Consider the Fork: A History of How We Cook and Eat (8 page)

The solution to many of these drawbacks was enameled cast iron: cast iron coated in a vitreous enamel glaze, the most famous example of which is Le Creuset. The principle of enameling is very ancient : the Egyptians and the Greeks made enameled jewelry, fusing powdered glass onto pottery beads by firing it at very high temperatures (1382°F to 1560°F). Enameling began to be applied to iron and steel around 1850. Then in 1925, two Belgian industrialists working in northern France thought of applying it to cast-iron cookware, the bedrock of every French grandmother’s kitchen. Armand Desaegher
was a cast-metal expert. Octave Aubecq knew about enameling. Together, they produced one of the definitive ranges of cookware of the twentieth century, starting with a round cocotte (we would call it a casserole) and moving over the years into ramekins and baking dishes, French ovens and tagines, roasters and woks, flan dishes and grill pans. Part of the appeal of Le Creuset cookware is the colors, which mark changing tastes in kitchen design: Flame Orange in the 1930s; Elysees Yellow in the 1950s; Blue in the 1960s (the color was suggested by Elizabeth David, inspired by a pack of Gauloises cigarettes) ; and Teal, Cerise, and Granite today. I have a couple in Almond (a fancy name for cream) and there is nothing better for long, slow-cooked casseroles, because the cast iron warms up evenly and retains heat superbly, while the enamel stops your stew from taking on any metallic flavors. Mostly, they score high on lovability; the sight of one on the stove makes the heart sing.

One of the best cooks I know (my mother-in-law) does all her cooking in blue Le Creuset. She was Cordon Bleu trained before she got married, and her meals have an Anglo-French panache. In her neatly kept pans, she whisks up dreamy béchamels, buttery peas, smooth purple borscht. The pans seem utterly in keeping with her style of cooking. She would never dream of serving food on cold plates or with the wrong cutlery. Her enameled cast iron serves her well. It is only when those of us with less discipline venture into the kitchen that cracks appear. For one thing, these pans are heavy, and I always fear my wrists will go limp and I’ll drop one. There’s also the fact that none of them is big enough for pasta. But the real trouble is the surface. If you are used to cooking on more forgiving stainless steel, it’s a shock to find how easily things stick to the bottom of Le Creuset at high temperatures. Several times, I’ve left one of my mother-in-law’s pans slightly too long on the burner and nearly ruined it (at which point she comes in and briskly saves the day with bleach).

When nonstick pans first arrived on the scene—they were first launched in France by the Tefal company in 1956—they seemed like
a miracle. “The Tefal pan: the pan that really doesn’t stick,” was the original pitch. The reason food sticks to a pan is because proteins react with some metal ions at the surface. To prevent food from sticking, you need to stop protein molecules from reacting with the surface in this way—either by stirring it so vigilantly that it doesn’t get a chance to stick, or by introducing a protective layer between the food and the pan. Traditionally, this layer is provided by “seasoning” the pan. With unenameled iron pans—whether a Chinese wok or an American cast-iron skillet—seasoning is a critical step; skip it, and your cooking will suffer (and the pan will rust). First, the pan is soaked in hot, soapy water, rinsed and dried. Then, oil or lard is rubbed into the surface and very slowly heated for several hours. Some of the fat molecules “polymerize,” leaving a slick, shiny surface. Each meal that you cook adds a further layer of polymerized fat. Over time, the pan becomes as slick as Brylcreem. In a nicely blackened wok, the food slides and jumps. You can cook a whole panful of cornbread in a well-seasoned skillet, and when it is done, it will simply drop out, like a pill from a blister pack. But it takes a certain attentiveness to maintain a seasoned pan. It must never be scoured. The surface can also be ruined by acidic ingredients such as tomatoes or vinegar. When the seasoning on a cast-iron pan wears away, you have to start all over again.

In 1954, Marc Gregoire, a French engineer, came up with another way. PTFE, or polytetrafluoroethylene, had been known by chemists since 1938. The slippery substance was used for coating industrial valves and for fishing tackle. As the story goes, Marc Gregoire’s wife first suggested he try to use the PTFE he had been using on fishing tackle to solve the problem of her sticky cooking pans. He found a way of melding PTFE to an aluminum pan.

