Abstract: A composite closure for a container having carbonated contents includes an outer closure cap having a top wall portion, and an annular depending skirt portion. A disc-shaped sealing liner is positioned within the closure cap adjacent the inside surface of the top wall portion. The liner includes an inwardly facing sealing portion at the periphery thereof, and further includes an annular seal bead which projects downwardly from the liner in a direction away from the top wall portion. The closure is configured for enhanced sealing with an associated container, with the top wall portion of the outer closure cap preferably including a relatively thick, peripheral reinforcing region which overlies the annular seal bead of the liner for further enhancing sealing.