Black soot-like stuff on eggs from cast iron

Whenever i cook sunnyside up eggs from my cast iron, i always get this black soot-like stuff on the bottom of the eggs where it touches the cast iron pan. Is this normal? Is this harmful to eat?

My first thought is how are you cleaning your pan? Some cleaning methods can leave a residue. But, no, as long as it's not a cleanser residue, this discoloration isn't unsafe.

Welcome to Permies Marie!

I grew up being told it was from the food picking up iron from the cast iron pan. I usually only notice it on egg whites, I guess cause they are light in color.

You called it right:  I think it is soot.  In other words, charred residue from food that came before.

I notice this a lot in two cases: when the skillet is not yet seasoned all the way, and when it has been seasoned but for some reason food sticks, then other food keeps sticking to that food until it forms a wide, shallow "hill" of char that looks like normal cast iron.  If you can scrape a fingernail across the surface of the pan and get black soot under your nail, that's probably it.  In that case I use a griddle scraper to tear it down then add another seasoning base layer.

The best tool I've found for preventing this is chain mail.  It's stainless steel links that are softer than the cast iron but harder than whatever you're scraping off.  It leaves a smooth surface behind and is really fast to clean a pan.  Here's a link to more info.  I don't have any experience with this company's products but the explanation is good.

cast iron scrubber

Here is an article about The Ringer, which is the one I have.

Rob Lineberger wrote:Here is an article about The Ringer, which is the one I have.

Thank you. I'll give this a try.

Carla Burke wrote:My first thought is how are you cleaning your pan? Some cleaning methods can leave a residue. But, no, as long as it's not a cleanser residue, this discoloration isn't unsafe.

That's good to know. I was worried we were eating something that's not safe.

Here's what over-easy eggs look like when cooked in cast iron at my place.

It's like any cooking: You get out what you put in. If you put soot into your recipe, expect soot to come out of it. In other words, if your pan has charred food in it before you start cooking, you can expect it to get transferred to the food. If anything gets charred in my cast iron skillet, I clean it thoroughly before cooking anything else. I'm not a fan of soot or charcoal in my food.

If that was my pan, I would scrape it vigorously to remove the charred food. Perhaps even scraping while vinegar or water is boiling in the bottom of the pan. Then scrub it vigorously with a stainless steel scrubbing pad to get back down to bare metal. Then start over on seasoning the pan.  Light coat of flax-seed oil in the oven at 350 F for an hour is typical in my home when starting a new seasoning coat for cast iron. The stainless steel scouring pads that I use are sold at all the local grocery stores. Sometimes I see copper pads which are similar.

On a sorta related topic, the cooked egg in the original post looks like it was cooked on very high heat. Cast iron cookware seems more suitable to me when used on medium to low heat. The pan's seasoning gets burned by high temperatures.

I typically rinse the cast iron pans as soon as the food is served. Perhaps with a light scrub using a stainless steel pad. Food rarely sticks to them when properly seasoned and used on low/medium heat.

I've heard that at least some burnt/charred food can be carcinogenic, so I would try to eliminate the charred specs. What I normally do with cast iron skillets is put just enough water in it to cover the bottom as soon as I dump the food out and return it to the stove to let the remaining latent heat warm the water. I let it soak while I eat, and it usually cleans right out with a brush. If something really dried out in it, I let it soak overnight (filled with water). If it's really bad, bringing the water to a boil before scrubbing usually takes care of it.

I have this same problem. I bought a new seasoned pan and same thing happened. So I think it’s seasoning not carbon from previous food. What do I do?  I had this happen to an older pan too and I figured it was food which is why I bought the new pan. Thanks

Jann,

Just scrape the pan hard with a metal scraper and then wash it with water and a cleaning sponge, and if it's not enough use some detergent. It will not hurt the pan. I've been doing it for 15 years on various cast iron items. They developed perfect non-stick surface.

Hi Jann,

Welcome to Permies.

ive noticed an awful lot of newer cast iron pots and pans in stores, when I look, that are extremely rough finish inside. compared to the antiques I use and am grateful to have. first thing I would do with one of those newer ones with rough sand cast finish is take a power sander to the inside and make it as smooth as a good stainless steel pan. then season it.. some used ones ive seen in thrift stores have to have such a build up of  hardened burned grease, seasoning, to overcome the sand cast finish that I figure they got disgusted with it and gave it away to the thrift store charity. but who knows? just my little opinion on observations ive had when seeing what cast iron cookware is up for sale locally.

I have this same thing happening to me and I don't think it's anything burnt. The black spots of the egg whites seem to part of the egg white itself. They are soft, not crispy, like you would expect from burnt stuff. Moreover I got this even when i completely scrubbed and reseasoned my pan. (Maybe I'd done that wrong...)
But it looks more like the egg whites are reacting with the iron or something in the pan. When I make pancakes in the same pan right after, they are spotless. When I bake in the pan, I get spots on the pastry as well. But it's actually in the pastry, not stuck to it.
I think it's probably the result of improper seasoning and the food is reacting with the iron.

It depends what you consider as "scrubbing". I use cast iron every day. To clean it I scrub with steel spatula and hot water. If I want it perfectly clean for pancakes or frying eggs then I just wash it with rough (green) side of the dish sponge and detergent untill it's clean. Only then I do not have black spots on my first two pancakes or fried eggs.