Why you should start using flaxseed oil to season your cast iron skillet is a little more scientific than I first thought, I have been using cast iron pans for a while now and I have had mixed results with the seasoning process for the first year, I hated my cast iron pans, everything stuck to them!
Now, I use them daily it’s because I got a little more scientific with how I treated my pans, and that’s how I started using flaxseed oil for my cast iron skillets, and now? I cook everything on them!
Why should you use flaxseed oil for your cast iron skillet?
My thoughts on flaxseed oil for cast iron came about when my husband and I redid the wood floors in our home and we used linseed oil to refinish the timber, which is durable and long-lasting.
Flaxseed oil is the edible version of linseed oil, and in fact, you do hear of people using linseed oil on their cast iron pans. (I wouldn’t)
Linseed oil is used by quality carpenters and artists, as a protective coating, it brings wood up to a beautiful and natural finish by either coating it with linseed oil, or artists use it by mixing it into oil paints and it creates a tough, durable surface that remains protective for many years.
Linseed and flaxseed are drying oils, which means they can transform into a hard tough film. Not through drying, but the transformation is through a chemical process called “polymerization”. ( in linseed oil’s case(which is boiled flaxseed) it dries over 24-72 hours and binds with the fibres it’s applied to which is an oxygen form of polymerization)
In order to succeed with fat polymerization, you should choose an oil high in omega 3’s especially ALA.
Now I know, that’s how all fats bond to cast iron through fat polymerization but when you have fats that are refined and not very high in omega 3’s, such as vegetable oil like canola, or today’s lard, you don’t have enough of the omega 3’s that release and bond with the cast iron and the effect is not as durable as fat that is high in omega 3’s especially in ALA- alpha-lipoic acid.
The highest percentage of omega 3’s (ALA) is flaxseed oil at 57% (which is what makes it a drying oil) and because it is so high in these omega 3’s the science of fat polymerization and using flaxseed oil on your cast iron makes sense. Canola oil which is always recommended to be used on your cast iron comes in at 11% ALA.
A quick google will tell you that other fats high in these ALA omega 3’s are lard, and lard is what your great grandmother used, and her mother and her mother before her for generations, these days lard isn’t your best option unless you are raising your own pigs, commercial lard is not very high in omega 3, as the pigs are fed mostly grains and other nasties which means their fat is very low in omega 3’s.
Sourcing the right flaxseed oil for seasoning your cast iron skillet
I have seen some reviews on flaxseed that aren’t great and I am convinced that they used the wrong flaxseed.
- Flaxseed is very high in omega 3 fats, and these fats tend to go rancid in light, oxygen and warm temperatures.
- Flaxseed, which is cold-pressed and still possesses all the omega 3’s should not be mixed with any other oils, which some companies like to do so you can store it on the shelf for longer.
- It should be organic, cold-pressed and unmixed. I don’t have any problems finding it, it’s at my local coles, but you can also find it at a health food shop and some pharmacies.
- You will have to store it in the fridge and its shelf life is relatively short. It is expensive, but there are many uses for it, as it’s very good for you, I also use it for my chickens as a supplement as well as in smoothies and sauces.
Do you need to worry about those free radicals and smoke points with flaxseed oil?
Flaxseed oil has a very low smoke point, and while it’s not good to cook with, the low smoke point is only another point in its favour for cast iron seasoning.
This is often brought up by people who don’t like flaxseed for cast iron.
You might have heard the term ‘smoke point’ and ‘free radicals’
All over the internet is advice that you should only use oils with high smoke points as to not heat your cast iron pan up on the stove for cooking and have the oil you used to season your pan with, start ‘smoking’ and fill you with the horrible nasties of free radicals that are released when oil gets heated beyond its smoke point.
This is a total myth when it comes to cast iron seasoning.
- The process of fat polymerization is initiated by the release of free radicals at the smoke point.
So yes you are releasing free radicals, every time you season with any oil.
- What releases free radicals in fat?
Iron does in itself, as well as high heat, light and oxygen for some.
And so, as we use high heat, which is explained in this Wikipedia article, you can understand that the release of free radicals from high heat, called radical polymerization, is how we season our cast iron pans.
And so, no. No matter what oil you use and its smoke point, the process of releasing the free radicals is done and you do not have to worry about it once your pan is seasoned, no more can be released.
In fact, it’s why I will never try a very high smoke point oil like avocado oil for seasoning cast iron, because of its high smoke point, trying to achieve the very process of radical polymerization is much harder and therefore harder to attain the glossy non-stick finish in your cast iron pan.
The process of seasoning a cast iron skillet
The process with flaxseed is much the same as other oils.
- Strip the pan, scrub with steel wool or sandpaper then wash in hot water
- Dry by heating on the stove as well as for opening the pores for the oil coating
- Rub with the flax seed oil, about 2 tablespoons, Be sure to do it while the pan is hot (not hot enough for oil to smoke) and the pores are open.
- Rub the oil off. Yes, it will look like there is almost no oil on there!
- Place upside down on a shelf in a cold oven
- Preheat to 240 Celcius with pan in the oven
- Once heat is reached bake for an hour.
- Cool till cold in the oven to close the pores and seal
- Repeat 5-6 times.
Common mistakes during the seasoning process
if you have ever seasoned and had a pan come out blotchy, sticky, it flakes after a while and is generally terrible to cook on then you may have made these mistakes when seasoning your pan.
