When you decide that you’ll use only a good grade of chocolate like pure chocolate for making chocolate candy, unlike for chip cookies or chocolate fudge, you should especially temper to a achieve a smooth, shiny, velvety finish for your chocolate candies. Not tempering will make the chocolate candies unattractively dappled, gritty and powdery, a condition called blooming, and a chalky sheen and white speckles may stay on the chocolates.
Due to a process called polymorphous crystallization, the fatty acids in cocoa butter, the basic ingredient for making chocolates, crystallize into six varieties of crystals under dissimilar temperatures. Tempering is done to prevent this; all types of chocolates, because of the cocoa butter content, must undergo tempering to become attractive.
The molecules of the cocoa butter form into crystals by bonding together. The type and quantity of crystals that form depend upon the temperature that is maintained. These crystals also melt and freeze at their own temperatures. When the temperature comes down and nears the freezing point, the chocolate crystals formed by the molecules occupy the space of the liquid crystals forcing the liquid to become solid. The stability of this solid depends upon the density and uniformity in size of these crystals.
When you temper chocolates, these crystals become solid and stable and this is why a properly tempered chocolate remain in shape at room temperature. Only if you heat at a high temperature of 96 degrees Fahrenheit, which is the melting point of chocolate, do the tempered chocolate crystals disintegrate. That’s why it’s imperative that you maintain chocolate temperatures with the help of a Mercury-Gauge Chocolate Thermometer that has a capacity to read even low temperatures like 80F.
Tempering is done using the three steps of heating, cooling and re-heating. If you lapse in maintaining accurate temperatures, different crystals dominate during tempering and you’ll fail creating the ideal temper. But only type V crystals can make the chocolates shiny, smooth, firm and crisp and stable. These tempered chocolates do not melt till they reach near-body temperature. Tempering should be repeated if the chocolates reach such high temperatures.
The melted chocolate or mush is cooled by working upon it on a heat-absorbing surface such as a marble slab so that type IV and type V crystals proliferate and act as “seeds” to guide the other crystals in their multiplication. When you observe that the chocolate has thickened, it means you have the required quantity of these crystals. By re-heating the mush, you remove the type IV crystals and only type V crystals remain. These specific temperatures differ from one variety of chocolate to another.
Chocolates temperatures should not oscillate. If you set the tempered chocolates in a bain-marie or hot pad, ideal tempers are extended longer so you can have more time to dip and mold the mush.