An apparatus is provided for molding plastic preforms into plastic containers, including a transport unit, on which a plurality of molding stations is provided and which moves the molding stations along a predefined transport path, wherein the molding stations respectively have blow mold parts that are movable relative to each other, the parts are movable relative to each other for opening and closing blow molds; and including a clean room that surrounds a transport path, along which the molding stations are transported, and which is separated from an environment by at least one wall; wherein the apparatus includes a cooling system for cooling at least one element of the respective molding stations; and wherein the apparatus includes a supply unit that supplies a gaseous medium to the clean room. The apparatus also includes a drying unit for drying the gaseous medium supplied to the clean room via the supply unit.