First "Scorchprint" Duel--Cast Ivon vs. Aluminum on Gas

[kaleokahu]

Inspired by my muse and scourge Caroline, today I ran the first of what I hope to be a series of stovetop experiments designed to test heat "eveness" in pans of different materials and compositions. Today's bout was between 8-inch skillets (both pans having 7" diameter bottoms), one a black-enameled cast iron Le Creuset, the other a non-stick aluminum one by Swiss Diamond. Both pans' bottoms measured about 4mm thick

The test went as follows. I first cut 7" circles of cooking parchment, and placed them in the bottoms of the dry pans. Then I weighted them down by means of the clear glass beans I use for pie weights. The gas hob is a 2.25"-diameter ring, from which--on the dial marker "low"--flames extend to 3 inches overall. Everything started at room temp. My intent was to heat each pan to the point where dark scorching appeared anywhere on the parchment, then remove the beads and see how even any pattern was.

First I tried the aluminum pan. NOTHING for 5, 10, 15 minutes. At about 16 minutes, I could smell some definite toasting. By about 16:30 there was some browning, but only detectable by holding a fresh piece of white parchment up to it for reference. When I stopped the test at 20 minutes, there was NO SCORCHING WHATSOEVER, just a uniform browning across the parchment circle. There was a slight variegation, attributable to the parchment wrinkling as it cooked.

Next up, the Le Creuset. At only SIX minutes, there was darkening in a ring that perfectly matched the 3" flame diameter, which darkening was visible through the glass beans. White in the center and at the periphery. At 10:00, I had a bona fide black scorchspot, friable in the "ring", that was a solid 4" in diameter, but the outer 1.5" of the circle remained quite white. I ended the test at that point out of concern that the parchment might ignite.

My conclusions: (1) The aluminum pan showed no evidence at all of hot-spotting even after 20 minutes, and all signs were that, if it EVER completely scorched, it would be the entire 7" circle uniformly. In other words very even heat. (2) The cast iron pan hot-spotted very quickly at 6 minutes, scorched very strongly at 10 minutes, and never did even brown at the periphery. My sense was that the center of the cast iron parchment would have been ashes before the periphery scorched. (3) To cook evenly in the aluminum pan, you can pretty much leave it be; in cast iron, you have to watch it closely and move/stir your contents back and forth over the hot spot frequently. (4) The cast iron's hot-spotting problem would be even worse in a larger-bottomed pan, which means only a dependable 4" spot for searing, REGARDLESS OF PAN SIZE.

I will post photos of the tests and prints sometime in the next few days. And thyen hopefully repeat the experiment with copper and clad pans.

[paulj]

Here is the Korean 'reverse wok' that I was thinking of

http://store.gourmetsleuth.com/cast-i...

[kaleokahu]

paulj: Very interesting shape. Never seen one of those. I suppose if it's put on a mound of live coals (or over a "weedburner"-type jet) it'd be really effective. Anyone tried one?

[paulj]

Most commonly it used on a butane hotplate. I've bought ceramic and steel versions, though haven't used them recently.

[Politeness]

kaleokahu: "Very interesting shape. Never seen one of those. I suppose if it's put on a mound of live coals (or over a "weedburner"-type jet) it'd be really effective. Anyone tried one?"

Oh, my goodness, yes! we have "tried" one; we have used them for years and decades, over and over and over. tanuki soup explained it well, but for some reason omitted the name by which the "dome" it is universally known in Japan: "zhingisukan" or "zhingisu" for short, as in Ghengis Khan. The domed accessory looks a bit like a primitive iron helmet, such as one might imagine Ghengis Khan might have worn. http://en.wikipedia.org/wiki/Jingisukan

[tanuki soup]

A domed grill like that is a common accessory for hotplates and electric griddles here in Japan. It's used for making yakiniku ("grilled meat"), the Japanese name for the Korean dish.

[kaleokahu]

tanuki: Again, very interesting. Are these things capable of grilling thicker cuts of meat?

[tanuki soup]

Yakiniku meat is cut into very thin, bit-sized slices (like for sukiyaki) because it is intended to be eaten with chopsticks and to cook quickly. The domed grill is placed in the center of the table with everyone sitting around it. There is a big dish with slices of raw meat, and everybody has their own dish of dipping sauce and a bowl of rice. Each person puts a piece or two of meat on the grill whenever they feel like it and takes them off when they are done to taste (the thin slices cook in less than a minute). The meat used is kind of fatty, so the dome lets the melted fat drain off.

Basically, the domed grill is meant to be used on the table rather than in the kitchen. I don't think you could cook anything too thick on it. I'd use a grill pan instead.

[paulj]

And veggies, kimchi, bean sprouts and such can be arranged around the rim, where they cook slowly, and catch the meat drippings (at least in Korean use).

[paulj]

Here's a another material to test - glazed earthenware (Spanish cazuela)

http://www.spanishtable.com/mm5/merch...

[kaleokahu]

paulj: OK, I'm game. But before we start, is there anything special about THIS clay?

"The Internets" tell me that clays range in thermal conductivity from 0.16 to 2.5 W/mK (which range is about the same as leather to marble). Compare pyrex at 1 and SS at 54. Cast iron is supersonic in comparison. Unless I've missed a decimal point, aluminum is 100x more conductive than the most conductive clay.

Volunteers to pay my gas bill?

[Caroline1]

Actually, I had forgotten about clay simply because it's a painful memory of a self inflicted wound. For years I had a set of lovely hand painted clay "pots and pans" from Mexico. They were lead free, and during those years I used them for cooking on top of my electric stove as well as in the oven. For top of the stove cooking, I did mostly stews and such as I recall, but many of the recipes called for rendered lardons, and I feel pretty confident I did that in the clay vessels stove top as well. The only extra care I had to do for stove top cooking was to make sure any liquids I added were pre-heated so I wouldn't shock/shatter the clay. And of course I used them in the oven.

When I moved from Del Mar to El Paso, a friend in California had been lusting after them for ages, and in a fit of insanity I thought, "Hey, El Paso is on the border too,. I'll just pickup some new ones when I get there." To my everlasting regret, there were none to be found in the entire city of Juarez.

I would not do the experiment with clay over a gas flame. In the oven, maybe. We all know -- or at least anyone who has ever cooked in clay knows -- that it has great qualities for oven cooking. Not a lot of people use it for stove top cooking, and I wouldn't do it over gas because it will produce carbons on the surface of the clay from the flame contacting it, then those carbons will go into the pores of the clay and it will be quite ugly. Not unsafe for future use, but it will change your Lovely flower of a vessel into a very ugly weed. But also note: To the best of my knowledge, there are NO clay paella pans. If your goal is to test common materials in stove top cooking vessels, clay is waaaaaaaaaaaaaaaaaaaay down on that list! '-)

[paulj]

I brought it up last night because I just made a chicken pot pie in my 7" cazuela. As part of that I sauteed vegetables in the cazuela in my butane hot plate. I have to heat it slowly, but once up to temperature it cooks evenly and requires just a small flame. In fact when simmering with a cover, it is hard to get the flame low enough (using a deep Chinese sand pot).

The clay is thick enough that there's a lot of heat transfer across the bottom and up the sides. There aren't obvious hot spots, especially in the small sizes where the flame spreads across the bottom. It might be a different story with a 12" cazuela.

[Caroline1]

I assume your cazuela is glazed on the bottom? But I also suspect that your Chinese sand pot is not? Here's a little inexpensive experiment for you to do with a flame against ceramic. Take a match, any match, and a porcelain saucer, then hold the saucer in your hand and tip it to about a 45 degree angle. Then light the match and hold it so the flame is just crawling up the back of the saucer from the bottom edge. Esperiment with the distance between the flam and saucer rim until black soot begins to build on the saucer. Keep building the soot. Brush it off into a small container or dish. Wipe the saucer clean.

