Induction-Friendly Cookware Selection

[Johntodd]

1 hour ago, Laurentius said:

It's a terribly misleading video from a number of perspectives.  I could go into detail, but there are many doozers told here.

C'mon now, spill it.

 

If there is a small insert in the pan that does not cover the entire bottom then you will get those results.

 

[horseflesh]

4 hours ago, Johntodd said:

Here is a great video on why some pans are better for induction than others:

Why Some Induction Compatible Pans Work So Badly

 

The poster frame on that video shows a pan that I have, haha. It's the cheapest possible frying pan from a restaurant supply store. And indeed, it barely works on induction. 

[adrianvm]

When you say there is only one coil you mean the entire coil---both parts on both sides of the gap---just always fires up? 

 

I realized I had a compatible pan I hadn't tested---a Fissler pressure cooker with a very thick conductive disk base.  So I repeated my temperature test with the thermocouples.  I set the Freak to 250 F as before and after give it quite a while to settle (on low intensity) I got readings of 260 F at the center, 260 F at 2" off center and 246 F at 4" off center.  I waited several minutes more and got 254 F center, 254 F at 2", and 247 F at 4".   So that is the most uniform measurement I've seen.  I do again have the readings higher than the temperature reported by the Control Freak, which is a bit strange.  I wonder if hot air could be staying in the pan and heating the pan top surface.  (It's not clear why it wouldn't just rise out of the pan, though.)   If I blow into the pan for a moment the measured temperatures drop closer to 250 F.   This pan has tall sides. 

[adrianvm]

Why would I want to measure the sidewall?  I don't understand.  Presumably it will be much lower.  Do you think the temperature discontinuity at the sidewall transition would affect the temperature at the 4" radius mark, where the temperature was 247? 

 

Note that my primary motivation for testing the pressure cooker was that it's a representative of a pan with a very thick base that goes all the way to the edge of the pan.   It showed more uniformity than Demeyere Atlantis. 

[Laurentius]

3 hours ago, adrianvm said:

Why would I want to measure the sidewall?  I don't understand.  Presumably it will be much lower.  Do you think the temperature discontinuity at the sidewall transition would affect the temperature at the 4" radius mark, where the temperature was 247

Maybe because your data so far have been anomalous.

 

It's been my experience with disc-base pans that they tend to trap/ accumulate heat that would otherwise flow outward and up the sidewalls.  Some people think this is a good thing, but I don't.  The phenomenon is the one big reason thick disc pans are not responsive the way other constructions can be, even of similar thickness.

[adrianvm]

You think the pressure cooker measurements are anomalous?  They seem like the least strange data set of all the ones I've collected.  Maybe I should try the caramelization test with that pan. 

 

Are you saying that if I compare two pans that both have 3mm of aluminum but one has it as a disk and one is fully clad the clad pan will be more responsive?  It seems like it might be easier to cool down a clad pan because you would radiate more heat out the sidewalls, but also harder to heat it up for the same reason.   I don't know what the time scale is for that effect, though.  In my other tests it doesn't appear that heat is rushing to the outside edges of pans across the bottom, so I don't know why it would do it up sidewalls.  Your suggestion that heat "accumulates" suggests that we should see a higher temperature at the corner of the pan, which is not what I'd expect. 

 

I was curious about whether the thick disk construction would result in a more even temperature across the pan surface compared to thinner clad and disk construction.  It seemed like it did do that---so a thick disk may be better for uniformity.   Clearly a thick disk is going to sacrifice responsiveness, so it depends on the relative importance of these two metrics.

 

[Laurentius]

13 hours ago, adrianvm said:

I was curious about whether the thick disk construction would result in a more even temperature across the pan surface compared to thinner clad and disk construction.

 

Yes, although I'd express it as: thick disk does a better job of mitigating the intrinsic unevenness of induction.

 

You can think of your hypothetical 3mm clad pan as being all disc.  For instance, a 28cm Demeyere Proline is formed from a flat disc that is about 34cm in diameter.  There's close to the same volume of aluminum in that pan as there is in the thicker but much smaller disc of say a Fissler OP or a Paderno GG.

 

A problem with these tests on empty pans is that comparisons require waiting for the pans to reach thermal equilibrium.  Virtually no cook waits that long to preheat.  If you peruse Centurylife.org, you can see that Franz's evenness rankings suffer from this, as well as setting an arbitrary time-to-temp criterion well short of equilibrium.  Basically, pans that heat up faster are awarded a low handicap.

