A closure and method of making a closure are disclosed. The closure includes a cap body having a top portion and an opening extending therethrough defining a cavity in communication with said opening. A flow channel is defined within a portion of the cap body having an inlet and an outlet. A stopper is disposed within the cavity adjacent the outlet of the flow channel. The stopper is formed from a material adapted for flowing through the flow channel to form a pierceable portion, with at least one of the cap body and the stopper configured for closing a container.