Now, what you have in the dish is what fine artists of oil painting a long long time ago -- Remrandt and those guys -- used to call "lamp black," and they would mix it with linseed oil and turpentine and paint with it. Mix in a bit of fine quality ghee instead of the linseed oil and turpentine and get yourself a sterling silver applicator rod and you have traditional Indian eye liner, but do be warned that years of use wil likely discolor your sclera. Or get yourself a fine sable brush with a good pointy tip, dip it in the pure unadulterated lamb black and you have early Hollywood's traditonal eye liner until about the late fifties or early sixties when manaufactured cosmetic eye liner hit the marke. I used it for years.

What does this have to do with cooking? Well, you can get "lamp black" on clay and porcelain or glass pots with a gas or any other flame. Not a problem with porcelain or glass because they aren't porous and the lamp black will wipe off. It will also wipe off of clay *IF* the clay is glazed. But if the clay is porous, sooner or later you're gonna have a sooty pot with a lot of soot that will NOT wash or wipe away. Just askin'....Is this the effect you want on your clay vessels?

Oh, and yes, clay does have incredible cooking performance. I used to have one of those Romertopf clay chicken roasters you had to soak in cold water for a long time before roasting the chicken. Interesting. Nice flavors. But overall, the hassle just wasn't my cup of tea so I reverted to coq au vin as my "go to" chicken dish. Lazy, lazy me. Shame! '-)

[paulj]

The sandpot is just glazed on the inside. There's some staining on the outside, and on the unglazed interior of the lid, but nothing that I'd attribute to soot.

The Spanish cazuela is glazed inside and out - except for the outside base. There are some dark spots on the base, but nothing that rubs off on my fingers.

I also have a have Korean clay bowl that is glazed all over.

[paulj]

Since paella pans are sized to fit the number servings (with a 1/2" rice thickness), large diameter cazuelas would impractical. However clay comales (Mexican griddles) are traditional. Koreans also use clay and stone as griddles.

In some uses an uneven heat distribution is useful. Items that need fast cooking are placed in the center, while the rim is used for slower cooking and resting.

Another thought on paella pans - they require an even heat source. Traditionally this was a fire of coals or twigs (vine trimmings), though The Spanish Table will happily sell you a large diameter gas ring.

[kaleokahu]

paul: "In some uses an uneven heat distribution is useful. Items that need fast cooking are placed in the center, while the rim is used for slower cooking and resting."

Aha. This is what I was asking about above as a "hidden virtue" of stovetop cooking in CI. I can see it now: For the family of 3 who like their steaks WD, MED and RARE, you sear one at a time (and in that order) over the 4" hotspot in your new 15" LC skillet and let them rest at the edge--which will be about as warm as your front porch.

[Caroline1]

And where do you live that your front porch is THAT hot? Certainly not Washington or Hawaii! But that attribute of cast iron makes a very large cast iron skillet a "sort of" acceptable substitute for a wok, in that just as you can push foods up the side of the wok to keep them warm while you sear other things or make a sauce, you can push things to the side in a large centrally heated cast iron pan and do the same thing, except the sauce making isn't quite as successful and you do have to remove the food from the cast iron pan as soon as it's done to the desired degree or it will keep on cooking! But mostly for wok cooking, it works better to use a wok, IF your stove can get it hot enough.

[tanuki soup]

Funny coincidence -- I grilled a delicious 1 1/2"-thick steak in my 12" Lodge Signature cast iron grill pan yesterday on my induction cooktop. Since the steak was a bit thicker on one side than the other, it was handy to be able to position the thicker part over the hot spot of the pan. Both the thicker and thinner parts came out a perfect medium rare :-)

PS. I recently picked up an IR thermometer to play around with. After I had preheated the pan for a while, when the olive oil was just barely starting to smoke, the temp was 210 deg C (410 F) at the center of the pan, but only about 60 deg C (140 F) at 2 inches in from the edges. As I continued to grill the steak, the temp near the edges of the pan rose to about 160 deg C (320 F).

[kaleokahu]

Car and tanuki: You guys! The whole point of this thread was to test the evenness of CO on the stovetop. Now we're talking about restoring CI's honor by likening a CI skillet to a wok (like it's possible to get your food out of the oil in a skillet, or stir-frying in it), and cooking slanted steaks on it? L2xOL. Maybe a big 'ole CI oven might work as a sous vide bath, too, if you added a pump and thermocouple.

I do envy you your IR thermometer (and steak), tanuki. Athanasius has one too, and his posted temp data seem to fit the scorchprint data. I can see how the oil in the pan was helping heat the 12-incher from the top down, though. Can you do 3 steaks on the same hob and pan?

Oh, and Car: I need to resort to hyperbole sometimes, since 100-200F temperature differences in the same pan don't seem to impress people.

[tanuki soup]

I probably should have been a bit clearer regarding the olive oil. It was just a very thin coating (like what you would get using an oil spray bottle), so I don't think it had any effect on lateral heat transfer.

I like to put a bit of oil in the pan because I figure it's good for the cast iron, it seems to make cleanup a bit easier, and it helps to indicate the temperature when you are preheating the pan (when it starts to shimmer/smoke, it's time to toss on the steak).

PS. You might want the consider getting an IR thermometer. I was surprised at how inexpensive they are (less than $50, half the price of a Thermapen).

[kaleokahu]

tanuki: I get you now. Makes good sense.

What inexpensive IR gun would you recommend? Without help, I'd probably go with one intended for automotive use, i.e., up to 8-900F.

[tanuki soup]

Well, I'm certainly no expert on IR thermometers. Since I live in Japan, I got a Japanese one from Amazon Japan (the one in the pic I posted above). The temp range is -60 to +500 C (-76 to +932 F). It has a red laser pointer, which is useful for aiming and also a GREAT cat toy!

I looked at Amazon's US site, and they seem to have a wide range of choices for less than $50. This one seems to be pretty similar to the one I got, and also has good reviews (including a few focusing on kitchen/cooking use):

http://www.amazon.com/Actron-CP7876-N...

[paulj]

Looking at another thermometer on Amazon I saw this: Cooking for Geeks
http://www.amazon.com/Cooking-Geeks-Science-Great-Hacks/dp/0596805888/ref=pd_bxgy_hi_img_c
http://www.cookingforgeeks.com/

The author has a couple of CHOW TIP videos, one on temperatures in cook, and one on hacking a slow cooker.

[tanuki soup]

To quote Looney Tunes, "Hey, I resemble that remark!" You are also probably familiar with the "Cooking for Engineers" website http://www.cookingforengineers.com/

[kaleokahu]

All right, I'm ready to do the oven versions of this test. What do the cognoscenti consider the ideal temperature? If you wish copper to be included, I'm not going over 400F!

[Caroline1]

Just do one then. The cast iron, and go for 350F for... Oh, 45 minutes to an hour without preheating, either stove top or in the oven. Or maybe even less. I have no idea at what oven temperature flour will scorch, so the temp shouldn't be so low as to make the flour scorch proof or so high you'll end up with ashes.

The reason I requested the cast iron in the oven is because there was such a marked difference in not just the pattern of heat discoloration, but in the depth of heat discoloration. Now I'm curious whether cast iron has some inherent quality that makes it scorch, and whether the scorching produced in an oven will echo the pattern of the stove top scorching? I realize it's unlikely since oven heat is a lot more even, or maybe it will just get "scorch freckles!" THAT would be really interesting! Nothing ventured, nothing gained! And you are a sweetheart for doing this. No sense doing it with anything else though unless you have your heart set on it. '-)

[kaleokahu]

Car: Happy to do it. Remember this test has used parchment weighted by glass beads. Does that change your temp/time recommendation?

Did you ever get your magnetronic cooktop? Or did you ask Santa?

