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Dec 19, 2011 11:43 AM

Discoloration on DeBuyer mineral pans [split from "Is my cast-iron dirty?" thread]

Hello Chemicalkinetics,
I read another thread of yours regarding the DeBuyer mineral pans (two of which I recently purchased). I'm trying to move away from all the teflon stuff we used over the last 10 years and thought these pans seemed very organic and "safe".

Anyway, I followed all the weird instructions with boiling the potato peels before their first use and such and never using soap or soaking the pans, etc, etc... Coating them lightly with oil after cleaning them off.

With everything I cook, the pans are darkening and the food leaves outlines and markings (discolorations) on the pan's surface. Scrubbing them off with hot water and a brush after cooking something, does not make the markings go away.

I only rinse them with hot water and a brush and dry them off after that. I've never "seasoned" the pan per se (i.e.: coating in oil and baking for hours in the oven at 500 degrees???) I've never done that.

Regardless, of all the above, alarmingly, the mineral pans are releasing a dark residue onto the foods I'm cooking. (Mostly eggs for now--either sunny side up or scrambled) and I'm just feeling terrible about having my family consuming foods that appear to be getting "tainted", for lack of a better term, by the blackish stuff that is coming off of these DeBuyer pans and settling onto the food I cook in them.

I've sent a question to the company's [DeBuyer] website, but they never sent me a response. I'm hoping that you, Chemicalkinetics, and your apparent infinite wisdom regarding all these cooking vessels and utensils could maybe shed light on this problem??? These pans were rather pricey and I'd hate to think I've either ruined them or that they are defective, or worse yet---poisoning us in some way.

Thank you very much!

Helen Rainey
Alexandria, Virginia

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  1. i don't think the residue is poisonous and it probably adds some iron into your diet

    i would try the cleaning advice with salt and oil

    eggs seem to be very sensitive to the cleanliness of a pan, many users that use cast iron/carbon steel pans for eggs have a specific egg-only pan

    1. I don't think you're ruining them, and it's highly unlikely that you're poisoning yourself either. You shouldn't be seeing much / any dark stuff on cooked food, though -- it sounds like maybe you need to scrub it a bit more with a brush after use.

      I would suggest a variation on what dbchun says - try heating the pan on medium heat with a thick layer of kosher salt in the pan -- more than enough to cover the whole bottom of the pan. You can push it around, and push some up the sides of the pan. When the salt turns greyish, dump it out (careful -- it will be hot), apply a thin layer of oil with a paper towel or rag. Then wipe that layer off with a clean paper towel or rag until there's not really any visible oil on the surface - just a slight shine. Then heat it at medium-ish heat for a few minutes and let cool.

      2 Replies
      1. re: will47

        I will try this -- thanks for all the pointers guys! Just for some additional info regarding this pan though, I've scrubbed it clean after each and every cooking use (only with hot water) and I use a clean paper towel to wipe it down. The black stuff looks like a very small amount of something akin to gun powder, for lack of a better way to describe it.

        In other words, this black stuff is NOT any food residue which had not been properly scrubbed off from a prior use. It is definitely coming from the carbon steel or iron from which this pan is made??? This is quite troubling indeed. Ok, I'm off to try the trick with the kosher salt and oil mixture. Also, why do the instructions indicate never to "soak" these pans in water. Would they rust? I have noticed something which appears to look like rust on them before (after my husband accidentally placed the smaller pan in water to soak, I caught this about an hour after the fact).

        Thanks again for your help guys!

        1. re: Eleni15

          Yeah - cast iron and carbon steel pans can rust rather quickly, and the rust can be difficult to get off if there's a lot (though some small spots can probably be removed pretty easily with a little 00 steel wool). I think that's the main reason you don't want to soak them. You also want to heat them briefly on the stovetop after drying the pan -- even if you dry it pretty thoroughly, this will help prevent some rust build up.

          Even if it's coming from the pan, I wouldn't spend a lot of time worrying about it, but definitely try the salt thing. In my experience, with carbon steel, that will also help darken the surface of the pan, which may not help with cooking, but makes it look a little nicer.

