Extra virgin olive oil is defined as oil that have been produced by mechanical extraction only and not by chemical extraction. First step in oil production is crushing the olives into a uniform mixture. It could be done using a stone crushing the olives, or using a steel shredder with knives or hammers.

There are several methods to separate the oil from the mixture. The taditional one is pressing the mixture. The mixture is put in baskets made of fabric, and then the baskets are arranged in a pile and are pressed with a screw or a piston. The oil drips and gathered in the bottom of the pile.