[Caroline1]

Santa sent me an early and totally unexpected prezzy.... A broken water main on my side of the freaking meter! Thanks, Santa. My magnetic cooktop suddenly and unexpectedly turned into some two legged critter digging holes -- DEEP holes! -- in my front yard, then sweat soldering a six inch piece of pipe into the main where the leak occurred. Do you know plumbers charge more per hour than a Beverly Hills shrink!?!?! <sigh> Induction is back at the top of the wish list, meanwhile I've got to work on remembering to buy those damned lottery tickets!

I think inevitable senility must be braiding my dendrites because my train of thought jumped the track. I was thinking flour, not parchment and beads, on the cast iron oven meltdown. I don't think parchment would be as discretionary as flour when it comes to showing minute variations. Feel free to scratch the oven test. '-)

[kaleokahu]

Car: I'm sorry about the break.

This morning I closely compared the "oven" parchment with a new sheet, and the former WAS half a shade darker--but showed no variations.

[Caroline1]

Bless your heart! Thanks! So now we know cast iron is great in the oven but you gotta stir on top of the stove, right? '-)

[kaleokahu]

Car: No problem. Yes, either stir or strictly limit your pan size to the size of your flame spread.

N.B.: LC is now marketing a FIFTEEN-inch skillet, which will function on most gas ranges like a six inch pan.

[Candy]

In college we tested pans for hot spots with vanilla pudding. The scorching was quickly evident. Cast iron, whether is is Le Creuset or Lodge is going to have hot spots. The way it is cast is the cause, it is also why you can break them. Cast iron is brittle and there are small bubbles in the pan that cause weakness and hot spots.

I sell cookware. I have Le Creuset myself and Swiss Diamond and my oh so favorite Chantal with the copper and carbon steel center and is enameled inside and out. I don't use my LC as much as i used to, I still treasure it, but back issues can make it difficult to lift when full with some sizes.

[paulj]

With those vanilla pudding tests, could could you identify hot spots that were caused by material anomalies, as opposed to uneven heat? If so, what size were these spots? Coin size?

I have seen material hot spots on white enameled steel, off center regions that food starts to stick earlier, and retain a dark stain after cleaning.

With electric stoves, hot spots can also be caused by uneven contact between pan bottom and the heating element. Coils are not a flat surface, and pan bottoms can warp and bow.

[kaleokahu]

Candy: "...there are small bubbles in the pan that cause weakness and hot spots."

If this were the cause (rather than crappy conductivity), wouldn't the hotspots differ in location, and also differ across various pans--even the same model? In all the photos I've seen, and all the cooking I've done, the hotspots are always directly under the flame.

And wouldn't bubbles entrained in the iron actually REDUCE hotspots?

If you got an off-center scorch in your pudding, did you play with clocking your pan? I mean, did the scorch always happen at, say, 3-o'clock, or did it move when you moved the pan?

[kaleokahu]

I did repeat the test today with a 5-minute pre-heat as Politeness suggested. The result with aluminum was identical--test stopped at 20 minutes with no scorching. With CI, the test also stopped at 10 minutes for fear of conflagration, but the scorchspot was marginally (as in a 1/4 inch) larger with the pan preheated.

I'm having problems uploading the photos

[kaleokahu]

CI w/o preheat.

[kaleokahu]

CI with 5 minutes of preheat

[kaleokahu]

Aluminum w/o preheat

[kaleokahu]

Finally, aluminum with 5 minutes of preheat.

[Caroline1]

Great work, Charlie Brown! From looking at your magnificent pictures, my conclusion is NOT that aluminum spreads heat better, but that cast iron transfers heat FASTER! So again, with an EVEN heat source (if such a thing were available OUTSIDE of an oven), I'd go for cast iron. In my opinion, aluminum only diffuses the heat but appears not to transfer the same intensity of heat as cast iron. So to put it another way, cast iron appears to be more "transparent" than aluminum when it comes to passing along heat intensity. VERY INTERESTING! And thank you.

[kaleokahu]

Car: Don't thank me when I'm fixin to disagree with you. The same heat is going into both pans, and in the same places on the pans' bottoms. In the case of the aluminum pan, that metal's much better conductivity means it has the capacity to easily move the heat laterally through the pan's bottom and up the pan's wall so as to take OUT from the directly-heated center enough heat to prevent scorching. In this test at low heat, aluminum pretty much took all the heat to all corners of the pan without scorching.

The cast pan on the other hand, being 10x less conductive, can't effectively pass the heat out from the center, and so the heat tends to stay close to home. As such, it ACCUMULATES increasing heat faster there at home. And that's where the scorch is going to be,

If, as you speculate, CI is more transparent than aluminum, we should have aluminum handles on our copper treasures. We have CI handles on them BECAUSE of the lack of that material's transparency, Think of cooking in your favorite copper pot over high heat. At the flange and rivets, the CI gets quite hot, but it is very slow at pushing that heat out the handle where you'll feel the need to grab a towel.

[Caroline1]

Disagree all you like Sweetie Pie, but first try this: Forget about theory and all of the stuff you've read in books and look at your scorch sheets! *IF* you had the exact same flame at the exact same heat setting under both pans, then it is pretty damn obvious that the aluminum is NOT transferring as much heat from the outside bottom of the pan to the inside interior of the pan as the cast iron is OR the aluminum would have the same serious scorching that the cast iron produces, albeit there may be some variance in pattern as a result of convection heating patterns within the different metals, but they WOULD both be burnt!

As I have long contended, the best thing that could happen to ALL stove top cookware, from copper to really crappy spun aluminum and all that lies between is a hob that delivers EVEN HEAT on it's entire surface contact with pans. PERIOD!

Now, if someone reading these boards and this post specifically has the expertise and know how to put together a "trivet" that is basically a large flat container of a medium that will even out heat and deliver it to the bottom of pans, they have my permission to use my idea, BUT I want a whole bunch of freebies! It is possible. I don't know why someone hasn't already done it. It's not rocket science. Stove and cook top manufacturers could make it "built in." Sometimes I get rather impatient with the world and all this thinking inside the box. ....curmudge curmudge curmudge....'-)

[Chemicalkinetics]

They have, they just decrease the heat response and people don't like them.

[kaleokahu]

Car: "...it is pretty damn obvious that the aluminum is NOT transferring as much heat from the outside bottom of the pan to the inside interior of the pan as the cast iron."

Respectfully disagree, Ipo. The same heat is being transferred. The aluminum is dissipating the (low) heat over the whole bottom (and into the room, Politeness) at a rate that prevents any one point from scorching--at least for 20 minutes. The CI dissipates the same heat some, too, but most just stays within an inch or two of the flame. There it ACCUMULATES to cause a localized scorch. At some point of stasis (probably later than the 5 minute preheat) when it has soaked up as much heat as it can hold, the hotspot is going to give up more heat to the surrounding air--and burn the @#$% out of your food.

You are right about the need for evenly heated hobs. The AGA I want has them, as does the ancient institutional woodstove. My radiant cooktop comes close. And resistive hobs aren't terrible, either. Maybe if/when the stove geniuses come up with a continuous (or very tightly coiled) induction element, induction won't be bad.. I know some makers of high-end induction elements claim already claim their stoves can sense pot size and automatically adjust. My suspicion is that these things are just two concentric coils (remember the OLD two-element resistive coils?).

'...trivet..." I have one. It's a cutout from making a place for a ship's porthole, in 1/2" aluminum. Free piece of scrap. Works pretty good, but not sized exactly right for one hob. A 1/4"-thick round of copper sized to your hob should do the trick. Your son the electrician might know where to get the thick copper plate. The diffusers or "Flame Tamers" I've seen for sale all seem to be steel and thin; so you would just be buying yourself a little smaller hotspot and a little bigger utility bill.

