Chemistry of Cast Iron Seasoning: A Science-Based How-To

The post after this one on “black rust” describes why you should heat the pan before applying oil for seasoning. This helps the seasoning to adhere and makes the pan pleasantly black.

In a previous post, I illustrated how I cleaned and reseasoned an antique cast iron popover pan. This was my first attempt, and my seasoning technique was somewhat haphazard because I couldn’t find consistent, science-based advice. I used a combination of organic avocado oil and strained drippings from organic bacon. This worked pretty well on the popover pan, which doesn’t have a polished surface. But the smooth inner surface of a skillet showed an unevenness of color and texture, and the seasoning wasn’t hard enough. It was too easily marred by cooking utensils or scraping against oven racks.

I wanted to understand the chemistry behind seasoning so I’d know how to fix this, but there is nothing that addresses this issue directly. A Web page on cast iron posted by someone similarly obsessed with the science gave me two crucial clues, the phrases “polymerized fat” and “drying oil”. From there I was able to find the relevant scientific literature and put the pieces together.

The pictures below are both of the same antique cast iron skillet. The “before” close-up on the left is from a picture of the skillet in my previous blog post on making German Pancakes. I stripped the pan with oven cleaner and reseasoned it based on my new understanding. The “after” close-up on the right shows the result.

Griswold skillet closeups: old seasoning on left, new seasoning on right
Griswold skillet closeups: old seasoning on left, new seasoning on right

Start With the Right Oil (It’s Not What You Think)

I’ve read dozens of Web pages on how to season cast iron, and there is no consensus in the advice. Some say vegetable oils leave a sticky surface and to only use lard. Some say animal fat gives a surface that is too soft and to only use vegetable oils. Some say corn oil is the only fat to use, or Crisco, or olive oil. Some recommend bacon drippings since lard is no longer readily available. Some say you must use a saturated fat – that is, a fat that is solid at room temperature, whether it’s animal or vegetable (palm oil, coconut oil, Crisco, lard). Some say never use butter. Some say butter is fine. Some swear by Pam (spray-on canola oil with additives). Some say the additives in Pam leave a residue at high temperatures and pure canola oil is best. Some say it doesn’t matter what oil you use.

They are all wrong. It does matter what oil you use, and the oil that gives the best results is not in this list. So what is it? Here are some hints: What oil do artists mix with pigment for a high quality oil paint that dries hard and glassy on the canvas? What oil is commonly used by woodturners to give their sculptures a protective, soft-sheen finish? It’s the same oil. Now what is the food-grade equivalent of this oil?

The oil used by artists and woodturners is linseed oil. The food-grade equivalent is called flaxseed oil. This oil is ideal for seasoning cast iron for the same reason it’s an ideal base for oil paint and wood finishes. It’s a “drying oil”, which means it can transform into a hard, tough film. This doesn’t happen through “drying” in the sense of losing moisture through evaporation. The term is actually a misnomer. The transformation is through a chemical process called “polymerization”.

The seasoning on cast iron is formed by fat polymerization, fat polymerization is maximized with a drying oil, and flaxseed oil is the only drying oil that’s edible. From that I deduced that flaxseed oil would be the ideal oil for seasoning cast iron.

As a reality check of this theory, I googled “season cast iron with flaxseed oil” to see what came up. The very first hit is a page written by a guy who seasons his cast iron cookware with linseed oil from the hardware store because it gives the hardest surface of anything he’s tried. (I’m not sure how safe that is; I don’t recommend it.) Below that were several sites selling traditional cast iron cookware from China, which they advertise as being “preseasoned with high quality flax oil”. I don’t know whether they really use food-grade flaxseed oil (which is expensive) or linseed oil from a hardware store. What’s significant is the claim. Seasoning with high quality flaxseed oil is something to brag about.

With this encouragement, I stripped one of my skillets and reseasoned it with flaxseed oil. As you can see in the picture above, the result was a dramatic improvement. The finish is smooth, hard, and evenly colored.

