There is provided an aerosol generating device, including a heater element configured to heat an aerosol-forming substrate； a power source connected to the heater element； and a controller connected to the heater element and to the power source, wherein the controller is configured to control the power supplied to the heater element from the power source to maintain the temperature of the heater element at a target temperature, and is configured to compare a measure of power supplied to the heater element or energy supplied to the heater element from the power source to a threshold measure of power or energy to detect the presence of an aerosol-forming substrate close to the heater element or a material property of an aerosol-forming substrate close to the heater element.
