I have a ceramic grill that I have only ever cooked organic chicken breast and organic steak on. I have occasionally added spice but not for months as it makes too much mess. After cooking, I drizzle warm water mixed with washing up liquid on it from a soft cloth, whilst the grill is still hot (generating a lot of steam), then wipe it in order to clean it efficiently.

After I have cleaned the grill and it starts to cool, I have noticed white powder on it, as shown below.


Powder close-up

I can scratch this off gently with my thumbnail and it comes off cleanly, as shown by the highlighted area below:

Scratched off powder

This leaves a black substance under my nail that has a slight meaty smell:

Powder on thumbnail

Can anyone suggest what this is? My first thought was salt, but I don't add any to the meat (or is there enough in it to cause this?). Or could it be something to do with the washing up liquid I use to clean it?

(This is my first question here, be nice. And yes, I know I could write to the manufacturer, but trust impartial individuals on here just as much :))

  • 2
    If you're putting washing up liquid & water onto the hot grill, and creating steam, you'll leave dried up soap & water minerals on the surface of the grill. Normally all the soap residue would be rinsed away with fresh water. The steam will be only pure water, and all the minerals in the water+ soap will be left behind.
    – AMtwo
    Jan 26, 2020 at 14:54

2 Answers 2


These could be proteins precipitated from the meat and denatured resulting in coagulation on the surface of your grill by the heat of cooking. These come out of the juices that run when cooking meat.

Denatured proteins are generally insoluble, and are fairly difficult to remove (think cooked egg when it sticks to a surface). The insolubility accounts for your not removing them effectively when using water and detergent, and they generally only appear white when dried.

  • Oh wow, that's very interesting, thank you! This does make sense actually since I note that the powder smells a bit meaty. Is there any way that I could prove this at all that you can think of?
    – Wad
    Jan 26, 2020 at 11:24
  • 1
    You could try heating the grill and on a clean spot (i.e. no white residue) drip some meat juices and let sit for the time you would normally use for cooking meat, then see if something similar results after your usual cleaning.
    – bob1
    Jan 26, 2020 at 19:54

Not sure anyone would be able to tell you definitively, but, if you add water after each use, my guess would be minerals from your water.

  • Oh that's interesting, thank you. This powder does not appear on any other utensils though (saucepans, baking trays), so could it be on my grill purely because I put the water straight on the grill when it is still at cooking temperature (thus creating a lot of steam), do you think?
    – Wad
    Jan 25, 2020 at 20:21
  • 2
    As a test, drip your water/detergent mixture on a dark plate or counter. Don't wipe it up, rather, allow it to evaporate. It might take a day or two. See if you manage to reproduce the same residue.
    – moscafj
    Jan 25, 2020 at 20:29

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