Abstract: A storage bag (100) for storing, transporting, freezing, and thawing biopharmaceuticals includes a collapsible pouch (102) including an internal volume and an aperture; a non-collapsible port assembly (114) with a body, a snout (118) extending from the body into the pouch through the aperture, and at least one conduit (120A-C); and a reinforcing laminate (108) surrounding the port assembly and the end of the collapsible pouch including the aperture. At least one peripheral cavity (124A, 124B) is adjacent to a portion of the port assembly and extends from the aperture to at least one conduit so the conduit is in fluid communication with the internal volume through the peripheral cavity. The size of the peripheral cavity can be adjusted to control the volume of fluid trapped between the collapsible pouch and the non-collapsible port assembly, and as such this area advantageously experiences limited expansion during freezing.