[Caroline1]

Either you 're being too literal interpreting the world "trivet," or I should have come up with a better word. I'm talking about a hollow disk filled on the inside with a fluid of some sort and either a pump that forces circulation to keep heat even OR a fluid with natural convection patterns that would automatically stir itself and keep the heat even. I'm not talking about a solid disk of anything. Solids cannot distribute heat evenly in the way that fluids can.

[cannibal]

heating fluids in a sealed environment is a good idea in theory, the fluid will "stir" itself via thermal convection and distribute heat well. Oil will be the best (cost effective) candidate for that type of application, but the construction would have to be quite heavy duty and if any moisture were introduced at the time of manufacture a boiling liquid expanding vapor explosion could result (think boiler explosion). The thermal expansion of the oil within the contained metal might also cause the vessel to rupture. I'm not sure if that would be an issue or not, just my thoughts.

I am with kaleokahu on this one, i think a copper disk of 1/4 inch, and quite possibly even thinner than that, would be the best route. It might not be as good as liquid convection, but the heat would be distributed quite evenly to the cookware

[Caroline1]

Busy day. Sorry I'm so slow to answer. So my question is, WHY do you think a copper trivet would spread heat more evenly than my copper pans? My point is that there are NO pots and pans on the market today (that I've ever heard of) that both transfers heat directly and spreads it across the bottom of a pan uniformly. NONE! But an enclosed material that redistributes heat by interior convection currents OR a similar sealed disk with a less sophisticated interior fluid that distributes heat evenly because the fluid is pushed through a circulation pump would both do the trick.

I suspect a "solid metal" disk capable of doing that would not be solid at all but would, of necessity, be formed of a "honeycomb" of vented cells or miniature baffles and chimneys that redirect heat, spread heat and produce an even temperature on top of the honeycomed disk that has seriously modified the uneven heat hitting the bottom. Possible? Yup. If a company produced them and sold them at a reasonable profit margin, could I afford one? Sure. As soon as I finish paying off my Aston Martin! '-)

[kaleokahu]

Car: Jeez! I'M supposedto be the one who always overthinks things. Now you're doing it! Let's try imagineering together.

We just invented another doozer... Instead of our previous Ronco induction converter disc, we do away with the hob entirely. In its place, we sell everyone an IMMERSION CIRCULATOR BATH (think "sous vide"), except OUR bath is going to contain a VERY high boil-point, inflammable liquid that will put even heat into every pan floated on, or suspended in it. It can be so viscous it holds the pan like the old engravers' pitchpots. Hell, you and Politeness can even fire it with INDUCTION if you want. First Culinary Science Nobel goes to.... Car!

In response to yours to cannibal below, the copper trivet wouldn't offer any (or much) advantage over just using copper to begin with (see, today's "Second Scorchprint..." thread). But it WOULD even out the heat for (the bottoms of) poorly-conductive pans like steel and CI on gas hobs.

Also, appropos of your honeycomb/cellular speculations... I'm too lazy to look up the thread, but someone here recently reminded us of the existence and efficacy of baffled "heat exchangers" that clamp around the walls of mountaineers' flimsy aluminum pans to better insulate/wrap them in heat.

[paulj]

mercury bath?

high pressure steam?

[kaleokahu]

paul: Or liquid sodium?

I was a little tongue-in-cheek w/ Caroline, but it is a decent thought experiment, isn't it?

If Feran Adria came up with an implementation of Car's idea after his sabbatical from el Buli, it'd be big news and all the top chefs would be throwing $XXK money at it. Problem is, you'd ultimately have to mate it with something like an Antiskillet to improve beyond the responsiveness and evenness of... you-know-what.

[Caroline1]

Heat whatevers on campers' aluminum pans are magnitudes larger than what I'm talking about. I'm talking about amost or maybe true nano-technology. VERY small scale baffles and chimneys that redirect micro-currents of heat to deliver even heat to the top of a plate that has uneven heat applied to its bottom. But what corporation is THAT interested in helping home cooks get a more effective heat source than we currently have available when we've been cooking good to great food without it for millenia? All of the mega-corporations that have the funding, facilities and available brain power to do it are busy grinding other axes, so to speak.

But there is more to sticking and scorching that just uneven heat under a pan. Do you recall my mentioning I bought several MUI induction friendly pans? Well, they're a pain in the butt to cook anything beyond water in because they have a BRUSHED stainless steel interior. What IDIOT came up with that??? They are incredible at heat transference so I have to dial down the heat by at least a notch compared to what I use for the same cooking process with my copper OR cast iron. but that brushed finish instead of a mirror finish on the interior provides micro nooks and crannies for food particles to settle in, expand and scorch. Trying to make gravies or sauces in them requires constant a vigorous stirring to keep things like flour particles from settling out of suspension and coming to rest in the grooves and then expanding, locking themselves in and turning to cinders! Consequently water is the only thing that doesn't require constant stirring to avoid scorching. But hey, my StirChef automatic pan strrer is getting used for a lot more things than just making risotto...! If the MUI pans only outperformed my copper on heat utilization, I would attribute it to the aged warped moderately abused copper, but it outperfomrs my cast iron that has been given a long preheat as well, so I assume the difference has to lie in the thick layered very flat bottom plate. Probably.

Long and short of it all, a perfect world is a great thing to dream about, but after days like today, I'd be really happy with a world in which nothing breaks! '-)

Oh, and reading paulj's "high pressure steam?" comment, the stove top even heat we are wishing for is with us now in the form of pressure cookers. Only problem with them is that it's a bitch trying to stir a risotto in one of those puppies! Wish I knew what happened to mine!

[paulj]

Fortunately, a decent risotto can be made in a pressure cooker without the continual stirring - just stir after you take lid off. I don't know why it works, given all the emphasis on stirring in the open pot method. Maybe the higher heat does a better job of extracting the starches from the rice. It's the fluffy rice that's hard to make under pressure.

[Caroline1]

Interesting! Thanks. Gotta get me a new one. '-)

[kaleokahu]

Car: Re: "...MUI induction friendly pans... incredible at heat transference..."

What is the construction and thickness of these pans? I bet there's a better explanation than micronized food sticking in the brushed finish. Or are the folks at Mauviel, Falk and Bourgeat idiots?

[Politeness]

kaleokahu: "I did repeat the test today with a 5-minute pre-heat as Politeness suggested."

Interesting results. Thank you.

kaleokahu: "In the case of the aluminum pan, that metal's much better conductivity means it has the capacity to easily move the heat laterally through the pan's bottom and up the pan's wall so as to take OUT from the directly-heated center enough heat to prevent scorching. In this test at low heat, aluminum pretty much took all the heat to all corners of the pan without scorching."

OUT from the directly-heated center, to all the corners of the pan, around the rim, and out. Air ball! That's the way our Portland Trailblazers are shooting basketballs these days.

(Sorry, I couldn't resist.)

[kaleokahu]

Politeness: At least Portland has an NBA team! The way the Sonics usually "played", I'm glad the good folks of OK get to support them.

Re: your airball analogy, I appreciate the tweak. Don't you think all pans are going to act as a room radiator to varying degrees--even those that work on induction? Funny thing is, though, that a lot of the heat goes and stays in the pan where it's supposed to be. The aluminum pan here clearly got hot enough (on low) to brown the parchment, and it even cracked a few of the glass beads. Maybe a future evolution in cookware will be thick copper bodies with a thin steel disk stuck on the bottom, lined inside with nickel, and cladded outside with some super-insulator to keep our kitchens cold. And will go in the DW.

Overnight I was thinking of how best to do Caroline's oven test. Obviously I don't want to put my LC skillet's wood handle in the oven, and I was thinking of the other CI pans I have to use in various places. I drifted off to sleep imagining the stovetop test above using my largest LC skillet. Then I visualized the 12-inch parchment circle, and the same FOUR INCH hotspot I knew would ultimately result. I came to the conclusion that--for stovetop cooking with gas, anyway--one (yikes, that's me!) would be foolish to use a CI vessel with a bottom diameter more than an inch larger than the widest spread of the gas flame.