Seasoning Is Not Cooking: Different Principles Apply

The first time I seasoned a pan I chose avocado oil because it’s monounsaturated and doesn’t easily go rancid. It also has the highest smoke point of any edible oil, 520°F, so I could heat it in a 450°F oven without passing the smoke point. I knew that when cooking, you should never heat an oil past its smoke point because that causes the release of “free radicals”, which are carcinogenic. I was careful not to choose a polyunsaturated oil – and especially not an oil high in omega-3 fatty acids – because these are especially vulnerable to breakdown with heat and the release of free radicals.

Ironically, it’s for exactly these reasons that the best oil for seasoning cast iron is an oil high in omega-3 fatty acids – in particular, alpha-linolenic acid (ALA). Free radicals are actually what enable the polymerization. Drying oils, which produce the hardest polymers, are characterized by high levels of polyunsaturated fatty acids, especially the omega-3 fatty acid ALA.

The lard that was traditionally used for seasoning 100 years ago was much higher in ALA than fat from pigs today, because back then pigs ate their natural diet. Today they are raised on industrial feedlots and forced to eat grain, making their fat low in omega-3s.

Since lard is traditional but no longer readily available, many people substitute bacon drippings, but this is a bad idea. If it’s conventional bacon, you’re baking in carcinogenic nitrates. But even organic bacon is not good for an initial seasoning because it’s filled with salt.

The reason that Pam seems to work well in seasoning is that its main ingredient is canola oil, which is relatively high in ALA (10%), making it a “semi-drying oil”. Flaxseed oil, a drying oil, is 57% ALA. But it’s not a good idea to use a spray oil, no matter what oil it’s made with, because of its additives. You’re doing chemistry here. If you want good results, use pure ingredients.

Fat polymerization can be triggered or accelerated in a variety of ways. As best I can tell from my reading, the cast iron seasoning process is an example of “radical polymerization”. The process is initiated when something causes the release of free radicals in the oil. The free radicals then “crosslink” to form the tough, hard film you see in a well-seasoned pan.

So what is the “something” that initiates the release of free radicals in fat? Iron, for one thing. High heat, light, and oxygen, for some others. To prevent cooking oils from going rancid – i.e., breaking down and releasing free radicals – you need to store them in dark, tightly sealed containers in a cool location. To initiate or accelerate the release of free radicals, put the oil in contact with bare iron and heat it above its smoke point, which will cause even non-drying oils to release free radicals.

I haven’t defined “free radical” or “crosslink” because that gets into details of chemistry that you don’t need to understand to season a cast iron pan. All you need to know is that the molecular structure of the oil changes and becomes something else, something tough and solid. The process is initiated with the release of free radicals, which then become crosslinked, creating a hard surface.

Free radicals are carcinogenic inside your body, and also a cause of aging. So don’t ever heat oil you’re going to eat above its smoke point. If the oil starts to smoke, toss it out and start again. When you’re seasoning a pan, you’re not cooking food. By the time the seasoned pan comes out of the oven, there are no more free radicals.

The Recipe for Perfect Cast Iron Seasoning

The basic idea is this: Smear a food-grade drying oil onto a cast iron pan, and then bake it above the oil’s smoke point. This will initiate the release of free radicals and polymerization. The more drying the oil, the harder the polymer. So start with the right oil.

Go to your local health food store or organic grocery and buy a bottle of flaxseed oil. It’s sold as an omega-3 supplement and it’s in the refrigeration section because it goes rancid so easily. Check the expiration date to make sure it’s not already rancid. Buy an organic flaxseed oil. You don’t want to burn toxic chemicals into your cookware to leach out forever more. It’s a fairly expensive oil. I paid $17 for a 17 ounce bottle of cold-pressed, unrefined, organic flaxseed oil. As it says on the bottle, shake it before you use it.

Strip your pan down to the iron using the techniques I describe in my popover post. Heat the pan in a 200°F oven to be sure it’s bone dry and to open the pores of the iron a little. Then put it on a paper towel, pour a little flaxseed oil on it (don’t forget to shake the bottle), and rub the oil all over the pan with your hands, making sure to get into every nook and cranny. Your hands and the pan will be nice and oily.

Now rub it all off. Yup – all. All. Rub it off with paper towels or a cotton cloth until it looks like there is nothing left on the surface. There actually is oil left on the surface, it’s just very thin. The pan should look dry, not glistening with oil. Put the pan upside down in a cold oven. Most instructions say to put aluminum foil under it to catch any drips, but if your oil coating is as thin as it should be, there won’t be any drips.

