A method of manufacturing bulked continuous carpet filament, said method comprising: providing an expanded surface area extruder being one of a multiple rotating screw extruder, a twin screw extruder, a multiple screw extruder or a planetary extruder, wherein said expanded surface area extruder defines an expanded surface area extruder inlet and an expanded surface area extruder outlet; providing a pressure regulation system configured to reduce a pressure within at least a portion of said expanded surface area extruder below about 12 mbar; providing a spinning machine defining a spinning machine inlet, wherein said spinning machine inlet is operatively coupled to said expanded surface area extruder outlet; using said pressure regulation system to reduce said pressure within said at least a portion of said expanded surface area extruder below about 12 mbar; passing a plurality of flakes consisting essentially of PET flakes through said expanded surface area extruder via said expanded surface area extruder inlet to at least partially melt said plurality of flakes to form a polymer melt; substantially immediately after passing said plurality of flakes through said expanded surface area extruder, using said spinning machine to form said polymer melt into bulked continuous carpet filament characterized in that said method further comprising: providing a PET crystallizer; wherein the PET crystallizer comprises a stirring apparatues, one or more heating elements and one or more blowers configured to blow air that has been heated by the one or more heating elements over the flakes as the flakes pass through the crystallizer; and prior to passing said plurality of flakes of recycled PET through said expanded surface area extruder, passing said plurality of flakes of recycled PET through said PET crystallizer to at least partially dry a surface of said plurality of flakes of recycled PET, wherein the one or more blowers are moving hot air substantially across a surface area of the flakes as the flakes pass through the crystallizer and the stirring apparatus is configured to agitate or stir the PET flakes as the one or more blowers blow air heated by the one or more heating elements across the PET flakes. providing an expanded surface area extruder being one of a multiple rotating screw extruder, a twin screw extruder, a multiple screw extruder or a planetary extruder, wherein said expanded surface area extruder defines an expanded surface area extruder inlet and an expanded surface area extruder outlet; providing a pressure regulation system configured to reduce a pressure within at least a portion of said expanded surface area extruder below about 12 mbar; providing a spinning machine defining a spinning machine inlet, wherein said spinning machine inlet is operatively coupled to said expanded surface area extruder outlet; using said pressure regulation system to reduce said pressure within said at least a portion of said expanded surface area extruder below about 12 mbar; passing a plurality of flakes consisting essentially of PET flakes through said expanded surface area extruder via said expanded surface area extruder inlet to at least partially melt said plurality of flakes to form a polymer melt; substantially immediately after passing said plurality of flakes through said expanded surface area extruder, using said spinning machine to form said polymer melt into bulked continuous carpet filament providing a PET crystallizer; wherein the PET crystallizer comprises a stirring apparatues, one or more heating elements and one or more blowers configured to blow air that has been heated by the one or more heating elements over the flakes as the flakes pass through the crystallizer; and prior to passing said plurality of flakes of recycled PET through said expanded surface area extruder, passing said plurality of flakes of recycled PET through said PET crystallizer to at least partially dry a surface of said plurality of flakes of recycled PET, wherein the one or more blowers are moving hot air substantially across a surface area of the flakes as the flakes pass through the crystallizer and the stirring apparatus is configured to agitate or stir the PET flakes as the one or more blowers blow air heated by the one or more heating elements across the PET flakes.