Filter materials – The use of filtering materials is aimed at separating protein-tannin suspensions from beer wort and yeast and protein-tanning suspensions from beer..
Coarse diatomaceous earth is used to filter the wort (particles and perlites, for beer filtration, however: cotton mass, asbestos, diatomaceous earth, siliceous earth and perlites.
Characteristics and quality requirements for cotton mass.
Cotton pulp for beer filtration should consist of cotton fibers in length 7-11 mm and show good loosening at a temperature of 30-90 ° C. Longer cotton fibers may clump into lumps and form knots or thick threads. Such a phenomenon adversely affects the beer filtration efficiency.
Cotton mass has an adsorption capacity. It should easily form a homogeneous suspension in water. The proportion of short fibers should not be greater than 0,3%. In case of higher fiber content, the length is below 7 mm, losses during washing and rinsing of the mass increase. There is also a concern, that the short fibers can end up in the beer when it is filtered, despite its strong compression into filter discs. The composition of the filter mass should not contain foreign fibers, e.g.. hemp, cellulose and wood,
The method of preparing the filter mass. The preparation of the filter mass consists in washing and pressing it with the use of special devices - a mass washer and a disc press. After washing, the mass is formed into discs using a hydraulic or pneumatic press.
Care should be taken when pressing the mass, to make the mash infusion and time ; the flow of water from the press was uniform. This gives mass discs of equal thickness and uniformly compressed, which is essential in the filtration process.
Whitening of the filter mass. Wybielanie i przywracanie masie luźnej struktury przeprowadza się za pomocą dodatku niewielkiej ilości wody utlenionej. This method is used in the case of a high degree of mass contamination.
After washing the mass with cold or lukewarm water, do wody w zbiorniku dodaje się przy uruchomionej pompie lub uruchomionym mieszadle 25 cm3 H2O2 for each hl of water. In this way, a 0.01% water solution is obtained, the so-called. hydrogen peroxide. Thereafter, the contents of the kettle are heated to a temperature of 80 ° C and this temperature is maintained for 30 minutes, then the mass is cooled down with cold water.