Abstract: A process is provided for closing and hermetically sealing a bottom of a container. A cylindrical container body is provided which has an inside heat-sealable surface and an open bottom end. A flange is formed on and around the bottom end of the cylindrical container body which extends outwardly from the container body at a sharp radius of approximately 90 degrees to an outside surface of the container body and which defines a flat circular heat-sealable surface on an outer side of the flange. A generally circular membrane patch having an inside heat-sealable surface is positioned on the flat circular heat-sealable surface of the container body flange covering the open bottom end of the container body. The heat-sealable surfaces of the container body flange and the membrane patch are heat-sealed to each other for hermetically sealing the container bottom end.