After harvest, the sacks and crates of olives are taken to the press. Here in Abruzzo there are many small press mills; I found one on the street just below our house where many of the olives from local groves are brought to be pressed. First they weigh the olives, then they are run through a shaker that separates the olives that are still attached to branches before they are dropped into the press to be ground by the millstones.
The millstones press out the oil and water from the fruit and that is allowed to drain into stacks of fiber mats, which, when saturated are taken to automated pressing machines that apply steady pressure to the stacks of mats to press out the liquid and filter out any solid pieces of fruit. The oil and water drips out into a trough along the floor to the centrifuge that makes the final separation of the water from the oil. This press is in our village of Casalanguida; I wandered down one morning and they invited me inside to see everything and had me sample the oil coming out of the the end.