Abstract: A venting closure assembly for a milk tank where there is an outside stainless steel cover and a venting closure member positioned beneath the cover. The venting closure member forms a circumferential seal around the periphery of the cover, and it has a downwardly and outwardly flaring moderately flexible skirt which forms a peripheral venting channel. When there is a surge of milk in the tank (caused by acceleration of deceleration of the tank on the road), the surge of liquid upwardly against the closure member pushes the closure member upwardly to close a vent opening in the outside cover, thus preventing milk from escaping from the outside cover.