What's the best way to season a cast iron skillet?

Question

I just purchased a new cast iron skillet. What's the best way to season it?

And if I need to re-season an old pan, is the process any different?

Also see this related question: http://cooking.stackexchange.com/questions/261/how-do-you-clean-a-cast-iron-skillet — JYelton, Jul 11 '10 at 16:55

score 82 · Accepted Answer · edited Apr 09 '21 at 12:24

First, there is no difference between seasoning and re-seasoning, unless you need to do some extra work to remove rust (see instructions below). In fact, for new cast iron, scouring is also usually a good idea since you need to get off whatever wax or protective oil the manufacturer or seller may have put onto the cookware. (They don't use cooking oil for that sort of thing, believe me.)

If you need to remove rust: use a mixture of salt and oil and scrub that hard into the rust, then rinse thoroughly in hot water. Use steel wool if necessary.
Next, scour the pan completely under hot water. Do this for several minutes or until the water runs clean. I've heard varying things about whether soap or an SOS pad is OK at this step. My personal opinion is that it's OK, but you must wash the soap completely off before continuing with the seasoning so that your seasoning doesn't taste like soap!
Coat the cookware with grease or oil. (I do this with the whole pan, not just the cooking surface, to reduce the possibility of external rust.) Crisco, vegetable oil, and lard all work well. Don't pick something with a low smoking point, or too strong a flavor. Make sure it's a light coating... you shouldn't have pools of oil anywhere on your cookware.
Bake your skillet in a 250 - 350 °F (121 - 178 °C) oven for an hour. If you used liquid oil, you may want to put the cookware in upside down so excess oil drips off. But it's good to put a cookie sheet or something underneath the cookware to catch the drips if you do!
Let the cookware cool, and wipe off any excess oil.
For best results, do this two or three times, though a skillet can be satisfactory after a single treatment.

To keep the seasoning happy:

Don't let the cast iron sit too long without using it (you may notice a rancid smell or flavor if the seasoning turns bad; I'm not sure at what point this happens, but it's happened to me before).
Don't cook anything acidic (e.g. tomatoes) during the first or second use of your pan.
Don't use dishwashing liquid or soap on the pan (hot water and scrubbing only).
After cleaning the pan after each use, wipe it lightly with another bit of oil, using simple vegetable oil.

Another trick sometimes used to season Chinese woks: rub Chinese chives over the surface of the cookware when the oil is being heated (this works best on a stovetop, not in the oven). The juice of the chive has sulfur compounds that help remove remaining flavor from the previous coating of the cookware. Be aware that this technique really kicks up a lot of steam and smoke. I've never tried it on cast iron skillets, but I'd be curious if anyone out there has.

"Don't use dishwaser liquid" I usually do this with a very light amount between use and then after its dried take a small amount of vegetable oil and apply. Is this wrong ? By the way +1 for a great answer. — Chris, Sep 07 '10 at 01:12
I have a cast iron pot I'd like to use for chili; do these same instructions apply, or should I open a separate question? I've heard that cooking beans on cast iron can be a problem, but the tradition of cooking chili in cast iron makes that seem unlikely. — Goodbye Stack Exchange, Jan 28 '11 at 00:25
After cleaning my cast iron, I usually put it on the stove at medium heat for a few minutes to make sure its dry, as an extra precaution against rust. — keithjgrant, Mar 01 '11 at 15:58
I would add, for the benefit of the first answerer, that doing it in your girlfriends' apartment right under the smoke detector is probably not the best idea. — Rokujolady, Apr 10 '13 at 17:04
By the way, if you have a gas grill, that's a better choice than your indoor oven so you don't get the smoke fumes in the house. — orrd, Apr 15 '17 at 00:45
You absolutely can use soap or dishwashing liquid. This used to apply when soaps were lye based but as this is no longer the case they are fine to use — ljden, Nov 25 '22 at 06:08

Neil G · Answer 2 · 2011-03-01T15:22:29.120

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See this excellent article about the chemistry of seasoning. You want flaxseed oil (which incidentally has a low smoke point) but a high iodine value, allowing it to polymerize readily.

