These shots show the liquid from the mash tun being pumped out, over to the heat transfer tank. In this tank, there is a hot water heater element that is turned on and off by the PID installed in the red control pannel. The PID measures its temperature from the exit point of the 18 feet or so of 1/2 copper pipe that is coiled up. The liquid from the mash tun flows through this pipe, heating up just enough to be at my desired temp (150 degrees) and then gently flows out onto the top of the grainbed back inside the mash tun. This process goes on for about an hour and does a good job of keeping the temperature stable while also helping to filter the liquid.