A closure (40) includes a body (42) with a threaded portion (44) for engaging the closure with a container. Inwards of portion (44) is a liner (46) comprising a hydrogen generating device, wherein the liner includes one layer (48) which incorporates a hydride dispersed in a polymeric matrix and, on opposite sides of layer (48) are arranged PET layers (50, 52). Layer (50) acts as a control layer to control the rate of passage of water vapour from the beverage in the container to the hydride containing layer (48) and thereby control generation of hydrogen by the hydrogen generating device. In use, water vapour passes through layer (50) and contacts the hydride associated with layer (48) which results in production of molecular hydrogen which combines with oxygen. Thereafter, a reaction between the hydrogen and oxygen takes place, catalysed by a catalyst associated with the container thereby to scavenge the oxygen.