Abstract: A bottle cap is disclosed for use as a closure and as means for pressurizing a previously opened bottle containing a carbonated beverage. It has a body adapted to close over the mouth of the bottle; and has a resilient manually compressible and relaxable bulb mounted to the body. The bulb functions as a pump in conjunction with inlet and discharge valves in the body to pressurize the interior of the bottle and its contents with air. A pressure release valve in the body responds to development of a pressurized condition in the bottle above a predetermined value to release the excess pressure to atmosphere.