the present disclosure relates to a packaging system for producing a foam - in bag and method of mixing foam for the packaging of articles for shipment and storage , and in particular , to an improved , flexible , multilayered packaging system with a vented , deformable outer bag and an inner confinement structure made of paperboard box or a plastic bag with reclosable opening for optimal mixing and controlled release of the foam using preferential paths , score lines , weakness points , and / or obstacles to flow . in addition , the precursor fluids are placed in individually sealed pouches with calibrated and aptly positioned frangible seals to facilitate mixing after rupture inside of the inner confinement structure . in another embodiment , one of the precursor fluids is placed directly in the inner confinement structure , and in yet another embodiment , both sealed pouches are adhesively joined to the inner confinement structure . what is also disclosed is a method of mixing foam precursors in the different embodiments of the foam - in - bag packaging system .