Are scratched pots/pans safe?
February 13, 2009 11:53 AM   Subscribe

At what point do I throw out slightly scratched pans/woks?

I have a couple frying pans and a wok which over time are acquiring scratches. Is it still safe to cook with them? At what point should they be tossed?

I've tried to find some answer online, but, as is often the case, it is hard to find a clear answer.
posted by mateuslee to Food & Drink (17 answers total) 4 users marked this as a favorite
Are these coated with something (non-stick)?
posted by fiercecupcake at 11:57 AM on February 13, 2009

Response by poster: Some yes, some no (at least I don't think so)
posted by mateuslee at 11:59 AM on February 13, 2009

Can you explain why you think they would be unsafe?

I've heard that aluminum pots = bad, but even then without real evidence to back it up.
posted by Sova at 12:03 PM on February 13, 2009

When you see bits of teflon in your food, it's time to throw out your pan.
posted by gnutron at 12:16 PM on February 13, 2009 [1 favorite]

They won't do you any harm; they just get harder to clean. Throw them out when they become so ugly that looking at them makes you depressed and some nice new ones will be a lovely treat.
posted by nowonmai at 12:33 PM on February 13, 2009 [1 favorite]

For pans with non-stick coating, throw them out when the coating begins to flake off. For plain metal pans, scratches don't matter and you can keep using them as long as you want.
posted by amyms at 12:35 PM on February 13, 2009

For nonstick, throw out the ones with scratches.

For plain metal pans, scratches don't matter and you can keep using them as long as you want.

Unless copper is showing.
posted by rhizome at 12:38 PM on February 13, 2009

Non-stick coatings vary a lot in quality. A good one will put up with quite a few scratches before you go through to the metal. And some pans seem very resistant to the flaking you often see with damaged teflon.
posted by le morte de bea arthur at 1:02 PM on February 13, 2009

Scratches in metal and non-stick (teflon) pans are fine. If you scratch up a non-stick (teflon) pan just use it like a regular metal pan. If the non-stick (teflon) materiel starts to flake off use a brillo pad to take the rest of the non-stick off. Even if you do get non-stick (teflon) in your food nothing bad will happen because teflon reacts with almost nothing it will just pass through your body.
posted by gregr at 1:15 PM on February 13, 2009

Best answer: Short answer: when they bother you.

Cookware has to be made of stuff that's basically chemically inert, so that it doesn't interact with your food. If you found a teflon screw on the floor and ate it, it would probably just pass through your gut in a day or two. (disclaimer: don't do this.) This is much more like a metal than like something digestible.

Even if they aren't chemically reactive, though, putting two dissimilar materials in contact will result in some "leaching" between them. If you hold water in a pot (teflon, steel, copper, aluminum, iron, lead, gold, wood, salt, whatever), some of the material of the pot will dissolve in the water. This is faster with more heat, and depends on the material: obviously if you carved a pot from a brick of salt, it'd dissolve in water faster than an equivalent pot made of steel. If you consume the water, the dissolved material will muck around inside you doing healthful and unhealthful things before your kidneys remove it.

A scratched nonstick surface, as I understand things, provides a place where the nonstick coating can flake off into your food. Probably the flakes, like the hypothetical teflon screw I mentioned, mostly just pass through you. You already have some of the coating dissolved in you, since you cook with it. Having a flake in your gut for a day will increase this, since the flake spends a day simmering in your juices, but not much.

I don't think a scratched metal surface makes any difference at all.
posted by fantabulous timewaster at 1:34 PM on February 13, 2009 [2 favorites]

When the bottoms warp enough that they do not heat as evenly as they should (to the point that even your mad cooking skillz can compensate for it).
posted by variella at 1:49 PM on February 13, 2009

I remember reading somewhere that the teflon stuff (or some chemical therein) was only poisonous as an inhaled gas. And to become a gas it needed to be heated to some high temperature before it vapourised (i.e. higher than normal cooking temperature). I believe it resulted in flu-like symptoms. If this is the case then scratched teflon is probably OK.

If not, then I need to get new pans...
posted by jonesor at 3:53 PM on February 13, 2009

jonesor correct about teflon not being poisonous -- it's only dangerous if you leave an empty pan on the burner long enough for the teflon to vaporize.

