New approaches for kieselguhr-free filtration and characterization of filter aids

Finishing and Stability Session
Alexander Scheidel, Technische Universität München Weihenstephan
Co-author(s): Jens Voigt, Technische Universität München Weihenstephan, Germany

ABSTRACT: The clarity of a beer is the first impression of the consumer and one of the most important quality aspects of beer. The filtration process after a conditioning maturation is needed to reduce haze causing materials (e.g., polyphenols, proteins, yeasts, and carbohydrates) to increase this quality aspect before filling and sale. Conventional kieselguhr filtration with PVPP stabilization (polyvinylpolypyrrolidone) is mainly used as a precoat filtration in breweries to ensure stable beer quality. But, the use of diatomaceous earth (kieselguhr) as a filter aid bears a few problems. It is expensive to dispose of and furthermore the inhalation of SiO2 dust may be carcenogenic. A few approaches were made to substitute kieselguhr filtration. One of them is filtration with regenerable filter aids; another common method is the selection of membrane filters without filter aids. The chemical company BASF has developed a regenerable filter aid called Crosspure. This filter aid has comparable characteristics to diatomaceous earth. It is a combined filtration and stabilization tool, is available in two grades of fineness, and can replace kieselguhr in existing plants. Due to the availability of different grades, it allows the brewery to adjust this ratio to achieve an excellent filtration process and final beer quality. The possible separation of the mixture has been investigated successfully, and in a further step the filter cake resistance of the separated filter aid was determined. With knowledge of the filter characteristics of separated Crosspure, breweries are able to adjust an optimal ratio of the two grades of fineness. The separation process was investigated by particle size analysis and characterized by grade efficiency curves. The results of the regenerable filter aid were compared to kieselguhr, and the applicability was investigated by beer filtration tests at the Chair of Process Engineering of Disperse Systems in Weihenstephan. Separation of filter mud consisting of regenerable filter aids has a high innovative potential for kieselguhr-free filtration especially with filter performance comparable to kieselguhr and different sizes for optimal adjustment for different beer types.

Alexander Scheidel was born in 1987. He received degree a diploma engineer (M.S.) degree in brewing and beverage technology from TU München-Weihenstephan, Germany, in 2011. He began employment at the Chair of Process Engineering of Disperse Systems in Weihenstephan as a Ph.D. student. The focus of his work at the university is the filtration process with regenerable filter aids.