Study on the membrane filtration of mash with particular respect to the quality of wort and beer

The quality of a membrane filtered wort, and the beer from it, is different from that produced with a lauter tun or mash filter. A membrane is capable of producing a clear wort in terms of turbidity while solid contents, in particular larger molecular substances, are retained. The selectivity of separation is not directly set by the membrane's pore size but rather by the formation of the fouling layer. Thus an interaction between technical filtration parameters and selectivity determines the quality of the resulting wort and beer. The filterability of a beer produced with a membrane filter system for lautering was considerably better when a poorly modified malt was used and foam stability was worse when a normally modified malt was used. For all other properties examined in the beers, no significant differences between lauter tun and membrane filtration including sensory characteristics were observed.