An aerosol-generating system, a cartridge for an aerosol-generating system and a method of identifying liquid aerosol-forming substrate held in a liquid-storage portion (201) of an aerosol-generating system. The aerosol-generating system comprises a liquid-storage portion (201) for holding a liquid aerosol-forming substrate, a first electrode and a second electrode (304, 305) spaced from the first electrode and a control system. At least a portion of the liquid storage portion (201) is arranged between the first electrode and the second electrode (304, 305), the portion of the liquid storage portion (201) arranged between the first electrode and the second electrode (304, 305) holding liquid aerosol- forming substrate when liquid aerosol-forming substrate is held in the liquid storage portion (201). The control system is configured to: measure an electrical quantity between the first electrode and the second electrode (304, 305), and identify the liquid aerosol-forming substrate held in the liquid storage portion (201) based on the measured electrical quantity information.
