A closure device for releasing an additive liquid into a liquid in a container by operation of the closure device and to a container including such a closure device. The closure device including a cap member defining a fluid chamber having a neck at a lower end thereof and a casing substantially surrounding the fluid chamber. A plug member extends into the neck of the fluid chamber. The neck has an upper portion with a first diameter, and wherein the plug member comprises a primary seal adapted to seal between the plug member and the upper portion of the neck. An upper seal is adapted to seal between the plug member and the upper portion of the neck. A nozzle is directed away from the fluid chamber and in fluid communication with the exterior surface of the plug member below the primary circumferential seal.