Primary ingredient is Cocoa butter in chocolate, composed of fat molecules. It is the arrangement of these fat molecules that determines the structure of chocolate.
Cocoa butter has six crystal forms. polymorphism is the ability to display different structures of substance. The crystals differs the fat molecules arrangements. Which influences properties like appearance, taste and texture. Therefore affect the taste and quality of the chocolate.
The most desired chocolate form is form V; it has a shiny appearance and produces the desirable audible snap when broken, melts in the mouth and has a smooth texture. Unfortunately, it is not a very stable form.
If melted cocoa butter is allowed to cool naturally, a mixture of forms I – V will be formed. This isn’t ideal as forms I – IV have less desirable properties.
POLYMORPHS OF CHOCOLATE
Tempering Chocolate involves cooling the melted chocolate at a very slow rate in order to increase the amount of form V crystals formed. The chocolate is heated again to a temperature lower after cooled. Than the melting point of form V. And higher than that of forms I-IV. Hence, causing the forms I-IV to melt.
Form VI doesn’t form when melted chocolate solidifies. It only forms after several months when the fat molecules have enough energy to form it. This is when fat bloom occurs on the chocolate. Due to partial melting causing the fat molecules to rise to the surface. This can be stopped by storing the chocolate in the refrigerator i.e. at a lower temperature. So that the fat molecules don’t obtain enough energy.
Hence, Cocoa butter in chocolate required to be tempered to get expected crystal Form V.