Best Way to Season Cast Iron Pans - Flax Seed Oil

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Introduction: Best Way to Season Cast Iron Pans - Flax Seed Oil

About: I've worked for Instructables off and on since 2006 building and documenting just about everything I enjoy doing. I am now the Creative Programs founder and manager for Autodesk and just finished building out…

I try to use cast iron cookware whenever possible.  It has excellent heat dispersion properties, life long build quality, and an inherent ability to cook foods with exceptional control at both high and low heats.  It works on all kinds of stoves, electric, gas, induction - even a fire pit while camping.  

The only snag about cast iron (if you can really call it that) is the seasoning process.  "Seasoning" cast iron refers to a process of building up some amount of material, which I'll call a finish on the pan that aids in cooking, creates a semi-nonstick surface on the pan,  and protects the cast iron pan against any possible rust.

There are lots of theories on seasoning cast iron, from complex rounds of heating and oiling with different types of vegetable and animal fats, to doing nothing at all.  Having tried many of these seasoning processes myself, I feel inspired to write about the flax seed oil method.  It's the most durable and straight forward seasoning process that I've found, and the science behind the process agrees.

Step 1: Flax Seed Oil

You can find flax seed oil in the refrigerator aisle at the grocery or health food store.  Flax seed oil is the edible version of linseed oil, a very durable, hard drying finish that painters and woodworkers have been using for a very long time.  As Cheryl Canter writes on her site: "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."

What that translates to in practical terms is a durable finish, that even after just a few coats and short term heating results in a deep glassy black seasoning on the cast iron that has held up to months of my daily usage and cooking abuse.  

As with any other cast iron pan seasoning, You don't want to use soap on the pan when cleaning it, but with this method, I've found that using a mildly abrasive sponge when doing the dishes doesn't seem to affect the finish at all.

Step 2: Oil the Pan

Pour a small amount of the flax seed oil into the pan.  Less is more with this stuff, so shoot for more than just a few drops, but no more than a tablespoon.  Start with a teaspoon and go from there.  Then, using a paper towel or rag, spread the oil evenly throughout all the surfaces of the pan, including the bottom of the pan, the sides, and even the handle.

The pan should have a slight sheen to it, but no standing puddles of oil or thick areas of build up.  If you're really feeling inspired, use your bare hands to spread the oil around and envision yourself back in the old world.  Follow the rule of thumb for any other finish - shoot for a nice thin even coat.  You can always apply more, and, as you'll soon see, you will.

Step 3: Bake at 500F for 30 Minutes

Place the oiled pan inside a 500F degree oven for 30 minutes.  Some sources say to heat the pan for longer, but, if you've put on a thin coat of oil I've found that 30 minutes is plenty long enough.

The pan will smoke a bit during this process.  That is completely fine and natural, your oven will not catch fire.
The hot flax seed oil will smell a bit strange.  That is also completely fine and natural, the smell will go away.

PRESS ON! 

Step 4: Repeat 4 to 7 Times

Once you've "cooked" the pan for 30 minutes, remove it from the oven and let the pan sit until it's cool enough to touch.  When you're sure it's not still hot, reapply a thin coat of oil using the same method described in step 2, put it back into the oven and cook it for another half an hour.  

Keep repeating this process until you've gone through as many cycles as you'd like.  I've found that 4 to 7 rounds was enough to result in a semi-gloss, beautifully smooth, tough, black finish that is ready for use.

Step 5: Do All Your Cast Iron at Once

Final tip - do all your cast iron pans at once.  In my opinion, if you're gonna crank the oven up to 500F for several hours and make the house smell a little funny, you might as well make good use of it and season all your cast iron cookware at once.  The good part is that you won't have to repeat the process very often.  I've been going on the same seasoning session for several months now and they still look great.

Step 6: Use the Gas Grill

*update 1/30/12*

I now feel foolish for saying that this was the "best way" to season cast iron without mentioning this important tip that was brought up in the comments: if you want to avoid making your house smell like smoking oil - USE THE BBQ!

What a great idea - thanks to everyone who suggested this.  Next time, I'm definitely gonna use the grill.

photo attribution

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    175 Discussions

    0
    Legadoo NayNay
    Legadoo NayNay

    2 months ago

    I got caught rubbing Lintseed oil on the school Cormerant

    0
    uncle frogy
    uncle frogy

    4 years ago

    I love my cast iron cook ware! good advice on the primary seasoning never thought of raw linseed oil before but why not once it has carbonized into the iron's pours there is not much left but carbon anyway. I have used most kinds of fat or oil for the first time and have not had any trouble. When well seasoned they seldom need very difficult cleaning as any residue just rinses off with just a little scrubbing with a brush at most they really are none stick.

    one of favorite pans is a Teflon coated pan found in the trash, the coating was failing very badly. I used a small medium sharpening stone to clean and polish smooth the inside down to bare metal then seasoned it work great.