      2. Eleni (or Helen),

        Because you have not had seasoned the cookware, my guess is that you seeing rust on the pan. When rust is formed on a carbon steel pan, it cannot be simply wash away with water. You will have to do some scrubbing. will47 is spot on for suggesting the salt technique. You can scrub the rust away with just salt, oil and a paper towel. It is very effective method for removing things on a seasoned cookware because the salt is hard enough to remove most unwanted things, but not too harsh on the seasoned surface. That being said, your cookware has not been seasoned, so you can pretty much use any technique you deem effective. Afterall, there is not a seasoned surface to worry about.

        You will have to season the carbon steel cookware. There is an oven method, and there is a stovetop method. You are not comfortable, then the oven method is easier to do.

        Again, I think the black color you see is probably rust. You won't be poisoning your family member with it, but it is not good for the cookware to have rust. It will degrade the cookware in the long run.

        9 Replies
        1. re: Chemicalkinetics

          Hi everyone,
          Well, I did the kosher salt thing just about an hour ago. I heated the pan with a nice coating of kosher salt at its base and moved the salt about the pan with a silicone spatula every 5 minutes or so. I'd say total time I heated the pan with the salt in it for about 15 or 20 minutes (it got very hot even with the medium heat setting on the burner) until I noticed the salt turning the recommended grayish color. I threw away the salt (yes, it was VERY hot) and then ran very hot tap water over the pan. Lots of sizzling of course.

          The pan itself darkened during this salt heating process to what I can only describe as a bluish purplish brown hue. Very interesting. These are strange pans indeed. I dried it completely with paper towel and now that it has cooled, I will go back and apply another very thin coat of plain olive oil. Rust does not appear to be an issue, but--most certainly-- the pan looks nothing like it did when it was "new" about a week ago.

          I will attempt Chemicalkinetics recommendation of seasoning the pan in the oven. I will have to check exactly how one goes about doing this seasoning via Wikipedia or any of the other places that might describe how it is done.

          I can't thank you guys enough for answering my questions here today. This mineral pan sure is tricky to say the very least. I am hoping the next egg I cook in it will not release the dark and scary looking "gun powder" tinges like the last couple of times. The lady at Williams and Sonoma told me that these particular pans are "already seasoned" or that they "don't need seasoning"; I can't remember which.

          Regardless, thanks to everyone here who has offered advice. Clearly one needs to be a bit of a rocket scientist to venture into these types of cooking implements!

          1. re: Eleni15

            Hi Eleni,

            Apparently, I wasn't reading as carefully as I could. The salt can be used in many ways, and I was thinking something different than will47. I was just thinking about using the salt, oil and paper towel to remove the rust by rubbing -- very much like scrubbing with a pad -- no heating is required. Salt can be also used for seasoning the cookware, but that is another story.

            "I noticed the salt turning the recommended grayish color"

            Sounds like you are seasoning the cookware already. Here is a very quick video:


            Wok, frying pan... same idea.

            Here is an official deBuyer seasoning.


            "I will attempt Chemicalkinetics recommendation of seasoning the pan in the oven"

            I personally actually prefer stovetop seasoning like the two video above. The only reason I suggested oven seasoning is that some people are uncomfortable with the idea of stovetop seasoning. You can do the same thing you did with the salt/oil thing, except this time you can do it with oil alone.

            "The lady at Williams and Sonoma told me that these particular pans are "already seasoned" or that they "don't need seasoning"; I can't remember which. "

            Well, the DeBuyer Mineral pans are not, but the DeBuyer Force Blue pans effectively are seasoned. If your pans are Force Blue, then they should be blackish blue out of the box:


            If they are Mineral, then they are shiny silver just like any stainless steel cookware.

            1. re: Chemicalkinetics

              Thank you Chemicalkinetics. I really appreciate all of this help (infinitely!!) I am going to check out your videos you linked to [above] right now (I literally get only 1/2 hour free per day to check internet, web, and emails--as I run a very busy household managing 3 young children and a mother who is in the later stages of Alzheimer's).

              Therefore, I will see what is involved in this "seasoning process" you recommend above. My smaller 8" pan is now a very dark bronze-ish bluey color after the 20 minute dry salt heated cook-off.

              I cooked some eggs again this morning only to have this fry pan release the same "gun powerdery" looking residue on the bottom of the egg. The food item cooks up great and nothing really sticks to the pan (given its advertized natural "non-stick" properties), but I can't help but feel queasy about consuming this dark discoloring that comes off of the pan and onto the food.