I read so many blogs about oil "impregnating the cast iron," but this doesn't make any sense chemically. What happens is that the oil polymerizes, and you want an oil that does that really well.

edited Mar 01 '11 at 15:22

answered Feb 28 '11 at 06:30

Neil G

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Wow, that article *is* awesome. I've looked many times, over the years, for something exactly like that, and ended up following the advice that she says is common but wrong. My pan looks just like her ugly before shot. Thanks! – Mason Mar 27 '12 at 05:46
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For those who don't want to take the time to click-through and read, the other interesting tidbit I noticed there was that acidic foods such as tomatoes, lemons, or vinegar will cause *any* seasoning, including this one, to flake off. – James Oct 29 '15 at 20:26
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Just as an aside this is also the method that americas test kitchen recommends. They saw this blog post and tested it. – Benjamin Scherer Mar 16 '17 at 15:53
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There is notable controversy surrounding this article. For instance, see https://www.reddit.com/r/castiron/comments/5owtnm/why_i_dont_recommend_flax_seed_oil/ – cambunctious Jun 18 '20 at 17:25
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Echoing @cambunctious, Serious Eats says "For the record, we've found that the often-suggested flaxseed oil produces a fast layer of seasoning, but it has a tendency to flake off with use. We don't recommend it." https://www.seriouseats.com/2016/09/how-to-season-cast-iron-pans-skillets-cookware.html – Joel P. Apr 29 '21 at 03:24
Heartily disagree with flaxseed. It's just way too soft, smoke point too low. You want the complete opposite - *high* smoke point, *low* iodine - like lard. You want it to be *difficult* to polymerise. The end result is considerably tougher. – Tetsujin Sep 07 '22 at 14:53
@unlisted Do you have a source for that? Isn't the final polymer always nearly pure carbon? And isn't it a lot easier to get to that state if the oil is more reactive? – Neil G Sep 08 '22 at 07:00
I'm not a chemist, but that one source which sits so high on google search is so widely panned [pardon the pun] that it cannot be taken seriously. It's a piece of one-woman research with arm-wavy 'science' that now just gets repeated as 'received wisdom'. Check some of the links above. I did find some research pointing to the opposite of what she says… trying to track it down... – Tetsujin Sep 08 '22 at 07:15
The only empirical evidence I have myself is I used to use whatever veg-based oil I had in the cupboard for 20 years on a plain iron wok without any real issues though it was never really smooth & did flake a bit - my girlfriend made me throw it out because she didn't like how rough it looked.. These days I used lard on the one cast-iron pan I have [my wok now is non-stick] with no issues - which, of course, is too small a sample size to be considered proof. Who knows really ;)) – Tetsujin Sep 08 '22 at 08:21
Welcome. I still can't find the iodine research I was waving at, but see https://cooking.stackexchange.com/a/117104/42066 and https://cooking.stackexchange.com/a/94650/42066 It does appear that none of this has ever been truly 'chemically researched' it's all just one cook's limited test… so I guess the jury may be out for quite some time. Based on current performance on my, admittedly quite young [2yr] skillet, I'll stick with lard. I run it under the hot tap & give it a scrub with a plastic brush, then a quick heat with a tiny lard wipe-round & back on the rack. Good so far. – Tetsujin Sep 08 '22 at 09:48
It's a shame the pre-seasoned cast iron pan companies don't share how they do it - that would be fairly solid proof ;)) So someone, somewhere, does know how this is done… they're just not telling the rest of us. But note those pans are never 'glossy' like flax oil seaoning, they're almost matt black like lard. – Tetsujin Sep 08 '22 at 09:49
@unlisted It appears that one cast iron pan manufacturer uses flaxseed oil: https://www.youtube.com/watch?v=zGR-pyLHz1s – Neil G Sep 10 '22 at 23:59
@NeilG - I didn't watch the video [life's too short] but reading the info & looking at his web page, he's more an upcycler than manufacturer. He also credits the very same blog as everybody else for the flaxseed idea, which leaves us with little more than circular reasoning [or should that be seasoning? ;) – Tetsujin Sep 11 '22 at 11:07
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@unlisted The video includes of an interview with a cast iron manufacturer (Victoria). They explain a bit about the seasoning process, and their methodology. They say that they use flaxseed oil. So, it appears that you may be mistaken about your claim about wanting a "low smoke point". Which from a chemistry point of view makes sense since high smoke point oils are going to take longer to polymerize since they're less reactive. – Neil G Sep 11 '22 at 12:10
@NeilG - I never claimed low smoke point - in fact exactly the opposite. – Tetsujin Sep 11 '22 at 12:22
@unlisted Yes, sorry, I had it backwards in that sentence. The point is that this cast iron manufacturer uses an oil with a low smoke point since low smoke point oils polymerize more quickly since they're more reactive. – Neil G Sep 11 '22 at 13:55
This cropped up on a thread recently. tbh, a lot of the names are US trade names I've never heard of - http://www.castironcollector.com/seasoning.php – Tetsujin Sep 12 '22 at 11:45
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I am a (former) polymer chemist and flax oil has worked fine for me with no flaking, but it's more *finicky* than other oils. I believe the problem is the heat treatment. If you go too hot, too fast (>350°F for first few coats) with flax, it will indeed risk flaking. The protocol I use is start at 325°F for 1-2hr, with each coat I go up 25°, until 500°F. I use whatever oil for cooking. – DeusXMachina Dec 06 '22 at 22:32
@DeusXMachina Interesting. I'm interested in why going too hot causes flaking? Thanks for sharing your expertise. – Neil G Dec 07 '22 at 01:34
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@NeilG Hard to explain in 600char, but tldr there are several phases of chemical reaction in seasoning. As you go from hot to hotter, more and more reactive sites crosslink. When the polymer is fully crosslinked, its reactivity massively drops. Flax heated too fast rapidly creates a very rigid and brittle matrix which does not yield, so it chips easily. Heating slower gives time for chemical reconfiguration which results in more complete bonding, building larger molecular weight polymers, as well as more plasticity, mitigating thermal and mechanical shock. – DeusXMachina Dec 08 '22 at 16:21