Turn the oven to a baking temperature of 500°F (or as high as your oven goes – mine only goes to 450°F) and let the pan preheat with the oven. When it reaches temperature, set the timer for an hour. After an hour, turn off the oven but do not open the oven door. Let it cool off with the pan inside for two hours, at which point it’s cool enough to handle.

The pan will come out of the oven a little darker, but matte in texture – not the semi-gloss you’re aiming for. It needs more coats. In fact, it needs at least six coats. So again rub on the oil, wipe it off, put it in the cold oven, let it preheat, bake for an hour, and let it cool in the oven for two hours. The picture above was taken after six coats of seasoning. At that point it starts to develop a bit of a sheen and the pan is ready for use.

If you try this, you will be tempted to use a thicker coat of oil to speed up the process. Don’t do it. It just gets you an uneven surface – or worse, baked on drips. Been there, done that. You can’t speed up the process. If you try, you’ll mess up the pan and have to start over.

The reason for the very hot oven is to be sure the temperature is above the oil’s smoke point, and to maximally accelerate the release of free radicals. Unrefined flaxseed oil actually has the lowest smoke point of any oil (see this table). But the higher the temperature the more it will smoke, and that’s good for seasoning (though bad for eating – do not let oils smoke during cooking).

I mentioned earlier there’s a myth floating around that vegetable oils leave a sticky residue. If the pan comes out of the oven sticky, the cause is one of three things:

  • You put the oil on too thick.
  • Your oven temperature was too low.
  • Your baking time was too short.

It’s possible to use a suboptimal oil for seasoning, like Crisco or bacon drippings, and still end up with a usable pan. Many (most) people do this. But the seasoning will be relatively soft, not as nonstick, and will tend to wear off. If you want the hardest, slickest seasoning possible, use the right oil: flaxseed oil.

Editorial Note:

Many flax oils contain added ingredients to prevent rancidity, and it’s the tendency of this oil to go rancid that makes it so good for seasoning pans. Flax oil only works if it’s 100% pure flax oil with nothing added, so read the ingredients! People have reported mixed results, and this is probably why.

492 thoughts on “Chemistry of Cast Iron Seasoning: A Science-Based How-To

  1. @Matt :
    I doubt you temps are too high.

    I’m currently in process of stripping and resealing a pan of mine. The cast iron is a Lodge (10in) skillet and has the rough-textured bottom.

    I stripped it to the metal using the self cleaning oven method. Lacking power tools, I used a stainless steel scouring pad to remove any surface debris (ie carbon). I wiped it out with a plain paper towel then applied oil rubbing it around and applying more until the towel came out clean. Then, I wiped out excess oil and began the seasoning process.

    I’ve just finished my 8th coating. I am using the Organic Flaxseed Oil from Whole Foods. I’ve been carefully applying a thin layer followed by wiping as much as I could out of it. I bake mine as 550°F (oven high) and start timing it after its come up to heat. I started with a flour towel and thought I saw some fibers coming loose, so I switched to a microfiber rag. It appears to work great with no visible fibers coming loose. I have one more coat to go and then I’ll try it out on some eggs. The coating is a dark black and appears to be slick.

    I will update on well it works.

    BTW thank you sooo much Sheryl. You information was extremely helpful and appears to be working great.

    James Hearne

  2. Sheryl, thank you so much for the tip of using food grade flax seed oil, made a HUGE difference. My last batch of cast iron woks look like museum quality! Just reread your alert to heat pan first so it will adhere. Thanks again.

  3. Hi Shery,

    thanks for the great advice! I was wondering if the same process could be used on iron pans (I have a DeBuyer brand) also called black pans.


  4. Hi,
    I stripped my cast iron pans until they had no black left in them, and tried to season them many times the way you suggest. But they stick and my wife thinks they now have hot spot.

  5. I patiently followed all of Sheryl’s seasoning steps and indeed the pans looked as nice as ever. Now that I started using them the seasoning is coming off. I have doubts about this method along with many other people.

