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Shear Thinning

What is Shear Thinning?

In molecular gastronomy, fluid gels are the best examples for the use of shear thinning. Liquids are stabilized using additives such as agar- agar and gellan. Once it has gelled, shear stress is applied physically or mechanically to breakdown the molecules and lessen viscosity. The result is a fluid which is stable enough to hold without flowing out of place.

Shear thinning refers to the response of a fluid substance’s viscosity (also known as resistance to flow) when exposed to force. The force, also known as shear stress, is a strain that is parallel to the liquid’s surface. Shear thinning applies to non-Newtonian fluids, or liquids whose thickness is varied according to force applied. In such cases, reduction of thickness occurs in this type of fluids.

This property is commonly seen in complex solutions, polymer solutions and molten polymers. Some shear thinning substances also display thixotropic properties, which allow them to thin under stress and return to a more viscous state after time. Shear thinning of a non-Newtonian fluid is directly proportional to the length and amount of shear stress applied. This behavior is known as pseudoplasticity and shear thinning fluids may also be referred to as pseudolastics.