A mash/lauter tun and method of converting grains to wort. The mash/lauter tun comprises a container with a double false bottom filter having two perforated plates disposed parallel with a space therebetween for receiving filtration media. The container further comprises thermometers extending to near the center of the tun and a rotating heat exchanger. In use, mash is loaded into the container and heated via the rotating heat exchanger by passing hot fluid through the rotating heat exchanger. The mash is then sparged by increasing pressure in the rotating heat exchanger above a threshold pressure via closure an outlet valve of the heat exchanger. The wort then passes through the double false bottom filter and is subsequently transferred to a brew kettle for boiling.