  6. Hi Sheryl,

    Thanks so much for all your time, effort and informative posts. I have a Lodge skillet that I stripped several times (it was badly seasoned and sticky) as per your recommendation. I put it in the oven at 200 for 10 minutes to get it bone dry but then saw your post on black rust. I plan to put it back in the oven on 450 to get the black rust to form before applying the flax oil but was wondering if you’ve tried or if you recommend boiling the pan first before heating it? Thanks!

  7. what is created when seasoning is a layer of carbon on the pan which prevents predominantly rust and creates a less porous surface, some things like egg will stick to anything.
    Some things are going to be unavoidable, like smoke, and the need to re-season when the finish starts to wear down.
    But to re-season do not strip the old seasoning, only scrub off anything loose with soap, hot water and scouring pad, and otherwise never use soap to clean.

  8. I have a preseasoned Lodge wok I never used. I set a bag of onions inside the wok, and forgot they were there. The onions disolved, and rusted the wok. I cleaned the wok. I used sand paper to remove some of the rust. Then I tried seasoning the wok with peanut oil, since peanut oil has the highest smoke point. I contact Lodge to see if they can help me. At this point I think I am better off just buying a new pre-seasoned wok if Lodge does not help me out. What do you suggest? Michael

  9. I just tried this method to re-season a lodge pan that had some of the pre-seasoning chipping off. I used the oven cleaning method to strip the pan, and then started from scratch with the flaxseed oil. After 6 coats the pan looked good and i decided to test by cooking an egg on it. No good. Completely stuck. Maybe it just needs additional layers of seasoning. Or, similar to Frank’s question above, maybe because it was a pre-seasoned lodge pan I just need to buy a new pan? Any tips or ideas would be appreciated.

  10. Sheryl where did you get your information from that makes you want to type this?
    Lodge has been making cast iron since 1896. United States has the best quality iron ore in the world. With the technology of today Lodge is able to maintain consistent quality control on it’s cast iron. The casting process is excellent at Lodge. As far as machining the interior of the pan, that is debatable. Lodge used to machine the interior of pans until the 1990’s. I have just as much, if not better, luck getting the seasoning to adhere to the non-machined surface. After a few proper seasonings they turn out slick and smooth anyways. I see no need to machine them.
    Go to the Wal-mart and for 18 bucks you can get a 12 inch Lodge skillet that you will find is heavier than the old Griswold collectables. Even though the new ones come pre-seasoned, I still scour them and re-season them “my way” with leaf lard rendered from free ranging heritage breed pigs. They create fat that is mostly monounsaturated and high in omega 3 fatty acids and provide the hardest of seasoning for cast iron.

  11. Sheryl I was referring to your comment that the new Lodge cast iron is not as good as the old pre 1950 cast iron. 🙂

  12. Sheryl: Thank you for the above, oil types, temp, polymerization. See, turns out we can actually use those chemistry classes in real life:-). The only thing I have to add is that, in getting down to the thinnest coat of oil, I find it helpful to put the oil on a hot pan, not all 500 degrees hot but hot enough to get the oil to spread. Then I go over it with a dry paper towel a couple times to get rid of any free oil. Finally, after about 10 minutes in the hot oven, when little “dots” of oil may show up (esp. on the machined cook surfaces of high quality pre-1950 castings), as it is no doubt beginning to polymerize, I wipe one more time with a dry paper towel (being careful not to burn my fingers). You are so correct, many small coatings is the only way to go.

    Regarding the “never use soap” adage, I am more worried about letting my pans sit in water or the use of an abrasive scrubber. My pans go through a soapy wash with a soft cloth; there is particular way the water sheets off the cook surface of a well seasoned pan that tells me everything is good to go for next time. A quick go round with a hand towel to eliminate any dampness and my pans have not suffered going right back into the cupboard (dry Colorado maybe helps?). Easier to take care of than non-stick pans.

    Now I need to find some flax seed oil, best to you and your readers. Duba

  13. Hi Sheryl. Thanks for the tutorial – I am on my 3rd pan with your techniques. I have noticed though that after the first round of baking (when I get that great matte black finish) that my pans start to take on a reddish cast with subsequent oiling/baking rounds. Any experience with this? I am wondering if it’s normal or if I’ve taken a misstep somewhere.

