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So many recipes list olive oil in the ingredients, as the oil to fry things in. What are the benefits or reasons that I should use olive oil over regular generic "cooking oil" and should I always use olive oil over other oils?

victoriah
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  • This question includes an answer for you: http://cooking.stackexchange.com/questions/701/what-oil-or-fat-to-use-for-different-purposes – michael Jun 05 '11 at 16:56

4 Answers4

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According to Harold McGee, using olive oil to fry is basically a waste of money. "After I’d heated them, none of the olive oils had much olive flavor left. In fact, they didn’t taste much different from the seed oils."

According to a Spanish study I have access to, you could use high oleic sunflower oil for frying as it degrades better.

BaffledCook
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    I agree with him, there really is not much point in frying with olive oil. The flavour gets whittled down to nothing by the end, and the low smoke point makes the supposed health benefits a pretty tough sell. – Aaronut Jun 05 '11 at 22:52
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    I agree as well UNLESS we're talking about refined olive oil labelled as "pure olive oil" and not extra virgin. That has a much higher smoke point, and presumably the health benefits of monounsaturated fats would carry through to products fried in it. But generally using olive oil as a frying oil is just another piece of nonsense people latch onto for "health reasons." – BobMcGee Jun 06 '11 at 07:09
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    Compared to refined olive oil, Canola (rapeseed) oil is far cheaper and a fat profile at least as good. – derobert Jun 06 '11 at 20:10
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Olive oil is preferred for the flavor it imparts, and by many because it is healthier than other oils. As far as frying goes, it is actually not that great since it has a relatively low smoke point, meaning it will start smoking on you at a lower temperature.

Eric
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    Additional information: the smoke point of extra virgin olive oil is around 320F/160C, Virgin Olive oil is 420F/216C (hot enough for almost all uses), and extra light olive oil is 468F/242C. "Pure" (refined, not extra virgin) olive oil should smoke from 420-450F. – BobMcGee Jun 05 '11 at 17:42
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First at all I apologize for my English.

Basically remarks made before are not really true. Smoke point took alone does not mean anything. There are other consideration that must be done to analize oil transformation.

  • What is friying?

Let's go in order considering two aspects: oxidation parameters and healthy parameters:

Frying is an accelerated process of oxidizing (air oxigene attacks lipidic substratum).
The transformation is more accelerated as higher is the oil unsaturation (presence of double connection that is a point of weakness).

So the stability of fatty acids is related to double connections in its structure and decreases in the order of those categories:

-saturated: 0 unsaturation
-monounsaturated: 1 unsaturation
-poliunsaturated: 2-3 unsaturations

So it means 0 unsaturation are definitely more stable oils during frying.
But there's an healthy parameters to be considered: saturated fatty acid are hamful for cardiovascular illnesses.

satured: lard, palm;
monounsaturated: olive, sunflower (high oleic acid);
poliunsaturated: maize, soy, sunflower (high linoleic acid);

So until now the better choice are monosaturated oils!

  • The thorny subject of smoke point:

Often associated to formation of acrolein, is closely related to the physic state of oil and not to its fatty acid composition.

The presence of humidity and acidity (free fatty acid), decreases the smoke point.
So for the same acidic composition smoke point descrease for oil with more acidity.

  • So which is the better oil to fry?

Although smoke point is lowest you have to consider the oxidation stability as well.
Even if you can see an oil smoking it does not always mean that the oil decomposes.

That's because they wrongly talk about smoke point as the central point instead of a more complex process called pyrolysis that is:

Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures in the absence of oxidizing agent (normally oxigen).

So here we came!
Even if extra virgen oil has a less smoke point is the more oxidation stable oil thanks to its liposoluble antioxidant (Vitamin E) and idro-soluble (biofenoli).

I hope to have explained in better way why the smoke point is not the right (or better the only one) property of oil that has to be considered.