Then I thought more about preheating and its ramifications... Yesterday's 5-minute preheat of CI increased by 50% the energy used; 10 minutes would have doubled it! And apparently, all for nothing when it came to evening out the heat in CI.

I've read here of folks who preheat their CI in the oven in an attempt to even out the heat. That probably works after a fashion, but THAT must really make the gas/electric meter spin. And how long does it take to preheat the pan, considering you're starting with a cool oven? I visualize some LC afficianado out there who spends 15 minutes oven-heating their skillet, only to remove it to fry some eggs before the heat bleeds out.

I really need that IR thermometer (and a 220V watt meter). But it just makes common sense to me to use more conductive vessels on stovetop--preheat is accomplished as eggs are cracked and mixed, the skillet is even and right within a minute, and BOOM, it's breakfast. In retrospect, I probably could have cooked myself breakfast in the aluminum pan (and washed up) during the 15-minute (total) preheat test on cast iron.

Maybe there is some hidden virtue to CI on the stovetop. Maybe someone with experience has learned to simultaneously sear their steak on the CI hotspot and saute veggies around the periphery, I don't know.

OK, on to Caroline and the oven...

[MikeB3542]

Cast iron has no "hidden" virtue. It's all about the weight. All that weight means it can store a LOT of heat. That's important when cooking actual food (which contains lots of water) vs. parchment which is dry. The trouble with water is that it takes lots of heat to raise its temperature, and several orders of magnitude more than that as it transitions to steam.

Basically, a given thickness of cast iron has 50% more heat capacity than aluminum (the aluminum by weight can hold twice as much heat, but the aluminum will be 1/3rd the density). Practically, that means that during a sear, an aluminum pan will cool quicker than cast iron unless the range can keep up with the heat consumed by the warming food. Let any pan cool off too much during a sear, and you are steaming instead of searing.

Another other virtue of cast iron is that it is a pretty lousy heat conductor -- behaving like a ceramic rather than a metal. And like ceramics, that can help moderate unsteady temps.

Oh yeah. It is dirt cheap and durable.

And the "hot spot"? If you are using gas, direct the flame, if possible, to the edges. Move the pan a little. Oil helps. I don't have an IR thermometer, but a few drops of water will reveal spots that are lagging.

[kaleokahu]

Mike:

Sorry, I really meant some hidden virtue of turning hot-spots to some sort of cooking advantage.

Since you raised the subject of specific heat capacity, that of aluminum is .91 KJK/cc, and copper's is .39 KJK/cc, which amounts to about 40% greater capacity by volume for copper, because of aluminum's far lower density. Cast iron's specific heat capacity is only slightly better than copper's, at .46 KJK/cc. When you factor in the materials' densities (Cu: 8930 Kg/M3 vs Cast Iron: 6800 Kg/M3), cast iron is at best in a tie with copper for holding heat.

I like your sear example. What do the pans DO with the stored heat once you flop in your raw steak? Assuming that the Al and CI pans have the same system heat capacity at the time of flop, if the burner can't "keep up" as you put it, the stored heat in the pans is going to seek the now cooler area under the meat. What little heat made it past the hotspot on CI is now going to have to fight its way back (probably more like die trying). Whereas I think aluminum's much higher thermal conductivity (118 Btu/hrF/ft vs CI's 34 BTU/hrF/ft) is going to mean more of the stored heat gets put into the meat.

Put it this way: If we seared two steaks identically, and then moved them, one into a aluminum pan and the other into a CI pan of equal mass and equal center temperatures for finishing, the steak finished in the CI pan should finish more slowly. This is consistent with the excellent results I have gotten with finishing grilled steaks on one of those ancient cast-aluminum oval "draining platters", preheated on the grill.

"...moderate unsteady temps." Yes, you're right, but I don't see that as a virtue. The bane of my stovetop cooking in CI is to not overadjust the heat, and I find that I often do overadjust (up and down) because it takes the CI so long to respond. In reheating stews for example, I've observed nary a simmer, goosed it up a bit too far, and 2 minutes later I smell scorching about the time the simmer finally comes up. Sort of like steering a supertanker.

[paulj]

That heat capacity of iron is making up for the low power of home stoves. Cheap aluminum on a restaurant burner should sear just as well as cast iron.

[kaleokahu]

paulj: Funny you should mention restaurant burners... [You're absolutely right that Al on a high-output burner will sear just fine.]

That got me thinking about what was happening with searing in CI... Basically, the cook is using the hot spot as the only useful surface. In effect, you have a VIRTUAL pan only as large as your hotspot, regardless of actual pan size.

The same thing will happen on a high-output burner, too. This came to me when I was looking at LC's new 15" skillet yesterday. That behemoth will still only have a 4" searing surface on my range. The high output burner will only enlarge it, and you'd STILL be much cooler around the edges of a large pan. Maybe a roofer's tarpot burner would do the job!

It would be interesting to retry this test using much SMALLER Al and CI skillets sized to the hotspot. How would you expect the scorchprint and timing results to differ?

[c oliver]

I'm curious. Is there a pracitcal point to all of this?

[kaleokahu]

c oliver: Yes, I think there are several, but you seem to have decided otherwise. Your curiosity is contagious: Do you have something constructive to contribute?

[c oliver]

I think my question was potentially constructive. Do you intend/hope/whatever to change your own or other's choice of cooking materials? Or is this just a quasi-scientific experiment with no practical goals or applications? Is that constructive enough for you? What did I write that made you think that I "have decided otherwise"? I don't think there's anything wrong with just doing your little tests for the fun of it. I just haven't seen that the differences are great enough to have significant effects when cooking. Which is why I'm on CHOWhound.

[kaleokahu]

c oliver: "...intend/hope/whatever..?" My intent was to confirm my own suspicions and to pass the test information for others, with which results they may do whatever they wish. I apologize for being snarky, but I thought my little test was obviously of practical application; knowing that, under controlled conditions, popular CI skillets hot-spot within 6 minutes, whereas aluminum ones do not, even after 20 minutes, would be of considerable practical utility to folks. Harold McGee's versions of this test have already informed many readers in their choices.

I mistook your question for a declarative implication that you considered this test somehow merely theoretical, impractical or self-satisfactory. I apologize again if that wasn't the case.

"I just haven't seen that the differences are great enough to have significant effects when cooking." I and others have. See, eg., my post on caramelizing/carbonizing/deconstructing onions on the stovetop in a LC cast iron DO.

If you are super-vigilant over your hobs, cook in quantities only large enough to "fit" your hotspot, or LIKE to frequently stir/jump your contents around in your pan to get it all cooked evenly, perhaps the differences are not significant to you. But this IS a cookware board after all, and the differences these tests reveal are important in cooking.

[c oliver]

Apology accepted and I'm sorry also cause my latest reply to you was snarky also. My point is that when I'm cooking on top of the stove, I can't remember a time that I'm just leaving things to sit in the pan. They're always getting moved around. Except for really, really low heat and with my induction I can get so low that only an occasional bubble will break the surface. So if there are hot spots - and I'm not doubting you at all - I don't feel like it's making a difference. For me. Of course :)
PS: I'm one of the old ladies here also!

[kaleokahu]

c oliver: No problem. For me, I do have a little cooking ADD/ADHD, and so I often end up walking/turning/looking away from low hobs for longer than 6 minutes. I wish I were more vigilant. The shocking part of this for me was that this WAS a low heat test. I'll try pre-heating, but I think (with the exception of the "prints"), that ground has been plowed already by others (e.g.,athanasius???)

