hi there
fist of all what kind of Stirrer are you using to make to product for Shampoos and shower gels if they are very thick and the entrapped air is not separation on its own after a few hours and when you can not use a vacuum to get rid of it you need to use a viscojet stirrer . The surface of the product should only move but not be broken so that no or at least less air is incorporated.
If you can not use one of these then there is only the possibility to slow down steering so that you don’t entrap air if you stir by hand you properly will always have at least some air inside.
if you have a centrifuge you can separate the air for analytical purposes and density measurements there.
The easiest way is to reduce the Yield point of your formulation so that the entrapped air can separate over time but that can cause instabilities that need to be considert.
i hope that helps
Tobias