A method of generating an aerosol in an aerosol-generating system includes storing liquid aerosol-forming substrate in a liquid storage portion and delivering via a pump a liquid aerosol-forming substrate from the liquid storage portion to an atomizer. The method also includes sensing a puff via a a puff sensor in an airflow path of the aerosol-generating system and determining a puff intensity during the puff via a controller. The delivery flow rate of the liquid aerosol-forming substrate to the atomizer is adjusted in response to the determined puff intensity.