Today in 2003, US Patent 6666358 B1 was issued, an invention of William Field Warwick, for his “Beer Container.” Here’s the Abstract:

A beer container comprises an inner hollow shell of blow moulded PET to hold beer, an outer hollow shell of moulded high density polyethylene enclosing and supporting the inner shell and a spear structure including a dispenser tube extending from a bottom interior region of the inner shell through to a dispensing outlet at the top of the outer shell. The spear structure incorporates valves for supply of pressurizing gas into the interior of inner shell and for dispensing beer through the dispensing outlet, both valves being formed of PET. When the container has been emptied of beer, the outer shell can readily be separated from the inner shell and spear structure to allow separate recycling of the high density polyethylene material and the PET material.