The Kitchen Tool That Makes Tempering Chocolate A Breeze
"Badly-tempered chocolate" is one of TV cooking competition shows' nightmare phrases — along with undercooked chicken and overcooked steak — that mark a contestant out as one of the week's wounded gazelles, potentially up for elimination. The fact that tempering chocolate can be so tricky that it sends very skilled cooks home means that it can be incredibly daunting for home cooks to take on. Well-tempered chocolate feels like the line marking some desserts and candies as the work of professionals, and others as good, but homely, bakes.
Chocolate is made up of crystals that are loose when melted, and form into a grid when solid. There are six different ways they can configure themselves into that grid, and the shiny, snappy smoothness of tempered chocolate results from just one of those ways. Every tempering method requires you to melt the chocolate, so the crystals have a chance to form in the right way. More complex methods involve heating and cooling the melted chocolate several times, through specific temperature ranges that liquefy the undesirable shapes and promote good temper.
The good news is that you probably already have the equipment needed to take on tempering, and it's not nearly as terrifying as you've been told. You don't need double boilers, laser thermometers, or marble benches — a bowl, a spatula, a microwave, and a box grater are enough tech to give you snappy, shiny chocolates according to America's Test Kitchen.
The science of grater tempering
The box-grater trick is a modification of the seeding method of tempering chocolate. Rather than create new crystals from scratch by manipulating temperatures up and down, already-tempered chocolate is added to the melted chocolate and mixed well. The pre-existing crystals in the grated chocolate act as a guide for the rest of the chocolate to form tempered crystals as it cools. What the grater does is ensure you'll have small, but even chunks of tempered chocolate as your seeds. This means maximum dispersion of the target crystals throughout your chocolate, which gives you the best chance of a successful temper. Use good quality chocolate and make sure you don't try to do this in a tent on a warm summer's day!
In order to temper chocolate with a box grater yourself, just melt about half of the total amount of chocolate to temper. You only just want to melt the chocolate, and the quickest and easiest way to do so is by stirring it between short bursts in a microwave until no lumps remain. Grate the rest of the chocolate on a box grater in the meantime, and once the microwaved chocolate is entirely liquid, add the grated chocolate in one go, and stir continuously until it's all liquid again. The resulting chocolate should be in good temper for dipping and coating sweet treats. You can test for temper by spreading a little on some baking paper. If it sets solid in 3-5 minutes, it's tempered.