A method and apparatus are provided for transferring growth media or infection fluids to a bioculture bag having Could Process fitting thereon in fluid communication with the inside of the bag. The media or fluid is placed in a flask. A cap is threaded onto the neck of the flask. The cap has a spout with an opening in a distal end of the spout and a vent hole in the cap. The spout has a tubular end in which the opening is formed, with an O-ring seal adjacent the distal end of the tubular end. The tubular end fits within the fitting and the seal forms a fluid tight seal with the fitting to allow fluid transfer to the bag in reduced time with reduced spillage. The cap is preferably used on a flask having shaped baffles in the bottom. The baffles are highest toward the centerline, and decline in height linearly toward the corners of the flask at an angle of about 9° to the horizontal. The flask is rotated about 80-180 RPM, and the baffles have leading and trailing sides in the direction of rotation that are inclined at about 32° relative to the vertical. A growth media is also provided to culture the cells in the flask.