Here’s the deal. Melting chocolate is not like melting butter.
But before we get into melting chocolate we need to know that chocolate is made by roasting , fermenting and processing the beans of the cacao tree in combination with sugar. Once it is made, it is an ingredient in a variety of recipes. Knowing how to work with it helps us prevent burning it, seizing it, and breaking the temper.
So to melt chocolate extra effort is needed not to over heat it. Chocolate melts a little under our body temperature, thus it will melt in your hand as well as the mouth. Melting over a double boiler is a good way to melt large quantities of chocolate (over one pound in 1-2 ounce blocks) to prevent over heating. Remember to keep the bowl above the water level and keep the water barely simmering, not boiling. You don’t want to make steam, which can form droplets of water that can get into the melting chocolate and seize it up. So it is best to keep the chocolate over heat only as long as it melts but still holds it’s shape; then stirring until all is smooth and melted.
The microwave can be used to melt small amounts (less than one pound) of chocolate very successfully. Cut the chocolate into small pieces or start with good quality chocolate chips. Place into dry bowl and turn on a few seconds at a time (15-30 seconds). When it becomes shiny but hold its shape and looks like it is about to melt; remove from oven and stir to melt the entire batch using the residual heat of the chocolate. Good quality chocolate will hold its temper when done gently in the microwave.
Seizing can be prevented by melting the chocolate in the oven. When making a chocolate recipe like ganache it sometimes seizes or becomes instantly solid and granular. It is all wrong or so it seems. At this point the addition of a little more water (yep, water) will bring it back!
Most all good chocolate comes to us already tempered. So when we melt it being mindful of the temperature–keeping it around 88F or under body temperature, we can hold the temper after it melts.
To ensure the temper, reserve a little chocolate aside while melting the rest–gently and carefully. Then stir in the reserved chocolate into the melted to quickly temper the melted chocolate using this fresh reserved chocolate as “seed” to tempering.
Left to its own devices, when melted chocolate cools, it forms loosely arranged large crystals that gives the chocolate a dull finish and even a gritty texture. Some times the cocoa butter rises to the surface and forms a light brown chalky surface. The process is known as “blooming.”
Instead, cooling chocolate gently and holding it at a constant temperature of 88F while stirring helps make tight dense “seed” crystals that will continue to make tight crystals that when the chocolate finally cools completely will harden into a shiny smooth stable chocolate, and that’s what its all about!