Chef Bobby Amaral from Carlos Brazilian International Cuisine demonstrates how to temper chocolate.
1. MELT: Reserve 1/3 of the chocolate you plan to temper. The remainder is melted in a double boiler to no more than 120°F. Above 120 °F, the chocolate separates, burns and can no longer be used. When cocoa butter crystals melt at this temperature, they lose their shape and the crystals become unstable, so Step#2 is necessary.
2. COOL: The chocolate is then cooled by "seeding" or mixing in discs or wafers of solid chocolate because they are at a cooler room temperature of 68 to 70°F. The molten cocoa butter also does a kind of follow-the-leader and arranges itself after the fashion of the "seeds", which are already tempered by the manufacturer. Don't add too much at a time as it may not all melt and the mixture will become lumpy. If it does, use an immersion blender which is invaluable, or strain the lumps out, which is trickier. Don't use a mixer. The key is to keep stirring rapidly and to take its temperature frequently until the proper one is reached. This gets the crystallization of the good beta crystals started, but it does allow some undesirable beta-primes to form, too, so go to Step #3.
3. REHEAT THE CHOCOLATE: in the double boiler so it will harden with a perfect consistency. Here reheating melts any of the undesirable crystals that are formed in cooling during Step #2. When it reaches the desired temperature, the chocolate is now tempered. If it is reheated to more than 89 (milk) or 91 (dark)°F, it goes out of temper, and you have to start again from the beginning (For advanced chocolate-makers, test the temperature by placing a dab just below the lower lip. It should feel just warmer than warm milk.)
4. CHECK TEMPER BEFORE USING: A simple method of checking if the chocolate is in temper, is to apply a small quantity of chocolate to a piece of paper or to the point of a knife. If the chocolate has been correctly tempered it will harden evenly and show a good gloss within five minutes. Or, spread a thin layer on a scrap of parchment, wait five minutes, and then try to peel the chocolate from the paper. If you can, and it's not blotchy, you're in business. If not, start the tempering process again.
5. KEEP CHOCOLATE IN TEMPER DURING USE: Ideal temperatures are 88-90 °F for Dark; 86-88°F for Milk and 82-84°F for White. The chocolate will cool if not kept at a constant temperature, and gets thick and dull as is does. If chocolate cools too much and is still melted, you can reheat it multiple times back to "temperate zone" of 88 to 90°F (dark), 86 to 88°F (milk), 82-84°F (white). If the chocolate cools to the point of hardening, the tempering process must start again. Never let the chocolate's temperature exceed 92°F, for the dark chocolate or 88°F for the milk and white chocolate, or the stable cocoa butter crystals will start to melt and the temper will be lost.
THE THREE STEP TEMPERING PROCESS - for dark, milk and white couverture chocolates.
Stir constantly during the steps and avoid having moisture from coming in direct contact with the chocolate:
1. Melt chocolate, in a double boiler, to the following temperatures as measured with a chocolate thermometer: Dark 120°F, Milk 115°F, White 110°F.
2. Cool chocolate to the following temperatures: Dark 82°F, Milk 80°F, White 78°F.
3. Reheat chocolate to the following temperatures: Dark 90°F, Milk 86°F, White 82°F.