 

And of course food has it's own conductivity and other thermal properties within a realistic system.

Edited May 28 by Laurentius
clarity and misspelling (log)

[adrianvm]

I tested the Fissler pan again and this time measured the center, the inside corner, and a spot an inch up the sidewall on the inside.   I heated the pan on slow to 250 as before and the center temperature came to a steady state around 265 F.  The corner of the pan was 250 F.  That was pretty surprising.  The temperature up the side wall was 201 F.  I got to wondering whether that sidewall temperature was actually measuring convective heating from the inside bottom surface, so I moved the thermocouple to the outside of the pan side and there I got the reading of 168 F.  None of this seems particularly surprising.  There's no indication that heat is "accumulating" at the corners or in the sidewall as suggested above. 

 

I also tried another caramelization test, this time with the Freak set at 375 F, where I let it come up to temperature and then sprinkled sugar into the pan.  The fissler gave a very nice result with a very even brown across its surface.  The demeyere dutch oven (which is the same diameter) left a ring of white sugar around its edge, showing that it is definitely not heating as evenly as the fissler. 

 

Another bit of information:  I finally got Cristel to give me a number for the thickness of their disk based pans.  They report that the pans have 4mm of aluminum in the disk bases in the Mutin and Strate lines.  My understanding is that Fissler and Paderno have more aluminum, so the Cristel may outperform clad pans in terms of uniformity, since they typically have 2.3mm of aluminum or less, but it won't be as uniform as Fissler or Paderno. 

 

 

[Laurentius]

13 hours ago, adrianvm said:

There's no indication that heat is "accumulating" at the corners or in the sidewall as suggested above. 

It is accumulating in the center, as your data suggest.  They also verify that there is a gross thermal discontinuity at the sidewall--that was my meaning.  This large Delta T means foods stuck to or propped against the sidewall will receive a lot less heat than foods on the floor.  And liquid foods will have less complex convection currents.

 

IMO, you've reached the Realization Point about evenness on induction:  If very high evenness is important to you, you must choose very thick disc-based constructions.  But that choice entails slow downward response and effectively no sidewall heat.  If those aren't disadvantageous to you, then the Fissler OP type pans are good choices.

 

And of course the other realization is that the Control Freak doesn't produce completely even heat with any pan.

[palo]

I wouldn't suggest "accumulating" is the correct term for this instance. What you're commenting on is the migration of applied heat from the source.

 

p

[adrianvm]

Sidewall heat on induction is going to be negligible no matter the pan, is it not?  When I tested my Demeyere Proline skillet the temp was 205 on the sidewall, and that's a pan with a conductive sidewall.   If I use a clad pan, which seems to mean higher Delta T, then food that's anywhere close to the edge---not just the food that's touching the edge---will receive a lot less heat than foods at the center.  That's not an improvement.  It's a bit unclear to me what the benefits of sidewall heating are. 

 

Cast iron seems to be better at browning food than anything else.  I recall a situation where I cooked half the meatballs in the Demeyere Proline and half in a giant cast iron skillet and the ones in the cast iron browned while the ones in the Demeyere did not.  And the Demeyere was on the more powerful burner.  They were very wet meatballs that were hard to brown.  So what is the explanation for cast iron's ability to brown?  It seems like aluminum has a 5x higher thermal diffusivity I would think would enable it to transfer heat to the food faster.  Aluminum also has double the heat capacity of cast iron, so it holds twice as much heat per mass.   So what's the magic with cast iron?  Can I get the same browning with something that heats more evenly?  Is it simply about the mass of the pan? 

[horseflesh]

I had some Costco credit and a need for affordable new pans so I decided to try the Henckels knock-off of Hexclad pans: Hxagon.

 

https://www.costco.com/henckels-hxagon-3-piece-skillet-set.product.4000209381.html

 

A cheap knock-off of an overrated pan, how good could it be? Well, so far I think they are ... Not bad.

 

When searing in the biggest pan, and then making a pan sauce, it was easy to see the heat was pretty even. I was actually very pleased with how my seared pork tenderloins came out. And when I made some caramelized onions in the medium pan, it was ... Fine. No complaints. 

 

They are not really non-stick, but low-stick. An egg cooked without oil or butter will not slide around, but can be loosened without destroying it. (I knew this going in but those who are hoping for full Teflon slipperiness will be disappointed.) 

 

The pans are easy to clean... In slipperiness and ease of cleaning they seem similar to Circulon hard-surface non-stick pans. 

