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The Science of Nonstick Cookware

Here’s what you need to know about how it works, how to use it, and how to care for it.
 

by David Joachim, Andrew Schloss

fromFine Cooking
Issue 117

The advent of nonstick cookware was somewhat of an accident. In 1938, research chemist Roy Plunkett was experimenting with alternatives to the refrigerant Freon for the DuPont chemical company. One of his experiments involved freezing and compressing tetrafluoroethylene, a colorless, odorless gas; the gas transformed into a white, waxy solid. Dubbed polytetrafluoroethylene, or PTFE, this unique solid had an extremely low coefficient of friction (translation: it’s super slippery). DuPont trademarked PTFE as Teflon, and 20 years later it became the primary component of nonstick cookware. PTFE as well as more recently developed nonstick surfaces are now found on everything from skillets to waffle irons, and nonstick cookware accounts for the vast majority of cookware sales in the United States.

How does nonstick cookware work?

If you could magnify a metal pan, you would see that its surface is ragged and covered with thousands of microscopic nooks and crannies. When heated, the metal expands and these pores enlarge, allowing food to seep in, solidify, and stick. To minimize that sticking tendency, you can coat a metal pan with oil, which fills the metal’s fissures so that food can’t enter (that’s what you do when you season a cast-iron skillet), or you can use a pan that has been industrially coated with a nonstick material like PTFE, which fills the pores of the pan, making its surface smooth and virtually nonstick.

What are the best foods to cook in nonstick pans?

Foods that benefit from lower heat and that tend to stick, like fish and eggs, are good choices for nonstick pans; foods that need to be deeply browned don’t do as well. Heat energy moves through solid objects, like pots and pans, by making electrons in the pan jump from one atom to the next. Metal pans excel at conducting heat to food because the electrons in metals are more active and move quickly and easily through the metal. But the molecules in nonstick coatings hold their electrons tightly, so these materials don’t conduct heat as efficiently. As a result, coating a metal pan with a nonstick surface diminishes the pan’s ability to conduct heat. Although it’s possible to brown food in a nonstick pan, the level of browning isn’t as dramatic, and you don’t get enough of the brown bits that are essential to creating a rich pan sauce. Plus, the intense heat needed for thorough browning is not advisable in nonstick pans, since they degrade at high temperatures. (Keep reading for more about this.)

Are there any concerns about cooking with nonstick?

PTFE (found in Teflon, T-Fal, Calphalon, Swiss Diamond, Scanpan, Anolon, and many other brands) has some downsides. A plastic coating made up of molecules called fluoropolymers, PTFE starts to degrade above 500°F, releasing fluorocarbons and other fumes into the air. These fumes don’t permanently damage our health, but they can cause temporary flu-like symptoms in humans and could be fatal to birds, which have sensitive respiratory systems. For these reasons, it’s best to avoid heating nonstick pans above medium to medium-high heat on the stovetop, and to keep pet birds away from the kitchen.

Another concern for cooks is that, with improper use, the PTFE coating on nonstick pans starts to blister, flake, and fall off. Particles of PTFE nonstick coating are inert and pose no health threat if ingested, according to the Food and Drug Administration, but when a pan begins to lose its nonstick coating, it becomes less effective as nonstick cookware.

There have also been some environmental concerns with the manufacture of PTFE-coated pans. The synthetic compound perfluorooctanoic acid (PFOA or C-8) is used to smooth out PTFE in the manufacturing process. PFOA doesn’t end up in the pan itself, but it does persist in the environment and is carcinogenic to humans. As a result, most major chemical companies, at the urging of the Environmental Protection Agency, have committed to eliminating the use of PFOA in the manufacture of nonstick cookware and other products by 2015.

What about “green” nonstick?

The drawbacks of PTFE have led to the development of newer nonstick coatings based on ceramic and silicone, which are touted as eco-friendly because they’re entirely PTFE-free and therefore don’t release fumes at high temperatures or require the use of PFOA in their manufacture.

Ceramic nonstick coatings (found in Thermolon, GreenPan, EarthPan, Green Earth, Orgreenic, Cuisinart GreenGourmet, and many other brands) consist of ceramic powder baked onto the pan. The downside to ceramic is that, like PTFE, it begins to degrade when repeatedly subjected to sudden heating and cooling, and there is little evidence that it performs better or lasts longer than PTFE. Also like PTFE, ceramic is not a great heat conductor. The other “green” alternative is silicone-coated nonstick pans. But silicone doesn’t stand up well to direct heat, so it works better as a nonstick coating on bakeware than on stovetop pots and pans.

To spot the difference between nonstick surfaces, look at the finish of the pan. PTFE nonstick pans have a matte surface, while those with ceramic or silicone appear shiny.

Caring for Nonstick Cookware

As with other cookware, pan quality is mostly indicated by weight—the heavier, the better. But don’t blow your budget on nonstick pans, since all nonstick coatings eventually wear out. Here’s how to extend the useful life of your nonstick cookware.

• Before the first use, gently hand wash the pan to remove any dust and debris.
• Refrain from using cooking sprays containing lecithin, which may leave a gummy residue on the pan. Lubricate the pan with a light coating of oil instead.
• Don’t heat the pan above 500°F (medium to medium-high heat, depending on your stove). Avoid drastic or sudden changes in temperature, which will weaken the nonstick material. This includes running a hot pan under cold water to cool it down.
• Don’t heat empty nonstick pans.
• To prevent scratching, use plastic, rubber, silicone, or wooden utensils, and avoid anything sharp.
• Gently hand wash nonstick cookware instead of using the dishwasher. Avoid abrasive cleaners, steel wool, and steel scouring pads. To remove stubborn debris, put enough water in the pan to come halfway up the sides, boil the water for 5 minutes, and then wash. Or soak the pan in a solution of 1 cup water to 1 Tbs. dishwashing liquid.
• Hang pans side by side instead of stacking them, which can scratch the nonstick surface.
• Replace nonstick cookware when food sticks to it or when the pan shows signs of excessive scratching, blistering, peeling, flaking, or chipping.

Photo of Cuisinart's Green Gourmet Nonstick Skillet (Fine Cooking's top pick in nonstick skillets) by Scott Phillips

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