August
2008
When it Comes to Fat, How Hot is Too Hot?
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Are you using the wrong oil?
A dizzying array of glass bottles. Some more fitting for salads, others ideal for heavier meat dishes, perhaps one perfect for a dessert dish you have in mind. Imports. Domestics. Beautiful labels here and there. Organic – or not. Good culinary oils, to the most discerning tastes, can be almost as nuanced, as complex as the wines that accompany the dishes they grace.
But to preserve, even enhance, the flavors and fragrances of oils, it’s crucial to know how to use them. For some (the more delicate) even moderate heating will ruin the oil, darken and scorch it, incite a cloud of putrid smoke and even a flash of flames in your unsuspecting pan. (No one saw that, right?) Others are more robust, even outright brawny and can weather the higher heats.
How do we, then, best complement, care for, even coddle our most delectable (and, yes, costly) bottled stores?
Well, good taste aside, we look at it this way: for health purposes especially, you don’t want all the good stuff to turn to the insidious, injurious, noxious dark side. We’re talking rancid, sour, stale rotten oil. That’ll make your stomach turn. And for good reason. Why is rancid oil bad (aside from the fact that you just want to hurl hearing the words in your head)? Oil, when it’s overheated, literally deteriorates chemically. The rate of the breakdown (and total formation of toxic compounds) is dependent on the type of oil and temperature. Initially, the oil’s decomposition results in the creation of hydroperoxids and then increasing levels of aldehydes. (Aldehydes are toxic compounds and recognized “markers of oxidative stress in cells” and are known contributors to “degenerative illnesses.” What does this mean for anyone who eats rancid oil? They just invited in a Trojan Horse of free radicals galore that are now beginning their violent pillaging of the person’s innards. A truly unfortunate situation, if you ask us.
So, how do I know what is best for each oil? I can still cook with oil, can’t I? Yes, you have a number of choices for various cooking activities, but don’t just pick any oil. Got your label-maker ready? It’s time to get color code happy!
First off, oils are, surprisingly, each a unique amalgam of different kinds of fat. See here, you’ve got your monounsaturated fats, your polyunsaturated fats and your saturated fats. Some oils contain more of one kind of fat than another, and it’s important to look at both the kinds of fats that make up the oil and the ratios of each. After this, we’ll raid the craft box and whip up some awesome pie charts.
But here are the basics. If an oil is mostly saturated, it’s pretty stable. If it’s mostly mono-saturated, it’s pretty stable. If it’s polyunsaturated, it’s anybody’s game. More seriously, oils that contain mostly polyunsaturated fats will generally be less stable, but there’s significant variation. We’ll get to the full picture in a minute.
A quick aside: the exception to all of this is refined oil. There’s a lot of disagreement about refined oils. Some say they’re fine. Others say they’re terrible for you because of the usual harsh chemical solvent refining process. Let’s just say that we believe in using the real, unadulterated forms whenever you possibly can. (Yet, we also acknowledge that there are refined oils out there that use safer, non-chemical methods. These offer some good alternatives for high heat cooking.) Look for expeller-pressed oil, which indicates that the oil was extracted through mechanical means rather than with heat. If you can’t use a particular oil with higher heat unless it’s refined, look for a more naturally suitable substitute or (as a second choice) a non-chemically processed refined oil.
In order to judge just how hearty an oil is, how well it can take the heat, we look at its “smoke point,” the point of heating (temperature) at which an oil begins to smoke. There’s some minor haggling about the exact temps, but the big picture of these estimates holds.
Some specifics? Coming right up! We’ll include a few of our favorites and some common choices here, but check out these websites for more examples:
Keep in mind that once you’ve heated an oil, the second time around its smoke point will be lower. While most of us probably don’t have large vats of frying fat sitting around, you might want to keep this in mind when reheating oil-laden leftovers.
Think of it this way: saturated fats (e.g. palm oil) are ideal players for cooking at higher temps. The heartier unsaturated fats like olive oil can be used for low-medium, brief cooking. Other “low” heat oils (e.g. nut oils) are best left out of cooking all together. They fulfill their life’s quest by offering rich flavor to finished dishes.
And there you have it. Those oils are a complicated lot, but the fragrances, the flavor and the scrumptious fats (we love our fats after all) make them worth the extra thought and effort. Now, time to choose the wine….