[c oliver]

k, you may have hit on an important difference in cooks. You're a self-described ADD/ADHD while I'm of the 'is there a hyphen in anal retentive' school. So, at heart, we just don't understand each other. And perhaps we argue for that reason. I continue to appreciate CH.

[Politeness]

keleokahu (quoting c oliver): "'I just haven't seen that the differences are great enough to have significant effects when cooking.' I and others have. See, eg., my post on caramelizing/carbonizing/deconstructing onions on the stovetop in a LC cast iron DO."

Like c oliver, I don't have a dog in this fight. We have several pots and pans with thick aluminum disk bottoms, a few cast iron pieces, and some clad pieces -- and our energy source extends fully across the bottoms of most of our pots. So we are interested in, but have no rooting interest in, the results of your tests.

When we are using cast iron on the cooktop, we ALWAYS preheat the pan before we put any food into or onto it; I cannot recall ever starting by putting food in a cast iron stovetop vessel before starting the burner under it. This is exactly because, as you are well aware, cast iron has relatively slow conductivity. It is the analogue of preheating the oven before putting the baking dish or roast into it. Therefore, I suggest another test that you may wish to perform to create a full suite.

I would be interested to see what results you would get if you preheated the same two pans at medium heat for five to ten minutes, THEN put the parchment paper into the preheated pans. It may well be that the results would be similar to what you found starting cold -- I expect it to be more probable than not that they would be similar. But if the results were similar, it would be more relevant to the way that cooks actually caramelize onions, for instance.

(Another potentially informative but separate test -- probably needing a remote infrared thermometer -- would measure the amount that the temperature of the immediate surface of the pan changes when a quantity of food with relatively high specific heat -- like cold slices of onion -- is placed on, say, an aluminum surface and a cast iron surface.)

[kaleokahu]

Politeness: Thank you very much for your constructive and supportive input. In particular, your observation about preheating is insightful. With regard to the aluminum pan in the test, at 20 minutes before any appreciable browning, I think that pan WAS effectively--if unintentionally--preheated. But the 6-minute-to-scorch-from-ambient in CI was SO fast, that I will try the preheat you suggest; it IS a more realistic test assumption. While the graphic evidence of such hasn't (yet, cannibal?) been displayed, I believe the IR data has already been posted for CI preheat (athanasius???). So, yes, let's "see" with parchment. The Devil is always in the details, isn't it?

The small LC DO that I used for the stovetop onion carmelization complained of last week was preheated. Not that it mattered, since it Tom Keller's delicious-yet-stultifying FOUR HOURS of slow heat should have evened things out--if ever it was to happen. Which it didn't. But you are nonetheless wise to suggest printing and IR measurement with a food-like specific heat loading. I tried to do that with the glass beads serving as a heat sink, but perhaps cold chicken breasts would be better.

BTW, I bear no malice toward CI as a material. It's cheap to produce, easily and safely coated, and attractive. It is primal and traditional and heavy in all the best senses. I own a lot of it, and so would actually be pleased to be proven even partially wrong.

"...our energy source extends fully across the bottoms of most of our pots." I assume from prior discussions you are referring to your induction cooktop(s). I'm really not trying to pick a fight here, but are you saying that the induction coils underlying your Ceran surface fully cover the pan bottoms? You are more knowledgeable than I about induction and these things. The reason I ask is that I have sketchy recollection of seeing somewhere (Harold McGee???) photo "scorchprints" in flour purportedly showing translation of single-coil induction elements through the pan that looked like hot spots to me. So I am wondering--in the aspect of this test--whether cast iron on induction might yield "unevenness" results comparable to cast iron on gas.

Any additional advance suggestions for parameters would be welcome, but I do not yet own an IR gun.

[cannibal]

I haven't forgotten about you kaleokahu ;)
I am still on vacation but i remember my test being quite similar on the pre-heats to the room temp warm-up on cast iron. As a result, if i do anything in my cast iron that requires even heating on the whole surface of the pan, i will pre-heat in the oven. If less than perfect even heat is required and dont want to fire up the oven, i will pour 1/8 inch of high smoke point oil (usually grape seed) and cover the pan when preheating with pretty good results.

[kaleokahu]

cannibal: No special hurry. Enjoy your vacation. I'm just eager to read your data and see the prints whenever you get around to it.

[Chemicalkinetics]

Nice, kaleokahu. On the other hand, you aren't really surprised by the result, right?

[kaleokahu]

Chem: No, not surprised by the overall result, but I WAS surprised with the details. See, my response to Car above.

[Chemicalkinetics]

There is no question in my mind that an equally thick aluminum pan will provide a more even heating surface than a cast iron pan. I am guessing your aluminum pan is still thinner than your cast iron pan.

[kaleokahu]

Chem: "...no question in my mind..." Well, that was also my take, before and after, but the myth that CI heats evenly keeps getting slavishly repeated. And there are those who contend that pans higher-conductivity will actually hot-spot FASTER directly under the flame. This contention is sensible on its face, but it turns out it's wrong under this test. We'll see what happens with higher heat settings and what cannibal's data show.

"I am guessing your aluminum pan still thinner than your cast iron pan."

I thought so too at first. My calipers that will span the pans are not micrometer-accurate, but these two pans are both VERY close to the same thickness. The LC is the splayed-wall, stovetop-only pan with the wooden handle.

[Chemicalkinetics]

Kaleo,

McGee did a test based on pachment paper:

http://www.nytimes.com/2008/10/08/dining/08curi.html?pagewanted=1

Arnold did one based on flour:

http://www.cookingissues.com/2010/02/16/heavy-metal-the-science-of-cast-iron-cooking/

Athanasius did one based on IR thermometer:

http://chowhound.chow.com/topics/7381...

Now you did another one and all came to the same conclusion. I am sure there are many more out there.

Some people just choose not to believe, and no matter what you say, they won't be convinced. One more or one less test is not going to change them. Think about it. If someone refused to believe in McGee and Arnold's tests, do you think the same peson will suddenly change his/her mind after reading your results?

Hmm, if the aluminum pan is the same thickness as the LC cast iron pan, then the iron thickness of the LC must be less than that of the aluminum pan -- because of the enameled surface.

[kaleokahu]

Chem: Good points all. Hopefully, I can get the photos posted later today. The great thing about what McGee and Arnold did is that you can actually SEE the hotspots. You found those links, but you were LOOKING for them and knew what to look for. Unless someone here points them out (thanks), it's as if they don't exist. I don't expect anyone will believe me who doesn't believe McGee and Arnold.

The OVERALL thicknesses were the same in my two pans, so yes theoretically the metals were different to some minuscule degree. We can drive ourselves crazy trying to totally equalize all the variables.

[kaleokahu]

Chem: Regarding the persistence of the myth that CI heats evenly, I made an interesting discovery yesterday. I was looking at the LC website (on an unrelated matter). The site allows you to choose to browse their products. The CI page has options to browse by pan category, with a little blurb for each. Several times the blurb touts "even heat" that cooking on the LC products provides. I think their only cover for what otherwise would be a bald-faced lie is that they say "even" only about their French Ovens--as if they're only used IN the oven.

Think about how many TENS OF THOUSANDS of folks are going to put out their hard-earned money this month to buy and give this "even" heat. The new owner will be so excited, they'll try to cook and cook with the stuff for YEARS before they figure out it is anything but "even" on the stovetop.

[Chemicalkinetics]

Kaleo,

Well, everything are kinda of even heating inside an oven. It isn't like an aluminum cookware is more even heating on stovetop, but a a LC dutch oven is more even heating inside an oven. I am sure an aluminum Dutch Oven is also even heating inside an oven too.

The only defense I have is that the "even heating" is refering to time and not space. That is the temperature of the Dutch Oven is more stable in time due to the large heat capacity. Remember we had that conversation sometime ago about temporal vs spatial?

Like Mike said in the below post, if we are to drop a thick piece of steak onto a LC cast iron pan, the cookware won't cool down as much as an aluminum pan.

