Last week I visited olive oil mills with clients on three occasions. At one of the mills they had been making oil for about a week; the first olive oil is produced in the south of Spain in early November. A lot of the olives at this time are still green or just turning black. They produce less oil than ripe black olives, but the oli is of a very high quality. Below, is a photo of olives arriving at the mill and being introduced into a hopper
The second photo shows the oilves being taken along a convoyer belt. Before they reach the milling machine, leaves will be removed with a ventilator and the olives will be washed.
The next photo shows the oilves going into the milling machine.
The paste produced by the milling machine goes into a “batidora”, a machine that mixes the paste together while it is heated to around 24ºC, so that the oil can be extracted more easily. The mixing operation also causes the oil to form into larger droplets which also aids extraction.
The paste goes into a horizontally-axised centrifuge which separates the solid from the liquid part; the liquid part comprises water and oil. These are separated using a vertically-axised centrufuge. In the photo below, you can see the oil coming out.
We were able to taste olive oil that was just a day old. It was superb, with notes of freshly cut grass, tomato leaf and banana.