The science behind tempering chocolate

Unless you are a chef or have spent a few years at cooking school, you can be forgiven if you have no idea what tempering chocolate involves or why you would do it. But here’s the thing, it’s the art that French patisserie chefs have mastered and a technique that can open up your baking world like a golden key. Here’s how it’s done.
Let’s start by putting us all on the same page. Tempering is the process that ensures chocolate is smooth and shiny, and not dull and greasy-looking and it’s the process that will help you on your way to making chocolate moulds (like these mustaches) and cake pops.
Have you ever left a slab of chocolate in a hot car, and then put it in the fridge for the night? And the next morning it was a greyish, crystallized brick that looked nothing like the original product? Well, tempering will prevent that from happening.

The key thing to know is that chocolate, like candy, is made up of crystals. And as with candy, the texture of the chocolate depends on the type of crystal structure, which in turn depends on the temperature at which the chocolate forms. The tempering process basically involves heating and cooling chocolate to control the crystal structure.

If chocolate cools on its own, it will have a loose crystal structure made up of different types of crystals. This chocolate will have a dull, matt texture and a low melting point. However, by heating your chocolate and then cooling it slowly to a specific temperature, you can ensure that your chocolate has a dense structure of beta crystals (that’s the fancy name for them) and a glossy, shiny finish that won’t melt when you touch it.

So how do we temper chocolate? Happily for us all, it’s actually a very simple two step process.

Before you start, you’ll need to get hold of a thermometer that can measure in the range of 25°C to 50°C. I used a Kitchen Craft Digital Cooking Thermometer, which has a range of 0-200°C. And of course you’ll need some chocolate.
Step One

Make sure you keep about 3 blocks of chocolate aside. Heat the rest of your chocolate over low heat to 46-48°C, using any means you like (on the stove, over a double boiler or in the microwave) and stir constantly.
Make sure you keep the heat very low; if you use a pan, make sure it has a thick base. If you use the microwave then check on the chocolate every 20 seconds.

At 46-48°C all the chocolate crystals have melted, and can now be cooled to form a new crystal structure.
Step Two

Remove the chocolate from the heat and add your 3 blocks of unmelted chocolate to the mixture. These blocks will provide what is called the ‘seed crystals’ for our new chocolate structure. As the chocolate cools, the melted chocolate will ‘copy’ the structure of these seed crystals, forming those beta crystals we mentioned earlier.

Now, let the chocolate cool to 30-31°C*, gently stirring it all the time. And that’s it! Your chocolate is ready to be poured into moulds (like these mustaches) or to make a chocolate collar for a fancy cake. Or perhaps you want to coat some cake pops with it?
See, tempering is not that tricky after all. You should definitely try it. And if you are all out of ideas for what to do with your beautifully tempered chocolate, check out Miss Hope’s Chocolate Box for some inspiration.

*Note: The temperatures above are for milk chocolate. For white chocolate, cool to 27-28°C, and for dark chocolate to 31-32°C.

More in the Science Behind series:
The science behind pavlova
The science behind fudge
The science behind chocolate chip cookies
The science behind cupcakes
The science behind nougat
The science behind crème brûlée
The science behind marshmallows
The science behind toffee