Tempering is a word that means improving the consistency, durability or hardness of a substance by heating and cooling it. Tempered chocolate is very glossy, has a firm finish and melts smoothly at around body temperature. It is chocolate at its very best and tempered chocolate is what most good quality chocolate candies, candy bars are made out of.
Tempering is done by melting solid chocolate to a temperature high enough that the crystals in the cocoa butter break down. This temperature is between 45°C – 48°C. Once the chocolate is fully melted, it must be cooled to about 28°C, a temperature at which crystals will start to form again so that the chocolate can eventually re-solidify and can be worked upon. All chocolate – white, milk and dark can be tempered.
The crystals that start to form when the chocolate is cool are stable crystals contained in the cocoa butter of chocolate. They provide the necessary structure for the chocolate to become shiny, smooth and have a good “snap” when it is set. Chocolate that has not been tempered or that has been improperly tempered will look flat or discolored. It will lack the sharp “snap” of tempered chocolate and will typically not be as smooth as it melts.
Tempering can be done in several ways by hand, and there are also machines available for this. If tempering by hand, it is very helpful to have a good digital thermometer handy to get the temperatures correct. Experienced chocolate makers can often do this by feel alone, but a thermometer will help keep you on the right track as you work with your chocolate. Tempering by hand can be done by pouring melted chocolate onto a cool marble surface and worked with spatulas until it has cooled down sufficiently. More melted chocolate is added back and incorporated to the chocolate to bring it back to the working temperature.