Chocolate is temperamental. Melting it to incorporate into brownies and sauces is easy enough, but melting it with the goal of creating shiny, snappy coatings for candies and cookies brings out a whole different personality in chocolate.
A good-quality chocolate bar has a glossy sheen and a satisfying snap. But if you simply melt that bar and use it as a coating or for drizzling on baked goods, it will set up into a blotchy, dull-looking mess that melts willy-nilly all over your hands. This is because the crystal structure of the cocoa butter in the chocolate has changed. Cocoa butter can solidify into any of six different types of crystals, each of which forms at a different temperature. But only one type— beta crystals—sets up dense and shiny and stays that way even well above room temperature. When a chocolate is made up of beta crystals, it is said to be in temper.
Traditional tempering is a painstaking, multistep process. First the chocolate is melted so that all its fat crystals dissolve. It is then cooled slightly, which allows new “starter” crystals to form. Finally, it is gently reheated to a specific temperature high enough to melt the less stable crystals and allow only desirable beta crystals to remain, triggering the formation of more beta crystals that eventually form a dense, hard, glossy network.
We developed an alternate technique that’s easier and more foolproof. It uses the microwave to control the temperature and thus the structure of the cocoa butter crystals. Chop about three-quarters of the chocolate into fine shards and (mostly) melt it at 50 percent power, being careful not to let it get too warm. Then deploy your secret weapon: Finely grate the remaining chocolate and stir it into the melted chocolate to disperse these small flakes evenly throughout. As
they melt, their temperature stays low enough that most of their beta crystals remain intact, thus “seeding” the melted chocolate with beta crystals. This tempered chocolate boasts a lovely luster and great snap once it has cooled and set.
1 Chop about three-quarters of chocolate into very fineshards.
2 Grate remaining chocolate on fine holes of boxgrater.
3 Microwave chopped chocolate at 50 percent power, stirring every 15seconds, until just melted but not much warmer than body temperature (hold bowl in palm of your hand to gauge). Chocolate will still be slightly lumpy.
4 Add grated chocolate and stir until smooth, returning chocolate tomicrowave for no more than 5 seconds at a time, if needed, to complete melting.
5 IF DIPPING Dip item to desired depth. Tap item against surface ofchocolate 4 or 5 times, pulling up sharply each time, to remove excess.
6 To prevent thick “foot” of hardened chocolate, gently scrape bottom against edge of bowl.