A process for the production of a container (1) comprising an outer container (2), an inner bag (3) disposed therein and a pressure equalisation opening (10) disposed in the outer container (2), and also a container (1) produced according to this process, is described, wherein firstly a pre-moulding, comprising two coaxial tubes, is first produced by co-extrusion with the help of a blow mould and with an outwardly-projecting base seam (5) being formed. The process is to form a pressure equalisation opening (10) in the outer container (2) of the container (1) without endangering the integrity of the container (1), wherein a lower wastage rate and higher productivity are to be achieved. This is attained by a process wherein the base seam (5) is partially cut off and a force which acts in the direction of the seam is introduced into the pre-moulding, which still has a temperature of 40.degree. C. to 70.degree. C., which force breaks open and plastically deforms the base seam (5) so that a pressure equalisation opening (10) is formed in the base area (4).