A method and apparatus for freezing the contents of a freezer storage bag are disclosed. A cooling duct is mounted with or without spacers inside of a freezer storage bag that contains a liquid that can be frozen. A liquid coolant is first fed to a heat exchanger thereby forming a gaseous coolant. The gaseous coolant is fed to a manifold and from the manifold to at least one cooling duct present in the freezer storage bag. The gaseous coolant is circulated through the cooling duct thereby imparting freezing to the liquid in the freezer storage bag.