A volumetric displacement dispenser and method of using the dispenser is disclosed for dispensing liquid contents from an interior of a bottle with a bottle neck while preventing air from filling a void created within the interior of the bottle caused by the liquid contents being poured out of the bottle by gravity. The dispenser includes a stopper having first and second boreholes extending there through, the stopper being adapted to form an air-tight seal when it is seated into the bottle neck. An air pressure tube routed through the first of the boreholes has a first end open to atmospheric air and a second end open to the interior of the bottle. An expandable volumetric displacement balloon is attached to the second end of the air pressure tube and a one-way liquid valve is disposed in the outlet of the liquid flow channel in the stopper.