The Strainmaster, which is not as widely used as the lauter tun or the mash filter, was patented by Anheuser Busch and developed by Nooter Corporation. The Strainmaster consists of a rectangular hopper-bottomed tank that is fitted at the base of the hopper and that has downward opening doors for discharge of spent grains. Within the vessel are header pipes running longitudinally down its length, and attached to these are perforated straining tubes. The header pipes are connected by wort draw-off mains to wort pumps. Wort withdrawal and circulation is initiated when the top row of tubes is covered. The wort is then recycled through the straining tubes to the top of the Strainmaster. The action of drawing wort through the tubes creates a filter bed around the tubes in much the same manner that occurs relative to the lauter tun. Recirculation continues until the desired wort brightness is achieved, than the wort is run to the kettle.
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