Practical considerations of the QCM as a viscometer within the food industry: Performance deterioration with repeated use and surface roughness

The practical cost considerations of the repeated use and the degree of polishing of the QCM as a commercial viscometer are reported. We have shown that the QCM can be used numerous times with gentle cleaning when used with starch-based foodstuffs with some simple considerations. The change in resonant frequency, Δf, and therefore the viscosity response, is not shown to be affected even after 60 applications and cleans. The fundamental unloaded frequency however, showed a linear decrease and therefore the QCM exhibits a mild drop in sensitivity. The degree of polishing of the crystal is shown to be not critical in improving the accuracy of the viscosity response. Although polishing a roughened surface dramatically improves the viscosity response, further polishing does not significantly increase the accuracy. This is shown to be particularly true for low viscosity fluids. The findings here indicate that a viscometer based on the QCM viscometer is a viable alternative to many conventional viscometer methods.