Method for producing plastic containers having high crystallinity bases

A method of producing a heat set plastic container comprising the steps of:

• providing a mold cavity having sidewall surfaces and base surfaces;
• providing a plastic preform within said mold cavity;
• expanding and stretching said preform into conformity with said sidewall surfaces and said base surfaces to form the plastic container having a sidewall and a base;
• and
• inducing crystallinity in said base of the plastic container by applying heat from said base surfaces of said mold cavity to said base of the plastic container and by applying heat from an interior portion of the plastic container to an interior surface of said base of the plastic container, wherein said applying heat from said interior portion of the plastic container includes circulating a high-temperature fluid at a pressure in the range of 700 to 4200 kPa through said interior portion of the plastic container.