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Sheet pan concern

Hello all,

I am new to the forum and had a question about sheet pans. I have been using two different sheet pans to make Pizza Bianca (Cooks Illustrated), the recipe involves a wet dough poured onto a well oiled baking sheet and cooked on a baking stone at 400 degrees. It is very good; however, when I wash the pans it is like the pan is dissolving into the dishwater leaving the water a charcoal color. The more I scrub the more charcoal colored material is removed from the pan. I don’t know what the pans are made of, but they are not stainless, perhaps aluminum. Anyone have any idea what the material is and if it’s harmful? I am making this pizza a lot and I don’t want my family ingesting something that s not good for them.


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  1. sounds like they are aluminum which should never, never, never go into the dishwasher - some kind of chemical reaction occurs between the metal and the dishwasher detergent. Just handwash the pans, aluminum sheet pans usually clean very easily.

    4 Replies
    1. re: janniecooks

      The OP did not say they were washing the sheet pans in the dishwasher:

      "The more *I scrub* the more charcoal colored material is removed from the pan."

      You're scrubbing off oxidized aluminum, which is harmless. Or, these pans are nearly brand new and they weren't thoroughly scrubbed down before their initial use. Either way, they're safe to continue using -- just give them a good rinse after cleaning.

      1. re: Joe Blowe

        Right, the pans have not been washed in the dishwasher, but I have had to scub pretty well with an abrassive sponge to get gooey oil residue off the pan. Usually I wipe several times with a dry paper towel after washing until the towel no longer has the graphite colored smudging.

        Thanks for the input

        1. re: smalljaws

          Forget the the abrasive sponge. Attack it with an aggressive stainless steel pad. A thick coarse one, not some SOS pad. Aluminium is an extremely reactive metal. The aluminium which is bared will very soon become an inert layer as it reacts with oxygen.

          When you say the gooey residue I assume you mean like a layer of glue which is a dirty yellow-orange-brown. That is oil. An abrasive sponge will take forever and you will never get the stains out of the corner. But are you sure is is aluminium and not some coating. If it is aluminum then you can take the edge of a sharp knife and scratch a patch away that will be quite bright. The following day you should be able to see the scratches but the colour should be the same as the rest of the pan.

          My problem with the original post is the use of the word charcoal to describe the resulting colour. For this the oil residue would have had to be 'burnt'. This depends on the oil being used. Does your oil have a high enough smoke point for the temperature you are using? Should not get a dark brown residue at 400 with most oils.

        2. re: Joe Blowe

          joe, you're so right - on rereading the post I see that I read "dishwasher" where the OP wrote dishwater!

      2. Are these pans shiny/dull colored, probably aluminum or are they dark colored, coated with something like a non-stick or anodized surface?

        If something continues to come off when you are cleaning them, it is likely the remains of the oil from the pizza preparation. It's possible that you used too much oil for your "well oiled" baking sheet, and the oil darkened and thickened while the pizza was cooking on the baking stone at 400 degrees.
        The smoke point of extra virgin olive oil is 375 degrees. Beyond that, it begins to break down and it would darken and get gunky. It also becomes bitter and can affect flavor.
        Depending on what oil you are using, this could be the problem.

        I regularly use aluminum half sheet pans from the restaurant supply house at high temperatures but am careful about the oils that I use or am prepared to scrub.
        I also put them into the dishwasher with no ill effects, other than that the finish becomes dull. Big deal.

        1. Buy stainless sheet pans = problem solved.

          1. "but I have had to scub pretty well with an abrassive sponge to get gooey oil residue off the pan"

            Then don't do that. You can season an aluminum sheet pan just like you can season a cast iron pan. Leave the gooey residue on and toss it back in the oven at 400 degrees (F) for another 20 minutes.

            1. I wonder if the sticky goo comes from a cooking spray. Those sprays turn to sticky goo in non-stick pans.

              1. I just had this same question last night. My sheet pans (from restaurant supply stores) do the same thing, and even my All-Clad MC2 10-inch fry pan, which I thought was stainless steel. Sounds like it's not a health problem, but it is a little weird if you're looking for your pans to feel really clean. I'll pick up some steel wool and try that. Thanks for the post, folks!

