bag - in - container having an inner layer forming a bag filled with a fluid , the bag being separatable from an outer layer forming the container . the bag - in - container has a mouth fluidly connecting the volume defined by the bag to the atmosphere and separated therefrom by a seal . the container further having at least one space vent fluidly connecting the space between inner and outer layers and to the atmosphere . a vent provides a closure to control the gas flow between the space and the atmosphere . the space contains an amount of gas at a pressure insufficient to compress the bag to drive out more than 80 % of the fluid contained therein . the present invention also concerns a kit of parts including a bag - in - container and a dispensing appliance .