You can probably repair small scratches in your wok by seasoning it properly (this basically creates a new non-stick layer, which should fill in any scratches.)

And next time you buy new nonstick pans, throw away your metal cooking utensils and use wood or plastic ones instead, and you won't have this problem anymore.
posted by ook at 5:03 PM on February 13, 2009

Best answer: 1. Teflon/non-stick coating is poison if its damaged. You don't want to eat this...ever. If the coating is ever scratched, it means theres a breach in safety. Think of it as a pothole in the street. A small one will turn into a bigger one....but with a teflon/non-stick pan, you can bet that you're ingesting that stuff. As soon as you see a scratch, toss it. Thats why you should only use non-metal silverware when cooking with it.

This is positively untrue, and tends to be the yowling of yuppies who are afraid of "chemicals" in general. These are often the same people who'll happily revel in the new car smell of their Expedition while simultaneously bitching about the smell of current generation latex paint in their newly-renovated office. I'm not saying you're necessarily one of these people, hal_c_on, but I do suggest you stop listening to them.

Teflon is an implant grade material. You can surgically implant it in your body with no ill effects, although one of those links is to a teflon joint implant that's been recalled due to foreign body reaction--not poisoning, that particular implant just wasn't "invisible" enough to the body for the immune system not to go after it. Here's the MSDS (pdf) for PTFE, which is Teflon. You can absolutely eat the stuff in giant spoonfuls, if you want to. It's going to pass right through you--unless you have an extraterrestrial physiology that uses oxidizers instead of acid in your stomach.

The only safety issue with teflon is that at high temperatures (650*F), teflon decomposes and produces a number of caustic flouride vapors (just as many plastics do). For this reason, it's suggested that you not leave an empty teflon pan on the fire. Those gases are carcinogenic... but, the more immediate problem (and the cause of the carcinogenic properties) is that they're severe irritants. They can even cause chemical burns in high enough concentrations.

Likewise, there's evidence to show that inhaled teflon powder (used in the coating process) can be carcinogenic; but practically *every* inhaled powder winds up being carcinogenic, regardless of chemical makeup. Powder in the lungs tends to nucleate other inhaled materials, which causes damage and eventually cancer. If you routinely inhaled silicon or titanium powder, both even less bioreactive than PTFE, you'd still eventually get lung cancer.

Also, you're not going to encounter the powder... I'm not talking about little pieces of teflon coating, I'm talking about the micro-sized chemically pure powder used in the teflon coating process.

So, to answer your question, OP: when you get annoyed by your food sticking to the pain, it gets too hard to clean, or it no longer evenly heats your food. If it's not a coated pan, then you can actually just polish the cooking surface and get rid of the scratch. Just make sure you wash it very well after using the polishing compound. (BTW, I'm not talking about silver polish, but abrasive polish.)
posted by Netzapper at 5:40 PM on February 13, 2009 [6 favorites]

Pure Teflon probably just passes through the body pretty harmlessly, but the impurities from half-assed consumer-grade manufacturing processes might not.

And the impurities might give you cancer or subtly poison you. Not a definite thing, probably will never be rigorously studied before current products and processes naturally fall off the market, but enough reason in my opinion to avoid eating scratched-off Teflon bits.
posted by TheOnlyCoolTim at 5:42 PM on February 13, 2009

Sorry, I fucked up the MSDS link. It should be: PTFE MSDS (pdf). I do apologize.
posted by Netzapper at 5:43 PM on February 13, 2009

Pure Teflon probably just passes through the body pretty harmlessly, but the impurities from half-assed consumer-grade manufacturing processes might not.

The only impurity I've ever heard of is PPOA. Which must be evaporated in the curing process, or the teflon wouldn't stick. You're not working around the coating process, so it's really not an issue. You are exposed to more carcinogens breathing city air than you are eating flaked teflon. But, really, I'd be avoiding the flakes because they have no place in food (like hairs and mouse turds), not because they'll hurt you.

The newer teflon-coating processes, which probably aren't being used for cookware yet, are plasma disposition and some patented thingie where it's teflon in a metal matrix. Both of these essentially heat the teflon (or teflon + steel) up to plasma temperatures, and then spray the plasma at the surface in question. There are no other chemicals needed or used, and the resultant coating is much stronger and resistant to scratching than the spray-on approach is.
posted by Netzapper at 5:56 PM on February 13, 2009

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