A domestic carbonation appliance. The appliance has a replaceable CO2 cylinder, and accepts a refillable bottle. The appliance has a processor for controlling the functions of the device. The appliance comprises: a chassis having a filling chamber； a fill head in the filling chamber, the fill head being attachable to a source of pressurised carbon dioxide gas； the filling chamber having a safety door and locking device； the device having a sensor for detecting a door state and transmitting door state information to the processor； and the processor being adapted to initiate a carbonation process in response to the door state information.
