A vaporizer includes a thermally conductive anesthetic container and a temperature sensor positioned in the container and in the liquid anesthetic. A breathing-gas delivery tube has a delivery end positioned in the liquid anesthetic at least about 5 mm beneath the top surface of the liquid anesthetic. A heater is positioned outside the container. Control circuitry is configured to receive signals from the temperature sensor and is connected to the heater in order to cause the heater to maintain the temperature of the anesthetic above a predetermined temperature. A method of vaporizing inhalation anesthetic is also provided.