The seed is placed into the feeder either by labor or by conveyor. Then through the huge pressure or violent motion in the closed press, the original structure of oil seeds are broken and a series of changes happened inside. Finally the oil is expressed out of the the oil seeds.
Cold pressing is temperature controlled below 120°F (49°C) during the pressing process. It is used for oils with a more delicate flavor that could be negatively affected by the heat of regular hot pressing, such as virgin olive oil. Hot pressing generates heat in the range of 140 to 210 degree F, and this heat is not regulated. However, the oil output is higher as applying this method for oil pressing.