(EN) A closure (1) for a beverage keg (90) is provided, the closure (1) comprising an inlet for admitting a pressurised gas into a headspace of the beverage keg (90) and a valve housing (20) defining at least a portion of the closure (1). The valve housing (20) has a housing wall (21) that defines at least a portion of the valve housing (20). The closure (1) is provided with a barrier (29), separate from the inlet, that is integrally formed with the housing wall (21) and configured to seal the closure (1) such that the closure (1) is able to retain the pressurised gas within the keg (90) in an unvented configuration. The barrier thickness is configured such that the barrier (29) ruptures by internal pressure from within the keg (90) in order to switch the closure (1) into a vented configuration in which fluid communication between the headspace of the keg (90) and an exterior of the closure (1) is possible, through the ruptured barrier (29).