Beer filtration: instrumentation and strategy for control.

Freeman, G.J., Smedley, S.M. and Atkinson, B.

Abstract
Beer filtration usually entails a certain wastage of filter aids due to the difficulty of ensuring that the minimum necessary bodyfeed dosage rate is achieved without using considerably more than the minimum amount required. A system for preventing this wastage is described. An optical instrument for the continuous on-line measurement of the suspended solids content of the rough beer is used in conjunction with a flowmeter, enabling the computer which controls the bodyfeed supply to calculate the optimum dosage rate on the basis of a mathematical model which involves not only the rough beer solids content and flowrate but also certain properties of the filter aid and the type of beer being filtered. The system has been successfully tested in a commercial brewery since April 1994. Cost savings through reduced filter aid consumption and longer filtration runs (which in turn prolong the intervals between successive cleanings of the filtration equipment, thereby saving on cleaning materials, effluent treatment, etc.) are estimated at US $44600/year for a brewery with an annual output of 1 million hl. In addition, the greater consistency of the filtration process should improve bright beer quality and facilitate improvements in other aspects of beer treatment.
Keywords : automatic beer dosage filter aid filtration process control