Today, we get to talk about where science and baking meet—one of my favorite things! On the baking side, we have icings and glazes: a crucial finishing touch. On the science side, viscosity: the measure of the thickness or resistance to flow of a fluid.

Why measure viscosity?

Because it will help you know how to handle and adjust your process and equipment. A thicker icing will be more difficult to handle. If it’s too thin, it won’t stay on or properly cover your product.

So how do I measure it?

This is where the science comes in! Viscosity is the measure of shear stress/shear rate. Shear stress is the force per unit area used to move a material.  Shear rate is a measure of the change in speed at which the intermediate layers of a fluid move with respect to each other.

But don’t worry, there are tools to help:

• Viscometers
• Rheometers
• Plastometers

 Samples may be gathered during processing and lab tested by QA staff. Another option is an inline system allowing constant monitoring during production. It is important to remember a material’s viscosity is not a single point measurement, but often depends on a number of factors, like time and temperature. Small variations of processing conditions and raw materials can affect flow behavior and final viscosity.