              I am hoping with the next step I take to remedy the situation (the actual seasoning process) it will somehow stop this process of the dark stuff being released from the pan. The larger 10 inch pan still retains its more silver-ish looking color, as I have not subjected that one yet to as much use or any higher heating or the salt trick. I do know that these mineral pans are supposed to darken with repeated use to a much darker, almost blackish color. Thank you again Chemicalkinetics for your continued assistance!
              Alexandria, VA

              1. re: Eleni15

                ""gun powerdery" looking residue..."

                I remember you said that you don't think the residue looks rusty. If not, it is possible that it is excessive carbon. In my experience, rust looks more red and yellow, while the excessive carbonized curd particles are black or very dark brown. There really isn't much of anything else can come off a pan like these. Either it is from the pan itself which is some form of iron oxide like rust, or it is from the loose carbon from the seasoning.

                Assuming it is the latter, it is an easy thing to fix.

                Pour a very small amount of cooking oil in the pan and apply a tablespoon or more salt, then just scrub this "oil and salt" mixture with a paper towel. Very simple. You do it one or two times, and you should able to remove all of these black residue.

                Grace Young here demonstrated the same technique, but she did it with a heated wok. I just do it on a room temperature pan. Jump to 1:30 min and just watch a few seconds and you will get the idea.


                P.S.: If it is excessive carbon, then it is entirely safe. You may still want to remove some to keep the pan to function well.

                1. re: Chemicalkinetics

                  Infinite thank yous from me Chemicalkinetics! This latest recommendation of yours will now go into tomorrow's "to-do" list and I'm hoping it does the trick. Absolutely, this is definitely not a rust issue--more of a carbon type of thing going on. I will update you tomorrow and have a very nice evening!


                  1. re: Eleni15

                    Great. Best of wish. Let us know if it need additional advise.

                  2. re: Chemicalkinetics

                    Is it the Mineral B? If so, I don't know whether the beeswax coating makes anything different than with standard carbon steel -- the instructions are identical, but I don't really understand their claim that the beeswax increases the pan's nonstick properties.

                    1. re: will47

                      "I don't really understand their claim that the beeswax increases the pan's nonstick properties."

                      Hi will, where did you read the nonstick property part? I haven't come across it yet. It does not make much sense because beeswax melt at a fairly low temperature.

                      1. re: Chemicalkinetics

                        Looks like I read wrong, but in any event, I agree it's unlikely that the beeswax is anything other than a protective coating. I guess what I was wondering, though, is if it's possible that the coating didn't get removed properly.

                        As you say, it should melt at a pretty low temperature, so probably that's not it.

          2. I stripped down my crepe pan and then replicated your method of cooking an egg.

            My results were similar to yours.

            As the butter melted I could see that it was causing black dust to release into the butter. The black dust was apparent when drying the pan but I continued wiping it until a paper towel remained white. Then after the eggs cooked I could see the greyish residue on the eggs. And yes it was different than browning caused by the butter as time went on.

            What I believe is occurring is that the pan isn't seasoned enough at this point and that the little seasoning that is there is partially being removed when it is being cleaned. The silver metal color should no longer be visible on the interior of the pan.

            The method I use with Kosher salt is to use enough oil to saturate the salt. I think it provides lubrication which makes it a little less abrasive and acts as a carrier for the particles. If you have been too aggressive the oil will coat any metal exposed. I would try to refrain from using the salt method until a decent seasoning has been achieved. If you have gummy residue then I would use the salt and then immediately season the pan after cleaning.

            After I cleaned the pan following the egg test I did the following:
            I use lard to season my pan. I put the pan on medium heat and then added enough lard so that I had around 1/4" of melted lard covering the bottom. I swirled it around a few times and let it begin to smoke gently. I then poured the lard off into a can, wiped out the pan with a paper towel and then repeated that process again. Now I used a small amount of lard and wiped the pan with a paper towel insuring all areas remained coated. The smoking remains gentle to moderate and I control the temperature by moving the pan off the burner if it gets too hot. The color should go from amber to orangish to brown and then continue to darken as the process is repeated.

