A removable cap assembly maintains a cap having a curved side wall with an inner surface and an outer surface, a top portion extending from the curved side wall, a boss extending perpendicularly from the top portion, and a circumferential rib extending perpendicularly from the top of the boss. The boss and rib define an opening in the cap. A stopper, dimensioned to seal the opening, has a hole therein configured to allow a fluid to flow through. The stopper is maintained in the cap by the boss. The stopper includes a sealing surface flange and a cylindrical wall portion. The sealing surface flange receives the bottom edge of the boss. A sealing ring is formed separately from the stopper and is configured to fit against an inside surface of the top portion of the cap. A stopper lock is configured to press against the stopper, sealing surface flange and the sealing ring, sealing them against the inside of the cap. The stopper lock locks in place against the boss of the cap. An appliance member is adapted to be positioned within the hole of the stopper and extends through the opening.