  14. Hello Sheryl! Thanks for the tip–I just bought a new 12″ pre-seasoned Lodge skillet and immediately scoured off the factory seasoning before using the method you shared. Now, my skillet looks great after the six rounds of seasoning (I’m pretty sure it was six rounds)–the bottom and sides are noticeably smoother than when I bought it with it’s rather ridiculously rough surface. First cooking: bacon. Mostly, I avoid bacon despite loving it; but this bacon was fried with an explicit purpose. I then used some of the bacon in my second experiment: skillet cornbread. That “loaf” slid out of the pan so fast it almost ended up on the floor! Tomorrow, I buy the 10″ so I’m a little more versatile… Thanks again!

  15. I just finished seasoning a cast iron skillet with flax seed oil, and it came out great. Unfortunately, I then left the skillet on a burner and it has discolored the finish. Is it possible to start over again by putting the skillet in an oven and running the self-cleaning cycle to remove the baked on flax seed oil?

  16. Wok Seasoning Instructions

    These instructions came with a plain iron hand-hammered wok. I didn’t write this and am simply forwarding for informational purposes. (FYI, I took the wooden handle off.)


    Coat lightly, interior and exterior with cooking oil. Bake in hot
    oven, 425 degrees for 20 minutes. Place upside down in oven.. Cover
    the wooden handle with a damp cloth and cover cloth with alum foil.
    This will protect the wooden handle.

    Remove from oven, let cool to touch and scour wok with an abrasive
    pad. Scour the “seasoning” or patina away…like you want the wok
    back to its original finish.

    Wash, dry, coat and bake again – same process. Do this 2 times.

    After the last baking, you will not be able to scour the seasoning
    away and that is the result you want. The wok is seasoned.

    The more you use the wok, the better and blacker it gets., You
    cannot ruin the wok. If you neglect it and it should get rusty,
    not to worry, Just scour away the rust and season again. A wok
    should last almost a lifetime. A wok also gets better with age…the
    older the better.

    If you use a gas stove, you can try seasoning the salt method; just
    wash wok thoroughly and dry. (does not work efficiently or quickly
    on an electric stove). Pour l cup of table salt into wok and with
    a high flame, stir salt constantly 20 minutes to 1 hour. Wipe wok
    clean and oil lightly with cooking oil. Voila! a seasoned wok
    with no muss no fuss.

    You can use your wok to not only stir fry, but deep fat fry, steam,
    braise, stew, boil, saute, smoke and pop popcorn. A wok just gets
    better and blacker with use. Your wok will develop a nice patina
    and will get to a point where it will be almost non-stick.

    After the wok has been seasoned, it would be a good idea to preheat
    the wok, add a little bit of cooking oil (1 tsp) and pre heat the
    oil; then add some pungent veggies. e. g.sliced onions, green onions,
    ginger, garlic and stir fry in the wok until burned – then toss out
    the veggies. Your seasoned wok will be ready and the wok will be
    so nice!.

    Happy Wokking!

    Thank you. Ms. Tane Chan


  17. Hi Sheryl,
    You have some very interesting information on seasoning here. Too much work for me so I just start using a pan and let it season naturally.

    What I wanted to comment on is about the “pores” in cast iron. To my knowledge there are no pores although one can read all about the pores on the internet in many places. Is this possibly just a myth that keeps getting passed around? Any voids (pores) in cast iron, from what I have gathered, are filled with graphite crystals which makes the iron a solid substance without voids. If cast iron is in the “as cast” state the surface would not have pores. When the iron surface is ground or polished that opens up the interior of the casting but will only expose the graphite crystals filling the pores or voids in the cast iron. I have tried to find more definite information about the existence of pores in iron including photos from electron scanning microscopes but without too much success. Have you confirmed from a reliable source that there ARE pores in cast iron?


  18. Sheryl,

    Someone turned me onto your seasoning instructions today, and I’m excited to try your method ASAP. Here’s a question you might be able to help with:

    I have a cast iron griddle with a flat griddle on one side and raised ridges (grill) on the other side. I most commonly cook on the griddle side, and I find that my gas stove tends to ruin the seasoning on the grill side when cooking on the griddle side. Any recommendations on how to preserve the seasoning on the grill side when faced with an open flame?


