Yeast and Fermentation Session
Martin S Lutz, ProLeiT AG, Herzogenaurach, Germany
ABSTRACT: Finding the right moment to stop fermentation
and release a tank for cooling down or pumping over to a lagering tank
is a common task in the fermentation cellar. Usually this moment is
determined by regular gravity measurements as a trend in a standard
fermentation diagram. Additionally the measurement of the VDK
concentration gives the final assurance that the fermentation stage can
be ended. Both measurements require the manual taking of the samples and
then analysis by the brewer or in the laboratory, which means a lot of
effort. In our work we investigated the possibility of concluding from
easy accessible data the progress of the extract attenuation and so
determining the current status of the fermentation. From a good start of
the fermentation on the first day we measured the temperature and
pressure on the tanks, which is standard in an automated fermentation
cellar, and also looked at the activation of the cooling valves. With
this we can deduct the amount of cooling energy needed related to the
degree of fermentation. The system has to be adapted to local
circumstances in the brewery and the influences of different wort types.
The results achieved indicate that the different stages of the
fermentation process can be distinguished. In particular, the end point
of the main fermentation can be predicted with enough accuracy for the
brewery to reduce the amount of sampling needed. Only one control
analysis should be necessary to assure that the degree of attenuation is
in a certain range and then to release the tank for switching over to
the lagering phase. As soon as the system parameters are introduced and
stable results are obtained there can also be a full automatic end to
the fermentation period without additional sample taking. This reduces
the workload in the cellar and provides significant advantages, for
example, on weekends when nobody has to come to the brewery for this
task. In the presentation real process values for a large brewery are
shown, and conclusions from the experiment are explained.
Martin
Lutz graduated as a brewmaster from Weihenstephan University in Munich.
After several years of working in medium- and small-sized breweries, he
joined ProLeiT AG in its business field of brewery automation. He has
gained profound knowledge in the various aspects of this business and is
connecting the technological requirements of the brewmaster with the
possibilities and structures of modern process control systems.
VIEW PRESENTATION 229
