Julia Steiner (1), Roman Werner (1), Thomas Becker (1), Johannes Tippmann (1); (1) Technische Universität München - Chair of Brewing and Beverage Technology, Freising, Germany


Filtration processes are utilized in many beverage producing processes, e.g., in breweries spent grains are separated from the wort using mash filter technologies. This kind of filter system is a membrane filter press, which uses large-scale filter cloth. While normal aggregates, machines or tanks are constructed in terms of hygienic design in order to enhance cleanability, and filter media are designed with a focus on appropriate filtration performance. The construction of these filters often features complex structures, where contamination has many possibilities for adhering to the surface or in the pores. In addition unattached residues consist of many diverse substances in different concentrations. In the case of beer mash proteins, low molecular as well as high molecular weight carbohydrates and multiple additional substances form difficult to clean agglomerations, which stick firmly to the filter cloth. For these reasons suitable cleaning concepts are needed to avoid contamination of the filtrate and to guarantee product safety. In order to develop appropriate techniques the remaining residues have to be investigated and contaminated areas on the filter cloth have to be identified. This research project presents a proper method that contaminates filter media reproducibly and homogenously with mash in order to perform precise residue analysis via image evaluation. The acquired information is used to demonstrate and compare the efficiency of two cleaning concepts based on pulsed and continuous jets. The results show the suitability of pulsed jet cleaning by reaching higher degrees of cleaning compared with the continuous method. The advantages are also demonstrated by parameter variation, e.g., pulse number or stream velocity, which shows the optimal adjustments needed to remove spent grain residues from filter media. Furthermore, the pulsed cleaning concept demands less detergent and shorter processing time, which indicates this model has economic and ecologic advantages. For this reason pulsed jet cleaning recommends itself as a promising concept for utilization in mash filter system cleaning.