What Einstein Told His Cook (11 page)

The smoke points of common vegetable oils, which come mostly from plant seeds, can range anywhere from 250ºF to more than 450ºF. But in spite of the ostensibly precise values listed in some books, exact smoke-point temperatures cannot be given because a particular type of oil can vary quite a bit, depending on its degree of refinement, the seed variety, and even the climate and weather during the plant’s growing season.

The approximate smoke-point ranges of some fresh cooking oils, plus lard. The exact smoke points depend on how the oil was refined and can be substantially lower in used oil.
Source, except lard: Institute of Shortening and Edible Oils.

Nevertheless, according to the Institute of Shortening and Edible Oils (there’s one for everything, isn’t there?), the approximate Fahrenheit smoke-point ranges of some common cooking oils are: safflower oil, 325–350º corn oil, 400–415º peanut oil, 420–430º cottonseed oil, 425–440º canola oil, 435–445º and sunflower and soybean oils, 440–450º. Olive oils may vary from 410º to 460º, depending on the type; extra-virgin oils are generally lower, while light olive oil is the highest because it has been filtered. Animal fats generally smoke at lower temperatures than vegetable oils, because saturated fatty acids break down more easily.

When heated to around 600ºF, most cooking oils will reach their flash points, the temperatures at which their vapors can be ignited by a flame. At even higher temperatures, around 700ºF, most oils will reach their fire points and burst into flame spontaneously.

With the exception of a few specialty oils, most oils are valued by American cooks for their blandness, for their lack of any intrusive flavor. Olive oil, on the other hand, is prized for its complex flavors, which can range from nutty to peppery and grassy to fruity, depending on the country and region from which it comes, the variety of olive, and its growing conditions. The cuisines of the Mediterranean owe their unique qualities largely to the almost exclusive use of olive oil, which is a flavor component of the recipes, not just a cooking medium. It is used in everything from baking to deep frying. And I’ve yet to hear a Spaniard or an Italian complain about a wisp of smoke in the kitchen.

Fortunately, the smoke points of several common cooking oils are higher than the most desirable range of temperatures for deep frying, which is 350–375º. If you’re not careful to control it, though, fat for deep frying can reach close to 400º, so there isn’t much leeway there. Except for the lowest-smoke-point cooking fat of all, unclarified butter, which begins to smoke at only 250–300º, smoke shouldn’t be a problem in sautéing unless you have a very heavy hand on the burner control.

It’s important to note that all of the smoke points quoted above are for fresh oils. When oils are either heated or oxidized, they break down into free fatty acids, which both lower the smoke point and taste acrid. Reused deep-frying oil, or any oil that has been exposed significantly to heat or air, will therefore smoke more readily and take on a disagreeable flavor. Moreover, hot oils tend to polymerize—their molecules join together into much bigger molecules that give the oil a thick, gummy consistency and a darker color. And finally, hot oils can break down into unhealthful chemicals such as those highly reactive molecular fragments called free radicals.

All things considered, then, the safest and best idea for both health and palate is to discard deep-frying oil after one or at most two uses—or immediately, if it has been allowed to smoke appreciably.

GET RID OF UNSIGHTLY FAT

After I fry foods, how do I throw the used fat away? It’s an environmental no-no, isn’t it?

Y
es. While edible fats and oils are ultimately biodegradable, they can gum up the works in a landfill for years. They’re not as bad as petroleum oils, however, which are digestible by only one or two species of bacteria and stay around essentially forever.

Small amounts of fat can be absorbed in a couple of paper towels and thrown in the trash. I pour slightly larger amounts into an empty food can that I keep in the freezer, where the oil freezes solid. When the can is full, I seal it in a plastic bag and put it into the trash, hoping that it won’t melt and leak out until it’s far, far away and untraceable back to me. That’s unconscionable, I know, but it’s vastly preferable to pouring it down the drain. Moreover, it makes a jolly flame when the garbage is incinerated.

