To control the brewing, I built a CraftBeerPi controller. It is able to control the temperature on the main brew pot (mash and boil) and a hot liquor tank for sparging. The recirculating is also controlled via the CraftBeerPi.

Inside my CraftBeerPi 
5V DC power supply and 4 Solid State Relays. To mains power cables are used to be able to power 2 x 2000w heaters on different mains circuits. 
Raspberry Pi board, SSR interface driver board, 5 to 12V power supply and buzzer 
Touch display mounted on front with SSR indicator LED’s
