Wort filtration - systems and techniques with a modern lauter tub.
A survey is made of the latest designs of lauter tun equipment and fittings, the essential role of which is to provide clear wort. A prerequisite for this is the dry milling of the grist with conditioning by a mist of steam or water. To ensure high yields of extract during lautering, careful depositing of the mash is necessary with even distribution through an adequate number of bell shaped inlets and feed in at a rate which is not too high. The mash covers the false bottom which is normally of stainless steel and has 12 to 15% free passage area composed of 0.5 to 0.7 mm slots. Clearance between the false bottom and the lauter tun bottom should be as close as possible to minimise the void volume. The optimum depth of the spent grain layer should be 35 cm. More time for run off is required if the wort gravity is high and the temperature of the lautering vessel should be maintained at not less than that of the mashing process. Leaching of the spent grains is favoured by use of the cutting machine, the knives on which should be unequally spaced, straight or zig zagged shaped. An adequate number of taps should be installed at the bottom of the tun preferably one per square metre of filtering surface. The various wort outlets are fed separately to two or more ring pipes through which the wort is pumped before being combined with that from other ring pipes. This allows optimum leaching of both outer and inner zones of the lauter tun. Another advantage of this system is that cloudy wort can be recycled. Cleaning of the vessel is restricted to rinsing of the false bottom after each brew although thorough cleaning using a cleaning in place system is made once a week. This system minimises water usage and effluent production.
Keywords: equipment lautering mash separation