A capsule for storing a fixed amount of syrup. The capsule includes a housing to store the fixed amount of syrup and is shaped to sit on the rim of a bottle of carbonated water. The capsule also includes a release mechanism to release the syrup in a controlled manner into the bottle. The capsule is shaped so that excess gas is released into the atmosphere between at least one of the outside walls of the capsule and the inner wall of the opening of the bottle of carbonated water. The invention includes a method for releasing syrup from a capsule into a bottle of carbonated water. The method includes the capsule being placed on a rim of the bottle and the capsule receiving a downward force.
