Chocolate: A Science Lesson

If you're a Masterchef tragic like myself, you may have noticed there's a term that keeps popping up- tempered chocolate. They touch on what it means in the show, but it’s one of those things that could always do with more explanation- it’s very easy to veer into a scientific report, but that goes beyond our needs here! This post explains why chocolate needs to be tempered, and in the next post I’ll explain how you can do it yourself. It’s often easier to understand the ‘how’ when you understand the ‘why’!

Tempering is a process which involves taking the material through a series of temperatures in order to produce the ideal results- it could be glass, metal, eggs (such as when making a carbonara to prevent them scrambling), or chocolate.

When talking about tempering chocolate, it’s the cocoa butter that is being tempered. Couvertures and high quality chocolates contain only cocoa butter- to make chocolate cheaper some or all of the cocoa butter is replaced with hydrogenated vegetables oils. If you’ve ever eaten chocolate that leaves a waxy feeling in your mouth, it’s because the oil melts at a higher temperature than your body heat, leaving behind a thin film of oil. Tempered cocoa butter on the other hands, melts below body temperature, making it feel smooth and creamy. Cocoa butter is polymorphic, which means it can crystallise in different formations, each of which have distinct characteristics. Cocoa butter has six crystal formations, but the one that we’re after when tempering is what’s known as the Form V or beta crystal.

So what does this all actually mean?

The best analogy for understanding the process is to think of a pile of Lego! If you simply heap a pile of differently sized bricks onto a table, they’ll mostly stay put, but they’re unstable, and you can’t do much with them! Push the pile and it will spread out, and some will connect to each other, but some won’t. But, if you use all the same size bricks and join them together, the structure is nice and stable, it takes up less room, and you can start to do things with it! This is the difference between chocolate setting in one of the other 5 crystal formations, but not being in temper- it may feel waxy or greasy with an odd mouthfeel, is unstable and melts at a low temperature and has most likely bloomed (which is cocoa butter that has not yet set working its way to the surface- think of those smaller bricks falling through the gaps of the larger bricks). Compare this to tempered chocolate, which melts at a higher temperature, which is not too far below body temperature, contracts as it sets, is glossy and has a beautiful snap. 

In order to temper, you need to coax the crystals into the correct formation. This means melting out all the crystals that may be present, introducing the crystals that we want, and then holding it at the temperature that we can work with it. There are three ways to temper chocolate- tabling, seeding and incomplete melting- keep your eyes peeled for the next post for the run down on these methods!

Questions, comments or you want to know more? Simply leave a comment below!