An aerosol generation system (36) for generation of an aerosol from an aerosol-forming precursor that comprises: an electrically operated heating system (30) to heat said precursor to generate the aerosol; a flow path (18) for transmission of flow, including the aerosol, to a user; the heating system arranged in fluid communication with the flow path; and electrical circuitry (8). The electrical circuitry (8) is configured to: measure a property of the electrical energy through the heating system; determine one or more characteristics from the result of the measurement of said measured property of the electrical energy; select, based on the determined characteristics, one from a plurality of different stored relationships between the measured property of the electrical energy and a property of the flow; and determine the property of the flow based on said relationship.