Abstract: A system for measuring a volume of a liquid has a keg with a nozzle and a dip tube extending into the keg, a coupler having a gas flow path and a liquid flow path, a transducer cooperative with the gas flow path so as to measure a pressure of gas in the keg and cooperative with the liquid flow path so as to measure a pressure of the liquid at a location above the nozzle of the keg, and a controller connected to the transducer so as to measure a difference between the measured pressure of the gas and the measured pressure of the liquid. The controller converts the measured difference into a value corresponding to a volume of the liquid in the keg. The system can also be used to monitor the temperature of the liquid within the keg.