How does it work? Stickiness happens when food bonds with the surface of the pan; but PTFE molecules do not bond with any other molecules. At a microscopic level, PTFE is made up of four fluorine atoms and two carbon atoms, repeated many times in a much larger molecule. Once fluorine has bonded with carbon, it does not want to
bond with anything else, not even with the usual culprits such as scrambled egg or steak. Under the microscope, says scientist Robert L. Wolke, a PTFE molecule looks rather like a spiky caterpillar, and this “suit of caterpillar armor” prevents the carbon from sticking to food molecules, hence that theatrical effect when you pour a tiny bit of oil into a new nonstick pan and it seems to be repelling the droplets out of the pan.

The world went wild for Teflon. In 1961, DuPont backed the first production in the United States, called the “Happy Pan.” Within the first year, American sales were 1 million units a month. Like a cure for baldness, a pan that cooks food without sticking is a universally sought-after invention. As of 2006, around 70 percent of the cookware sold in the United States has a nonstick coating; it has become the norm rather than the exception.

But as the years went on, it became obvious that nonstick was not flawless. I’d never make a stew or a saute in nonstick, because when nonstick works, you get none of the browned sticky bits you need for deglazing. All too often, however, you have the opposite problem: the amazing nonstick properties do not last. Over time, no matter how carefully you treat it—shunning metal utensils, shielding it from searing heats—the nonstick surface of a PTFE-treated pan will simply wear away, leaving you with the metal underneath, which rather defeats the purpose. After too many short-lived nonstick pans, I’ve decided that it’s not worth it. It’s far better to buy a traditional metal like aluminum or steel or cast iron and season it with oil: that way, your pan gets better with use rather than worse. Each time you grease and cook with a cast-iron pan, it gets an extra patina. Whereas each time you cook with nonstick, the coating gets a little less slick.

There are other reasons to pause before buying nonstick pans. PTFE is a nontoxic substance, but when heated to very high temperatures (482°F and above), it emits several gaseous by-products (fluorocarbons) that can be harmful, causing flu-like symptoms (“polymer fume fever”). When doubts first emerged about the safety
of nonstick pans, the industry replied that pans would never be heated this high under normal use; but by leaving a pan to preheat with no oil in it, it is perfectly possible to reach these temperatures. In addition, in 2005, the US Environmental Protection Agency looked into whether PFOA, a substance used in the manufacture of PTFE, was carcinogenic. DuPont, the main American manufacturer, has pointed out that the amount of PFOA remaining on a finished pan should not be measurable. But, whether fairly or not, many people have been left feeling uneasy about the miracle of nonstick surfaces.

Faced with all these hazards, how is one to choose the right pan? In 1988, an American engineer named Chuck Lemme, cited as the inventor on twenty-seven patents that range from hydraulics to catalytic converters, decided to approach the question systematically. He looked at all the available materials and rated them in nine categories:

For each category, Lemme rated the materials, using a scale of one to ten. He then tabulated his findings into an “idealness rating,” with 1,000 as the perfect score.

Lemme’s findings confirmed how difficult it is to produce perfect cookware. Pure aluminum rated very high for temperature uniformity
(scored 8.9, out of a possible 10)—great for evenly browning an omelette—but very low for hardness (scored 2): many aluminum pans end up misshapen. Copper was efficient (scored 10) but hard to maintain (scored 1). Overall, Lemme found that none of the “single material pots” rated above 500 in the idealness scoring; in other words, they landed just halfway up the scale. The best was pure cast iron (544.4). Those of us who continue to use cast-iron skillets are on to something. But 544 is still a low score.

The only way to get closer to the ideal rating of 1,000 was to combine metals by sandwiching them together. At the time of Lemme’s investigation, the consensus among high-end cookware experts was that the only copper pans worth having were fashioned from a hunk of copper as opposed to a thin, cosmetic layer. Yet Lemme found that even a very thin layer of copper “electroplated to the bottom mainly for decoration” could dramatically increase a pan’s conductivity. A 1.4 mm stainless steel pan with a 0.1 mm layer of copper attached would increase its ability to even out hot spots (temperature uniformity) by 160 percent. There’s a very easy way to check for hot spots in your own pans. Just sprinkle plain flour over the surface of a pan and put it over a medium-high heat. You will see a brown pattern start to form as the flour burns. If the brown patch spreads over the whole surface of the pan, you’ll know that this pan has good heat uniformity. More likely, though, a small brown dot will appear toward the center: a hot spot. Now imagine that you are trying to saute a panful of potatoes in this pan: unless you move them frequently, the ones in the middle will singe on precisely that spot while the ones at the outside remain pale. Better pans really do make a difference in the food on your plate.