 

These pans also have a perfectly flat and non-textured bottom which makes them good for the Control Freak. The smallest pan isn't quite heavy enough to push down on the CF temp sensor, though. Even with a single egg in it, the small pan sits at an angle, resting on the springy sensor without fully depressing it. It needs just a little more weight to sit flush, so depending on what I am doing with the tiny pan I may need to keep a wooden spoon resting on the edge to maintain good temperature control. 

 

For the money these seem to be reasonable pans. 

 

If anything interesting happens down the road I will post a follow up. 

 

[adrianvm]

I tested a couple more pans for temperature uniformity using the Control Freak induction cooker.  One is a Paderno Grand Gourmet 28cm (11 inch) fry pan.  This pan has a thick aluminum base which the manufacturer told me is 6mm of aluminum.  (Apparently in the past it was 7mm.)   It has  1mm total of stainless steel in the base.  The base is a bit over 8.75" diameter.   I measured the thickness of the base and found it to be 7mm total. The side of the aluminum on this disk is exposed for those that worry about that sort of thing.  Also this is obviously not flat: it rocks quite a bit on its base, so not the best quality either in design or manufacture.   In my testing with the Control Freak set to 250 on low intensity, the pan heated to 259 in the center and stayed at that temperature.  At 2" from the center it was 257 and at the edge it was 242.  (I didn't test the side wall.) 

 

The other pan I tested is a Breville Thermal Pro frying pan.   The pan is 12.5" diameter. This pan has has tri-ply clad sides with an aluminum base bonded to the bottom.  The aluminum disk is covered by stainless steel and its bottom is about 8.5" diameter.  I couldn't find advertised thickness data.  I found the total thickness of the pan bottom to be 7.3 mm (presumably including 3 layers of staniless and 2 layers of aluminum).  Pan sides are quite thin, maybe 2mm.  This line is discontinued and the pans are cheap on amazon at the moment.  The base of this pan is quite significantly concave.  This pan heated to 254 in the center, 258 at 2" and 248 near the edge.  The sidewall temperature was 215. 

 

One thing I've been wondering about is what makes cast iron good and can a pan with better heating uniformity deliver the same benefits.  It seems like people are excited by the searing power of cast iron.  I've seen cast iron work better for browning wet meatballs than my demeyere proline skillet.  (They browned in cast iron; they did not brown in demeyere.)  So what makes cast iron work better?  Presumably it's the thermal mass.  So what does that actually mean?  It seems that the number of most interest is the volumetric heat capacity. 

 

Cast iron 3.6 J/K cm^3

Aluminum 2.4 J/K cm^3

Copper 3.4 J/K cm^3

Stainless 3.8 J/K cm^3 (depending on alloy)

 

My cast iron is 5mm thick, so its total areal heat capacity would be 5*3.6=18 J/K cm^2. 

 

Falk Coeur has 1.9mm copper and 0.6 mm stainless, so 1.9*3.4+0.6*3.8 = 8.74 J/K cm^2.   So I predict that the Falk holds a lot less heat than the cast iron. 

 

What about Demeyere proline?  Reportedly it is 3.7mm aluminum a 1mm stainless.  So that gives 12.68 J/K cm^2.  So better than falk but not as good as cast iron.

 

I'll pause here to note the weight issue.  Of these materials, aluminum actually has by far the best heat capacity by mass at 0.9 J/g K compared to 0.46 J/g K for cast iron and 0.39 J/g K for copper.  This means we can get much more heat into less weight if we use aluminum.  That is, to match the 18 J/K cm^2 of 5mm of cast iron we need only 7.5mm of aluminum, and the weight of the aluminum is 50% that if the iron.  So that would suggest you could get the same searing capability as cast iron from a much lighter weight pan. 

 

Considering Paderno, at 6mm aluminum and 1mm stainless it's areal heat capacity is 18.2 J/K cm^2, which suggests it should perform similarly to cast iron.   I don't have data on composition for the Breville, but it's base is 0.3mm thicker and it seems likely it has more stainless steel, so its score will be similarly high. 

 

I haven't managed to find a way to clearly test searing or heat holding power of the pans, however, to make a comparison between the cast iron and the aluminum disk pans.  Does anybody have any thoughts on a way to test this?   And have I overlooked anything?  Aluminum has higher thermal diffusivity which suggests heat should move out of it into food faster than from cast iron.  That would be good, right?   By the numbers, copper seems to offer remarkable little gain for all the hype associated with it as the best pan material.  Its thermal diffusivity is 111 mm^2/s compared to 97 mm^2/s for aluminum.   Seems like barely a difference and

 

Regarding other notable pan options, there is Volrath Centurion which has a 5mm core of aluminum and 1.9mm total of stainless steel (19.22 J/K cm^3). There is (maybe) Cristel Casteline (which has vanished from the Cristel web site) which has (had?) a similar construction to the discontinued Breville line but a very high price tag and an interchangeable handle system whose usability isn't clear.  Scanpan Impact has a total base thickness of 6.4 mm. 