score 11 · Answer 3 · edited Sep 13 '10 at 17:26

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According to Yahoo!7:

To season a pan, preheat your oven to 300°F (150°C). Preheat the pan on the stove top. When warm, coat the inside surfaces of the pan with vegetable oil or lard. Continue to heat just until you see ripples appear on the surface of the oil. At this point, pour off any excess oil, give it a quick wipe with a folded paper towel held in a pair of kitchen tongs, and then put the pan into the oven for 45 to 60 minutes. Remove the pan from the oven and allow it to cool to room temperature.

edited Sep 13 '10 at 17:26

Sam Holder

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answered Jul 27 '10 at 12:59

AttilaNYC

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Solid advice. I'm a great lover of my cast iron skillet (http://www.herbivoracious.com/2009/11/my-skillet.html) and this is generally how I season it as well. Also, after every use and wash I heat it back up on the stove to make sure it is scrupulously dry, then give it a wipe with a little vegetable oil and a paper towel and let it cool down naturally. I find this maintains the seasoning perfectly. – Michael Natkin Jul 27 '10 at 17:21
good answer, except I find that it requires a couple repeats to really take hold and be durable against utensils – zanlok Dec 13 '10 at 20:59

score 9 · Answer 4 · answered Jul 11 '10 at 23:49

Personally I just re-season it by cleaning it well, covering the cooking surface in a frying oil and heating it until it just starts to smoke. This has always worked extremely well for me, and has the advantage of being quick if you need to actually use the thing right away!

score 4 · Answer 5 · answered Jul 27 '10 at 16:47

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The more important part may be how not to unseason the pan. You can never, ever, clean it with soap. Or scrape it with brillo. Just warm/hot water and cloth.

Seasoning is literally "greasing" the pan. And soap is the enemy of grease. Good when washing your hands. Bad when cleaning cast-iron.

This creates a bit of a catch-22 since a poorly seasoned pan will require heavy cleaning. But once you do it right, it will last for months as long as you don't undo the seasoning with soap or scraping.

answered Jul 27 '10 at 16:47

Ocaasi

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It's actually fairly hard to remove cast iron seasoning with modern dish detergents (as opposed to, say, lye). A light wash won't do it (though you should definitely heat it until completely dry & wipe with oil afterwards, and possibly you'd want to heat 'til smoking after wiping on a very light coat of oil). – derobert Mar 29 '11 at 18:16
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This is utterly untrue. If your seasoning washes off with soap and water, it wasn't seasoning, it was just grease. Properly polymerized oil does not dissolve in soapy water. – Sneftel Nov 29 '19 at 10:41
(Also, a proper seasoning won't just last for "months".) – Sneftel Nov 29 '19 at 10:41

score 3 · Answer 6 · edited Jun 16 '20 at 11:23

From the excellent Mike Saxon over at Chef's Tales:

On receiving a new, straight from the supplier, cast iron frying pan or sautéing pan, we used to first place it on a solid top stove, empty with absolutely nothing inside and get it so hot that it would be smoking.

