Beer colloidal haze and the filtration process.

Lenoel, M., Moll, M., Dodds, J.A. and Leitzelement, M.

Abstract
Hydrodynamic Chromatography (H.D.C.) in which particles passing through a chromatographic column are separated according to size and charge and detected by UV absorption has been used to measure beer haze particles in the size range 0.05 um to 1 um. A Light Scattering Analyser (H.I.A.C.) with a helium/neon laser sensor and optics responding to low angle forward scattering was used to measure particles in the range 0.5 um to 25 um. Using this instrument with a photodiode detector to measure the optical blockage occurring in an illuminated zone, particles in the range 2.5 um to 150 um were measured. These procedures were compared with classical nephelometric methods for measuring colloidal haze and haze stability. A model filtration system with a single candle filter was constructed to study beer filtration performance. Agreement between the results obtained with this filtration model and the performance of industrial filters was shown on a previous occasion. Results obtained with the model system were compared with those from a laboratory membrane (0.8 um) filterability test. This study has revealed that if the factors affecting beer filtration and beer stability are to be understood and the processes optimized then methods for determining the nature, properties, size distribution and charge of beer colloidal particles must be improved.
Keywords : beer colloidal distribution filtration haze particle size