Cocoa butter has the interesting property that it melts at human body temperature, which makes it a very useful base for cosmetics, particularly lipstick. The other option for cosmetic manufacturers is petroleum-based waxes, which typically melt at much higher temperatures. After pressing, the cocoa solids are taken from the cocoa press and ground to a fine powder. If the cocoa powder is destined to be made into chocolate candy, it is then combined with other ingredients. Dark, bittersweet chocolates are made by adding cocoa butter and sugar, at a minimum.
Milk chocolates add milk as well.
The ingredients are mixed under heat into molten chocolate. To conch the chocolate, there are large smooth granite rollers in the vats that keep the mixture stirred up and further grinds the cocoa powder into extremely small bits. Some chocolate production plants go on to use smoother steel rollers which give their chocolate a very smooth, velvety feel. The longer the chocolate is conched the smoother it becomes. Good chocolates are often conched for several days straight, while cheap mass produced chocolates may be conched for as little as 12 hours.