Large amounts of used deep-frying fat are a bigger problem. Restaurants often subscribe to a disposal service that collects their gallons of used “grease” and sells it to soap and chemical companies. But what can you do with it at home, short of gift-wrapping it, leaving it in your unlocked car in a rough neighborhood, and hoping it gets stolen?

A hydrogeologist (he studies how liquids flow through soils) I consulted at the Department of Environmental Protection advises that unless your house is on a septic system, you can mix the oil with a liberal amount of dishwashing liquid, which has a prodigious appetite for grease, stir or shake it thoroughly to homogenize it, and then slowly feed the mixture to the garbage disposer along with lots of cold running water, to be scattered down the drain and ultimately dealt with by the local wastewater treatment plant. I’m not recommending that, however, so if you plug up your plumbing or shut down your local sewage plant, don’t blame me.

Even better would be to turn an environmental liability into a conservation asset: Use the oil as an alternative fuel for your diesel-powered Volkswagen, Mercedes, or pickup truck. After all, when Rudolf Diesel demonstrated his new engine at the World Exhibition in Paris in 1900, he ran it on peanut oil. But don’t try it until you read Joshua Tickell’s book,
From the Fryer to the Fuel Tank
(Greenteach Publications, 2000), which tells how to do it.

If you use this suggestion, I advise that you stop feeding fat to your car when it starts getting too big for the garage.

WHEN IS AN OIL NOT AN OIL?

How do those nonstick cooking sprays work? Their labels say the contents are nonfat and low calorie, but when I spray it on the pan it sure looks like oil to me. Is there such a thing as a nonfat oil? Or does it contain some kind of chemical substitute for oil?

N
o, there is no such thing as a nonfat edible oil. Fats are a family of specific chemical compounds, and an oil is just a liquid fat. Nor do the sprays have to contain a substitute for oil, because—are you ready?—they
are
oil.

Those handy little cans, so great for coating baking pans and muffin tins instead of greasing them, contain primarily a vegetable oil, usually with some lecithin and alcohol added. Lecithin is a fat-like substance (Techspeak: a phospholipid) found in egg yolks and soy beans, among other places, and helps to keep food from sticking. But the sprays are still almost entirely oil.

Their main virtue is that they put you more in control of your calories and fat usage. Instead of pouring a heavy-handed glug of oil into your skillet, you just give the pan a quick spritz from the can. The alcohol evaporates and the oil and lecithin remain behind, coating the pan. You’ll still be cooking on a layer of oil, but it’s a very thin and therefore low-calorie one.

In the manufacturers’ effort to earn that highly profitable “nonfat” claim, the cooking spray labels can engage in some pretty bizarre arithmetic. The label on a can of Pam, for example, boasts that it contains “only two calories per serving.” But what is a “serving”? The label defines it as a one-third-of-a-second spray which, the label advises, is just long enough to cover one-third of a 10-inch skillet. (Just right, we must presume, for making one-third of an omelet.) In the race to claim even fewer calories, the label of one oil spray advises that a “serving” is a spritz that lasts for only one-quarter of a second.

If you don’t have the finely calibrated trigger finger of Billy the Kid, or even if you throw caution to the winds and defiantly spray your pan for an entire second, you’ll still be getting by with fewer than six calories. But even so, a little bit of fat isn’t
no
fat. So how small must an amount of fat be before a label can legally call it “none?”

According to the FDA, any product that contains less than 0.5 gram of fat per serving may be labeled as containing “zero grams of fat.” A one-third-of-a-second “serving” of cooking spray contains around 0.2 gram of fat; hence, it is legally “nonfat.” If they had defined a serving as a whole second’s worth of spritz, they’d be over the 0.5-gram limit and couldn’t call it nonfat. Cute dodge, eh?

By the way, if you’re a belt-and-suspenders type, spritz a little nonstick spray onto your nonstick frying pan. The food will brown better than it would without the fat. Excuse me—I mean without the nonfat.

A pouring spout for olive oil.