T. IRIE (1), Y. Ito (1);
(1) Asahi Breweries, Ltd., Moriya, Japan
Technical Session 10 - Fermentation
Wednesday, June 17
1:00–2:15 p.m.
Flores 1–2
In industrial brewing, we can obtain much information from the sugar attenuation profile during fermentation. We’ve made some indices from the profile to monitor the yeast activity and to provide the appropriate feedback to the next fermentation condition. Even with the practical larger scale they could help us to optimize the quality of our products. In this study, we examined a curve-fitting method to analyze the attenuation data in beer fermentation. By curve-fitting with a last square method, we could approximate a series of apparent extract data by a certain shape of model curve. And from the function of the model curve we could obtain information about attenuation rate with a mathematical method. We investigated whether this method would be useful for analyzing fermentation also on the industrial scale. We used some kinds of S-shaped (sigmoidal) curves with several parameters to fit a series of attenuation data in beer fermentation. Some of these curves showed good fitness (R2 > 0.97) even to the data from the large scale fermenter (2,000–5,000 hL). From each result curve we picked up some critical points, such as an inflexion point, and also calculated some values, such as attenuation rate, at the point. We analyzed the fermentation data for various beer brands in our several breweries through all seasons. The result from this analysis with various brewing conditions suggested that the shapes of these fitting-curves would change depending not only on beer characters such as row material composition and original gravity of wort, but also on the variety of brewing conditions in our different breweries. And the parameters from the curve function would help us to describe the fermentation features in each brewery and make a strategy to optimize fermentation quality regardless of brewery. We also made a hypothesis that the critical point for the attenuation would correspond to the changing point for the growth phase of the yeast, and from the fitting-curve we could monitor the period of the phase change. From this point of view we will discuss some examples that we used for these critical points as new milestones for controlling the formation of some aroma compounds which have important roles for beer quality, such as esters and sulfur compounds.
Taku Irie received an M.S. degree in engineering from the University of Tokyo in 2000 and began working for Asahi Breweries, Ltd. After a few years as a technological staff member in the Packaging Section in some breweries, he has been in charge of the technological development of brewing at the Production Technology Center and Fukushima brewery. From 2012 to 2014, he worked at the Lehrstuhl für Brau- und Getränketechnologie, TU München as a guest researcher. Since April 2014, he has again been working at the Ibaraki R&D Promotion Office, Production Technology Center.
View Presentation
