Abstract: An improved pressurizable wide mouthed vessel is provided which is capable of storing beverages under pressure and also of being used as a drinking vessel. The wide mouthed drinking vessel is closed by a closure urging a seal to sealingly engage the vessel. The closure is so configured that when the vessel is pressurized, the closure is deformed to transmit additional pressure to the seal to effect tighter sealing engagement with the vessel. The closure has pressure release means for venting the vessel in order to release the pressure on the seal, and so allow the closure to be more readily removed from the mouth of the vessel.