How to make Olive oil

First take some olives.. some heavy granite wheels.. an oxen or two ......... I think you will find this article about Olive Oil interesting.

Just about everything that you read about olive oil is positive. It is a near-perfect fat that can, potentially, change your life. Because olive oil is a monounsaturated fat, it helps to cut your risk for heart attacks. Olive oil may also help your cholesterol levels and blood pressure. And there is some evidence that olive oil blocks certain cancers.

Which brings up a good question — where does olive oil come from? When you look at an olive, say on your pizza or in a salad, you don't really see any evidence of oil. There are two parts to any olive — the fleshy outer part that we normally eat, and a hard seed at the center that has normally been removed. Most seeds contain oil — corn oil comes from corn, soybean oil from soybeans and so on. So olive seeds contain oil. But the fleshy part of the olive contains oil too, although it tends to be imperceptible when you are eating an olive. Some of the really high end olive oils remove the seeds and use only the fleshy part of the olive for oil.

To make olive oil, you start by harvesting your olives. You walk out to the olive orchard and survey the crop. You want to pick the olives at optimal ripeness. They can be harvested by knocking them out of the trees with your hands (usually while standing on tall ladders) or by raking them out of the trees with long rakes. The olives fall to the ground and land on cloths or nets that have been placed there to catch them.

The olives are them washed, and as many leaves as possible are removed.

Now it is time to crush the olives. The traditional way to crush them is with large granite wheels. Think about the wheels on your car. You could smash olives under your car's tires, but the seeds would be unscathed. They are hard and dense like a peach pit. So the wheels that crush olives are 4 feet in diameter and, being made of stone, weigh a thousand pounds or more. The olives go in a big tub. Two granite wheels go on an axle and a motor spins the axle at a sedate pace (before there were motors, a donkey or an ox might have provided the power). The immense weigh of the wheels crushes the olives — seeds and all — into a paste.

This paste has to be gently stirred for about half an hour, preferably in an oxygen-free environment to avoid oxidation. This allows the oil to be released and to consolidate in larger drops. This step is known as malaxing.

And now it is time to extract the oil. One way to do the extraction is to squeeze the oil out of the paste with a press. The more modern way is to use a centrifuge. If you spin the paste up in a centrifuge, the seed solids are the heaviest and they get flung to the outside. Then the watery parts of the flesh are next. The oil, which is lightest, collects in the center and can be extracted. It might go through two or three centrifuge processes to make sure all the water has been eliminated, and the resulting oil is then bottled for sale.

When you go to the store to buy olive oil, you will find extra virgin olive oil, virgin olive oil and olive oil. Virgin and extra virgin oils are made using the steps described above. No heat or chemicals are used in the extraction process. The difference between virgin and extra virgin oils lies in the acidity of the oil. Extra virgin has less acid. Virgin oils can have a higher acidity, up to a certain limit. The other olive oils you see in the store have been reprocessed to remove acid and blended to improve the yield. These lesser oils might be OK in a deep fryer, but would probably not be used in a salad dressing or a sauce.