We would then place enough course sea salt in the smoking hot pan to cover its entire cooking surface until it was about 2cm thick. We would leave the hot pot on the stove with the salt and slowly burn and cook the pot with the salt inside. The salt will very slowly “cook” by smoking, burning and turning the salt very slowly to a dark brown colour.

We would then discard the salt in a bin, get a piece of cloth (a towel cloth like an old bath towel or face cloth) dip it in oil and wipe or rub the pot until the hot metal would absorb the oil making the pan shiny.

When the pan is smoking hot, we would them wipe the pan clean with another piece of kitchen towel and then proceed with the whole process all over again from the beginning.

After doing this 2 or 3 times the metal will have absorbed the oil making the metal very shiny, “seasoned” and have a homemade non stick effect. When you have done this you need to try out the pan by making an omelet, if the eggs stick, you have to start all over again until the pan cooks an omelet without the eggs sticking.

The act of “seasoning” the pan may take a few days, a week on more than a week, but it is definitely a loving care process.

score 3 · Answer 7 · answered Jul 11 '10 at 16:26

Heat your oven to around 350F. Coat the pan with some sort of fat (vegetable oil works well), bake for at least an hour, and wipe. You're done!

Re-seasoning is similar to seasoning, as you say. To reduce the need for re-seasoning, make sure you're only cleaning with hot water (and possibly salt).

score 2 · Answer 8 · answered Jul 22 '10 at 19:21

This doesn't directly answer your question about a full re-seasoning, but is related to seasoning.

When cooking with cast iron, I find it easiest to clean the pan immediately, while it's still very hot, with very hot water (our tap gets hot enough to scald if you're not careful).

Then, I thoroughly dry it with a towel, then a paper towel (to get what the towel may have missed).

Then I immediately oil it (I use grapeseed because of its cost compared to its smoke point, but have used bacon grease, olive oil, or whatever else is around) and put it back on the hot burner.

Using this method, I haven't had to re-season my cast iron pans yet.

score 1 · Answer 9 · edited Apr 13 '17 at 12:33

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As long as you don't use soap or scouring pads on a (seasoned) cast-iron skillet, you should practically never need to re-season it. Just dry it thoroughly and rub on a little vegetable oil after you clean it and before you put it away.

Chris's answer is the right one for initial seasoning: Just "bake" the skillet coated in oil. Most cast iron cookware comes with directions regarding temperature and time, and there are minor differences between brands, but 350° F for 1 hour is a good rule of thumb.

edited Apr 13 '17 at 12:33

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answered Jul 11 '10 at 16:38

Aaronut

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Dish Soap is fine (pH 9-ish), just don't use dishwashing *detergent*. As long as the pH is below 10 you won't even bother the coating if it's polymerized correctly. You need pH >10.5 to start damaging it. Plus washing should be a short exposure. Leaving it wet is worse. – DeusXMachina Dec 06 '22 at 22:22

score 0 · Answer 10 · answered Feb 17 '14 at 19:11

One tip to use on a cast-iron that is severely encrusted or has burnt sugar residue is to burn it off. I have done this twice with great success. In one case we made a large hot charcoal fire in an outdoor BBQ grill and buried the pan in the coals. The other was done similarly in a fireplace hearth making sure that the inside and the outside were both in contact with hot coals as much as possible. After letting the fire burn out, and LETTING THE PAN COOL!!, it was necessary to remove a small amount of residue with sandpaper and/or wire brush. The pan is now in brand new condition except that it will look very rusty and will continue to rust unless you treat it immediately. First scour it with a stainless steel pad and some kind of oil (I actually prefer mineral oil for this step) to remove the rust. Wipe it thoroughly with old cloth towels and then proceed to season by one of the methods detailed above. I prefer to do this several times before cooking with the pan. I have always used a solid vegetable shortening for seasoning with good results.

You shouldn't use mineral oil. It has no chemically reactive sites, thus it'll make it harder for the coating to bond to the metal. You should use your seasoning oil directly on the fresh bare metal. — DeusXMachina, Dec 06 '22 at 22:15

What's the best way to season a cast iron skillet?

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