[Laurentius]

2 hours ago, adrianvm said:

Does anybody have any thoughts on a way to test this?

Heat your pan in an oven for an hour--don't change the setting.  Remove onto a potholders, and pour in a weighed volume of room-tempersture water.  Record the max temperature the water reaches.

 

Repeat for the other pans 

 

I ran this test to prove a 28cm Pro line "holds more heat" than does a 28cm Fissler Original Profi (basically a Paderno GG.

 

Or, instead of water, you can use strips of pork belly, laid wall-to-wall.

 

The only way cast iron wins in any of this is if it's thicker.

[adrianvm]

47 minutes ago, Laurentius said:

Heat your pan in an oven for an hour--don't change the setting.  Remove onto a potholders, and pour in a weighed volume of room-tempersture water.  Record the max temperature the water reaches.

 

Or, instead of water, you can use strips of pork belly, laid wall-to-wall.

 

The only way cast iron wins in any of this is if it's thicker.

 

Wouldn't the water test be unfair for disk based pans because the side walls are thin? 

 

Cast iron is thicker than proline, but only by 0.3mm, and yet when I cooked wet meatballs only the cast iron could brown them, not proline.  Perhaps I need to do a wet meatball test. 

[Laurentius]

20 minutes ago, adrianvm said:

 

Wouldn't the water test be unfair for disk based pans because the side walls are thin? 

 

Cast iron is thicker than proline, but only by 0.3mm, and yet when I cooked wet meatballs only the cast iron could brown them, not proline.  Perhaps I need to do a wet meatball test. 

It's a fair measure of how much heat a pan stores.  A 28cm Proline has more aluminum than a 28cm Fissler.

 

If anything, the test would favor Fissler.

 

[adrianvm]

Yes, the water test is a fair measure of the heat stored by the whole pan but I actually care about browning food.  Is heat storage the full story for browning power?  Is heat in the pan side walls available to brown food that is only touching the pan bottom?   Actually another thing occurred to me with regards to the water test.  Browning requires that the temperature be high but transferring heat to water does not.  Maybe this difference isn't fundamental, but it seems unlikely that in induction stovetop cooking you can get the pan sides over 275 so that they can reheat the pan center after it cools.

 

The fissler pan I have with the cookstar base is I believe 6mm thick, so it's thicker than proline, which is 4.7mm. 

[Laurentius]

16 minutes ago, adrianvm said:

Yes, the water test is a fair measure of the heat stored by the whole pan but I actually care about browning food.  Is heat storage the full story for browning power?  Is heat in the pan side walls available to brown food that is only touching the pan bottom?   Actually another thing occurred to me with regards to the water test.  Browning requires that the temperature be high but transferring heat to water does not.  Maybe this difference isn't fundamental, but it seems unlikely that in induction stovetop cooking you can get the pan sides over 275 so that they can reheat the pan center after it cools.

 

The fissler pan I have with the cookstar base is I believe 6mm thick, so it's thicker than proline, which is 4.7mm. 

The Fissler is thicker at the base.  But the Proline is a 36cm fully-clad body.  As you suspect, heat stored in those sidewalls will flow to the cool spots caused at the flop.

 

An opposite thing happens with a poor conductor like cast iron.  What little heat does move laterally, moves quite slowly.

 

Try the pork belly in two identically-heated skillets like Proline and your cast iron.

 

 

 

 

[adrianvm]

I did a simple test of browning where I made the meatball recipe that previously gave me browning trouble.  It has 2 lbs ground meat and 2 cups of water, so the high moisture content makes browning a challenge.  Previously it would not brown well in the Proline. 

 

I tested it on the Control Freak where I preheated to 400 using the Breville Thermal Pro 12.5" skillet, a Le Creuset cast iron 12 inch pan, and a Falk Copper Coeur 9.4" pan. 

 

The Breville browned very effectively and rapidly and produced a good crust on the meatballs.  The cast iron dropped in temperature and stayed cold and while it did brown, it took much longer, and the crust was thinner.  Furthermore, it didn't cook well around the outside part of the pan whereas the Breville cooked well over its whole surface.   The Falk pan also seemed to lose temperature rapidly and it took longer to brown, but it did recover and produced a nice crust eventually.   (I realized belatedly that I should have tested the proline, not the falk, but too late to change that.) 

