Application Note: Chocolate Processing

Chocolates have a wide range of flow properties which relate to enrobing and making blocks. In the viscosity measurement of chocolate products, it is common to describe the flow properties using the Casson flow curve, which incorporates the following two parameters:

• Yield Value is the shear stress required to initiate flow of chocolate and relates to the coating or decorating characteristics: thickness and how quickly the coat firms up.
• Plastic Viscosity is a function of the shear stress required to maintain constant flow. This determines how well the chocolate will flow into a mold.

Chocolate measurement typically utilizes the HADV-II+ PRO Viscometer and Small Sample Adapter (SSA) accessory in addition to the Brookfield TC-501 Circulating Bath. This instrument can accommodate a range of chambers and spindles; for chocolate, the recommended combination is an SC4-13R chamber with an SC4-27 spindle. When used with Brookfield's WingatherTM software for data gathering, the results can be plotted and the data further analyzed using a built-in mathematical model to calculate Casson parameters.