A closure for a container having a foil or membrane sealed opening. The closure includes a cap, a spout and a stem. The stem includes a downwardly extending piercing structure adapted for piercing the foil or membrane of the container upon rotation of the spout relative to the cap. The cap includes a cap top, a cap skirt depending from the cap top, an open sleeve and a stem guide. The open sleeve has an inwardly extending thread adapted to detachably engage the container. The open sleeve extends upwardly from the cap top. The stem guide extends along an internal surface of the sleeve. The spout rotatably engages the sleeve and includes a spout top having an aperture, an outer spout skirt and an inner skirt. The outer skirt depends from the spout top radially outward of the sleeve and rotatably engages the sleeve. The inner spout skirt depends from the spout top radially within the sleeve. The stem includes a substantially cylindrical body positioned radially within the inner spout skirt, a plug for selectively sealing the aperture, an outwardly extending spout-engaging thread, and an outwardly extending cap-engaging member. The spout engaging member engages the inner spout skirt and is adapted for helical motion with respect to the inner spout skirt. The cap-engaging member engages the stem guide and is adapted for axial motion with respect to the sleeve. Preferably, the stem guide includes a substantially vertically extending groove and the cap-engaging member includes a tab received in the groove.