Olive oil is a liquid fat obtained from olives (the fruit of Olea europaea; family Oleaceae), a traditional tree crop of the Mediterranean Basin, produced by pressing whole olives and extracting the oil. It is commonly used in cooking, for frying foods or as a salad dressing. It is also used in cosmetics, pharmaceuticals, and soaps, and as a fuel for traditional oil lamps, and has additional uses in some religions. The olive is one of three core food plants in Mediterranean cuisine; the other two are wheat and grapes. Olive trees have been grown around the Mediterranean since the 8th millennium BC.
How is Olive Oil Made?
Scholars believe the oil was made by a process where olives were placed in woven mats and squeezed. The oil collected in vats. This process was known from the Bronze Age and has been used by the Egyptians and continued to be used through the Hellenistic period. Olive oil is produced by grinding olives and extracting the oil by mechanical or chemical means. Green olives usually produce more bitter oil, and overripe olives can produce oil with fermentation defects, so for good extra virgin olive oil care is taken to make sure the olives are perfectly ripened.
The process is generally as follows:
The olives are ground mechanically, until the olives resemble a paste.
The olive paste is then spread on fiber disks, which are stacked on top of each other and placed into a press. The press extracts the vegetal liquid from the paste, however this contains a lot of water, which will be removed in a centrifuge. The water and oil are seperated in the centrifuge.
Modern grinders reduce the olives to paste in seconds. After grinding, the paste is stirred slowly for another 20 to 30 minutes in a particular container (malaxation), where the microscopic oil drops aggregate into bigger drops, which facilitates the mechanical extraction. The paste is then pressed by centrifugation/ the water is thereafter separated from the oil in a second centrifugation as described before.
Sometimes the produced oil will be filtered to eliminate remaining solid particles that may reduce the shelf life of the product.
The olive oil will then be packaged.
A Video Showing the Production of Olive Oil
Olive Oil Termanology
The oil produced by only physical (mechanical) means as described above is called virgin oil. Extra virgin olive oil is virgin olive oil that satisfies specific high chemical and organoleptic criteria (low free acidity, no or very little organoleptic defects). A higher grade extra virgin olive oil is mostly dependent on favourable weather conditions.
Olive oil is a very common, very old, and very important commodity. It is often used in cooking, religious ceremonies, skin care, and many other things. It has been used throughout the ages, and is still used to this day. Olive oil has shaped the strongest Greek city states, as well as the Roman Empire, and every other great Mediterranean empire. Truly, olive oil is more important than gasoline.