Automating temperature dependent processes at a beer brewery
Beer brewing has been a craft where knowledge passes from generation to generation.The fundamental process of brewing has stayed the same with methods developed through trial and error. With the introduction of automation, modelling and control theory this ancient craft can be modernised and portrayed with mathematical models. This opens the possibility for new found precision and repeatably in production,specially for the growing craft-beer market.
Controlling the temperature during beer brewing is essential for the quality of the end product, as well as ensuring an efficient production. By eliminating manual control in the production of beer a more consistent product can be produced. During this thesis project the temperature control strategies for a heat exchanger and the fermentation process has been modelled and developed.
During fermentation of beer, a brewmaster wants to control the temperature at which the fermentation occurs with great precision. Not only does the temperature need to be steady, different temperatures are needed during different stages of the fermentation process. With a precise controller capable of ensuring a unique temperature profile the brewmaster can repeatably create the best tasting beer possible. This is due to the temperature during fermentation affects the flavour profile of the finished product. With the additional benefits of being able to monitor the progress of the fermentation through the online monitoring system, being present at the brewery is no longer needed for routine checks of the beer.
By modelling the biological behaviour when yeast fermenting a variety of different sugars into ethanol and carbon dioxide, precise control of the temperature is achieved. Implementation of a mathematical model based on a modified version of the equations derived by Engrasser was used in Simulink.
During the beer brewing process, the last step before the fermentation starts is the cooling of the wort. This is done by pumping the boiling hot wort through a heat exchanger. By modelling the thermodynamical system a controller could be developed. It is of importance to ensure that the wort is at a precise temperature when the fermentation starts, in order to give the yeast the best possible environment. By implementing our controller the flow used in production can be increased as much as 65%, with the added benefit of a consistent and predictable temperature in the fermentation vessel, eliminating the guesswork from manual control.