Closure for a retort processed container having a peelable seal

A closure for maintaining pressure against a seal affixed to a container lip as a sealed container is exposed to relatively high temperature and pressure conditions, said closure comprising:

• a. a cap, having a top with an interior surface and a skirt depending from the top and defining a skirt interior surface, and having at least one thread affixed to the interior skirt surface in a spiral;
• and
• b. a liner, having a resting thickness at ambient temperature and pressure conditions, said liner being made from a material capable of being compressed to a thickness less than the resting thickness and being capable of recovering to a recovery thickness in a sealing zone such that said seal is sandwiched between said liner and said container lip at a pressure sufficient to retain said seal against said lip when said sealed container is subjected to retort processing conditions.

A method for maintaining pressure against a seal affixed to a container lip as a sealed container is exposed to relatively high temperature and pressure conditions, said method comprising reversibly affixing a closure to said container such that a liner of said closure abuts a surface of said seal so as to sandwich said seal between said liner and said container lip, said liner defining a resting thickness at ambient temperature and pressure conditions and said liner being made from a material capable of being compressed to a thickness less than the resting thickness and of recovering to a recovery thickness sufficient to allow said liner to maintain a positive pressure against said seal upon exposure to elevated temperatures, elevated pressure, or a combination of elevated temperature and elevated pressure.