They are most likely carbon deposits. This happens due to overheating of fats and oils. Using an oil with a low smoke point will carbonize at high temperatures and cause residue from the pores of your pan to rub off onto your food. While unappealing, they won't hurt you in such a small amount.
Occasionally, the seasoning on your pan may break down and leave black specks, especially if the cookware is not well-seasoned, but it is not harmful in any way.
The “black stuff” you see is a result of burn marks, dirt, dust, spray starch and fabric fiber buildup. Additionally, if you leave water inside your iron, it could begin to rust cause rusty spots. It's important to maintain your iron to avoid it from damaging or ruining your clothing.
This build-up usually happens if the food has started to burn and burnt food or greases have started to build up in the bottom of the pan. It's not harmful, but it will give your food more of a charred taste when you're frying and could cause it to stick (some people love the extra layer of flavor, though).
The black residue on a cast-iron pan isn't harmful, but it's not appealing either.
To remove flaking from cast iron, rub regular old table salt all over the skillet with a lint-free cloth. The salt is hard enough to remove the flakes without being so hard as to remove the rest of the seasoning.
Yes. The black bits of seasoning are primarily carbon made up from the various foods that have burned onto the surface of the cast iron, mixed with a bit of oil that makes the carbon nonstick.
Sticking your skillet into a roaring fire might seem like a good way to heat it up in a hurry, but overheating or uneven heating can cause your skillet to take on a permanent warp, or even crack. Same goes for pouring cold water into a red-hot pan.
Do not use scouring pads or steel wool on cast iron skillets as these will remove the seasoning. Dry the skillet immediately with a clean rag or paper towel to prevent rust.
All cooking oils and fats can be used for seasoning cast iron, but based on availability, affordability, effectiveness, and having a high smoke point, Lodge recommends vegetable oil, melted shortening, or canola oil, like our Seasoning Spray.
Black specks occur when heat gradually degrades thermoplastic molecules, breaking them down into carbon residues. This commonly happens during machine shutdowns/startups.
Generally, we recommend seasoning your cast iron about once per month, but after every time you use it works as well if you find that it could use some seasoning.
The residue could be actual flakes of the nonstick coating, or food residue that stuck (non-nonstuck if you will) to the pan where it was no longer nonstick, or the result of some reaction between food/cleaner and base metal (unprotected aluminium tends to create black residues when in contact with aggressive foods or ...
Acidic foods (like tomato sauce, wine-braised meats, etc.) enter the red zone when they spend too much time cooking in the skillet. It's particularly important to not marinate anything in a cast-iron pan, as many marinades are quite acidic in order to tenderize the meat.
Yes, you can boil water in cast iron. To keep the layer of seasoning intact, don't boil water for more than 10 to 15 minutes. You can heat water to a gentle boil or simmer dishes for over 15 minutes – sometimes up to an hour. Be extra careful with acidic dishes like tomato sauce.
Cast-iron cookware is porous, and the oil works to fill those pores and create a smooth, nonstick surface. Enough oil soaks into those pores during the initial coating, so you can go ahead and wipe off as much as you can. Leaving too much oil on is a common mistake that will leave your skillet sticky.
You can use olive oil to season cast iron, but you need to choose a high quality extra virgin olive oil, which should have a smoke point close to 400 degrees Fahrenheit.
You're not doing enough cast-iron cooking
While seasoning does wear down with use, the more you use your cast-iron cookware, the better it performs. Every time you use it, you're also adding new molecules of polymerized oil. Over the long haul, your cast-iron will darken and grow shinier.
Rust is not a food safe material so it should not be ingested. If you see rust on the surface of a utensil such as a cast-iron skillet or knife, remove all the rust before using it.
Can I use soap to wash cast iron? Contrary to popular belief, you can use a small amount of soap to clean cast iron cookware! Large amounts of soap can strip the seasoning off your pan, but you can easily re-season your pan as needed.