Thoughts? Questions? Suggestions or recipes for favorite oils? Thanks for reading!
monkeycat!, In Praise of Sardines Flickr Photos (CC)
Further Reading:
More Fat Posts:
Mark Sisson is Not Afraid of Fat
Smart Fuel: Walnut Oil and Olive Oil
Modern Forager: The Tropical Oils
Omega 3 Fatty Acids Round Up: Omega 3 to 6 Ratio, Omega 3 Daily Dose, Omega 3 Food Sources, Cooking Omegas
Great article very useful to know this and provides me with much satisfaction as I have been using Coconut oil (Sometimes butter) for my frying for a while now. I used to be keen on Olive Oil but could always tell something wasn’t right especially at high heats.
Glad to see you got over the disruption from the hacking!!
I didn’t see the smoke point of palm oil on that chart (did I miss it?).
Also, I’m confused as to why the smoke point of coconut oil is so low given the abundance of saturated fats (seems low to me). Finally, anyone cook with avocado oil? I’m specifically asking because I enjoy searing a steak on the stovetop and then cooking it in the oven at 500F, but that seems like a bad idea. Perhaps even with Avocado oil its still a bad idea to cook at that high a temp.
Justin -
The smoking point of palm oil seems to be around 450 degrees Fahrenheit.
So, are sense of taste and the lack of smoke a reliable indication that the cooking temp is not too high? I usually cook my eggs in olive oil over a low flame. I never see any smoke, and it tastes fine.
Hmm, something’s strange about that chart. Soybean oil and safflower oil are some of the most polyunsaturated oils, yet according to the chart, they have some of the highest smoke points. I wonder where those numbers came from.
I think it makes sense when you compare the temps given for unrefined versus refined versions of these oils. With any oil, refining will make it better able to hold up to high heat.
Great article!!
I had no idea that oil could be an invitation to illness. I just used what was cheap at the store…I guess I will be label checking and fact checking now. Nice usage of the word amalgam by the way.
Great post! Never knew the difference between virgin, extra virgin, and light olive oils. Thought it didn’t matter, but with over 100 degrees in smoke point between light and extra virgin, that will definitely inform my cooking.
I’d heard Safflower had one of the highest smoke points, which is what I use to sear my steaks, though I much prefer the taste of olive oil. Anyone know of a comparative price chart with all these different oil options?
Like Chris, we do all our cooking with coconut oil and would highly recommend this. Once you have tried it you never go back, as the smell and taste are great.
Its also worth reading up on, as you will you find out all kinds of positive things about its health benefits and the way it is metabolised differently.
Eating raw coconut flesh is also a great healthy snack if you can be bothered with the effort of cracking it open!
Great post. Like a lot of the commentors I too was not aware that cooking heat could have such an effect on the goodness of oil. I assumed that when it started to smoke and burn this was bad (as it is when you cook most things) but I didn’t know there was such a discrepancy between the different oils. I mainly use olive oil to fry my foods so I will definitely be taking more care in the future to keep my frying pan on a low to medium heat.
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I’m supprised that sunflower oil & the nut oils have a higher smoke point than coconut oil thats contrary to what i’ve always heard & even what Mark wrote in this very article ie cook with saturated oils, add nut oils (pufa) to salads, avoid n6 pufas like sunflower, soy as they damage easily & have little benefits anyway, i’m a bit confused by the data here.
Good post Mark, thanks. I wish to add that while coconut oil (hopefully virgin and not processed) has a low smoke point, from all the books I have read on this oil and its health properties the molecular structure is not changed/damaged at high temperatures thus does not become a trans fat as does other delicate/nonprocessed oils such as olive, etc. Also the shelf life is minimum of one year for virgin coconut oil. One more point, respected naturalists/nutritionists advise that Extra Virgin Olive Oil should never be heated period; it should be used after food is removed from the stove and tossed, rubbed, poured, etc. with the food. Lastly, I believe those who advise that foods (preferably whole foods) should never be minimally cooked and never beyond medium heat. I hope this information is helpful.
Sorry, made an error in my typing. The Lastly portion should state that foods should be (not never be) minimally cooked and never beyond medium heat.
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