A myth that just doesn't seem to go away. In fact it has become so engrained in the minds of many, that I have even heard top chefs repeating the fallacy that great Extra Virgin Olive Oil should be used cold and never to cook with.
The fact is, Yes, you can cook and really should cook with Extra Virgin Olive Oil. Here are a few reasons why.
A Fast Chemistry Lesson
For the most part, oils are created predominantly of fats called triglycerides. These are made up of three (hence the'tri') fatty acids attached to a chemical called glycerol.
In addition, oils also contain a small number of free fatty acids -- in other words, fatty acids that are not attached to glycerol and are 'floating' on their own. The level of free fatty acids varies between oils and varies with the quality of the oil. This is crucial!
The fatty acids in the oil, either as part of a triglyceride or free, can be saturated, monounsaturated or polyunsaturated. These names come from the chemical structure of the fats and the number of what are called'double bonds'. Saturated fats have no double bonds, monounsaturated fats have one, and polyunsaturated fats, as the name implies, have many.
Damage to oils can occur with exposure to light, to air and to heat, especially very high heat and prolonged heat. As a consequence, this is why you are best to keep any petroleum in a dark, chill pantry and also to use it up before the best before date to guarantee freshness. It is also why we need to take care with our selection of oils when cooking with them.
Understanding Smoke Points
The smoke point is defined as the temperature at which you will see a bluish smoke rising continuously from the oil. Extra Virgin Olive Oil is a natural product and contains a small amount of water. This means that if you heat it in the pan you'll often notice steam rising well before the oil reaches its smoke point -- don't confuse this and think you are damaging the oil) Heating the oil above its smoke point increases the chances of oxidative damage and the growth of potentially harmful compounds.
Since polyunsaturated fats have an assortment of double bonds, these fats are the most fragile and prone to damage. In contrast, saturated fats with no double bonds are extremely stable, while monounsaturated fats with only double bond are also highly resistant to oxidative damage.
Free fatty acids are also more vulnerable to oxidative damage and so oils with higher levels of free fatty acids are also more fragile, especially . The smoke point is generally given as the definitive guide as to whether a type of oil can be used for cooking. However, it's not the only essential factor and it varies, even amongst one kind of oil.
Extra Virgin Olive Oil
Observing just Olive Oils, you'll discover a variety of smoke points given, based on the source of the data. That's mainly because it is dependent upon the quality of the oil, how fresh it is, how it has been stored, the amount of free fatty acids and the levels of protective antioxidants.
Ultimately, Extra Virgin Olive Oil has three key qualities that make it an exceptional cooking oil:
It contains predominantly stable monounsaturated fatty acids
It has a low level of free fatty acids
And it has a high level of protective antioxidants
If we observe the smoke points of Extra Virgin Olive Oils, these usually range from about 190-220°C. The best quality oils, such as Cobrm Estate Extra Virgin Olive Oils, come in at the higher end of the range.
How does this compare to cooking? Well sautéing on the cooker equates to a temperature of around 120°C, deep-frying is usually in the range 160-180°C and roasting in the oven 180°C. It is not often you would cook at any temperature higher than this.
Importantly there is no further advantage to using an oil or fat with an even higher smoke point. In other words, if you are roasting your veggies in the oven at 180°C, your extra virgin olive oil is perfect as it has a smoke point above this. Selecting an oil with a smoke point higher than 220°C is not any safer.
We Should Cook With Extra Virgin Olive Oil
A handful of exceptional research have confirmed the stability of Extra Virgin Olive Oil during cooking. Essentially, these studies have really pushed the boat out to test the point at which various oils will break down. They repeatedly heat the oils, heat them for long stretches of time and take them up to temperatures.
These conditions would almost never happen in home cooking so the fact that extra virgin olive oil stands up consistently well in these tests really does confirm the safety of using the oil at home. The same is not true of oils high in polyunsaturated fats such as sunflower or generic 'vegetable' oil.
Plus we have studies showing that when we cook veggies in extra virgin olive oil, the overall amount of antioxidants and other beneficial compounds rises significantly. So we get a double whammy benefit of the fats present and a greater availability of protective compounds.
Extra virgin olive oil has an unqualified body of research supporting its function as a protective, beneficial food in a healthy diet. It is very versatile and can be used cold in dressings and for drizzling, as well as in almost all cooking applications. In this regard it is not just safe but also beneficial to our health, and of course delivering exceptional flavour!
So do as the Mediterranean nations have traditionally done for hundreds of years and enjoy cooking with your extra virgin olive oil.