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.
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 also stand up to (medium to high) heat but you’ll lose delicate flavors. 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)
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