ON-LINE MONITORING OF BREWERY FERMENTATION BY MEASUREMENT OF CO2 EVOLUTION RATE

To take full advantage of computer monitoring and control systems already in existence in many breweries, there is a need for reliable and inexpensive on-line sensors. Prior to the development of any system for production scale conditions, the underlying principles of the method of measurement adopted have to be investigated. Work at the laboratory (1.5 Litre and 11 Litre), pilot (30 Litre) and experimental brewery (100 hl) scales of fermentation has demonstrated that a good correlation exists between evolved CO₂ and changes in specific gravity. During the period from the onset of CO₂ evolution to the end of a fermentation, it was found that evolved CO₂ yield was ca. 1.0 gCO₂/Litre/degree gravity drop. Metering systems based on evolved CO₂ determination are nonintrusive, simple to install and cost effective.