  19. I have just seasoned my cast iron skillet to these instructions. The pan came out beautifully after the process was complete, and my first cooking attempt was great. However during clean up, I turned the cook top on high heat (as is my normal cleaning method) and rubbed it down with a damp rag. To my dismay, a good deal of the seasoning was removed. If this oil can not support high heat, how am I to sear meats properly?

  20. Wonderful Blod Sheryl, I’ve been cooking with cast iron for years and years and found most of your information very validating. I have always used an flax oil for when i reseason a pan from the ground up and I usually do it every few months and now I know why I had to.
    I also finish off with a softer oil after washing every week or so like lard or bean grease from refried beans. I put on the softer seasoning to protect my harder seasoning.

    Now I havent reseasoned a pan in a long time save the softer seasoning of lard every week or so which is fast and easy compared to several coats os flax oil.

    The reason why was what I believe to be a trifecta of seasoning and iron destroying foods.

    1) you cant do marinara sauce big no acids from tomatoes.

    2) Never boil water, that includes hamburger helper, it destroys seasoning and leaves bare spots in the bottom and sides of the pan.

    3)Bacon…. I know it sounds wierd but there is something in store bought bacon that ruins the seasoning and I figure this because when I smoke my own bacon from fresh jowl meat, I can cook that in my cast iron, but bacon from the store is a big no no so I never cook prepackaged bacon in my cast iron. I figure it has something to do with the nitrates or preservatives.

    So there is my exerimental years of experience. I havent re-seasoned my pan in over 4 years and am just now stripping it to reseason. I have always left it in the oven with a light coat of rust after stripping, the rust turns a bluish charcoal grey and is no longer rust after sitting in the oven at 500 for an hour to dry. It comes out hot and I rub my first layer of flax seed oil on there and it smokes as I rub it in all over with a thinly oiled rag. I immediately return the pan to the oven for an hour and then let it cool after that for at least two hours in the oven and repeat very similarly to your method. The only thing I do different now is what I mentioned above I wont boil water cook acidic foods or fry sub par bacon in my pan. those foods get to go into the stainless steel pan. Thanks again for the blog just thought I should add some food for thought.

  21. It appears as though you are trying to make home-made teflon! Cast iron should ONLY be seasoned with animal fat products, e.g., bacon fat or NON-HYDROGENATED lard. Also, NEVER scrub!

  22. This guy must be a Yankee. Back to home to loosen the ‘crud’ we use good ole Parsons Ammonia. Put the cast iron thing in a plastic kitchen garbage bag with ammonia. Tomorra it takes a little scratchin and the skillet’s clean. No lie – no lye. It don’t matter what oil you use to season it. Just oil it up, turn it upside down on the stove and let er burn. Smokes a lot. Do it a few more times and you’re ready for for some good down south cooking. Pass them grits and gravy.

  23. Sheryl I just tried your seasoning method and it didn’t work. I assume I’ve done something wrong. The Flax seed oil I used was organic but it did not require refridgeration. That is the only thing that was different. Let me know what you think. Thanks, Becky Mayers

  24. I purchased three old crusty cast iron skillets at a garage sale. They were disgusting-rough surface with years of cooked-on crud, and very rusty. I used the techniques described in your popover post(mainly oven cleaner). Next, I purchased organic flax oil, refrigerated, in-date, and followed your instructions. U N B E L I E V A B L E !!!!!!!!!!! These skillets look like they just came from a high-end gourmet cooking store and that was just one round of seasoning. Thank you so much for doing all the background work on this!

  25. Hi Sheryl – first, thank you for taking the time to post this information. I also have a question about the type of flax seed oil. I bought a bottle of organic flax seed oil from GNC, and while it does require refrigeration after opening, I noticed that there are other ingredients in there: Organic Rosemary Extract, Mixed Tocopherols (Vit. E), Ascorbyl Palmitate (Vit. C), and Citric acid to protect freshness. It also contains soybeans.

    Is this ok to use? Thanks.

  26. I think those added ingredients would do exactly the opposite of what you want seasoning-wise, and I suspect the ubiquity of added ingredients in so-called “flax oil” solves the mystery of why some people have had such good results seasoning with flax oil, while some have not.

