To improve process efficiency and ensure the clarity and stability of finished beer it is necessary to monitor the concentration of suspended solids in incoming liquor, whirlpool, centrifuge and wastewater effluents, yeast pitching and the finished beer. Most monitoring procedures currently used by the brewing industry are based on optical techniques where instruments use reflected, scattered or absorbed light to measure solids content. Recently a number of acoustically based instruments have been used in brewing applications. Their advantages over optical devices include, resistance of the acoustic sensor to losses in sensitivity and shift in calibration, independence of product colour, ability to monitor on-line process streams directly, good correlation between acoustic particle counts and total solids content and the ability to adjust sensitivity so as to allow selective monitoring of particles in a given size range. The principles of ultrasonic particle monitoring are outlined. The application of these instruments to modern brewing listed and their performance critically appraised and compared with optical procedures currently in use. Data from the commercial testing of an acoustic particle monitor is presented and evaluated. Future studies have been recommended.
Keywords : analysis brewery filtration on-line particle size ultrasonic