Oil Press

An oil press, also called an expeller or expeller press, is a mechanical screw device that extracts oil from seeds, nuts or algae in a single continuous pressing step, squeezing the material through a caged barrel so oil seeps out through small openings while the spent solids are expelled as a hardened press cake. Friction inside the press generates substantial heat, commonly 140 to 210 degrees Fahrenheit and up to 250 degrees if the material is preheated, which helps free the oil from the plant tissue. The name Expeller began as a trademark of the Anderson International Corporation, whose founder Valerius Anderson patented an interrupted screw design in 1900 that let material build up and compress more effectively than earlier continuous screw presses, and the term later became generic for this kind of mechanical oil press.