A chocolate tempering machine solves this problem by automating a process that causes the molecular crystals of the chocolate to take on a specific uniform structure, called a Beta V form. The chocolate tempering machine does this by heating the chocolate to a very precise temperature, then cooling slightly and reheating, while mixing the chocolate in a regulated manner.
The combination of heating to the exact temperature — which is different for semi-sweet chocolate, milk and white chocolate — and mixing just the right amount, causes the proper crystals to form. A chocolate tempering machine that is computer-controlled can keep chocolate in the tempered, melted stage for hours at a time, allowing you to make candies without tending to the tempering process itself. When tempered chocolate cools it will be even colored, shiny, and crisp, yet will melt to a smooth, creamy consistency on the tongue.
To temper chocolate without a chocolate tempering machine you would use a double-boiler, a candy thermometer that can register temperatures as low as 82.4 degrees Farenheit (28 degrees Celsius), and a rubber spatula. However, even tiny variations in the temperature of the chocolate will spoil the outcome, and over-mixing will cause the fats to separate, while under-mixing will prevent the Beta V crystals from forming! Additionally, even if the chocolate is tempered successfully, you must keep moving it on and off the heat to keep it tempered, while simultaneous making your candies! If you have made homemade chocolates without a chocolate tempering machine you will really appreciate the work this machine does and how you are left free to enjoy the candy-making process.