Is it misleading? It sure can be for many people. Is it the top 10 or top 100 misleading advertisements I have read? No.

Below is a beautiful ceramic pie dish from Emile Henry. Now, I am sure it is a great bakeware, but I thought one of the statement is bit misleading and had a conversation about this on CHOW before. It states: "Each pie dish is shaped from Burgundian clay, which absorbs, distributes and retains heat evenly"

http://www.williams-sonoma.com/produc...

Well, if it heats evenly, that is only because of the oven giving off heat evenly. Ceramic is a very poor heat conductor, much worse than cast iron.

[ThreeGigs]

I've said in other posts that it doesn't matter what material you use in the oven, the only difference will be how quickly heat gets from the air into the food. That's why I use my AC 8qt stock pot as my dutch oven.

[kaleokahu]

3G: Yes, you're right. It's one of those instances where common sense can be empirically proven to be correct. If only everything were so simple...

[Caroline1]

Good on you! Interesting results. I am a bit surprised you got no scorching from the aluminum. Live and learn! You are a scholar and a gentleman!

As to our earlier discussion about aluminum and onions. I don't boil onions a lot, but I do boil them in soups and such. It's many years since I've seen a solid non-anodized aluminum pan but back in the middle of the last century they were common fare. The chemical interaction between the onions and aluminum emits an unmistakable odor. Few people ever created it a second time. I have always suspected it was a major impetus to the anodization process. Thank heaven!

EDIT: I am still curious whether you would get scorching in the cast iron pan in an oven? Or more to the point, would the scorching be patterned in an oven? You're a good man, Charlie Brown! '-)

[kaleokahu]

Car: I was very surprised that there was no scorching with the aluminum, too, especially because this Swiss Diamond pan was only 4mm thick, way thinner than some of the disc-bottomed pans now out. What shocked me the most was not the result with CI, but HOW FAST it scorched. With my attention deficit, 6 minutes' unawareness is nothing!

I can try the pans in the oven, but I have a high confidence that all pans will perform in an oven pretty much the same. MAYBE in a gas oven, if you crowd a CI pan to the very edge of the very bottom rack (basically over the flame source) you might get some more scorching in CI, but I doubt it. If that were the case, I'd expect a linear pattern at the edge, rather than the center of the pan.

[Caroline1]

The thing I'm most curious about with cast iron in the oven is whether it will show more even heat in that "even heat" environment, or if the hot spots are inherent to cast iron and I haven't realized it for lo, these many decades simply because I grew up with cast iron and have accepted it on its own terms all of my life. If it shows hot spots in the oven, then it is absolutely a flaw inherent in cast iron.

So now, where were you when I was talking about getting a Swiss Diamond induction omelette pan and someone was bad mouthing Swiss Diamond? And how much do you like it? I still haven't gotten it, but my Sabatier fluting knife DID arrive yesterday. Mushrooms of the world, BEWARE! As for the even heating with the Swiss Diamond, for me that raises some question as to whether all aluminum would be as even tempered, pun intended. Too bad the crappy old super cheap spun aluminum pans of the 50's aren't still around. I'm sure they are, but probably exclusive to third world countries. I was forced to use them or eat raw in my early months in Turkey, until the base exchange got in a shipment of Le Creuset. If I didn't like the shape of a pan, I could reshape it with my bare hands! Yay, spun aluminum. Other than being nasty for boiling onions, they were cheap and efficient, but I suspect that they WOULD reflect the heat shortfalls of any given burner.

[kaleokahu]

Car: I would be greatly shocked if cast iron in an oven showed hotspots or any unevenness, but for you I will try. I think the best way to think about it is that your oven IS even heat, regardless of what you put in it.

Swiss Diamond: This pan was a gift to me, although it is now my wife's go-to. You know my views on PTFE, and for that reason I have a hard time recommending non-stick to anyone. It was the only straight-gauge aluminum skillet I had for this test within reach in that kitchen that was of equivalent thickness to the LC.

But since you asked... I was impressed by the evenness with which it heated, it's steadfast refusal to scorch (albeit on a low flame) over 20 minutes. Coincidentally, my wife used it last night to brown some "cocktail weenies" (!!!) prior to putting them into a chafing dish, and I was also surprised how well it browned them, given PTFE's hydrophobic property. My only MINOR annoyance with the pan itself is that the handle is affixed by a single screw that occasionally needs re-tightening.

[Caroline1]

Well, I was surprised by the results of your scorch test with cast iron and aluminum. I expected at least an echo of similarity in the results instead of poles apart. So now I'm wondering if there may be something inherent in the smelting of steel that makes cast iron less conductively "homogeneous" than other metals? And yes, cast iron *IS* steel. It is incredibly expensive to to smelt pure iron because any exposure to open air allows oxygen bonding and Voila! You have steel, not iron. But it's not a greatly refined form of steel, but steel nonetheless.

Are you sure the Swiss Diamond contains PTFEs? damn. I can't remember the brand, but a few days ago I read an ad for a non-stick brand that said it had none and was oven safe to 500F. What I'm looking for is an excellent non-stick 8" skillet for omelets that won't be ruined when the housekeeper puts it in the dishwasher, and that stays "good as new" no matter what kind of abuse it gets. In my dreams, or is this reality possible? The quest continues...

[Chemicalkinetics]

Swiss Diamond cookware absolute have PTFE in them. It caused some controversy because the company claims Swiss Diamond cookware do not contain Telfon when in fact they contain exactly the same chemical. They simply did not buy the PTFE from Dupont, so it is not Teflon, like Frisbee vs flying discs or Kleenex vs paper tissue. Telfon, Frisbee and Kleenex are trademark names.

http://www.naturalnews.com/021059_Tef...

I don't think it is a matter of smelting. Steel simply has lower thermal conductivity than aluminum, just like aluminum is less conductive than copper. It is their chemical properities, not the processes.

[Candy]

The company says no POFA's. NOT PTFE's. They admit there are some ghosts of PTFE's remaining after application of the diamond surface. Most are burned off in the process if application. Of course you'd have to be able to heat that pan to over 700F to release them and having a bird cage next to a cook top is a pretty poor idea.

[tanuki soup]

To further clarify, the following Q&A's are taken from Swiss Diamond's website:

Do you have “PFOA” in your “PTFE”?

NO!!! The reasons are that the nano-composite containing real Diamond Crystals requires such high temperatures in the production process that any particle of PFOA which might have been contained in the PTFE will be eliminated thus NO PFOA can be traced on Swiss Diamond products’. We have a test result from the Danish Technological Institute, clearly testifying that our products do not include PFOA. Nevertheless, since March 2008 we have been using PTFE that is manufactured without any PFOA.

Do Swiss Diamond products contain “PTFE”?

YES! PTFE is the component that gives non-stick properties to the surface of the cookware and many other consumers’ products. Our patented inherent slippery coating is reinforced with Diamond Crystals which are amalgamated into a nano-composite (mixture of extremely thin particles). Thus it requires lower quantity of PTFE, much lower than most of other non-stick products.

[Chemicalkinetics]

"The company says no POFA's. NOT PTFE's. They admit there are some ghosts of PTFE's remaining after application of the diamond surface."

No, I am afraid you are confused. PTFE is the main ingredient for the Swiss Diamond. Without PTFE, Diamond won't work one bit. It is PTFE which gives the nonstick property not the diamond. The company actually used POFA in the original ingredient.

Finally, what got many people upset is that Swiss Diamond has promoted the cookware are Teflon-free. No Telfon.

Well, here is a problem Teflon is PTFE, exactly the same chemical. The only difference is that Telfon is a trademark name of PTFE, just like Frisbee is a trademark name for flying discs. Now, imagine you ask someone if he is playing Frisbee and he said "No, I am not playing Frisbee. I am playing flying discs" or "I don't have a Kleenex to give you. I only have paper tissue". Except, Swiss Diamond didn't even brother to say the latter part.

