I needed to season a piece and decided to give this some love too. It has been used on a griller over hot coals, and the back of it looked like it didn't like taking that radiative heat head on.
So I'm on my 4th layer if seasoning it with avocado oil. 450 degrees, 2h, then let it cool overnight with the oven. The back is looking much better, but the cooking surface just began flaking (see picture). I've brushed it with a plastic bristle brush. Pretty sure the light spots are the metal underneath.
What went wrong? And how to fix this, do I just keep on seasoning?
11 Comments
billionsandbillions@piefed.social · 13 pts · 3d
Seasoning is a mix of carbon and polymer created from fats. It is susceptible to high heat, acids and physical actions(scraping). You will never have a bullet proof seasoning unless you do not use your pans. It will always be created and destroyed. Some of the best advice you can get is don't heat it too high, don't cook very acidic ingredients too long and its okay to wash your pan. Okay let's do this. I'm feeling generous today. sigh
Saturated fats: Don't have any available double bonds to create a polymer.
Monounsaturated fats: Have only one double bond available to bond with another molecule to create a polymer
Polyunsaturated fats: Have multiple available double bonds to bond to multiple molecules creating a stronger polymer.
Cooking oils are composed of these three types with different percentages of each. Some like avocado oil are low in mono and poly and high in saturated fats(do not bond without breaking the molecule).
Scroll down to "Comparison to other vegetable oils" to find % https://en.wikipedia.org/wiki/Grape_seed_oil
Oils high in polyunsaturated fats are considered drying oils. They use oxygen to form polymers that make them hard. These will harden at room temperature over several weeks. Polymerization happens at room temperature, increasing the temperature(heating in an oven) increases the rate of polymerization. They have been used in woodworking and oil paints for centuries(?). Ex. Flaxseed aka linseed and tung oil.
The bonds are what create the polymerized layer of oil(aka seasoning). The oils only chemically bond with each other but physically bond with the pan. Meaning the pan can not be too smooth. It has to have a slightly rough surface for the polymer to adhere.
According to some people you need to reach the smoke point(aka burning) in order to break the molecular bonds for them to bond together to create a polymer. You don't need to do this. This only needs to be done with saturated fats which also creates smoke because they are burning. This creates carbon as well as a polymer. One thing I don't know is whether or not the added carbon creates a better seasoning.
You need to use the correct oil with a high amount of polyunsaturated fats and heat to under smoke point of that oil. I don't go over 375°f for any oil.
Some oils seem to be too high in polyunsaturated fats and may become too brittle and flake off such as flaxseed. Ive never tested flaxseed so I don't know the reason but I suspect people heat their oil or seasoning too high. I believe all seasoning will eventually flake due to the nature of heating and cooling and also heating high enough(ei browning meats) over normal use.
Heating your seasoning too high will also begin to burn off and begin to flake. Temperatures over 500°f will burn off your seasoning. Think about oven cleaning temperatures. It will burn everything in the oven. This is also why grill(BBQ) grates will also rust. The fats from the food just eventually burn, leaving bare iron that will rust.
Okay, after all of that the recommended oil is usually grapeseed oil. I haven't used it since I've had corn oil which worked well enough for me.
Its possible to blend oils to attain the holy grail of seasoning but I don't have the money or time for all of that.
My method for seasoning in a oven:
You can also heat the pans on the stove top just under smoke point and add layers this way. Its just more difficult to get all the oil to polymerize this way.
I think that's everything, if I forgot something its because my brain has become mush.
Good luck!
Edit 1: I swear is someone says I used ayeeye for this I'm going to quit.
Edit 2: over time the polymers will eventually become more carbon(through heating) over time, that's why pans become dark black. Again I don't know if this technically weakens the "seasoning" or not
Edit 3: place the pans in the oven upside down
Edit 4: I just checked the smoke point(burning) off flax seed. Its apparently 225°f. Which is the reason I suspect it flakes so easily. It just burns off easily.
Denalduh@lemmy.world · 5 pts · 3d
This is fantastic! Thank you for taking the time to write this all down. My wife has been wanting to get into cast iron for a long time but has always been afraid to start. This will help tremendously!
billionsandbillions@piefed.social · 2 pts · 3d
Youre welcome!
Onomatopoeia@lemmy.cafe · 7 pts · 3d
If it flakes, then a layer didn't adhere properly. You'll want to start over.
I've had the same problem, in fact re-doing a pan right now for the same reason.
Each layer has to be really, really thin. Everything I've read says so thin you can hardly tell it's there. America's Test Kitchen says it should even look almost dry.
Peak temp for the oil, and how fast it gets there also make a difference. If it heats too quickly to peak, it will form bonds more quickly, which are weaker.
