A lot of homebrewers convert a chest freezer or refrigerator into a kegerator and they plug the fridge or freezer into an external controller to manage temperature. And if you want to go digital there is not a controller better suited for the job than a RANCO ETC-111000-000 controller. RANCO uses a thermistor on the end of a 8' cable to sense temperature & this gives you enough room to mount the controller on the side of your kegerator or on the wall behind your kegerator.
But RANCO ETC-111000-000 controllers to not make good mash controllers! The reason they don't is because they are just smart thermostats and a thermostat is always catching up to its set temperature. For example, let's say for example that you were to set your RANCO ETC-111000-000 up as a mash controller and you set your mash temperature to 145F. If you start at a strike temperature of 135F the RANCO would stay on until the mash temperature at the thermistor read 145F then it would turn off & the mash would cool until the lower trip temperature of 142 is reached & it will turn on, starting the cycle all over again. This cycle would continue and your average mash temperature will be right in the middle - at 143.5F. The correct temperature controller for your mash is a PID controller. A PID controller works to maintain 145F, not catch up with 145F. A PID controller will slightly over-shoot 145F to maintain your set temperature at an average of 145F. And a smart, tuned PID controller can easily maintain your mash to within 1/2 degree F of your set temperature.
Tom - www.kegkits.com