Oil mill

An oil mill is a grinding mill designed to crush or bruise oil-bearing seeds, such as linseed or peanuts, or other oil-rich vegetable material, such as olives or the fruit of the oil palm, which can then be pressed to extract vegetable oils, which may be used as foods or for cooking, as oleochemical feedstocks, as lubricants, or as biofuels.

The pomace or press cake – the remaining solid material from which the oil has been extracted – may also be used as a food or fertilizer.

Oil-rich vegetable materials have been processed mechanically to extract the valuable oils for thousands of years, typically using vertical millstones moving around a central post (edge runner stones or kollergangs in an edge mill) to crush or bruise the seeds or fruit which can then be stamped or pressed to extract the oil.

A treadmill, windmill or watermill was later used to drive the milling and pressing machinery, replaced in modern times with steam and later other power sources.

Historical wind-driven oil mills could process between 100 and 200 tons of raw materials per year.