pots_and_pans2009.pdf

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THE CURIOUS COOKWhats Hot, Whats Not, in Pots and Pans

October 8, 2008By Harold McGee

I hadnt recharged my batterie de cuisine with a new pot or pan for a couple of years, so when I

went on a recent reconnaissance mission through Zabars, I was startled by all the choices. Every

manufacturer seems to offer a different metallic mille-feuille, with layer upon layer of heat-

conducting alloys and food-friendly surface coatings. There are a variety of nonstick coatings:

supposedly more durable versions of Teflon, more environmentally friendly versions of Teflon,

green alternatives to Teflon. Even good old cast iron has had a makeover. It now comes

conveniently preseasoned.

Pots and pans have a straightforward job: to deliver heat from the burner or oven to the food, and

release the food to us neatly and cleanly when we want it.

Are the differences in how pans heat and release really significant? Would I improve the odds of

getting my favorite potato galette to slip intact from the pan if I used something other than my

usual stainless-coated aluminum?

To find out, I experimented for a few days with a dozen or so different pans, some old and some

new. I learned that metals and surfaces do matter, but so do fat and heat management.

I focused on five medium saut pans. One was made of seasoned cast iron, one of heavy copper

top-coated with stainless steel, one of aluminum sandwiched between two layers of stainless.

Two were aluminum top-coated with new non-Teflon coatings: a ceramic material called

Thermolon, and a silicone-based material called NP2. Like most Teflon pans, the NP2 pans come

with instructions to use low heat, but Thermolon is said to perform well up to 870 degrees. Thats

charring, pizza-oven heat.

The prices ranged from $25 for the new aluminum nonsticks to as much as $480 for French

copper.

First I wanted to see what difference the kind of metal makes in how the pans heat up. Copper

conducts heat twice as fast as aluminum, and five times faster than cast iron. But the copper and

iron pans each weigh more than five pounds, while the thinnest aluminum pan weighs barely two.

Is lots of expensive copper better than a little cheap aluminum?

I started by timing how long it took the pans to bring a cup of water to a boil over the maximumgas flame on my stovetop. The copper and the cast iron each took 3 minutes, the aluminum-

stainless combination 2.5, and the thin nonstick aluminum just 2 minutes. Light and cheap win for

speed.

Then I put the heat-tolerant all-metal pans and the Thermolon on a high flame until their

temperatures reached around 600 degrees, measured with a hand-held, point-and-shoot

thermometer. I dropped a cold steak on the surface, then checked the pan temperature under the


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steak after a few smoking minutes. All of them stayed up around 575 degrees, replacing the heat

lost to the steak and browning it deeply. Light and cheap held its own with the heavyweights.

But would these pans evenly distribute the heat? In a good conductor, heat will flow quickly

throughout the pan; with a poor conductor, the heat should build up into a hot spot in the metal

just above the burner. To make the pans heat landscapes visible, I put a round of parchment

paper into each pan, weighed it down with pie weights and put the pan on a medium-high burner.

When I saw or smelled the paper browning, I removed the parchment.

The heavy copper and the light aluminum pans produced evenly toasted heat maps. The

stainless-clad aluminum did pretty well, too. But the cast-iron pan scorched a small area, and the

pattern was familiar. For years I made risotto every week or two in my favorite enameled cast-iron

pot, and always found a solid brown ring of stuck rice grains right above the flame.

Still, I was surprised, because Id always heard and thought that cast iron was a slow but even

conductor. I wondered if it would perform better if I heated it more gradually over a low flame, or

on an electric heating coil, which would contact more of the pan bottom than the gas flame. I was

wrong. The low flame caused even browning over a small area at the center of the pan, and noneelsewhere. The electric burner gave a pattern much like the flames.

When I spot-checked the cast iron with my thermometer, there was a consistent 100-degree

difference between the pan center and an inch from the edge. Thats easily enough to make the

difference between browning and scorching. My cast-iron pan makes a much better potato galette

in even oven heat.

Sticking isnt a problem when youve browned the food and want to harvest the stuck-on flavorful

brown bits by deglazing with some wine or water. In fact, its good. It is a problem, though, if

youre frying an egg or fragile piece of fish. Its especially likely if youve used the least oil

possible and put the flame on high to heat up quickly. Oil plus high heat plus maximum exposureto air quickly produce oxidized, gummy residues that stick to the pan surface and to the food.