    0
    mlaiuppa.
    mlaiuppa.

    Reply 4 months ago

    Don't use linseed oil. You have to use something that is food safe. Use pure flaxseed oil. You'll find it in the refrigerated sections of the healthfood store or places like Whole Foods.

    0
    M2aestro
    M2aestro

    Reply 4 years ago

    Old Teflon coating are applied in a resin base that, when cured, places about 90% of the Teflon in the top 10% of the coating. I can't comment on what's been done in the last 15 years, because I'm no longer concerned with such coatings on my products (retired). Old Teflon pans tend to have all the Teflon worn off. When heated past 550 degrees F, any Teflon coating would be converted to volatile and toxic materials, and would lose its non-stick properties. I can say nothing about what happened to the resins with which it would have been applied (the coating substrate), for toxicity, but they would not be non-stick. They might not be so toxic when over-heated, but I cannot vouch for their safety. Good ideas to polish the old surface to bare metal. BTW, non-stick coatings, especially the so-called ceramicised aluminum coatings that were done in a type III hard anodizing process with colloidal Teflon in the bath, coated much thicker and stronger when the aluminum surfaces was first etched to give a quite porous surface. Alternatively, it could be roughly machined to rougher than a 30 AA surface to get a good anodize. The important message here is that if you are using Teflon-coated cookware, keep the temperature below 500 degrees F to prevent toxic vapors from being formed by breakdown of the Teflon.

    0
    jharold
    jharold

    10 months ago

    I recommend putting the pan in the oven upside down to ensure any additional oil drips out of the pan and doesn’t stay in it.

    For those that are doubting the flaxseed oil. I’ve tried many and Lindsay oil which is from the same plant as what the old Masters used to protect their paintings for hundreds of years. There’s a reason to use it.

    0
    carrionangel8911
    carrionangel8911

    Question 1 year ago on Step 1

    I thought flaxseed oil isn’t suppose to be heated over 225 degrees? My Carrington farms flaxseed oil states not to go over 400.
    Pushing a oil past it’s smoking point is TOXIC and dangerous. It can lead to smoke inhalation. Which can be fatal.
    I tried this method and the smoke was awful. I’d rather use shortening or vegetable oil at 350 for a hour.. Take it out and do one more layer then repeat.

    0
    kcbaltz
    kcbaltz

    Answer 1 year ago

    The answer is that you're not cooking, you're seasoning, and so the free radicals released are not harmful (I would make sure the last cycle of baking is a little longer to ensure they're all baked off). Check out the article the OP links to from Ms. Canter. It explains in more detail.

    0
    donw101
    donw101

    Question 2 years ago on Step 1

    Can I use virgin flax seed oil ?

    0
    cchubb
    cchubb

    8 years ago on Introduction

    Why does the "no soap" mantra keep coming up. I've been cooking on cast iron all my life and I use Ultra Dawn on mine after every use, usually using either a regular sponge, or one of those twisted stainless pads if it's really caked on crusty stuff.

    I usually season it every two or three years, not because it needs it regularly but because it usually suffers some kind of abuse like having something salty left in it (usually soy sauce) overnight or if the patina gets too thick and I have to clean it in the self-cleaning oven and then reseason it.

    I will agree that you never want to use a brillo or other abrasive cleaner (comet, chore boy, etc.) on your iron. It's not as much the metal but the "soap" is much too aggressive. If whatever is in there is that caked on, just soak overnight in the sink, clean in the morning and wipe dry without allowing water to pool on it.

    Me, I just use olive oil to season it. Flax oil is "edible" but so is mineral oil and I wouldn't want to use that in my pan.

    One thing that looks different from my pans is that the pans in the picture don't appear to have a machined inner bottom, they look more rough, direct from the mold. Perhaps that's just the camera, but when the bottom of your pan isn't flat, you need to fill all of the nooks and crannies with oil to keep stuff from sticking. You have to look a lot harder to find pans with machined bottoms.

    None of this comment is meant to be disparaging to the original poster and I'm sure your process works well for you and your pans. But please be aware that too many people are scared away from iron because they think it's too temperamental. I put my iron pans and dutch oven into harms way (melting candy sugar, using soy sauce, scrubbing with dish soap, sauteeing directly on the grill, frying potatoes, caramelizing pork butts, all kind of hot, acidic, salty food and they come through it just fine with little more than an oil wipe down before use and another if it's looking "tired" after washing, followed by a quick heat on the burner to about 300 degrees, then let it cool off in place.

    0
    mlaiuppa.
    mlaiuppa.

    Reply 3 years ago

    The reason you have to keep reseasoning it every few years is because you use olive oil to season it and you scrub it with Dawn or detergent often.