                1. Peter Reinhart bakes his focaccia on a sheet pan lined with heavily-oiled parchment. I don't see why that shouldn't work for your pizza bianca. It would save a lot of washing up.

                  1. Wow glad I checked back in with the post. The pan does not have a nonstick coating and is not hard anodized. The burnt on oily residue is not really a concern. My main concern is the graphite (charcoal) colored material that comes off the pan during cleaning. It acts like a fine powder turning the water a dingy color. Even after the pan is cleaned and dried rubbing a cloth over the pan will leave the cloth with a charcoal colored smudge. The stuff is NOT BURNT OIL, it is something coming from the pan and not the result of any kind of food product.

                    I found a stamp on the back of the pan it is an "Advance 18-8A-13" an internet search shows the current model is aluminum. Mine is 12-15 years old, dull and pitted, not like the shiny pan that will be shown with an internet search. It must be aluminum, but why does my pan shed this material when others don't? Is 450 degrees too hot for an aluminum pan?

                    13 Replies
                    1. re: smalljaws

                      Sorry if this sounds dumb - are you sure it not something being generated by the cleaning agent ( eg by using SOS pads) reacting with a freshly created reactive aluminium surface? Do you get the same effect scrubbing with a steel pad with no cleaning agent?

                      Other than that I'm stumped.

                      1. re: smalljaws

                        Ever considered lightly coating the pan with a layer corn flour or corn meal? Oil and water do not mix especially on the pan, so it could help in absorbing excess water causing deposits of those burnt offerings.

                        Some Pizza makers do not like to use solid pizza (or bun/biscuit) pans, prefer to use perforated pans or pizza screens when the crust demands some support. However- there can be a trade off in perforated pans or screens as you may get some added crunch. (oops almost forgot about dimpled pans as an alternative)

                        Well there is alternatives that is not all that costly if you feel game to try them out. Provided that you are a thrifty shopper and wish to retire your old pan.

                        1. re: smalljaws

                          i have the exact same issue with my jellyroll pans (chicago metallic). i scrub and scrub them in the sink using BKF and a stainless steel pad. then i rinse thoroughly and when i dry them with a paper towel there is a gray/charcoal stain on the paper towel. is this normal? is it harmful? i find myself not wanting to use the pans (even though i love using them) because it might be a harmful substance (that causes alzheimers or something).

                          1. re: tamizami

                            Probably aluminum oxide. Everything in life is harmful.

                            1. re: Chemicalkinetics

                              This (and the other threads I've seen on the issue) seems odd, I use aluminum half-sheet pans all the time and wash them in the dw whenever there's enough space to cram them in. Other than baking spray baking onto them I've never had a residue problem once.

                              1. re: buttertart

                                I second that, I have cooked with aluminum for many many years and have never seen anything like this.

                                1. re: ZenSojourner

                                  But have you use Bar Keeper's Friend on it, as Tamizami did?

                                  1. re: Chemicalkinetics

                                    OMG, no! (so THAT's what BFK means! You guys use so many TLAs - three letter acronyms - are you sure you don't work for the gubmint?)

                                    THe original poster wasn't doing that though.

                                    1. re: ZenSojourner

                                      I know. I can follow some acronyms like Bar Keeper's Friend (BKF) and Le Creseut (LC), but something I have completely no no idea when people type things like Your Mileage May Vary (YMMV).

                                      Yeah, you are correct. The original poster did not do that.

                                2. re: buttertart

                                  My husband occasionally "forgets" and puts our aluminum sheet pans in the dishwasher, and while the pans seem no worse for wear, the other dishes in the dishwasher get a gray residue on them that doesn't come off - really bothers me to see this on my nice china. That may be due to our water being well water, but the safest course of action is to hand-wash aluminum.

                                  1. re: janniecooks

                                    Have you tried using Bar Keeper's Friend or like to wash your nice china to get the gray residue off? If not, try it.

                                    1. re: janniecooks

                                      Maybe, for me it's been done in upstate NY well water and NYC and northern NJ municipal water w/o any ill effect. Must be a chemical reaction with the minerals in the water supply.

                                3. re: tamizami

                                  I wash my aluminum pans with baking soda and water paste with a washcloth when I need to de-gunk them. it takes a little elbow grease but leaves the pan without the "chalky gray surface".