To see which pans are more likely to stick, I fried dozens of eggs, pounds of flaky white fish, and

a dozen or so potato galettes, which are disasters if the spiral of potato slices doesnt release

when you flip the pan over.

The nonstick pans released with a minimal wipe of oil, a hardened Teflon type most reliably. The

Thermolon needed more lubrication after its steak-searing ordeal than it did before, but its surface

didnt mar as easily as the Teflon and NP2, which had tiny nicks and scrapes after just a few

uses. All the other pans, metal-surface or enamel, behaved much like each other. They released

foods reliably if theyd been greased with nonstick sprays or with butter, and usually but not

always if theyd been oiled.

Why does butter release foods better than other fats and oils, clarified butter included? After

going down a couple of blind alleys, I realized that whole butter carries emulsifiers, substances

that coat the droplets of butterfat in milk, separating them from direct contact with each other and

from the milks water. And emulsifiers, lecithin and others, are the active ingredient in nonstick

sprays. Clarified butter and vegetable oils, meanwhile, contain few if any emulsifiers. I found that,


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by dispersing a pinch of soy lecithin in a little water and then whisking the mix into some canola

oil, the resulting oil released foods easily.

The problem with nonstick sprays and butter is that they all begin to break down at relatively low

frying temperatures, around 350 degrees. To get a good deep brown on many meats and

vegetables, the temperature needs to get up into the 400s. And its the combination of a hot

surface, oil and food that can get sticky.

I was baffled by the occasional sticking of eggs and fish and potatoes that I saw in all but the

nonstick pans, so I decided to go back to square one and think about the hot pan and the oil. I

scoured a stainless surface clean, added some oil, turned on the heat, and just watched. I saw

something Ive seen many times before, but I saw it for the first time.

As the temperature of the pan surface rose above 350 degrees, the oil began to move and form

thick ridges and thin troughs, a stage that some recipes refer to as the oil rippling. As the

temperature kept climbing, the thin areas spread out and the ridges became fewer and higher.

The pattern reminded me of the long drops that run down the inside of a glass of wine or spirits.

Eventually the thin areas seemed to run completely dry, and most of the oil had collected in a ringaround the pan edge.

With some research, I soon learned that I had been observing Bnard-Marangoni convection,

which is related to Marangoni convection in a wineglass. Uneven temperatures at the pan surface

cause regional differences in the oils surface tension, and this causes the oil to get pulled toward

the cooler areas.

I saw the same thing happen on each pan. The hot areas near the pan center end up with thinner

and thinner coatings of oil. And the combination of high heat and thinning oil means food is more

likely to stick. But the thinning and sticking are unpredictable: they depend on the burner heat,

how the pan is placed over it, how much oil you start with, how much you even out the oil bystirring and scraping.

What can we do to work around the curse of Bnard-Marangoni convection? Heres what I came

up with, and if you have a pan that sticks at high heat, you might try it.

Add enough oil to coat the pan surface and the food completely. As little as a half-teaspoon of oil

will coat a medium saut pan (for fat watchers, thats just 20 calories) for cooking eggs and

pieces of fish; for chopped vegetables, triple that to coat the additional surface area of the little

pieces. Heat the pan until the oil ripples. Then turn the heat down, tilt the pan to even out the

troughs and ridges, and wait until it cools just enough that the oil layer stays mostly flat. Then add

the food, and let it cook for some time before turning the heat up again. If possible, keep the food

and oil moving around.

And another thing: clean pans gently, with enough pressure to remove stuck and gummy

deposits, but without scouring down to bare metal. I noticed that as my experiments wore on and

I got lazier about cleaning between tests, the pans were less likely to stick. This seasoning effect

may be the kitchen version of the hygiene hypothesis in medicine: just as extreme cleanliness

may leave people more susceptible to some kinds of illness, it may make pans more susceptible

to malfunction.


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So what to do about getting pots and pans that work best? Choose the ones that you like, for their

heft or their lightness, for cachet or economy, for finickiness or ease. Mind the rippling oil. And

cook with them often.

Copyright 2008The New York Times Company

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