— written by Shivani Seth
Whether it’s a classic bar, a cold fudge pop, or a steaming cup of hot chocolate, we’ve probably all indulged in a chocolatey treat. But where does this chocolate come from? How is it made? And what is that grey stuff on the bar I accidentally left in my car...? Toronto based food scientist and chemist Selvyn Simones has the answers.
A Brief History of Chocolate
White seeds in a cocoa pod.
Chocolate is produced from the fruit of the Theobroma cacao tree. This fruit is commonly referred to as a cocoa pod and if you slice one open you’ll find it contains white seeds, commonly referred to as cocoa beans. These seeds contain a fat known as cocoa butter and can be processed into cocoa powder.
The first cocoa plantations can be traced back to 600 CE, in Central and South America. Chocolate was important to Aztec and Maya cultures, and was originally consumed as a beverage. After harvesting and roasting the beans, a stone mill would be used to grind them into a paste. This paste would be added to water with honey and spices to create a beverage. “There is a huge gap in history between chocolate as a beverage, and chocolate as an eaten product, today,” explains Selvyn. In fact, it wasn’t until the 1800s that people began producing solid chocolate.
Today, cocoa trees and cocoa plantations can be found all over the world. Some of the largest producers of chocolate include Brazil, the Ivory Coast, Ghana, Indonesia and Malaysia. What do these countries have in common? They are all close to the equator, and have the hot, humid climate necessary for cocoa trees to grow.
From Bean to Bar
Although the chocolate making process looks very different today from how it did in 600 CE, the basics remain the same. Manufacturers begin by harvesting, fermenting, and roasting cocoa beans. Fermentation is a process in which microorganisms are used to bring a chemical change in our food. Yeast, for example, is a microorganism that converts sugar into carbon dioxide, and commonly allows bread to rise. Fermenting the cocoa beans ensures that we get correct chocolate flavours in the later stages of preparation. Next, the cocoa beans are dried out to prevent mold from forming - usually outside in the sun! The beans are then roasted, to further enhance the chocolate flavour. Selvyn equates this to putting bread in the toaster – the flavour of bread and toast is completely different!
The impact of roasting on cocoa beans.
Once the beans have been roasted, the shells are removed. The beans are ground with sugar into small particles. As the beans are ground, cocoa butter is released, coating each particle. Eventually, the particles become so small your tongue can’t tell they are individually there. This is what gives chocolate a smooth and creamy sensation in your mouth.
Melted chocolate is quite viscous, making it difficult to pump to different parts of a factory. And sometimes, a thinner chocolate is desired, such as that of dipping chocolate. To reduce its viscosity, we add emulsifiers. Emulsifiers are molecules with an end that is attracted to water (hydrophilic) and another end that is attracted to fats (lipophilic). This allows two liquids that are normally unmixable (like oil and water) to come together. Although there is no water in chocolate, the presence of an emulsifier makes it easier for the chocolate particles to move past each other. This creates a thinner, less viscous liquid that is easier to work with.
Solid Chocolate
When discussing the history of chocolate, Selvyn points out that the solid chocolate bars we are familiar with are a relatively recent creation. And one that is interesting on a molecular level.
Polymorphs of chocolate: Chocolate has at least six different structures, or 'crystal forms', each with different properties.
The particles in a solid are arranged in a certain way, giving the solid unique properties. But cocoa butter can take on six structures. Each structure has different melting points and attributes. Type I chocolate, for example, has the lowest melting point and Type 6 has the highest. Type 5 is the structure that we want in our chocolate – this chocolate is smooth, glossy, and snaps when you break it into two.
So how do we ensure we get this specific structure? By tempering the chocolate. Tempering is a process in which chocolate is heated and cooled. Because each structure has a different melting point, we can use tempering to gain the desired molecular structure.
Chocolate Bloom
If you have ever left chocolate in a hot car or found a piece of Halloween candy in December, you may have seen a white-grey coating on the surface. This waxy coating is known as chocolate bloom. Don’t worry – the chocolate is still safe to eat! However, it will taste different. “This is because it has gone from the structure that we want to the next structure,” explains Selvyn. The chocolate has moved from Type 5 to Type 6.
Chocolate bloom occurs naturally over time, as chocolate moves from one structure to the next. It can also occur with changing temperature. The most curious part of this phenomenon is that scientists are still unsure exactly why this happens.
The next time you dig into your favourite chocolatey treat, consider all of the history and science that goes into each bite and maybe share a few tidbits with your friends and family - we’ll let you decide whether that’s knowledge or chocolate...
Watch the full Science of Chocolate presentation now on YouTube. Follow Selvyn and his food and science-related shenanigans at @selvyn.simoes on Instagram.