Abstract: Growth medium filtration devices are provided which are particularly well adapted to sterilize gelatinous substance based growth mediums including agar, agarose and other polysaccharide derived growth mediums for use in agar plates and the like for culturing microorganisms. The devices may include one or more filtration units and at least one heat source for filtering the growth medium in a heated filtration process. Methods of filtering a growth medium, such as an agar growth medium, and methods of preparing a growth medium having low gelling point and lower molecular weight characteristics are also provided.