A pressure vessel assembly is provided for use in a beverage dispensing assembly. The assembly comprises a pressure vessel comprising a housing provided by at least two shell parts, the housing comprising, a gas inlet for receiving a gas in the pressure vessel and a beverage dispensing passage, wherein the at least two shell parts are releasably connectable for forming the housing and for receiving a compressible beverage container assembly filled with a substantially non-carbonated beverage in the housing. The assembly further comprises a compressible beverage container assembly, comprising a flexible bag defining a beverage storage volume, a filling gland, connected to the flexible bag providing a gland beverage passage to the beverage storage volume, and female adapter part, connectable to the filling gland, arranged to receive at least part of a male adapter part of a dispensing line, wherein a sealing member is provided in the gland beverage passage.