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I see many chefs/people in food channels who use olive oil to fry stuff (like salmon). However, when I add olive oil for frying it quickly burns releasing dark smoke. Is there a specific type of olive oil that they use for frying that doesn't burn? or am I just possibly doing something wrong?

Aaronut
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Cemre
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  • Related: [Is cooking with olive oil bad or toxic?](http://cooking.stackexchange.com/q/6148) – Aaronut Aug 04 '12 at 14:25
  • Peanut/groundnut oil has high breakdown temperature. It's also more expensive than ordinary cooking oil but certainly cheaper than olive oil. – Cynthia Aug 14 '12 at 06:30

3 Answers3

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You're heating the oil past its smoke point.

There is no trick or technique that will prevent oil from smoking and oxidizing ("burning") at temperatures above the smoke point. It is literally being slowly destroyed at that temperature.

I honestly don't know why TV chefs are so attached to the idea of cooking with olive oil when most serious attempts to compare it to other oils (for frying purposes) strongly indicate that it loses all or almost all of its unique taste by the end. Some cite dubious health benefits, but the low smoke point of virgin/extra virgin olive oil may also make it worse for you health-wise due to exactly what you've witnessed - smoke and oxidation.

EVOO is great as a dressing but it's a terrible choice as a cooking oil. If you absolutely must imitate these confused TV chefs, you can either fry at very low temperatures (as in, just barely a sizzle), which will take considerably more time, or used a refined (not virgin) olive oil which has a much higher smoke point. These would typically be the "cheap" olive oils you find in large plastic or metal containers.

Aaronut
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  • I am currently making the transition from (non-virgin) olive oil to grapeseed oil, the latter being much more versatile, I find. – ElendilTheTall Aug 04 '12 at 15:07
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    Frying in "just barely a sizzle" is the wrong frying temperature for many things. It is not just that you need more time, starches can soak up the oil, getting greasy. But if you really want the taste of "fried in olive oil", you can fry the item in neutral oil, then lightly brush on it EVOO and return it to the pan for 3-4 seconds (so the oil will warm up without burning). – rumtscho Aug 04 '12 at 15:29
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    @rumtscho: Yes, it is the wrong temperature... just like EVOO is the wrong oil. It'll still *cook*, it's just that the end result won't be particularly desirable, hence "if you must". That's good advice about the brush though. – Aaronut Aug 04 '12 at 16:22
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    @ElendilTheTall: Indeed, every "serious" cookbook and chef (that I am aware of) tends to recommend frying with a neutral oil or clarified butter. Very little flavour is imparted during those few minutes, so there's very little point in using a flavoured oil; most of the flavour is either going to come from marinating/brining/rubbing/seasoning beforehand or saucing/brushing/seasoning afterward. Any olive oil is just going to limit your options vis-a-vis the before and after, because even a subtle hint of olive (which may taste like nothing on its own) can seriously clash with other flavours. – Aaronut Aug 04 '12 at 16:29
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    What makes olive oil "virgin" or "extra-virgin" is avoiding air contact in the pressing process - it is graded by the "acid value", and that increases if the oil oxidises. The oxidation which results from frying with it changes it into an inferior grade as it fries! Having said that, there is a "black" form of olive oil that can impart a unique and interesting taste when used for frying. I had a bottle from a factory in Northern Cyprus once, wish I had bought more. Never seen it in a shop. – klypos Aug 04 '12 at 19:20
  • @klypos: I'm pretty sure that's not correct. *Virgin* means *not deliberately altered* (i.e. chemically processed to remove strong flavours and raise the smoke point), confirmed by [several reliable sources like the IOOC](http://www.internationaloliveoil.org/web/aa-ingles/oliveWorld/aceite.html). I suppose, if it was left exposed to air long enough, it could eventually oxidize enough to no longer be "virgin", but that has nothing to do the labels on commercially-bottled oils - those are all about processing. – Aaronut Aug 04 '12 at 19:52
  • Bottled OO in unlikely to be EVOO, as light causes oxidation nearly as quickly as exposure to air. Only EVOO in a air tight tin or other light proof container should be considered EVOO. Unless you live next door to a Olive Press :-) IOOC describes virgin as it's acid value – TFD Aug 04 '12 at 23:40
  • @TFD: IOOC includes *maximum* acidity as part of the definition, it's completely possible for a lower-grade or refined oil to meet the acidity requirement. As for your other comments, you seem to be making the same mistake as klypos; normal oxidation over a few days of shelf storage, whether due to light or heat, is not going to have such a dramatic effect as to change the category from EV to V or worse. Please don't present such claims as facts without evidence. Refinement of olive oil is **not** oxidation - in fact, it makes the olive oil more resistant to oxidation. – Aaronut Aug 05 '12 at 00:28
  • @Aaronut Days of storage? How long do you think stuff sits around in warehouses for? Olives are only picked once per year. EVOO is chemically tested (acid < 0.8) and then tested by a panel of trained judges to have zero flavour faults. That's it! IOC is not a global standard. It probably isn't possible to make EVOO with chemical/heat extraction methods and pass those tests. Here is our local ONZ standard http://www.olivesnz.org.nz/wp-content/uploads/2010/10/Declaration_of_Compliance-2010.pdf – TFD Aug 05 '12 at 06:11
  • @TFD, no matter what kind of container the oil is in, it's going to be in a sealed, temperature-controlled box or carton at the warehouse, and probably in transit as well. The only storage you'd really need to be concerned about is the time it spends on the supermarket shelf. Even if it were several weeks instead of days, you're simply assigning far too much significance to the effects of light and/or heat. Heating at or near the smoke point causes *rapid* oxidation; leaving it on a shelf for a while doesn't suddenly turn EVOO into ROO. That's unscientific and frankly elitist. – Aaronut Aug 05 '12 at 15:05
  • @Aaronut you're getting off the point. As Klypos refers to, heating EVOO turns it into an inferior grade. I assume you agree that heating destroys the interesting flavour compounds in EVOO? EVOO is a chemical test AND just as importantly a trained judge test. That part is effectively elitist and potentially unscientific, but that is what EVOO is! – TFD Aug 05 '12 at 20:39
  • @Aaronut a few different tests here recently showed that while bottle/cans of EVOO where potential good at point of production, after purchase at modern supermarkets many where not really EVOO, one ref http://www.consumer.org.nz/reports/olive-oils/products-compared – TFD Aug 05 '12 at 20:44
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You want to use 'extra light' olive oil, not 'extra virgin'.