    Flax oil works because it goes bad so fast. That “going bad”-ness is defined by the release of free radicals, and is what enables the polymerization. (I explain this in the article.) The ingredients that preserve freshness for eating (especially if the preservation is so extreme as to prevent the need for refrigeration), reduce the release of free radicals and thus reduce the oil’s ability to polymerize.

    You want pure flax oil for this – the kind that goes bad quickly.

  27. Iron isn’t porous. That’s just misinformation that keeps passing around the ‘net.

    Best way to season cast iron: make a roux in it.

  28. Sheryl,

    I have a cast iron griddle with a flat griddle on one side and raised ridges (grill) on the other side. I most commonly cook on the griddle side, and I find that my gas stove tends to ruin the seasoning on the grill side when cooking on the griddle side. Is there any way to preserve the seasoning on the grill side when faced with an open flame?

  29. I know that the cleaning chemicals you used are very aggressive on aluminum and I will handle them accordingly. My question do you feel that this use of high quality flax seed oil will work on other metals such as aluminum?

    I have a downdraft Genair stove with a cast aluminum griddle and 2 cast aluminum grill grates which I would like to re-season. I also was wondering why not re-season over the current surface since I have all my cast iron and aluminum cooking units seasoned the old fashioned way. My grand mother and mother along with their relatives used cooking with all forms of fat and even putting the iron ware directly in wood coals which created the non-stick seasoning. I will not be touching my old Cast iron because the seasoning is unblemished and I use the Crisco seasoning method for them each New Years day.

    Will the Flax seed oil work on aluminum directly or to save time should I seal the current seasoning in a Flax seed Hard Polymer?

    Thanks Bill Hunt

  30. Sheryl,

    Good info. Thanks. One question, where can I purchase cast iron pans that are not pre-seasoned?

  31. Hello Sheryl,

    I did ‘the whole tour’ with my Iittala cast iron pan. It worked out fine! Many thanx for your helpfull article with possitive advise.

    I have a final question. Is it possible to create a black matt finish?

  32. If you have a self cleaning oven more eco-friendly way than oven cleaner to clean cast iron is to stick it in and run the cleaning cycle for about 2 hours. After it’s cooled the remaining white ash can be removed with a rag. To remove any remaining rust fill the pan with distilled vinegar and bring it to a boil on your stovetop, then let it set for 24 hours or so. Any remaining loose rust can be removed with a scrubby. This method has a side benefit of removing kitchen odors and pouring the used vinegar down the toilet helts clean the pipes.

  33. Please Help! I just purchased 3 Lodge Cast Iron pieces and already seasoned two of them. I washed the pans with soap and very hot water, dried them and re-seasoned them with bacon fat in the oven for quite a while. They actually look very nice, even got darker, but I really, really want the finish and care you gave to your cast iron. Can you tell me where to start? I sure wish I had found you before I worked on my cast iron, but at least I have not done my 8 Quart Camp Oven yet!!!
    PS, Now I understand that I never even really got the first factory coat of seasoning off of them from the scrubbing I did! Can this be fixed? Help!

  34. I have a different situation that needs attention. I am sitting in a new restaurant kitchen and am staring at a 48″ flatop griddle. The griddle has been constructed of cast iron instead of the usual polished steel. What should be my method of “seasoning” a griddle of this size that obiviously cannot be put into a hot oven. It has 3 mega btu burners underneth, and the gas control knobs all go to 450. Also, the cast iron surface was not smoothed. It is in it’s rough state complete with grooves, faultlines and rough sandpaper feel.
    Any thoughts on how my methods of seasoning might change from those who are using pans and other smaller items?
    I am on my 6th application of Flax oil and have the feeling that I may have left too much oil on after applying it. It appears like it is “caking” in some spots and if I scrap it with my fingernail, it comes off. Not sure if it goes down to the first layer or not.
    I did scrub it with a green nylon pad and soap/water. Didn’t seem to remove what has hardened so far.

  35. I just did a first layer on seasoning on a new de buyer carbon steel fry pan I purchased (their carbone plus line), and after a first bake the entire pan turned a very bright blue, except for the spots where it’s starting to develop the darker patina. I’m really curious about this. Does anyone have any insight on how that happened and what it means? I’ve never had that happen before with any of the iron pans I’ve had… Is that normal with carbon steel? Is the pan still safe to cook in?

