Soft Solid Materials: Is There A Perfect QC Test For Viscosity?

Mashed potatoes are a good example of a soft solid material that Quality Control must test for viscosity prior to shipment. The food industry may have the greatest challenge of all in coming up with a method that can successfully measure the variety of products that have thick paste-like consistency.  Some products, such as mashed potatoes, can be both homogenous and creamy with the easy ability to dish out or heterogeneous containing chunks of whole potato and markedly stiff behavior when serving. What method might prove acceptable for testing such broad variance in flow behavior?