M-45: Solid-liquid separation of high-gravity mashes with a decanter centrifuge

S. HENKE (1), F. Steinmüller (2), K. Sommer (1); (1) Technische Universität München, Chair of Process Engineering of Disperse Systems, Freising-Weihenstephan, Germany; (2) Caspary GmbH, Chieming, Germany


The lauter tun, along with the mash filter, is still the most common device for mash separation in the brewhouse. However, mash filtration in the lauter tun is limited due to the principles of cake filtration. Solid-liquid ratios of the mash, as well as the particle size of grist, can only be varied within tight limits without affecting filtration time and wort quality. Furthermore, problems arise with the use of high amounts of huskless adjuncts like corn and rice because these affect the filter cake negatively. Especially when high-gravity worts are produced, all mentioned parameters are relevant. In this work a decanter centrifuge was used to investigate the ability of this continuous centrifugal separation technique to process high-gravity mashes. The solid-liquid ratio was varied up to 0.5 with a resulting original wort of 27.0°P. Furthermore, different machine and process parameters were varied with the major purpose to achieve the lowest possible solid content of the wort. The results of this work showed that a decanter centrifuge is a suitable way to conduct mash filtration, especially with high solid-liquid ratios and very fine grist particle sizes. Although the machine parameters were chosen to achieve the best wort quality, what affects the water content of the separated spent grains negatively, the water content of the spent grains, was still low enough to use them as an energy source in direct combustion. In former studies, conducted by Richter et al., it was shown that the resulting beers from decanter worts have no quality reduction compared to conventionally produced worts, although the wort turbidity and trub content do not fit in the quality parameter range of a lauter tun.

Simon Henke graduated from Technische Universität München in 2009 as a degreed engineer in brewing science and beverage technology. In 2010 he started his work at the Chair of Process Engineering of Disperse Systems, Technische Universität München, as a research associate. His fields of activity are mass transport phenomena and procedural aspects of the mashing process. Simon is involved in student education in thermal and mechanical process engineering. He is responsible for the laboratory for wet and dry particle size analysis.

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