And each oil has a different peak temp. I would take a slower approach to heating with avocado because it polymerizes more slowly than say flax or grape seed.
One final thought - in my experience, any temp above 425 runs the risk of breaking the polymerization - I've done it many times. So better to slowly heat the pan (I like to do 30 min at 300, 350, then an hour at 400), giving the oil the time it needs to polymerize properly.
America's Test Kitchen's approach is to put the pan in a cold oven, set the temp to 450, knowing it takes a good 30 minutes to get there. Enough time for the pan to heat slowly. Then they leave it there for an hour, then turn the oven off and let it cool in the oven for an hour. All this gives the polymerization layer time to cure without crazing.
It's a lot like powder coating.
acockworkorange@mander.xyz · 4 pts · 3d
Oh crap.
Good here. I've been very diligent about having only a thin layer of oil. I'd spread it with my fingers and buff it gently with a paper tower until the texture is visible with only an increased sheen.
That's what I think I went wrong. I was following a guide to bake the pan at 500 F, which I thought was too much and dropped to 450. It didn't say anything about heat up, so I pre-heated the oven to 450 while I was oiling the pieces, so they went in with a hot oven.
Now, to fix this... How bad would it be if I just added another 6 layers of (properly cured) seasoning instead of trying to remove what's there first? And if that's a no-no, how do I even remove the layers it's got? Dish-washing machine?
panda_abyss@lemmy.ca · 4 pts · 3d
500+F destroyed my seasoning once, so I’m wary of that temp range.
It was probably closer to 550 though
Onomatopoeia@lemmy.cafe · 3 pts · 2d
In my experience 500 is for burning seasoning off. This is where I disagree with ATK - they say go to your ovem's max temp. I tried that and it just burns off the seasoning. I now target about 425 and just give it the time it needs.
Flax is too hard, so it flakes too easily for me. It's beautiful, but seasoning needs a little give, which is why I think avocado and grape seed work well. My flax seasoned pans don't go in the oven anymore. Someday I'll redo them with grape seed oil.
Best approach is to start over. But if these are truly tiny spots, and the area around them is strong, you may be able to get away with more layers.
Try scrubbing those areas with stainless steel wool (it's pretty coarse stuff). If more flakes off then you know the problem is bigger than these little spots. Unfortunately I always find the problem is bigger than it appears. 😕 As I said, I'm dealing with this same issue on 3 pans right now. They'll be getting grapeseed instead of flax.
acockworkorange@mander.xyz · 1 pts · 2d
This is a centerpiece for a grill, so I don't expect it to last long. When the time comes for a renewal, I'll try scraping it bare first.
snooggums@piefed.world · 2 pts · 3d
From the pic it looks like you lost a few speckles, is it just that or did you have any big chunks come out?
If you just lost some little bits here and there you can either give it one or two seasoning runs or just let it fix itself through usage if you use it regularly. When you cook with it and get done, clean it well with dish soap, then towel dry and put it back on an medium heat to dry. Once it gets warm add a small amount of oil and use a lint free cloth to wipe it all around and wipe it really well so it looks kinda wet/dry. Let it get hot until it just barely starts to smoke then remove from the heat and wipe it really well with the cloth to remove the oil that kind of 'sweated' after it got hot. Just let it cool and use it again the next time you cook. Do this for as many uses as you want until it seems to have a solid seasoning again.
I use paper towels instead of a lint free cloth and it works fine, but lint free is the right way to do it. This approach basically adds a semi polymerized layer that will finish itself over time as you use it and as long as you wipe out all of the excess after applying and then again after heating each layer will be very thin.
acockworkorange@mander.xyz · 2 pts · 2d
Just speckles, yes. Thank you!
0ops@piefed.zip · 1 pts · 2d
I just went through this. If this is a recent issue then I guess it wouldn't hurt to at least try cooking through it, see if it heals itself, but I kinda doubt it will work with flakes like that. Your foundational layers are apparently shot. I have this one cast iron pan (of several) that I was struggling with for years that I simply could not get any seasoning to stick too, the seasoning would just flake off not unlike yours. I even tried grinding the seasoning off before reseasoning and that still wasn't good enough. As a last ditch effort I decided to totally strip it by leaving it outside in a couple layers of garbage bags soaking with oven cleaner, simmered some white vinegar in there for a couple minutes (not sure if necessary, just read about it on the internet somewhere), and then I seasoned from scratch with grape seed oil. So far much better! It'll take time to get a great seasoning, but it's been a couple months and it's already pretty good, but most importantly stable! Nothing's flaking off anymore, so I know that it will only get better with use now.
If I had to guess what ruined the old seasoning, my guess is taking the bad advice of seasoning with flaxseed oil (too brittle) and accidentally leaving it on the stovetop on and empty a couple times over the years.