Aerosol-generating system with fluid sensor

A vapor-generating system, comprising:

• a first fluid channel connected to a liquid source;
• a pump connected to the first fluid channel and configured to deliver a liquid from the liquid source towards a second fluid channel;
• a fluid sensor configured to generate a sensor signal indicating a presence of a liquid in the second fluid channel based on measuring an electrical property of a fluid in the second fluid channel, the electrical property being an electrical resistance or dielectric constant of the fluid in the second fluid channel, the sensor signal indicating a type of liquid in the second fluid channel based on the electrical property of the fluid in the second fluid channel, the fluid sensor including,
• a carrier defining at least a portion of the second fluid channel between a first channel wall and a second channel wall,
• a first electrode in the carrier at the first channel wall of the second fluid channel, and
• a second electrode in the carrier at the second channel wall of the second fluid channel opposite the first electrode;
• a vaporizer configured to receive the liquid from the fluid sensor;
• and
• a controller, the controller configured to control the vaporizer based on processing the sensor signal generated by the fluid sensor to determine which type of liquid vapor-forming substrate is in the second fluid channel.