            Chem, after the warping I decided it was better to just use induction capable cookware and not use any type of interface disk be it a carbon steel pan or a dedicated stainless steel disk. While it may work for some, I found the two long handles less than ideal.

            3 Replies
            1. re: SanityRemoved

              Thanks Sanity. I suspect it is rusting as well. Although Eleni told us that it is not rusting, so I would really like Eleni to verify for sure. The papertowel and oil method I suggested earlier to really to verify the cause. The challenge is that remedies are different depending if the pan is rusting or if the pan has too much carbon buildup. Once we have confirmed it is indeed rusting, then we should reseason the pan. As for how to reseason the pan, I am still debating what is the best method for Eleni. In other words, in my mind, the reasoning process depends on the rusting situation of her pan. So far, I don't have a good description of the extend of the rusting.

              "While it may work for some, I found the two long handles less than ideal."

              Actually the energy transfer is very bad with that setup. Remember that I said, this setup is very similar to an electric heated coil? If you have ever used an electric coil stove, you will noticed that you can get the coil red hot, while your water has not even start to boil. This is because the energy transfer is poor.

              In your case, what happen is that carbon steel pan was magnetic induced to a much higher temperature (just like the electric coil) than your copper cookware. So the carbon steel pan wrapped before the water started to boil. Even if the wrapped did not occur, this illustrates the energy transfer is poor in a setup like this. A true induction stove provides fast response and high energy efficiency. In this setup (forget about the wrapping), you get neither. I would get a induction capable cookware.

              1. re: Chemicalkinetics

                I debated letting it "flash" rust but when I saw the powdery residue at the end of the cleaning I was pretty sure I was going to end up with similar results.

                You are definitely correct about the energy transfer and I knew there was going to be a performance hit. My curiosity was fueled by what impact would the copper core have in lessening the energy loss. Would it behave like a carbon steel pan where the heat is more focused based on the induction coil location or would it disperse well due to the copper? It did appear that the copper had a positive effect although the dissimilar behaviors of the two pans didn't fare well together. The experiment leads me to believe that the de Buyer Prima Matera must be a joy to use on induction.

                1. re: SanityRemoved

                  "I debated letting it "flash" rust"

                  Hmm, that is a thought too. I was focus on removing the rust using oil and papertowel to prove it is rusting. I still have hope that it can prove what is going on. On the opposite end, we can just let the pan rust. A well seasoned pan would not readily rust. Anyway, I think we are confusing Eleni now.

                  "My curiosity was fueled by what impact would the copper core have in lessening the energy loss. Would it behave like a carbon steel pan where the heat is more focused based on the induction coil location or would it disperse well due to the copper?"

                  Well, coppercore will definitely disperse the heat pattern well due to both its copper and aluminum.

                  "dissimilar behaviors of the two pans didn't fare well together."

                  I would say it has more to do with incomplete contact. When you put one pan on another, you don't really get a complete contact. They may look smooth to our eyes, but the two pans have a lot of gaps in between. In a microscopic view, the two pans are separated. There are probably only a few true contact points. This causes the poor energy transfer because there are only a few tiny points for direct thermal energy transfer.

                  "the de Buyer Prima Matera must be a joy to use on induction."

                  Yes, it should.

            2. Everyone here, thanks so much for all the ongoing assistance. I am horrible at navigating threads so I want to leave a quick thank you here on this thread to all the people involved in figuring out the mystery of the DeBuyer mineral pans!

              Many thanks,

              2 Replies
              1. re: Eleni15

                On a cooking show last night entitled "Easy Chinese" they took a new carbon steel wok and seasoned it by frying chives in some peanut oil. I was surprised how quickly it blackened. It looked like a wok with several months of seasoning on it. When she moved the chives up the sides of the wok you could see it darkening there too. She said you can use canola oil instead of peanut oil.

                1. re: Eleni15

                  Hello everyone,

                  I will be out of town until Jan.3rd. I will find a way to upload the photos of the two DeBuyer pans in question, as well as the two photos of the two eggs from the other night. I simply haven't had enough time here on Christmas day, to figure out how to upload the photos. I hope to resume this discussion just after the new year, once I'm back in town, regarding the ongoing learning curve with the rust and/or carbon-- which is coming off these pans-- and onto the food. Thank you everyone!