Optimization of fermentor operations using a fermentor instrumentation system.

Stassi, P., Fehring, J.F., Ball, C.B., Goetzke, G.P. and Ryder, D.S.

Abstract
Because of its fundamental role in the development of flavour and other beer quality characteristics, fermentation is widely regarded as the most important process in the brewery, but much of the available knowledge about it was obtained from laboratories and pilot breweries, and is not necessarily applicable to fermentation in the large cylindro conical tanks used in most commercial breweries. A system for monitoring industrial scale fermentations on-line, consisting of a thermal mass flowmeter to measure carbon dioxide production, a capacitance level transducer to measure foam height, a temperature sensor, a Digitronics "SIXNET" data acquisition system and a personal computer (used for data storage and processing), which in turn is connected to the main brewery data processing/process control system, is described. Using the data obtained by the instruments, the effects of process variation on fermentation performance can be studied and the consistency of the process can be evaluated. For instance, the relationship between foam formation and product and/or equipment characteristics can be studied and the optimum fill level for a given brand and fermenting vessel (i.e. the maximum volume that is compatible with the avoidance of overfoaming) can be calculated. Data from the system can also be used to optimize carbon dioxide collection. Trials carried out in the Miller Brewing Company's breweries have demonstrated the usefulness of this system as an aid to the improvement of process consistency. The possibility of combining the data recording system with an expert system based on artificial intelligence technology is discussed.
Keywords : carbon dioxide computer data processing fermentation foam measurement on-line process control sensor temperature