Control of fermentation foaming using temperature profiling.

Stassi, P., Rice, J.F., Kieckhefer, T.J. and Munroe, J.H.

Abstract
A major influence on fermentation capacity is the headspace requirement, necessary to allow for the foam produced during fermentation. If the headspace allowed is insufficient, "overfoaming" (loss or release of foam from the fermenter) can take place, with deleterious effects on the brewing process. The usual countermeasure is the addition of substances known as foam breakers, which present problems of their own; in some fermenting vessels they can cause cleaning/hygiene problems, they are capable of impairing the foam quality of finished beer, and where law or tradition condemns the use of additives in brewing, they cannot be used. However, research has shown that (other things being equal) the level of foam production during fermentation varies in relation to the carbon dioxide evolution rate (CER), which can be altered by controlling the temperature. As a result of laboratory experiments, a temperature profiling procedure was developed which reduced the maximum CER (and therefore the foaming) without prolonging the duration of fermentation or otherise affecting brewing parameters or beer quality. Pilot scale brewing trials showed that this procedure could be used to reduce the headspace requirement and thus increase the effective capacity of commercial type fermenters. The results of the tests are given in the form of graphs and tables.
Keywords : brewing carbon dioxide fermentation fermenter foam headspace process control temperature