Shampoo Characterisation: Measuring Consistency with Back Extrusion

Why Measure Shampoo Consistency?

Shampoo consistency plays an important role in product quality, ease of use and consumer experience. A shampoo must flow readily from its bottle, spread easily through the hair and provide the desired texture during application. Manufacturers must therefore balance viscosity and thickness to achieve the right product characteristics.

Changes to ingredients, surfactant concentrations and formulation processes can all influence the consistency of shampoo. Measuring these properties helps manufacturers compare formulations, optimise product texture and maintain consistent quality between production batches.

How Does Back Extrusion Work?

Back extrusion provides a practical method for assessing the consistency of viscous and semi-solid products, including shampoos, conditioners, gels and creams.

During the test, a disc-shaped plunger moves downwards into a container holding the sample. This compression forces the product upwards and around the edge of the disc, creating resistance as the plunger moves through the material.

The texture analyser measures the force required to move the plunger through the sample. This force provides an indication of the product’s consistency and resistance to flow. A higher force generally indicates a thicker or more resistant product under the specified test conditions, while a lower force suggests less resistance.

Manufacturers can control parameters such as plunger speed, penetration depth and test temperature to improve repeatability and compare samples under consistent conditions.

Comparing Formulations and Maintaining Quality

Back extrusion allows product developers to compare shampoos with different formulations and identify variations in texture. It can help assess the effects of ingredient changes, support the development of new products and investigate differences between production batches.

The results also help quality control teams establish acceptable consistency ranges and monitor manufacturing processes. By combining back extrusion measurements with other relevant tests, manufacturers can build a clearer understanding of shampoo performance and handling characteristics.

Texture Analysis with Lamy Rheology

Lamy Rheology texture analysers offer a practical solution for evaluating the consistency of personal care products. Back extrusion testing provides objective force measurements that support formulation development, product comparison and routine quality control.

Discover the Lamy Rheology texture analyser range to explore solutions for characterising shampoos and other viscous formulations.