How Olive Oil is Made

Olive oil is one of the world’s oldest food products, but when you’re drizzling it over your salad or cooking up a sizzling stir-fry, have you ever wondered how olive oil is made? It was called ‘liquid gold’ by ancient Greek poet Homer and ‘the great healer’ by Hippocrates and today, the finest olive oils are seriously expensive. Read on to discover the answer to the question ‘how do they make olive oil?’

Engineering How It’s Made
1 July 2022

It’s believed that the first wild olives originated in Asia Minor, or modern-day Turkey, around 10,000 years ago, though no-one knows with any degree of certainty when olive trees were first cultivated.

The fruits of the olive tree have been used for thousands of years for anointing, as fuel, as a lubricant for Roman chariots, as a commodity, as medicine, for making soap, skin and hair care products and of course, for cooking.

But how is olive oil made and more importantly, what is olive oil made from?

Olive Oil - A Short History

There are very few foods that have withstood the test of time quite like olive oil and the process of making it today has barely changed from that used by the ancient Greeks, Phoenicians and Libyans in the warm, dry climates of the Middle East and Mediterranean. In fact archaeological evidence suggests that olive oil was being produced around 8,000 years ago, and it’s still being made in huge quantities today.

The Different Types of Olive Oil

Bottles of different olive oil (Photo: Gary Yeowell via Getty Images)

Before we answer the question ‘what is olive oil made from’, it’s worth taking a minute to explain the different types of olive oil.

Olive Pomace Oil – Low quality oil extracted from the residue (known as pomace) after the olives have been pressed.

Refined Olive Oil – A higher quality oil than pomace, where the oil is treated, removing the antioxidants and anti-inflammatories. It has little to no colour, smell or flavour.

Virgin Olive Oil – An unrefined oil extracted by a cold-press method with an acidity content of between 1-4%. It has a natural aroma and flavour.

Extra-Virgin Olive Oil – The highest quality olive oil available. Again extracted by a cold-press method with a lower acid content than virgin oil (usually around 0.8%), it retains all the health benefits the oil is famed for and it has a wonderful taste, aroma and texture.

Over half the world’s olive oil comes from Spain, but there are also major producers all over the Mediterranean including Italy, Portugal, Greece and Turkey. So how is extra-virgin olive oil made?

How Olive Oil Is Made - The Tree

Olive trees in the sunshine (Photo: Westend61 via Getty Images)

Olives themselves are a type of fruit that grows on olive trees. The trees are native to the Mediterranean region and have been cultivated for thousands of years. There are many different types of olives, all of which have their own distinct flavour. Some of the most popular types of olives include Kalamata olives, green olives, and black olives. A litre of extra-virgin olive oil requires around 2,000 olives.

The first step in the process of making olive oil is simple, harvesting olives from the tree. The olives are literally shaken from the trees and end up in huge nets placed at the foot of the trunk. The olives are assessed, and any bad olives are picked out by hand.

Before the olives are pressed, they are taken to the processing plant and stored anywhere from a few hours to a few days. Not long enough for them to ferment, but just long enough so they are warm. It’s been said for thousands of years that warm olives release their oils more easily and the taste is richer.

How Olive Oil is Made - The Clean

Handful of Olives, freshly harvested (Photo: Enrique Díaz / 7cero via Getty Images)

This is where the answer to the question ‘how do they make olive oil’ starts to take shape. The olives are loaded into a vat of water and end up on a conveyor belt where they are thoroughly washed. Any detritus from the harvesting process – such as stalks, twigs and leaves – are separated. Next, the clean olives make their way to the crusher.

How Olive Oil is Made - The Crush

Machinery washing olives in oil mill (Photo: Nico De Pasquale Photography via Getty Images)

The olives are pitted, and then crushed into a thick paste. In ancient times the olives would be crushed with heavy stones or in a pestle and mortar, but today, the answer to the question ‘how is extra-virgin olive oil made’ is slightly more technical. The olive paste is now added to a tank with slow rotating blades in a process known as malaxation. The slow churn which takes between 20 and 40 minutes allows the liquid oil to be more easily separated from the solid. Next, it’s the pressing.

How Olive Oil is Made - The Press

Olive oil is on the list! Grocery shopping in a supermarket (Photo: d3sign via Getty Images)

The olive paste is spread evenly onto burlap or hemp mats and a hydraulic press slowly comes down onto it and squeezes the oil out drop by drop into vats, leaving the solid residue (which is then used for the less pure varieties of olive oil).

The pressed oil is then added to a sealed vat known as a centrifuge and is spun at up to 7,500 revolutions per minute. As they are of differing densities, the oil and residual water are now forced apart in the rotating drum, and filtered separately out of the machine.

The pure extra-virgin olive oil is tested for purity and bottled or canned on a production line. It’s then ready to be shipped out to shops and supermarkets around the world. This completes the core process of how olive oil is made.

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