Swiss Diamond was very misleading when it advertises the cookware are Teflon-free.

[Politeness]

Caroline I: "I can't remember the brand, but a few days ago I read an ad for a non-stick brand that said it had none and was oven safe to 500F. What I'm looking for is an excellent non-stick 8" skillet for omelets that won't be ruined when the housekeeper puts it in the dishwasher, and that stays "good as new" no matter what kind of abuse it gets. In my dreams, or is this reality possible?"

What you may have read was something about Sitram Cybernox. It has no PTFE and is claimed to be safe to 1800° F. Cybernox is nonstick-ish, but, like Chantal enamel (which also is nonsrtick-ish), it is not as nonstick as PTFE. Cybernox can be thrown in the dishwasher.

We tried one piece of Cyvbernox, and returned it. The surface on the sample we tried (typical? sample defect?) seemed to be about as scratch-resistant as some of the softer versions of stainless steel; after a while using metal utensils, I doubt that it would look "good as new"; but, again, ours may have been a one-off defective sample.

It does seem cheap enough to take a flyer on, however. http://www.wilhelmsonline.com/sitram-...

[Caroline1]

Thank you , kind sir, but that's not it. If only I could remember where I left my thinking cap, maybe I could put it on and remember what the brand was! I really need to top off the sticky of my memory! <sigh>

[Caroline1]

TaDAAAH! I found what I was talking about. Scanpan from Denmark! You can see a skillet and read about their technology here:
http://www.cutleryandmore.com/scanpan...
It's PFOA free, so now all I have to figure out the difference between PFOAs and PTFEs. <sigh> When did cooking get so complicated? '-

)

Oh, and that Japanese cast iron fry pan you provided the link to is GORGEOUS! hmmm... Was that here or on that "other venue?" Whichever. If it was non-stick and free of all of those alphabet-soup things, my order would already be in!

[tanuki soup]

PFOA is an emulsifier that is used in the production of PTFE (Teflon). Since PFOA is toxic, carcinogenic, and persists indefinitely in the environment, producing PTFE without the use of PFOA is "green" technology. The PTFE nonstick coating on the cookware is the same.

[Caroline1]

Thanks! I could have Googled, but there are so many gracious people here, such as yourelf, who will just ell me. I am in your debt! Now all I have to do is figure out which omelette pan I really want!

[kaleokahu]

Car; You should re-read the Mod-locked thread about the safety of non-stick. It has a lot of info about PFOAs. They are used in making PTFE. And are very toxic.

Dupont signed a consent decree to EPA promising to phase out all PFOA by 2012, and were allowed by the Shrub Administration to keep using it til then as a necessity. If Scanpan is making their nonstick without it, I guess it wasn't such a necessary, was it? Sounds innocuous, except for that little town in West Virginia getting poisoned and all..,

[kaleokahu]

Car: "homogenous..." Maybe. I dunno. CI has been around a long time if you count the time when it was a Chinese trade secret. Nothing like copper at 7,500 years, but nearly 2,000. I would have thought that, within that span--even if measured from Darby's invention in 1707 that allowed for mass production of cookware--they would have all the lumps smoothed out.

I am not sure (in a bet-your-life way) that Swiss Diamond is PTFE, but I know there was a recent semi-boring subthread here addressing the advertising shenanigans of SD where they slyly denied that there was any TEFLON in the coating, i.e., equivocating about, yet not denying, generic PTFE.

Our SD gets the DW treatment all the time [I really wish for a reason to throw this pan away]. It's probably 4 years old and seems fine--water beads strongly, doesn't sheet. And we use (gently) metal utensils. It has discolored slightly in- and outside. I WON'T put it to 500F, but others here are sanguine about the physical chemistry and safety. I don't know what to tell you.

[Chemicalkinetics]

The nonstick ability of Swiss Diamond is from PTFW, better known as Teflon to most people.

http://www.swissdiamond.com/us/info/f...

The diamond is simply a way to create "hill and valley" similar to the logics behind what Circulon does to its cookware. It makes the PTFE/Teflon a bit more stable against physical damage.

[Caroline1]

Car: "homogenous..." Maybe. I dunno. CI has been around a long time if you count the time when it was a Chinese trade secret. Nothing like copper at 7,500 years, but nearly 2,000. I would have thought that, within that span--even if measured from Darby's invention in 1707 that allowed for mass production of cookware--they would have all the lumps smoothed out..........kaleokahu
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Yes, but... I think you might have missed my point. What if there is something inherent in cast iron that cannot be modified by different smelting methods or whatever. Something that is impervious to technology? Metals are not that dissimilar to rocks. They are all "mineral deposits" in the earth. When you examine the coloration and actual colors of rocks, you can tell all sorts of things from how the magma cooled, whether the rock was formed as a result of magma extrusion or from sedimentation and pressure, what temperature the rock solidified in the cooling process, and whether it separates into mottled patches of color, striations of color, uniform color. Now, what if the color differences we see in rocks are equal to a heat conducting variability in metals, in this case cast iron specifically. What if cast iron is inherently incapable of heating and conducting as uniformly as aluminum or copper or silver? What if that particular metal always cools into a mottled pattern of hot and not so hot spots when it comes to heat conduction?

That's what I'm curious about, and if it turns out that cast iron does produce scorch spots in an oven, then it is a characteristic of cast iron. Either way, we do have to just live with cast iron on its own terms, but it is curiosity soothing to know if that's the case.... '-)

[kaleokahu]

Car: Good observations and Imaginative questions and above my pay grade to try to answer. My inner Inspector Clousseau observes that the hot spot is always directly above the gas flame and notices that one characteristic of cast iron is its good fluidity. So I don't know. I'll try your oven test.

[Caroline1]

Bless our heart. You are a love! :-)

[cannibal]

I did a similar test but with four and a sifter. I didnt publish my results though, it was just out of curiosity :P
I used a ratio of 1/4 cup of flour for every 50.25 square inches (an 8 inch pan has an area of 50.25) and i did heating from room temp to low and room temp to mid. Also did preheated to low, med, and high if the cookware could take it. I cant remember what my time constant was for how long i let the flour sit at each temp. I used a infrared thermometer with an accuracy coefficient of +/- 2 degrees to make sure the pans were all at the same temp.
I did several different materials and i took pictures of it all, but i dont want to trump your post with my results but i will share if you like (when i get home, on vacation right now)
Ovbiously this was done before my daughter was born. Same experiment would now take a week rather than an afternoon :P

Edit: the measurement for the area was from the flat part of the pan, not including the sloping sides. 1/4 cup of flour was converted to weight for greater accuracy

[kaleokahu]

cannibal: Really good news! Yes, PLEASE share your data and photos. I have no interest in reinventing the wheels here, and little pride of authorship. Sounds like you have already done much good work.

Someone ought to be doing these scorchprints for all cookware lines. We should also integrate your data with my feeble prior tomfoolery and the good work of others like athanasius.

[cannibal]

I agree that some sort of standard test should be part of a pan review. Especially when every manufacturer seems to claim their cookware has no hot spots.

[kaleokahu]

cannibal: Totally agree, but standardization would necessarily be somewhat arbitrary. And what do you do when it comes to different hobs? There must be 250 different gas hobs alone out there! I tried once to get Viking to give me their induction burner wattage ratings (by numerical knob setting) so I could better apple/apple induction+clad with radiant+copper. They won't do it.

Big Corporate Pan and Corpostove probably wouldn't like it anyway , because it'd put the lie to the 7-layer bars and Deloreans they're making such killings on.

[ThreeGigs]

Repeat with the burner on a higher heat, too. Not many people use cast iron for low heat tasks.

[kaleokahu]

OK.