Flexible container made of film material and filling method for filling such a container with a fluid substance

Filling method for filling a flexible container with a fluid substance, comprising the following steps:

• placing the flexible container in a relatively rigid container, the flexible container being provided with a film material for containing a fluid substance comprising a fill opening and a partitioning means along the which a first container wall part is placed against a second container wall part, the partitioning means dividing the container in a first and second compartment, characterised in that the partitioning means comprises a restraining member which maintains a substantially fluid tight separation of the first and second compartment until a predetermined pressure is achieved in the first compartment, wherein at the predetermined pressure, the restraining member is released by the fill pressure for placing the first and second compartment in fluid communication;
• filling the first compartment with the fluid substance via a fill opening in the container,
• activating the film storage means via the fill pressure such that the second compartment is released, and
• filling the second compartment until the film material of the flexible container is at least largely in contact with the wall of the rigid container;
• wherein, during filling, at least one of a flow rate and a fill pressure is measured and a change in the at least one of the flow rate and the fill pressure is determined on activation of the film storage means.