If the melting point is too high it will result in a waxy mouthfeel and not melt entirely. If the melting point is too low the product may not be stable during storage in summer or in hot climates. Fats melt over a temperature range and so at any temperature below the melting point a part of the fat is in solid state and a part is liquid. Crystallisation Cocoa butter is polymorphic and has more than 6 crystal forms, of which only form V or beta form has the necessary heat resistance and melting properties. To ensure that only the stable beta crystals are formed during confectionery production the chocolate mass needs to be tempered prior to solidification.
Correct tempering ensures a stable shelf life.
The addition of milk fat to make milk chocolate can soften the product and make it less heat resistant. Milk fat has a different crystalline form to cocoa butter and the resulting incompatibility can lead to a destabilisation of the product. The fat element of the cocoa butter can be replaced wholly or in part with vegetable fats in order to improve heat resistance. In countries with a warmer climate the addition of CBEs may significantly improve the shelf life of a chocolate product. CBEs are vegetable fats derived from palm and shea oils which are chemically and physically very close to cocoa butter.