A beverage sealing cap that absorbs oxygen keeps a bottled beverage, such as a bottle of wine, fresh after opening and re-sealing. The beverage sealing cap is made with a thermoplastic elastomer stopper containing an oxygen absorber. When inserted into an opened beverage bottle, the stopper seals the bottle to prevent ingress of air, while the oxygen absorber removes the oxygen present in the air inside the bottle. As a result, the contents of the bottle are preserved in a fresh state, avoiding degradation of flavor and waste due to spoilage.