Cain F., Smith K., Talbot G., Controlling Viscosity, Confectionery Production, June 2005, 2-23
The chocolate industry normally uses the viscosity of chocolate measured at 40°C as a means of quality control. Whilst such measurements do ensure batch-to-batch consistency they bear no real relationship to the viscosity of the chocolate once it is tempered. There are two main reasons for this. Firstly, the temperature of the tempered chocolate will be some 10°C or so lower and this alone will contribute to a higher viscosity. Secondly, a proportion of the fat phase will have crystallised at temper leaving less of the fat in the liquid phase. This also will contribute to a higher viscosity. So tempering chocolate will increase its viscosity. The questions which then arise from this are (a) by how much, and (b) is the viscosity increase dependent on the way in which the chocolate is tempered?