by Bee Wilson
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:
1. Temperature uniformity (my translation: Will it even out heat spots?)
2. Reactivity and toxicity (Will it poison me?)
3. Hardness (Will it dent?)
4. Simple strength (Will it survive being dropped?)
5. Low stick rating (Will my dinner get glued on?)
6. Ease of maintenance (Will it wash easily?)
7. Efficiency (Does it conduct heat well vertically through the base?)
8. Weight (Can I lift it?)
9. Cost per unit (Can I afford it?)
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 mar
keted 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.
There is also the question of skill. I decided to try out Myhrvold’s theory on my own decidedly inferior gas burners (though at least the switches work most of the time, which is better than the stove in our old house). I took my smallest skillet and set it to heat on the largest burner to saute some sliced zucchini. The heat conduction was appreciably more even and powerful. The discs of zucchini practically jumped out of the pan. Then they burst into flames. Since then, I have happily returned to my imperfect mishmash of too-big pans and too-small burners. I’d rather put up with the annoyance of hot spots than suffer scorched eyebrows.
The ideal pan—like the ideal home—does not exist. Never mind. Pots have never been perfect, nor do they need to be. They are not just devices for boiling and sauteing, frying and stewing. They are part of the family. We get to know their foibles and their moods. We muddle through, juggling our good pots and our not-so-good ones. And in the end, supper arrives on the table; and we eat.
Rice Cooker
WHEN ELECTRIC RICE COOKERS ARRIVED IN Japanese and Korean homes in the 1960s, life changed. Previously, the whole structure of the evening had been dictated by the need to produce steamed sticky white rice—the bedrock of every meal. The rice needed soaking, washing, and careful watching as it cooked in an earthenware pot, lest it burn.
The rice cooker—a bowl with a heating element underneath and a thermostat—removed all this work and worry In today’s versions, you just measure out the rinsed rice and water, and flip the switch. The thermostat tells the cooker when the water has been absorbed, and it switches from hot to warm. More deluxe cookers keep the rice warm for many hours and even have a time-delay function so that you can set the cooker before you leave for work. Rice cookers were an ideal match between culture and technology. Early models replicated the slow simmering of a traditional earthenware Japanese rice pot. Unlike the microwave, which changed the entire structure of family meals, rice cookers enabled Asian families to eat the same traditional meals, but with far greater ease.
“Where There Are Asians, There Are Rice Cookers” is the title of a 2009 monograph by Yoshiko Nakano. Forget TVs, rice cookers are the most important electrical gadget in the Japanese home. Yet it’s all happened remarkably fast. Electric rice cookers belong to the “Made in Japan” electronics boom of the 1950s. The first automated rice cooker was launched by Toshiba in 1956. In 1964, less than ten years later, the rate of rice-cooker ownership in Japan was 88 percent. From Japan, they traveled to Hong Kong, mainland China, and South Korea (where new cookers were designed with added pressure, to cook the rice softer, which is how Koreans like it). In tiny rural kitchens in China, the rice cooker may be the only stove, used to make gooey congee (rice porridge) as well as steamed rice.
What rice cookers are not so good for—thus far—are the long-grain rices of India and Pakistan. Basmati grains should be fluffy and separate. The slow steaming of the rice cooker does long grains no favors; they turn gummy Which may explain why India does not yet fully share China’s rice-cooker addiction.
2
KNIFE
The poet with his pen, the artist with his brush,
the cook with his chopping knife.
F. T. CHENG, 1954
I WAS MAKING A PILE OF CUCUMBER SANDWICHES ONE day when I sliced off a sliver of finger instead of cucumber. My injury was the result of getting overexcited with a Japanese mandolin slicer (newly acquired). “Lady with a mandolin,” they shouted with cheery nonchalance, when I arrived at the ER: clearly I was not the first idiot to hurt herself with this relatively obscure gadget. Many enthusiastic cooks have a mandolin permanently discarded in some neglected cupboard, spattered with dried blood. “Watch your fingers!” it said on the box, which should have given me a clue, but somehow the thrill of seeing a heap of transparent cucumber disks emerge distracted me, and before I knew it, there was a slice of myself on the wrong side of the blade, lying among the cucumber. It could have been worse. As I waited for the paramedics, I felt a stab of relief that I had put the mandolin on its thinnest setting.
Kitchens are places of violence. People get burned, scarred, frozen, and above all, cut. After the mandolin incident, I booked myself into a knife skills co
urse, in a shiny new cooking school on the outskirts of town. Most of the men in the course had been given their enrollment as a present by wives and girlfriends, the assumption being that knives are the sort of thing men have fun with, like train sets or drills. They approached the chopping board with a slight swagger. The women stood more diffidently at first. We had without exception signed up for it ourselves, either as a treat (like yoga) or to get over some terror or anxiety around blades (like a self-defense class). I hoped it would teach me how to dice like a samurai, hack like a butcher, and annihilate an onion at ten paces like the chefs on TV In fact, most of the course was about safety: how to hold vegetables in a clawlike grip with our thumbs tucked under, keeping knuckles always against the body of the knife so that we couldn’t inadvertently baton our thumbs along with our carrots; how to steady the chopping board with a damp cloth; how to store our knives in a magnetic strip or in a plastic sheath. Our terror, it seemed, was justified. The teacher—a capable Swedish woman—warned us of the horrible accidents that ensue when sharp knives are carelessly left in a bowl of sudsy dishwashing detergent. You forget the knives are there, plunge your hand in, and slowly the water turns red, like a scene from Jaws.