    0
    tubeist-d
    tubeist-d

    Reply 6 years ago on Introduction

    Mineral oil is 'edible' but indigestible; which makes it a good lubricant for constipation: that stuff ain't going nowhere but out. It also doesn't polymerize. Period. It cannot be used for seasoning.

    Olive oil is fine, but people should bear in mind that the smoke point of olive oil varies widely with cold-pressed, virgin, extra virgin, extra-virgin acidic, etc., and it's slow to polymerize to get to a film condition. Flax oil is best for people who are seasoning their first pan. I happen to use the similarly-behaving walnut oil because I cook with it a lot anyway. Once you have a pan with a good ol' coating, re-seasoning goes well on the old film without much worry.

    0
    MacA5
    MacA5

    Reply 4 years ago

    Is it safe to use flax seed oil that does not need to be refrigerated? My bottle says it is 100% virgin (or unrefined) flaxseed oil. It does not list any other ingredients. However, it does not require refrigeration. Safe to use for seasoning? Everything I'm seeing with regards to using flaxseed oil says to use the refrigerated kind.

    0
    HolgerW6
    HolgerW6

    Reply 4 years ago

    As long as it is 100% flax seed oil, you can use it for seasoning. There are different approaches in storing flax seed oil. One is the supermarket approach, which basically is, "We don't care if the oil starts tasting awful". Try one of those 100% flax seed oils that are not refrigerated in the store. They all taste very bitter (still not rancid).

    If stored properly, flax seed oil should not taste bitter at all. That can only be achieved by storing it at low temperatures right from the beginning.

    Also, flax seed oil should not be stored longer than 4-6 weeks.

    For seasoning a pan, the bitter taste is no issue.

    0
    EricO49
    EricO49

    Reply 4 years ago

    The very thin layers of flaxseed oil, after each one is baked for 30 minutes at 500 degrees, are essentially no longer flaxseed oil. Or at least they are drastically changed flaxseed oil. The hard, shiny, dry surface of a seasoned cast iron pan is not going to "go rancid."

    0
    mlaiuppa.
    mlaiuppa.

    Reply 4 years ago

    Mineral oil is great for seasoning cutting boards.

    Olive oil will turn rancid so shouldn't be used for boards or seasoning cookware.

    Vegetable oil never cures and is always sticky.

    Flax seed oil is the only edible drying oil. For that reason it is great for seasoning cookware. I don't use it on the cutting boards because the entire point of oiling them is to prevent drying.

    So flax seed oil for seasoning cast iron and mineral oil for seasoning cutting boards.

    0
    gregs12
    gregs12

    Reply 5 years ago on Introduction

    thanks for the explanation of WHY not to use mineral oil

    0
    BearM
    BearM

    Reply 5 years ago

    Mineral oil is ingestible, I've been using it for years on my cast iron. I'm not sure where people come up with the nonsense they spew? As a side note: mineral oil is great for constipation; a tablespoon at a time. Not as a thin coat on cast iron!

    0
    M2aestro
    M2aestro

    Reply 4 years ago

    First, I do not use mineral oil on my cast iron, for I have many kinds of vegetable oil handy, and for seasoning, tend to use one that doesn't smoke at too low a temperature. That said, there is absolutely no reason that one could not use a mineral oil for seasoning, if one use the right one. Food grade mineral oils are used in this country (but not in EU countries) on baking machinery, and if you were to eat much commercially baked goods regularly, you could be consuming up to about 80 mg (eight hundredths of a gram) of mineral oil in your diet. 100 mg of mineral oil is considered a safe limit for a person of average weight. Your body cannot process it, and too much can cause some adverse effects. So, go ahead, season pans with it, but always wipe away any excess that has not polymerized onto a surface or penetrated the surface. By-the-way, in this country, so-called food grade mineral oils, which I'll just lump as highly refined paraffin oils, are used on salad bowls, cutting boards, wooden serving utensils, etc. to minimize ingress of water and bacterial and fluids that could become contaminated by bacteria in the wood's pores. I suspect that this is not approved in the EU, where I think they are overly cautious. This could stem from the fact that less highly refined mineral oils are generally lumped with carcinogens in food use and on food preparation and processing surfaces. So, be careful, find out what your oils really are, and then make your informed choice.

    0
    ctgypsy
    ctgypsy

    Reply 4 years ago

    There are food-safe mineral oils on the market, you just have to take the time to look for them. We make bamboo and hardwood cutting boards for sale in our Etsy shop, and we always coat them with food-safe mineral oil and refresh them with a new coating every 6 months or so because washing the cutting boards strips the oil and dries out the woods.

    0
    Stanley DavidR
    Stanley DavidR

    Reply 4 years ago

    Thank you for your knowledgeable reply. Much appreciated.