Katsuyuki Seki (1), Taku Irie (1), Itsuo Nishitani (1), Takeshi Sasamoto (1), Kazuhiko Uemura (1); (1) Asahi Breweries, Ltd., Tokyo, Japan
Yeast, Fermentation, and Microbiology
Poster
The fermentation process in brewing contains a lot of factors that
regulate the flavor of beer. In particular, it is important to control
temperature precisely in the fermentation process to ensure stable beer
quality. Fermentation is generally regulated through temperature control
during the various yeast growth phases. We measure sugar attenuation
and the number of yeast daily in beer to obtain information about
appropriate time to control fermentation temperature. As a result of
this, the flavor substances in yeast products are regulated in beer. In
an effort to improve this technique, we developed a method to
theoretically predict the changing point in the yeast growth phases by
fitting the attenuation data during fermentation to a sigmoid curve
(Irie, 2015). In consequence, we found out the inflection points
associated with flavor control and applied it to decrease undesirable
flavor in industrial scale fermentation. On the other hand, in this
report, we developed the method to control fermentation temperature
precisely in cylindroconical tanks. The temperature inside the tanks
have usually been monitored with a single thermometer. However,
distribution of temperature in the tanks was found to be nonuniform when
we measured it at multiple locations. Additionally, the distribution of
temperatures was confirmed to differ among fermentation tanks. To
minimize this difference among tanks as much as possible, we established
a way to predict the distribution of temperature without measurement.
In particular, we found an indicator that predicted it in tanks from
coolant flow rates and the period of cooling during fermentation. And,
we adjusted the valve position of coolant for appropriate flow rates in
cylindroconical tanks using this indicator. Thereby, the distribution of
temperature among the tanks could be made uniform. This indicator
allows temperature control in fermentation to be regulated precisely so
that it contributes to ensuring the stable quality of beer. By following
the approaches described above, we aim to reduce differences in
fermentation conditions among the tanks, further improving beer flavor.
Katsuyuki Seki graduated from the Faculty of Agriculture, Tokyo
University of Agriculture and Technology, Japan. After that, he received
an M.S. degree from the Graduate School of Agricultural and Life
Sciences, University of Tokyo, Japan. He began employment with Asahi
Breweries, Ltd. in April 2006 as a technical staff in the brewing
section. After he had worked at several breweries, he was transferred to
the production technology center in September 2014. He has been
involved in researching factors to control fermentation in practical
brewing.
