A colloid mill does its work by hydraulic shear, bringing to bear a tremendous amount of energy on a small portion of material in the form of a thin film. This will reduce particles to their ultimate crystal size by breaking up the agglomerates into which they form. In the case of emulsions, the same principle holds. As the particles of the dispersed phase of the emulsion get smaller, it requires progressively more energy to overcome the surface tension holding them together. Enormous hydraulic shear is needed to do the job and a colloid mill is the ideal device to apply this force.
