The history of olive oil is as old as the history of civilisation. Clay tablet records tell of olive groves being planted and maintained in the ancient city-state of Elba, modern day Syria, some 4400 years ago. There is some evidence of use of olives dating back 6000 years and fossilised olive tree remains have been found that are many tens of thousands of years old.
Phoenician traders promoted the spread of olives and the culture of olive oil throughout the Mediterranean around 3600 years ago, reaching Egypt where the oil was prized by the Pharaohs. Importantly the culture of olive growing and oil making reached the island of Crete; home of the Minoan civilisation.
Olives probably reached mainland Greece around 3300 years ago and have been an essential part of life there ever since. Some 2400 years ago decrees were issued regulating the growing of olive trees in Greece, perhaps the first instance of a regulated market.
It is believed that olives were introduced to North Africa, Tripoli, Tunis and eventually to Italy around 2600 years ago. The Romans spread an olive culture through the northern side of the Mediterranean while the Moors did likewise along the southern shores, eventually reaching into Spain around 2200 years ago.
By AD1560 olives had reached Mexico and North America. The first olive trees to make it to Australia arrived in 1805 and were planted at Parramatta.
Extra Virgin – funny name?
The traditional technique for extracting oil from olives involves crushing olives under stone wheels, then spreading the resulting paste onto fibre mats and loading these mats into a press. As weight is applied to the mats, olive oil would seep out – the first pressed “virgin” oil. This “Virgin” oil was traditionally saved for guests and special occasions.
This system of classification worked fine for centuries until the advent of the modern, high tech continuous presses in the 1950s. These presses work by spinning the paste at high speed to separate the oil, water and solids. This style of press enables the production of a consistently higher quality oil in a continuous flow, rather than the slower batch processing of a mat press. Traditional mat presses are still used to extract the oil from the paste and many of the world's finest oils are produced this way.
To be classified as "virgin" oil must be extracted mechanically from the olives without use of chemical additives to assist the process. The process must take place at less than 30°C i.e. "cold processed" or "cold pressed".
The classification "Extra Virgin" was introduced to enable to distinguish the very best quality virgin oils. Extra Virgin Olive Oil (EVOO) must have a free fatty acid level of less than 0.8%, be free of defects and have a detectable level of fruitiness.
Why “Cold Pressed” olive oil?
The hotter the olive paste during the separation of oil and solids, the more oil will be extracted, up to a point. However, the hotter the paste the more of the volatile aromatic compounds will be lost. These aromatic compounds are what gives olive oil its distinctive flavour.
In order to produce excellent tasting oils the paste needs to be kept fairly cool during processing – to qualify as Extra Virgin a cut-off point of 30°C has been set by the International Olive Oil Council.
All Extra Virgin Olive Oil will be cold pressed, whether or not it says so on the label, although to be technically more correct it should state “cold extracted” or “cold processed” unless the traditional mat press has been used.
Should I cook with Extra Virgin Olive Oil?
Yes. Absolutely yes. The flavour of a robust olive oil will bring out the traditional flavours of a classic pasta sauce. Combined with other bold flavours such as onion, garlic and tomato the flavour of a good olive oil makes all the difference. Ask any Mediterranean chef, or his mother!
Other oils, described as mild are ideal for baking to replace the saturated fat of butter with the infinitely more healthy mono-unsaturated fat of olive oil. This style of oil is also ideal for aioli and vinaigrette or where a more delicate touch is required - with fish for example.
Because olive oil has a fairly low smoke point it is not suited for recipes requiring deep frying or high heats. In any event olive oil will lose its flavour if subject to too high a temperature.
Extra Virgin, Pure & Lite Olive Oils
Oils ain’t oils, to borrow well worn ad. The highest possible quality of olive oil, extracted mechanically without any heat of chemical means is categorised as Extra Virgin. But only around 7% of the world’s olive oil makes this exalted level. The vast majority of the world’s olives are not processed by this means and usually are not pressed within 48 hours of harvesting.
Extended delays to processing leads to spoiling of the fruit as a degree of decomposition of the olive flesh begins and the resulting oil will increasingly assume “off' flavours. This renders the oil more suited to a refining process to be purified. The resulting “Pure Olive Oil” is fine for frying but has little or no flavour. In many cases some extra virgin oil will be added to try and rectify deficiencies in flavour and colour, but this is still simply basic cooking oil.
If the resulting oil has no colour or flavour it can be called “Lite (or Light) Olive Oil”. It is no lower in calories than any other olive oil, just light in colour.
The Health Benefits of Olive Oil
Much has been said and written about the health benefits of olive oil and Mediterranean style diets. While it should not be assumed that olive oil is cure for everything there is ample evidence to suggest that it will help to reduce the risk of some cancers, heart disease and the onset of diabetes. That is not to say that more olive oil is better. It is also about achieving a balanced diet.
Extra virgin olive oil typically contains around 40 antioxidants which potentially helps lower the chances of atherosclerosis. Because the fats in olive oil are mono-unsaturated they are less prone to be retained by the body and therefore lower the opportunity for weight gain.
Many factors influence the style or flavour of any given olive oil, including:
- fruit variety There are more than 800 different varieties of fruit bearing olives, of which about 20 are grown locally in any numbers.
- climate and weather Traditionally, olives have grown in a Mediterranean-style climate i.e. with wet winters and spring and dry summers. However, with modern horticultural practices there are few places with a reasonably temperate climate where olives can't be grown successfully.
- soil It is said that olives prefer to struggle a bit in poor soils. To some extent this simply reflects the fact olive trees tended to be planted in the poorer parts of Mediterranean farms, leaving the better soils for annual crops. In fact olives trees do very well in good soils and respond well to love and attention as much as any other fruit tree
- irrigation While olives are hardy plants capable of withstanding long dry periods there is no doubt that irrigation helps production of fruit, in the absence of sufficient rain at the right times
- ltiming of the harvest Fruit can be harvested for oil processing from the time it is has reached a yellowy green colour until it is quite black. Fruit harvested early will have a more peppery flavour, while a later harvest produces a more mellow oil. Consumer tastes can vary greatly and it is increasingly common now to see oils promoted as “mild” or “robust”.
- blending Part of the skill of producing olive oil is to achieve the right balance between being too peppery and too mellow. Oil processed at different times and from different varieties is frequently blended to achieve a happy compromise. This in no ways detracts from the “extra virgin” label provided of course that the oils used are each “extra virgin”.
In many ways processing olive oil is just like processing wine. Great oils will have certain defining characteristics that remain true from year to year, but each year will also have some unique aspects reflecting the conditions of the season. That is part of what makes it so interesting!