This quality, coupled with natural antioxidants, prevents rancidity – giving it a storage life of two to five years. The velvety texture, pleasant fragrance and emollient properties of cocoa butter have made it a popular ingredient in products for the skin, such as soaps and lotions. Physical properties Cocoa butter typically has a melting point of around 34–38 °C (93–101 °F), so chocolate is solid at room temperature but readily melts once inside the mouth. Cocoa butter displays polymorphism, having different crystalline forms with different melting points. Conventionally the assignment of cocoa butter crystalline forms uses the nomenclature of Wille and Lutton with forms I, II, III, IV, V and VI having melting points 17.3, 23.3, 25.5, 27.5, 33.8 and 36.3 °C, respectively. The production of chocolate aims to crystallise the chocolate so that the cocoa butter is predominantly in form V, which is the most stable form that can be obtained from melted cocoa butter. (Form VI either develops in solid cocoa butter after long storage, or is obtained by crystallisation from solvents). A uniform form V crystal structure will result in smooth texture, sheen, and snap. This structure is obtained by chocolate tempering. Melting the cocoa butter in chocolate and then allowing it to solidify without tempering leads to the formation of unstable polymorphic forms of cocoa butter. This can easily happen when chocolate bars are allowed to melt in a hot room and leads to the formation of white patches on the surface of the chocolate called fat bloom or chocolate bloom. References Components of chocolate Vegetable oils Excipients Cosmetics chemicals