    Thanks for any insight

  36. Sheryl – thank you for the interesting read.

    I am concerned about the free radicals, however. You say that they will be gone by the time the seasoning process is done, but can you elaborate on this? I’m concerned that this process leaves dangerous free radicals and carcinogens in the coating that can leach into the food I cook. However I have no scientific basis on which to say why this is or isn’t true.

    I too am trying the avocado oil because of its high smoke point but clearly you state that this is the exact opposite!

    Safety is #1 though.

  37. Been reading this page and all the comments and have only come to one conclusion: this is way too complicated for a cooking device that can put up with more abuse than any other. Seasoning it with something like Crisco or bacon grease will not end your life or anyone else’s. It works just fine. If it worked for our ancestors it will work for us. And just cook a ton of bacon in it to *really* season it. We basically did this with our Lodge and we’ve only re-seasoned it once in about the 6 years since we started using it. Even then we didn’t strip it down, just a re-season.

    It’s pretty much non-stick at this point and is an absolute, indestructible workhorse. Have used metal utensils on it, including spatulas, and we haven’t lost any of the seasoning. It’s cast IRON, not a FabergĂ© egg.

  38. Hi Sheryl,
    What a disaster! 500 degrees indeed! It wasn’t long before my kitchen filled with smoke! I guess I put too much oil on but it didn’t seem so at the time. My wife thinks you and I are both crazy! I solved this problem by moving the cast iron grills to the barbeque where they should have been from the start. I don’t know how you avoided this problem but I suspect you’re going to tell me that I used too much oil. Comments?

  39. Yup, Sheryl has it correct. THIN flaxseed oil at 450+ (on the BBQ so as not to stink-up the house – cooking surface down). Follow her recommendations. I’ve tried a number of other methods prior to her’s – bacon grease, olive oil, lard… They end up spotty and/or sticky and don’t have the ‘slick’, coal-black seasoning that you want. Do at least four sessions.

    As she mentions, seasoning is NOT the same as cooking. I use olive oil for cooking. The final thing I do for skillets after seasoning is to cook some ‘throw away’ eggs in olive oil. Scrape them around the entire bottom of the skillet with a good stainless steel spatula. I use a Dexters (which are collectables in their own right and made in the USA!). The eggs will stick at first. Scour the skillet with kosher salt and oil. Repeat two or three more times. After that you’ll find the eggs slide around like teflon. Fantastic!

  40. Hi Sheryl,

    I followed your instructions on a Griswold Cast Iron Skillet. However, when the skillet was resting on a table, my son spilled milk on the bottom side of the pan. It took awhile before my wife noticed it and the milk has left this annoying stain on the bottom of the pan. I tried cleaning it with flax seed oil, but no luck. My friend thinks the milk has reacted with the seasoning and I might have to start all over again. Any ideas on what I should do? I would hate to start all over again. Is there any hope for me and should I disown my son (just a joke)?


  41. I purchased a 10 inch cast iron dutch oven at a flea market. We plan on using it over an open fire. I have followed all of your instuctions for stripping and prepping to start the seasoning process. My question is, do I need to season the outside and bottom of the pot since we are going to use it over fire.

  42. I tried this again with a LOT less oil and it went off without a hitch! I guess less is more when it comes to seasoning a cast iron skillet.

  43. I am curious if there a reason the skillet must cool off over such a lengthy period of time? After an hour of seasoning, why not just open the door and let it cool twice as quickly?

    Thank you tremendously for this site.

  44. Sheryl, I’ve been working on this pan for 2 weeks with miserable results, I’ve followed several different methods, none seemed to work well. My skillet just came out of the oven for the first round and it came out superb! Flaxseed oil works great. As a side note to anyone that is reading this, if you get small black dots, start over, completely dry the pan as mentioned and when putting the oil before baking, make sure to wipe it down until it appears to be dry. I now have a smooth, evenly seasoned skillet!

  45. Thanks for this article Sheryl. I’m just wondering if this applies to stainless steel as well? Thank you.

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