The false bottom’s free passage area—Important feature or negligible?

Brewhouse Operations Session
Simon Henke, TU München - Chair of Process Engineering of disperse Systems, Weihenstephan
Co-author(s): Jens Voigt and Karl Sommer, TU München, Chair of Process Engineering of Disperse Systems, Weihenstephan, Germany

ABSTRACT: The lautering process is the most time-consuming step in wort production. Besides mash filters, the lauter tun is still the most common device used for mash filtration in the brewhouse because no other separation techniques have been established. For this reason equipment suppliers have done a lot of development work on existing lauter tuns that has led to acceleration of this filtration step. Nevertheless, there are still many open questions regarding the performance of mash filtration in the lauter tun. Specifically, causes of filtration problems during this unit operation have not been fully investigated. High flow rates through the filter cake often lead to increased compaction of the compressible filter cake. This work investigates how false bottoms with different free passage areas influence the lautering performance and composition of the grain cake. For this reason a pilot scale glass lauter tun was constructed, offering the opportunity to make an image analysis of the grain cake during the whole process. The lauter tun is equipped with four different false bottoms with defined free passage areas between 6 and 20%, which cover the range of available industrial scale systems. Besides optical analysis the most important physical parameters of lauter wort are recorded in-line. The presented filtration equations allow the determination of filter cake permeability and the development of permeability during filtration with these measurements. The experiments conducted provide an answer to the introductory question whether the false bottom’s free passage area is important for filtration.

Simon Henke graduated from Technical University Munich in 2009 with an engineering degree in brewing sciences and beverage technology. In 2010 he started his work at the Chair of Process Engineering of Disperse Systems, TU Munich, as a research associate. His fields of activity are mass transport phenomena and procedural aspects of the mashing process. He is responsible for the pilot plant brewery at the Chair of Process Engineering.