  • About the taste:

Of course the extra virgen oil has a strong taste and it's used for food without own taste as said potatoes, fries.
To not alter some taste food (fish) can be used for example peanut oil that does not have a strong taste (for its good combination of oxidation parameters and smoke point).

Other staffs should be considered.

  • Not use the same oil to fry? it's true, but there is something called polar compound formed during frying that is the health indication of frying oil.
    That means that should not exceed a limit value (defined by healty department; some place the value is 25g/100g, but that means pretty more than 8 home frying; it is to control restaurant industry).
  • heat the oil before but not cross 180ºC / 356ºF
  • do not bathe cold food even if the box says yes
  • try to keep the temperature constant
  • do not salt/sweeten during frying but after it
  • fry little portion of food to shorten the fry time

I hope I've been helpful!

Kind regards!

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  • Editing to answer to comments:

@Aaronut I completaly agree with you. I always advice to not believe surfer doctor improvisation. This is just a place for opinions!
I agree that you need reliable source! I'm gonna give you some!
But first of all I want to say. Don't trust on everything because market business let say many deceitful things! Market business is misleading! It's able to corrupt everything.

I'm just pretty surprise of your doubt: "saturated fatty acid are hamful for cardiovascular illnesses"
Satured fatty acid are responsible for cholesterol. Cholesterol is responsible of coronary disease.
Do you agree with me about it?
Anyway if you think this is my opinion...
here you some reliable sources! (All are Government Institutes! No privates or indipendents!)


I'm sorry but I don't have time to find more!
By the way I want to show all theory :) There is an opposite one.
But in my opinion a single researcher can be corrupted very easy. He's Ronald Krauss and I don't really have time to find his study.

@rumtscho I definitely prefear Extra Virgen Olive oil. For some frying (very few) I use Peanut oil to not alter some food taste.
I will answer to other comments as soon as I can.


Kind regards to everyone!