Lemme’s own suggestion for the “near-ideal” pot was to fabricate a composite. The inner core of the pan would be a stainless steel-nickel alloy. The inside would be coated with one of the more durable nonstick surfaces, such a flame-sprayed nickel. The outer bottom layer would be laminated with pure aluminum: 4 mm thick on the bottom, thinning out to 2 mm on the sides.

When Lemme was writing in the late 1980s, such a pan did not exist: it was a concept in the realms of sci-fi. Lemme never produced or marketed his ideal pan; it existed only in his brain, and having conceived it, he returned to other kinds of engineering. Yet even Lemme’s imaginary and near-ideal pot only rated 734 on his scale. It turns out that some of the many things we want from a pan are simply incompatible. For example, a thin base makes pans more energy efficient—more quickly responsive to different heats from the burner. This can be useful for sauce making or for foods that need quick, hot cooking such as pancakes; and it results in lower energy bills. But for getting rid of hot spots, a thick metal base is better. The thickness ensures more uniform temperatures on the base of the pan and great heat retention. Thick cast iron takes ages to heat up because of its density, but once hot, it stays hot, so nothing is better for searing something like a meaty chop, because it maintains most of its heat when the cold meat hits the pan. So thin pans and thick pans are both desirable, but you can’t make a pan that is thick and thin at the same time without breaking the laws of physics. Lemme’s study shows that no matter how much you balance out the various factors, there will still be trade-offs. There will probably never be a pan that scores even close to 1,000 on the Lemme scale.

Nonetheless, in the intervening two decades or so, the technology of cookware has gone up a notch. As Lemme predicted, the action is all in the sandwiching together of multiple materials. All-Clad, one of the top American brands of cookware, has come up with a patented formula made of five layers of different materials, alternating higher conductive metals with lower ones to “promote the lateral flow of cooking energy and eliminate hot spots,” says the company website, with a stainless-steel core to promote stability. These pans are specially designed to work with the newest-technology induction cooktops. I’m sure an All-Clad pan would score high on Lemme’s scale in all ways but one: the cost runs to several hundred dollars for a single pan.

According to Dr. Nathan Myhrvold, the outlay for top-of-the-range pans may not be worth it. Myhrvold, who was the chief technology officer for Microsoft before turning to food, is the main author (along with Chris Young and Maxime Bilet) of
Modernist Cuisine
(2011), a six-volume, 2,438-page work that aspires to “reinvent cooking.” Working in a state-of-the-art cooking laboratory near Seattle at his company, Intellectual Ventures (which deals in patents and inventions), Myhrvold and his team of researchers questioned the thinking behind numerous cooking techniques that had previously been taken for granted. If Myhrvold wanted to find out how food really cooks in a pressure cooker or a wok, he sliced one in half and photographed the results, midcooking. Among Myhrvold’s many surprising and useful discoveries were that berries and lettuce stay fresher for longer in the fridge if you first plunge them in warm water, and that duck confit does not need to be cooked in its traditional fat—a sous-vide water bath works just as well. Myhrvold also applied himself to the problem of the ideal pan.

After extensive experiments, the author of
Modernist Cuisine
found that “no pan can be heated to perfect evenness.” He noted that many (wealthy) people have expensive copper pans “hanging in a kitchen like trophies.” But even the most highly conductive pan could not ensure even cooking. In all the obsessing over pots and pans, people had forgotten another basic element of the cooking process: the heat source. Myhrvold’s experiments taught him that the typical small domestic gas burner, only 6 cm in diameter, was not big enough to diffuse heat evenly “to the far edges of the pan,” no matter how fancy that pan might be. His advice? “Skimp on the pan, but choose your burner carefully.” Assuming you have a sizable burner—ideally, as wide as the pan itself—Myhrvold found that an inexpensive aluminum-stainless steel bonded pan cooks “with nearly the same performance as that of the copper pan.” Which is good to know, though not all that helpful if you are cooking in a normal, ill-equipped kitchen with average-sized burners.