They are most likely carbon deposits. This happens due to overheating of fats and oils.
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 residue or black specks coming off your cast iron cookware is carbon deposits formed during the cooking process. It is generally created from overheating of cooking oil or fats used while cooking, or bits of burnt food that accumulate in the pores of the cookware.
Seasoning is the black patina that builds up on your cast iron skillet with regular use, a non-stick surface that's slick enough for eggs to skate across the pan, but tough enough to withstand the blazing heat needed to properly sear a steak.
Black Oxide Finish for Cast Iron
It forms a durable, black magnetite coating that is RoHS and Mil Spec compliant. The process also avoids the reddish/black tint and white salt leaching problems commonly seen with conventional Hot Black Oxide.
Over-cleaning your cast iron pan is unnecessary and will only stand to damage your seasoning.
If vinegar alone doesn't work, try making a baking soda paste by mixing three parts baking soda with one part water. Apply the paste to the scorch mark, let it sit for 10-15 minutes, then gently scrub it off with a toothbrush.
To clean the cast iron skillet, rinse it first under hot water to remove any excess food or residue. Then, use a wet, clean paper towel to wipe out the inside of the pan until it's fully clean. Easy enough!
Generally, black oxide or black iron oxide refers to the oxide of iron known as magnetite (Fe3O4) that is formed when a ferrous metal is exposed to special oxidising chemicals. It is a type of conversion coating, thus the surface layer of a metal is formed into its oxide through conversion.
Over time, dirt, dust, spray starch and fabric fibers build-up on the bottom soleplate of your iron. In addition, old water inside your iron's water reservoir can begin to cause rust spots. While you may be inclined to toss your iron for a newer, cleaner model, regular cleaning is relatively easy.
You should only need to fully re-season your cast-iron cookware one to two times a year, but you may also want to give it some extra seasoning love anytime you cook something that requires a heavy-duty cleaning.
Black Oxide for Cast Iron
With a uniform 0.000030 inch (1 micron) thickness, the porous crystalline structure of the black finish makes it an excellent absorbent base for a rust preventive top coat. Once sealed, the Presto Black finish resists up to 1,200 hours humidity test without chipping or peeling.
We recommend using a pan scraper or the Lodge Chainmail Scrubber to remove any stuck-on residue.
Common cooking oils like olive oil will gradually produce seasoning, but won't be as effective as grapeseed oil. Canola, other vegetable oils, and shortening are a little better.
First, the black specks you see coming off into your food are not harmful. 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.
Put the oiled pan in a preheated 450°F (230°C) oven, and leave it there for 30 minutes. It may get a little smoky, so keep your kitchen well ventilated.
Black oxide or blackening is a conversion coating for ferrous materials, stainless steel, copper and copper based alloys, zinc, powdered metals, and silver solder.
This layer is known as the patina and offers cookware a dark and glossy finish. The patina will only improve over subsequent uses as additional fat and oils are heated into the pan. Beyond its natural look, this layer is an essential part to any cast iron cookware, providing a stick-resistant surface.
Black oxide coating is the process of coating ferrous materials, stainless steel, copper, copper based alloys, zinc, materials with a chemical coating process. It takes products, and it coats them in iron oxide. This provides many benefits. First, it reduces light reflection.