1 hour ago, paulraphael said:1 hour ago, paulraphael said:
Now you're just making stuff up. Only suggestibility would lead someone to believe there's a perceptible differenc in conductivity of a lining that's 1/10 mm thick.
It doesn't matter to me what stories someone tells themselves to feel good about a purchase, but people come here for information. It's not fair to clutter the airwaves with superstitions.
That's what you do when you preheat a pan. It's the whole point.
Push a pan with food in it to 450° you have a different kind of trouble: burned food. The point of the preheat is so the pan drops to the right temperature when the food hits it.
There's a reason that even in old kitchens equipped with copper pans, cooks seared food on spun steel.
Different courses for different horses. I'm perfectly happy and safe (as have chefs been for hundreds of years) searing meats anywhere from 400F to a bit above 550F in tinned copper. That includes preheating the pan, just not completely empty. Attaining wok hei, or blackening without any fat at all, not so much.
Even on a 12k BTU hob, a thick (3mm or greater) pan preheated to 400F and then goosed higher after being oiled is not going to drop all that much with a single steak. And what heat it does drop will be recovered far faster than with any other construction (except solid silver). Sam Kinsey used the metaphor of pipes into and out of a reservoir. Copper is the biggest pipe of all, and 3mm of copper is a prodigious reservoir. Chef Wise has it right when he says: "We [at Craft] use all-copper cookware for the meat because it heats up fast and offers even heat distribution,” Wise explained. “You get a better sear on the meat and it cooks faster.” http://www.craftrestaurantsinc.com/craft-new-york/gallery/
I have experimented with pizza "stones" made of steel, aluminum and copper. A 1/2" steel sheet works wondrously, because the toppings can fully cook in 3 minutes or less in a home oven before the crust is scorched. A copper 1/2" sheet will burn the shit out of the crust before the toppings are even close to cooked. Aluminum at 1/2" is not an immediate fail, but requires a close and full broil to balance out the toppings finishing at the same the crust leopard-spots.
Of course clad is lesser cookware; that's not superstition. For instance, All-Clad's lining and outer cladding layers are each 0.41mm thick--this is typical. The latest infatuation, adding interior steel layers, only adds more. So you can easily have >1.2mm of heat-blunting SS in a clad pan. Then, to make the whole thing light enough for consumers, the conductive layers are shaved down to the point of being inconsequential. For example there is <1mm of copper in All-Clad's Copper Core (and not much aluminum, either--A-C's original SS-Al--SS performs better). It's not only less responsive, it holds less heat than the same overall thickness of copper. Even the copper bimetal pans (Falk, Mauviel, Bougeat, deBuyer, etc.) have 0.2mm linings, which are about the thinnest that will remain bonded to the substrate. I don't know of any maker that offers clad with 0.1mm (<.004") linings.
Look at the best clad skillet out there, the Demeyere Proline 5*. It has 4.8mm of aluminum, swaddled in SS. It comes close to holding as much heat as a 3mm copper pan of the same geometry, but it has dramatically poorer responsiveness. It is a near match for evenness.
Part of the issue is that there is no full clad out there with more than 2mm of copper inside. deBuyer Prima Matera has only 1.8, as do some lines of "2mm" Mauviel. Falk and Mauviel's best bimetal lines have only 2.3mm of copper. To use Kinsey's term, the "pipes" aren't big enough to move much heat laterally--this is one reason why thin copper pans will puddle tin faster and at lower sustained temperatures in the center. They're so thin, they hot-spot without being able to push the heat up to the rims. Grab a contact thermocouple and compare, I have.
At one point in the 1960s and -70s, there were a few truly thick bimetal pans made (e.., 3.2mm copper + 0.2mm SS). They come up for resale a couple times a year on eBay. They would be ideal for dry, high sears where an integral sauce is planned. Frankly, if the cook is simply griddling meat dry, a bare copper pan would do fine, because there are no acids to which the pan could react.
I'm working right now with a group of thermal scientists to apply a new technology that may eclipse thick copperware as the performance standard in cookware. Prototypes have been built which offer 5x the effective conductivity of copper. But until this comes to market, there is nothing better-performing available than what was around in 1900 or 1700.