 

Based on my observations I don't see that cast iron is a good choice for induction. 

[Laurentius]

18 hours ago, adrianvm said:

don't see that cast iron is a good choice for induction. 

It's not.  But I'd put it the other way around:  Induction isn't a good choice for cast iron if you want even browning.

[adrianvm]

22 minutes ago, Laurentius said:

It's not.  But I'd put it the other way around:  Induction isn't a good choice for cast iron if you want even browning.

Usually people have the cooking technology they have and have to choose pans to use with it.  This thread is about what pans to pick for induction.   But my observation isn't just about EVEN browning but about browning at all.  The cast iron, even in the center, did not brown as well. 

 

Is there some reason I'd expect to get different results if I repeated the test with gas heat?  

[Laurentius]

33 minutes ago, adrianvm said:

But my observation isn't just about EVEN browning but about browning at all. 

 

Oh, I thought you said "I did a simple test of browning."

 

Yes, you probably would get a different result using gas.

 

IMHO, I think your results favoring the hybrid Breville (Meyer) pan have much to do with how the CF senses, reports and adjusts temperature at the one point in the center.  You might draw different conclusions if you let the heavier Coer and CI pans come to thermal equilibrium before the flop.  IOWs, if you fully preheated. Same with Proline.

 

Some of us actually choose the cooking mode that works best with certain wares we already own, but if you only have a PIC like the CF, then you may have to search for optimum pans for it 

Edited Sunday at 03:45 PM by Laurentius
Typo (log)

[adrianvm]

Uh, yes, I did a simple test of browning where I browned some stuff in pans under the normal use pattern likely to occur if I actually cook stuff, and observed how things browned, namely evenly and well in the aluminum base pan, likewise, though slower, in the copper pan, and poorly and unevenly in the cast iron. 

 

Why should I think the pans aren't "fully preheated".    As shown by thermocouple measurements, the Coeur pan overshoots the control freak target temperature generally, and it's smaller, so why wasn't it "fully preheated"?  It doesn't take long to heat that pan and if anything I expect it was hotter than the target.   The predicted behavior of the Coeur pan was for it to deliver the worst browning performance, because it has the least thermal mass of the three pans; it did better than predicted. 

 

The cast iron I heated on low and I didn't time how long it took, but something between 10 and 15 minutes.  I think that's longer than I generally have preheated it when using it on gas.  The cast iron did not grow more even over time in my previous observations of pan temperature.  It seems like preheating in the oven is the only way to "fully preheat" cast iron, but that's no longer stovetop cooking and not something I'm likely to do just in order to fry something, so it has no practical relevance.   

 

If you have the flexibility to "choose the cooking mode that works best" that's great.  But most people have just ONE range, not three, so they have to work with the cooking mode that is available.   This thread is about choosing pans for induction, not about choosing your stove to fit your pans.   But if I were to use the pan on gas, is there a way to make cast iron deliver superior performance using only the stovetop?   Certainly I have the same uneven heating issues with the large cast iron pan on the gas heat source. 

[Laurentius]

Just now, adrianvm said:

Why should I think the pans aren't "fully preheated"

 

Because CF is only sensing at the center point, and it's only inputting 110 VAC.

 

Did you time the preheats?  Did you read the actual temps across the pans before the flop?  The three constructions you tested are quite different from each other; each would take a different time-under-heat to be comparably preheated.

[Laurentius]

31 minutes ago, adrianvm said:

if I were to use the pan on gas, is there a way to make cast iron deliver superior performance using only the stovetop? 

 

Yes, but I'm not sure you want the answer.

 

The heat input from induction is only from the cast iron molecules in a thin skin  directly above the coil.  That means that any spread of heat inward, outward and upward is dependent on cast iron's poor conductivity (Contrast with your other pan choices).  The upshot is that this internal-only spread can be slow and limited.  And even then the intrinsic hotspot may never be overcome.

 

The same CI pan on gas gets its heat input not only from the direct flame, but also from the outward and upward flow of the combustion gases and heat from the grate.  There will still be a Delta T, but overall more evenness.

 

Maximal evenness with any cookware--but especially cast iron-- requires an even, continuous cooktop, as in a solid-top, placque, wood stove or hearth.

 

 

Edited Sunday at 04:59 PM by Laurentius (log)