Community
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soneangel
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    I find your information on the difference between smoke point and pyrolysis very interesting. Still, I have two issues with this answer. 1) I don't clearly understand if you are for or against frying with olive oil (I think you support it, but it isn't entirely clear) 2) The other answers mentioned not only smoke point, but the obvious loss of taste when non-refined olive oil is heated at frying temperatures. Even if the fatty acids don't pyrolise, the aromatic compounds probably do. So why use the expensive EVOO for frying when the cheap sunflower oil (monounsaturated, has Vit E) will do? – rumtscho Jun 06 '11 at 16:14
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    I very much appreciate a lot of the technical details here, but I have a problem with this statement: *"saturated fatty acid are hamful for cardiovascular illnesses"* - can you back this up with some reliable source? I know that this is true for *trans fats* but I do not believe this statement to be the scientific consensus for saturated fats. – Aaronut Jun 06 '11 at 16:23
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    Also, my understanding is that oil smoking does in fact indicate oxidation, and that the antioxidants in olive oil (or any oil) are a *component* of the smoke point. Now that could very well be wrong, but as above, I'd really like to hear that from a reliable source. – Aaronut Jun 06 '11 at 16:28
  • @Aaronut WHO, and most western government health organisation recommend low saturated fat diets to avoid CVD, diabetes and other complications. In some cultures/countries the evidence is outstanding (e.g. Pacific peoples). You can't quote USDA food safety and then ignore their CVD warnings – TFD Jun 07 '11 at 01:57
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    @TFD: First of all, yes I can; food safety and general health are two very different subjects as we've made plainly clear in the past. More importantly, vague allusions are not citations; I'd like to know specifically where this was stated and in what context. I've seen certain limited evidence to suggest that *increasing* the intake of *monounsaturated* fatty acids (relative to other kinds) can *reduce* the risk of heart disease, but that's a very far cry from cutting out saturated fat entirely and/or claiming that it causes heart disease. – Aaronut Jun 07 '11 at 02:06
  • As I understand it Pyrolysis of olive oil is around 500°C (930°F) and oxidation of olive oil it over 180°C (350°F). Oxidation happens very slowly as only the oxygen exposed surface reacts, and this forms a "plastic" film which prevents further oxidation. Vegetable oils tend to catch fire long before any large amount of oxidation has occured – TFD Jun 07 '11 at 02:08
  • @Aaronut there are years of studies published, and many show direct correlation (google search, wikipedia etc). Sure some don't but that happens with every research process. You have to average them out. The insignificant results could be due to saturated fats being replaced with other stuff that is just as bad. This issue is currently being researched – TFD Jun 07 '11 at 02:12
  • @Aaronut other than that just visit a pacific island where mammal based saturated fats have been introduced in the last few hundred years and see what happened (sugar and wheat came much later) – TFD Jun 07 '11 at 02:14
  • @Aaronut also with pacific peoples high saturated fat diets are strongly linked to diabetes even though they may not yet have progressed to CVD and/or obesity. Our local studies are quite clear on this. Local doctors even get pay bonuses for encouraging this diet change – TFD Jun 07 '11 at 02:21
  • @Aaronut some background to above http://www.phac.health.govt.nz/moh.nsf/pagesmh/5505/$File/DiabetesPreventionALindsay.pdf – TFD Jun 07 '11 at 02:28
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    @TFD: I still don't see a single credible reference. I repeat, a vague allusion is not a citation. This is exactly why we generally disallow discussion of health topics here; aside from it being an immature field even among scientists, laypeople seem to form very strong beliefs based on flimsy and often anecdotal evidence. Maybe you're right, maybe you're not, but I would appreciate it if you and everyone else could refrain from making unsubstantiated claims about subjects that are only tangentially on topic. – Aaronut Jun 07 '11 at 02:30
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    @TFD: OK, from your link: *"The three recognised modifiable risk factors for diabetes are obesity, diets high in saturated fats, sugars and low fibre, and physical inactivity".* This is credible - people who do all of those things are at a higher risk of diabetes. However, diabetes is not heart disease and the diabetes risk is only applicable to an already-at-risk group (most people are not genetically predisposed to diabetes). – Aaronut Jun 07 '11 at 02:32
  • @Aaronut The risk factors are part of most westerners normal lives. How many geek use a stand up desk even? Diabetes is now considered an indicator to CVD etc. Diabetes risk is not always a genetic thing – TFD Jun 07 '11 at 03:13
  • I've edited to answer to your comments because it exceeded character limit. KR – soneangel Jun 07 '11 at 11:01
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    Here's a study (found via wikipedia). http://www.plosmedicine.org/article/info%3Adoi%2F10.1371%2Fjournal.pmed.1000252 In the US, the saturated fat -> CVD link seems to have been born in the 70s out of a series of political events. It was enshrined as national policy and continues to drive federal health guidelines. The tide is turning against it only slowly as more studies seem to counter this notion – Ray Jun 07 '11 at 11:09
