Abstract: A regulating apparatus for a pressure activated one-way valve. The one-way valve is for mounting on a container to permit the release of gas from within the container and to control the ingress of atmospheric air. The regulating apparatus comprises a sealed and expandable chamber containing a gas. The chamber is operatively associated with the one-way valve such that when the chamber is exposed to elevated temperatures and/or reduced external pressure the gas within the chamber expands and exerts a force upon the one-way valve or portions thereof. The force tends to maintain the one-way valve in a closed or semi-closed configuration.