What Kind of Pan is This

I've seen these pans at one of the local cookware/houseware stores as well and wondered the same thing. The best I've been able to dig up so far is the following:

GreenPan's official statement about their material is:

GreenPan™ does not use PTFE, but brings with Thermolon™ non-stick technology a healthy alternative to the market. Thermolon™ is heat resistant up to high temperatures. This means that GreenPan™ has an extra safety feature; if you overheat your pan, even up to 450°C/850°F, no toxic fumes will be released and the coating will not blister or peel.

Obviously I can't verify the claims about overheating and the absence of fumes or blistering/peeling, but one thing is for certain: The pans are not Teflon. Instead they use a Thermolon compound, which really and truly does not use PTFE, the "harmful" compound in Teflon products.

Of course, as we all know, that doesn't mean it's safe. This "Thermolon" stuff is brand-new to the market so there's been very little real-world testing done. And nobody seems to know exactly what it's made of. If you look at early sources you'll see them blathering on about it being made with "nanotechnology", but I found an interesting little tidbit on Mother Nature Network:

UPDATE: Thermolon’s non-stick formulation is actually not the product of nanotechnology. It turns out that one of the company’s “over-enthusiastic” copy writers slipped that description in because it “sounded high-tech,” not because it was true.

This information seems to be confirmed at SuperEco. None of them cite a source, but apparently this came straight from the horse's mouth (Thermolon) - they refuted the nanotech claim themselves.

So one thing we do know about this company is that they've made at least one bald-faced lie. That's not enough to indict them on safety terms but it certainly does cast a suspicious light on them. The company is also in South Korea - again, not that this necessarily means anything but SK has a pretty dismal track record when it comes to safety.

It's also interesting to read some of the reviews. I've seen several go like this on one the MNN page:

Obviously all these great comments about the pans were from people who most likely had only these pans for a few months. They worked great for about 6 months and then every single think I cooked started to stick and burn to the pans.

Other people say they lasted for a year, two years, etc., but all seem to confirm the same basic fact: the non-stick coating wears off over time. If it wears off, it has to go somewhere, and that somewhere is probably in your food. Whether or not these incredibly tiny amounts of unspecified ceramic material are actually dangerous remains to be studied.

So to summarize, here's what the reality seems to be:

• Is it Teflon? No, and it doesn't use any PFOA/PTFE.
• Is it safe? Inconclusive. So far there's no evidence of safety issues.
• Is it eco-friendly? Given that the company is so defensive about its manufacturing process, I'm inclined to believe that their "green" claims are exaggerated at best.
• Is it actually any good? Only with very light use, according to the reviews.

ANOTHER UPDATE: GreenPan™ appears to have added more relevant information to their new site greenpan.us since this original Q&A occurred. They now describe their coating as "ceramic" and claim that it is a formulation that is a patented solution of sand and water:

Thermolon is the ceramic non-stick coating used on all GreenPan non-stick cookware. It is a coating that is manufactured without PFAS, or PFOA, and does not contain any lead or cadmium. It is made from Silicon (not to be confused with silicone), basically sand, that has been transformed into a spray-able solution and then cured onto the pan in the oven.

However, this once again appears to be a bit inaccurate. This appears to be the Thermolon Patent (from Google's Patent database). The patent describes the coating as containing "silane or an oligomer derived therefrom", silicone dioxide, one or more of "tourmaline, yellow ocher, sericite, amethyst, bamboo charcoal, obsidian, elvan and lava", one or more of "strontium, vanadium, zirconium, cerium, neodymium, lanthanum, barium, rubidium, cesium and gallium", and pigment. While silicon dioxide (basically sand) is one of the main components, the additional components include a lot more than just silicon.

Induction cooking works by generating an electric current in the metal cooking vessel and converting that current into heat, which requires a resistive material (i.e. a poor conductor).

It's a bit of a catch-22, because you need a good conductor to actually distribute that heat. This is why some of the best induction cookware is clad metal - two layers of (magnetic) steel around an inner layer of highly-conductive aluminum or sometimes copper, sometimes layered multiple times this way. The thick magnetic sheets generate heat, and the thin conductive sheets transfer it.

Thicker metal means that the surface is slightly farther away from the magnetic field source, but also has significantly more resistance (since resistance is proportional to length, and we are talking about doubling or even tripling that), so theoretically it should be much more effective at converting the electric current to heat, and heat up faster.

The disadvantage of a thicker metal - assuming that there is no additional heat transfer material - is hot spots. This doesn't matter at all for a skillet, but if you're trying to cook with, say, a cast-iron stock pot or dutch oven, you'll find that the hot spots are even worse on an induction cooktop than an electric or gas cooktop, since the surface heat is generated very rapidly but takes forever to spread.

Carbon steel is a pretty good compromise, which is why it's generally the material of choice for woks, and that's the material I'd choose for an induction cooktop for any vessel other than a skillet or frying pan (assuming I had to choose a single material; again, copper/aluminum-clad stainless steel works better). For pans/skillets, you want the heat to stay focused on the surface, which makes heavy/thick cast iron a better choice.

I can't honestly say that I've had much experience with forged iron, but all my instincts are telling me not to bother with it because it would be combining the worst of both worlds - lower resistance at the surface but still relatively high resistance up the sides. The only caveat to this would be a possibly significant difference between the magnetic susceptibility/permeability of forged vs. cast iron, but this is likely going to vary from vessel to vessel anyway (not all cast/forged iron is the same) so I think your best bet there is to try sticking a magnet to it. If it sticks much harder to the forged than cast iron (doubtful) then it might be good for surface cooking; I still wouldn't choose it for a larger pot.