Abstract: A container system for beer formed of a bottle body, a cap and sealing gasket formed of a blend of butyl rubber and one or more thermoplastic polymers. Preferably, the butyl rubber is present in an amount of from about 20 to about 60% by weight of the composition and the one or more thermoplastic polymers are present in an amount from about 40% to about 80% by weight of the composition. The system provides good sealing properties and prevents oxygen, and chlorinated substances such as chlorinated phenols or anisoles, that may be present in the packaging, from entering the bottle.