A beverage preparation machine is provided and includes a heater (1) for heating up a supply of liquid from a supply temperature to a beverage preparation temperature, in particular an in-line heater and/or a heat accumulation structure such as a thermoblock; and a control unit (2) for controlling the supply of liquid and the heater so that the heater is energized to reach and be maintained at an operative temperature (“RUN”) for heating up the supply of liquid to the beverage preparation temperature during beverage preparation. The control unit is further arranged so that the heater is energized to reach and be maintained at a reduced temperature (“ECO”) out of beverage preparation.