  • @Aaronut, current research seems to lean towards: polyunsaturated fat instead of saturated fat is good for the heart; overall reduction of saturated fat is controversial. See following metastudies: http://www.ncbi.nlm.nih.gov/pubmed/20711693, http://www.ncbi.nlm.nih.gov/pubmed/18937892, as well as Ray's link. I didn't find data specifically about monounsaturated fat. Of course, such studies are not immune to biases, but that seems to be the best data currently available. – rumtscho Jun 07 '11 at 11:41
  • @Ray, I don't understand your comment. First, you say that the policy against saturated fat had political reasons, but don't give a source for this. Second, you link something which I assume you count as "[countering] this notion", but the study's conclusion is "These findings provide evidence that consuming PUFA in place of SFA reduces CHD events in RCTs" (PUFA=Polyunsaturated fatty acids, SFA=Saturated fatty acids, CHD=Coronary heart disease, RCT=Randomized controlled trial), which means that replacing sat. fat leads to fewer CVD. – rumtscho Jun 07 '11 at 11:43
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    @rumtscho--yes, I ought to have made that more clear. Aaronut was looking for a source for saturated fat linked to CVD, so I was providing that. I don't have a source for the political background; I wasn't trying to post an answer with that info, just wanted to provide some perspective as someone who has grown up in a country where we are indoctrinated about this from childhood, and hear it in schools, see it on food packaging, read it from CDC, FDA, AHA, etc. It's so ingrained in American minds, anyone questioning it is treated as someone wanting people to die from heart attacks. – Ray Jun 07 '11 at 11:51
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    @rumtscho: Thanks for the correction, you are right; as confirmed by Ray's link, it is poly and not mono substitution that was tested. Unfortunately, poly is also the most prone to pyrolysis, so cooking with too much of it could lead to other problems associated with rancidity/free radicals. Unfortunately, a lot of these nuances seem to get lost in translation when studies are reported in news and repeated by laypeople; "substituting a certain amount of poly for sat reduces CVD risk" is *not at all* the same thing as "saturated fat causes CVD". It's a dangerous oversimplification. – Aaronut Jun 07 '11 at 14:52
  • sone: The first link seems pretty sensationalist to me; the last one looks promising although unfortunately I can't read Italian. I do appreciate you taking the time just to find those links, but I don't suppose you could try to translate one or more relevant parts from one of the more... *formal* sources you listed? – Aaronut Jun 07 '11 at 15:22
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    Unfortunately/fortunately I don't get english or american humor ;) *"one of the more... formal sources" *. Anyway I thought the effort that foreign people do contributing in international forum writing and thinking in english is something should be appreciate!! You wanted some reliable sources and I gave to you! Those are all Italian governament institution and a law as well. It would be too much for me to facilitate in english. Your effort could be copying into a google translator and try to get the sense. By the way I will translate for you when I'll have time because I'm quite serious. KR – soneangel Jun 07 '11 at 16:05
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    1. @soneangel I for one appreciate the effort you are putting in your contribution. English is my third language, and I know how hard it is to produce good arguments in a foreign language. The problem is, you can't convince anybody if they don't understand the arguments you make. If you don't find the time to translate, I will vouch for you: the sources you linked indeed state that the eating of saturated fat causes elevated cholesterol levels, which are linked to heart disease. But I don't think that @Aaronut doubted that a similar statement is contained there; more likely he wanted to judge – rumtscho Jun 07 '11 at 16:28
  • 2. their credibility, for which the whole text is needed. I for one don't accept these documents as convincing. I agree with @Aaronut on the first. The second and third documents are indeed government policy. Sadly, governments are not always correct - not in Italy and not elsewhere. This is why a scientific, and not legal source is better. The fourth source is from the "background" chapter of a PhD thesis in nutritional science. It says "many studies have shown that" without citing a single study. I wouldn't accept work in this quality from my bachelor students, let alone in a PhD. – rumtscho Jun 07 '11 at 16:38
  • 3. This does not mean that we think that your statements are wrong. We don't know if they are, that's why we ask for sources. Sadly, the sources are not good enough to convince me personally that they are right. So at the moment, I am not sure if olive oil is indeed better for the heart than butter or not. You can trust a government or any other source, and anybody who agrees with you is likely to upvote your answer. I think Aaronut's first comment was intended to show that there isn't universal agreement, rather than start a long discussion on a topic even top scientists don't agree on. – rumtscho Jun 07 '11 at 16:45
  • I really appreciate everyone remaining civil throughout this discussion. However, comments are not really built for such lengthy discussions. Please feel free to continue this in [chat] though! – hobodave Jun 07 '11 at 18:31
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I think the best thing to do is use olive oil for cases when you are drizzling it on or cooking for a short time. Otherwise, use vegetable/canola/etc.

Naomi Campbell
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