An underback is integral in maintaining the wort flow and saves time when a batch is more than one kettleful.
An underback is a vessel that collects wort from the mash/lauter tun. A pump is plumbed into the underback instead of the lauter or mash tun. Gravity then pulls the wort from the mash tun and this minimizes the grain bed from compressing. A float switch can turn the pump on when the underback is full, and this frees the brewer from having to micromanage the procedure.
When the correct volume of wort is in the kettle, it can be boiled. Meanwhile, the wort can continue to run into the underback. The wort in the underback is held at temperature until the previous kettle contents has boiled and been sent on to the fermenter or whirlpool; then the contents in the underback are moved to the kettle.
The first batch of wort moved to the underback is traditionally called first wort. A wort holding tank saves the brewery and the brewer a lot of time as the underback can be used to collect the first wort while the other is boiling in the kettle.
Underback / Wort Grant / Wort Holding Tanks should be regularly cleaned as the wort is held at fluctuating temperatures.
Every Bevo Tech tank pressure vessel is designed and fabricated according to PED and AS standards.