Abstract: A wireless parameter sensing system for a flask for use in lyophilization as well as a method of controlling a lyophilization process based on the sensed readings is disclosed. The wireless parameter sensing system may include a stopper adapted to be removably secured to an open end of the flask. A control unit may be positioned within an inner portion of the stopper. A parameter sensor may be connected with the control unit. A radio frequency transmitter may be connected with the control unit, wherein the control unit is operable to periodically transmit a parameter reading from the parameter sensor with the radio frequency transmitter.