An aerosol-generating system includes a liquid-storage portion configured to hold a liquid aerosol-forming substrate, a first electrode, a second electrode, and a control system. The second electrode is spaced from the first electrode. At least a portion of the liquid storage portion is arranged between the first electrode and the second electrode. The control system is configured to measure an electrical quantity between the first electrode and the second electrode, and detect a draw on the aerosol-generating system based on the measured electrical quantity information.