Not stripping the pan properly.
This is one I was guilty of, since using flaxseed oil I have never had to actually strip my pan, but I have used other oils and had to start over when the process didn’t leave me with long-lasting results, if I do need to strip a pan, I use a handheld sander, and it takes about a minute to strip away the old layer of oil, if you have a hand sander you can use that or you can just use sandpaper.
I don’t think just steel wool does a good enough job, so buy some 80 grit sandpaper for stripping your cast iron skillet. sand the skillet when it is dry and then scrub with hot water.
Not heating the pan before applying your oil
Think of the pan like your face, the pores on your face open when heat is applied and it’s known that you should wash your face after a shower with cold water to close your pores.
It is crucial that you heat the pan to apply oil but also to dry it after scrubbing!
A cast-iron pan is the same, the pores of the metal open when hot. I like to let mine heat up to release any water after scrubbing and then let it cool so the oil won’t sizzle and apply a tablespoon, using cloth I rub the oil over the pan until it’s completely coated and then rub some more with a clean cloth until any extra oil is removed before placing into a cold oven.
Too much oil
Have you been told that you should place a tray under the pan to catch any drips?
If you have drips, you are using way too much oil.
This extra oil, that the metal hasn’t absorbed will eventually partially cook-off, creating a flaky sticky mess on your pan. The goal of seasoning is not to force on a sticky coating that hardens, but rather to bond the metal of your pan to the oil and create a non-stick surface.
Too much oil negates this, all you did was bake oil onto your pan.
You shouldn’t be able to see oil on your pan when you place it into the oven, it will look a little shiny but not slick, you should use a cloth, not a paper towel, as the paper towel won’t absorb the extra oil.
Not allowing the pan to cool to cold in between layers
The need to apply the oil when the pan is hot and the pores are open, just as important is allowing your pan to cool till cold, and allowing the pores to close ad seal the coating you just created.
Each layer needs to be sealed by completely cooling the pan before you start the next layer.
This is why it takes two days to do six coats, the cooling time can be a drag but is very necessary.
Not baking on a high enough temperature
Radical polymerization occurs at high heat. We also know, the process is initiated at the smoke point on the oil.
Flaxseed oil has a very low smoke point at 107 degrees celsius (or 225 degrees F) this means at approx 110 degrees celsius, you reach the smoke point of the oil and the polymerization is initiated.
You could cook your pan at that temperature if you wanted.
It would just take longer to harden.
This is another reason to use flaxseed, if you don’t have a good oven, which I have had in the past in rentals, some ovens just don’t get to 240 c, they can barely make it to 200, and with oils with high smoke points like canola or rice bran, this is a problem.
My advice is, go as high as your oven can, if it’s not very high that’s fine, as long as it can get over 110 for flaxseed, just change your bake time, add an extra hour if you are under 200 c.
If you can go to 230-240 you’ll be fine to bake for an hour. Be sure to start your timer AFTER you preheat the oven with the pan inside.
Using and cleaning a cast iron skillet
At the moment I have two skillets, I find that’s enough for me, and I have two because I like to cook sweet and savoury dishes in my skillets and I find that I don’t like mixing the two cuisines in my skillets as you can get the savoury flavours cooked into things like pancakes.
Washing your cast iron skillets
you should clean your cast iron, but you shouldn’t wash them. this is why I have two and I don’t mix them up.
When the pan is still hot is the optimal time to clean, when the oil and particles can be simply wiped out with a cloth, leaving you with a slick finish.
If you don’t like the idea of leaving it with just a wipeout you can rinse it in hot water, no dish soap.
For me, I am perfectly fine with wiping them out, I use them every day and so, they don’t go rancid and if you heat them up correctly before cooking with them then all germs that could be there are removed, which brings me to my next point.
Not heating your skillet correctly
you need to heat your skillet before using it.
It needs to be done gradually, not on too high heat, but you want it high enough that when you crack an egg on the surface it turns white almost immediately, between medium and high heat.
The temperature does matter if you cook on very high heat. I was using my skillet in my bbq and found that the high heat we liked cooking our bbq’d whole chook on was overtime, destroying the seasoning on my pan.
It’s fine in small amounts, but if you do it often, you may need to reseason a little more often and care for your pan after each cook.
Not drying your pans with heat and not applying oil after washing
Once you have cleaned your pan, you need to dry it, and the most thorough way to do this is to dry it on the stove or in the oven.
While you’re cleaning the kitchen after a meal simple wipe out your pan if you have given it a rinse in water, place it back on the stove on medium heat for 10 minutes until it’s fully dry.
If you want you can add oil to the surface once it’s dry, this is a good idea, and I use flaxseed oil, just a little on the pan and spread with a cloth will keep your cast iron pan in tip-top shape.
Cooking the wrong foods
Adicid foods can be a no-no.
I say can be, because if you take care of your cast iron and it’s seasoned and oiled and just in tip-top shape, then sure, simmer that tomato sauce, but if not and you think that it be may the cause of a not so great surface of your cast iron then you should stop with acidic foods, like tomato sauce.
Wines and vinegar which can be used for sauces or deglazing in some recipes I would not use on cast iron, as it can taste kinda funky if the acid in these liquids removes that cooked on oil and it ruins the finish of your pan.
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The exact cast iron pan I use is from an Australian company, I bought mine on amazon. https://amzn.to/3iCxEuK
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