Abstract
Specification of a grade of perlite or kieselguhr is best achieved using mean hydraulic radius which is a value based on effective bed voidage. A numerical prediction of clarification capability has been obtained from filtration trials even when the filter bed structure has been disrupted by beer solids. Rapid grading of perlites is possible from assessment of powder permeability. Removal of very small haze particles from beer by fine grades of powder was attempted but not achieved. This effect would be explained by the relatively high shear forces experienced by the beer particles on the pilot candle filter employed in the trials, compared to full-size beer filters.