It's more refined, and has a significantly higher smoke point. It's closer to 240°C, while many other oils used for frying, such as peanut oil, smoke well below that temperature.

Don't just go for the cheap bottle of olive oil and assume that the price indicates that it's 'extra light' ... there are a number of companies that will blend olive oil with some other oil to reduce the price, but it doesn't necessarily increase the smoke point.

Joe
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Actually extra virgin olive oil has one of highest smoke points so it's perfect for frying. The only problem is that it's expensive. Probably you are using a refined olive oil or a cheap one that has a low smoke point ..try to use extra virgin and not to over heat the oil not only to avoid burning the oil but also to avoid undercooking the food. Regular vegetable oils degrade when heated beyond the smoke point and because of their low smoke point they start forming free fatty acids which are bad for health. Extra virgin olive oil is more stable with a high smoke point and will not loss it's beneficial properties by frying or heating that's why it's preferable oil for cooking and frying.

Some more information:

Olive oil is ideal for frying. In proper temperature conditions, without over-heating, it undergoes no substantial structural change and keeps its nutritional value better than other oils, not only because of the antioxidants but also due to its high levels of oleic acid. Its high smoking point (210ºC) is substantially higher than the ideal temperature for frying food (180ºC). Those fats with lower critical points, such as corn and butter, break down at this temperature and form toxic products.

Another advantage of using olive oil for frying is that it forms a crust on the surface of the food that impedes the penetration of oil and improves its flavour. Food fried in olive oil has a lower fat content than food fried in other oils, making olive oil more suitable for weight control. Olive oil, therefore, is the most suitable, the lightest and the tastiest medium for frying.

It goes further than other oils, and not only can it be re-used more often than others, it also increases in volume when reheated, so less is required for cooking and frying.

Community
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  • The downvotes are because you've got it backwards. Extra Virgin olive oil has a low smoke point. Refining oils (olive oil included) raises the smoke point. – Jolenealaska Jun 18 '14 at 10:22