A thermostat is a component of a control system which senses the temperature of a system so that the system’s temperature is maintained near a desired setpoint. The thermostat does this by switching heating or cooling devices on or off, or regulating the flow of a heat transfer fluid as needed, to maintain the correct temperature. The name is derived from the Greek words thermos “hot” and statos “a standing”.
Coffee equipment need thermostats to regulate the brewing temperature. Brewing temperature is important, and by maintaining a precise water temperature during coffee extraction we ensure the proper taste and flavor.
Commercial espresso machines have temperature dial on the front of the machine which lets the barista know if the thermostat is in need of repair.
Other common domestic uses of thermostats would be in building heating including central heating and air conditioning, in ovens and refrigerators as well as in any device which is required to maintain any consistent temperature, be it hot or cold.