A dispenser for dispensing material into a container has a base, which can be coupled to the container, and a rotatable portion that is mounted to the base and rotatable about an axis of rotation. The rotatable portion includes a storage compartment for storing the material. The storage compartment has a dispensing aperture of which at least a portion of the periphery extends in a direction non-perpendicular relative to the axis of rotation. The dispensing aperture is positioned such that the material stored in the storage compartment falls into the container when the dispensing aperture is uncovered. A pierceable membrane is sealed along the periphery of the dispensing aperture. A piercer, which forms part of the base, is offset from the axis of rotation and is positioned to pierce the membrane from the outside of the storage compartment during a full rotation of the rotatable portion.