less sour (and more pleasant) taste.
Roasting further develops flavor and also sterilizes the beans, killing microorganisms (like bacteria) on the outer shell. Successful fermentation is an important microbial process and will naturally create ideal conditions for bacteria, fungi and molds. Roasting is therefore essential to eliminate these potentially dangerous pathogens.
Roasting also helps get rid of some of the lingering sour flavors and makes the next step much easier.
The roasted beans are crushed by applying pressure with a cocoa grinder, separating the shells from the beans.
Winnowing removes the lighter husks and dust particles, leaving the heavier or “feathered” kernels.
Originally, winnowing was done by hand in a winnowing basket. The beans would be thrown into the air before being caught in the basket again, causing the brittle shells to break and separate from the beans. If done outside on a windy day, the lighter shells would fly away and the heavier feathers would fall back into the basket. Clever!
Today it is mostly done by a winnowing machine. Vibrating shelves shake the beans, knocking them through a series of screens before a vacuum removes the lighter hulls, leaving the precious feathers ready for the next step.
The now shellless beans are ground and sugar is added. Cacao nibs are naturally quite bitter with a strong flavor, so adding sugar makes them sweeter.
The addition of sugar was a later development in chocolate production, occurring in the 16th century, after the beans arrived in Spain.
Slowly heating and cooling the chocolate allows the fats to crystallize evenly and the chocolate to break up with a satisfying snap. It also helps give chocolate a smooth, shiny finish.
The mixture is poured into a mold where it cools, before being packaged and shipped to distribution centers ready for consumption.
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