It turns out he takes his cast iron abuse to a new level: as soon as he's done with it and it's cooled, he puts it away, not even scraping food into the garbage. When he needs it again, he just cranks up the heat until it's billowing smoke, at which point he scrapes the char away from it.
I can't get behind that approach, but knowing my friend, I have no doubt that he's been doing that for two decades or more.
"The repeated reheating of cooking oil changes its composition and releases acrolein, which is a toxic and potentially carcinogenic chemical." https://www.medicalnewstoday.com/articles/324806
Other links.
https://www.nature.com/articles/s41598-019-39767-1
https://www.ift.org/news-and-publications/food-technology-ma...
> First of all, cooking with vegetable oil in the home (frying or sautéing) presents very little risk as the oil is typically used only once and heated for a short period of time (often less than 10 min). It is also possible to control the temperature of the oil, which should not exceed 190°C (374°F) and is best heated to 180°C (356°F) or lower. The oil should also not be heated at or above the oil’s smoke point.
Then it explains that the actual risk is from frequently consuming deep fried meals produced commercially.
Basically everything that comes out of a pan or fryer and is even slightly darker than "basically raw" will have some carcinogenic compounds. Frying any biomatter will create some measurable quantity of carcinogens, depending on the temperature and composition. First you will get the likes of Acrylamide, polycyclic aromatic hydrocarbons (e.g. Furan), Amines. In the presence of salt, spices, certain oils you can get even nastier stuff like Dioxines. And if you heat it even further, getting a few black spots, you are left with basic carbon. Even that isn't harmless, carbon modifications that you will produce in some minute quantity, like nanotubes and fullerenes, are carcinogenic.
Denaturing hydrocarbons like in cooking will inevitably produce some of the above compounds, there is no way around it. You can try to avoid producing some of them by carefully steering conditions in a way that reduces some of the above compounds. But usually that increases the risk of other ones being produced. You can also undercook everything, but then you'll be left with unsafe food because of the bacterial risk.
All of the above are carcinogenic in (comparatively) huge quantities. Usually "in mice". The link to cancers caused by preparation of food is vague at best, totally speculative at worst. I don't worry about it, and neither should you.
If you really want to learn about risky foodstuff, read up about cyanide in almonds and other fruits with a stone (people even eat that stuff "for health reasons"..., e.g. https://www.webmd.com/cancer/cancer-apricot-seeds ), coumarin (basically an anticoagulant, in higher doses rat poison) in cinnamon, tonka beans and woodruff, and the funny flourinated compounds you get from overheated PTFE-coated cookware (the presence of acid lowers the "fun" temperature but at least might prevent production of gaseous hydroflouric acid). There, the risky dose is much much much closer to the usual kitchen use. In comparison, all of the kitchen cancer scare is harmless.
You can use the sous vide approach, cooking to the safe temperature and no higher.
But browning is tasty and the cancer contribution is very low.
But you have to buy new cookware... And theses things are not exactly cheap (if you want something that works reliably)...
(Not that I would want to give up browning)
Nowadays you can get a model that clips onto one of your pots and works great for under $70. It is a bit specialized, but I use mine a lot.
My point being that, as with any tool, there are practices that will limit the lifetime of the tool and eventually render it unfit for its intended purpose. Learning about the best practices for using a tool can help avoid that fate.
Perhaps a lot is implicit in my "within reason" that some people willfully violate.
People who don't cook with plenty of fat, they have problems.
Some users claim flaxseed oil is the ideal oil for seasoning cast iron, as it is a drying oil w/ a high smoke point. https://www.cooksillustrated.com/how_tos/5820-the-ultimate-w... Others claim the "drying oil" is an incorrect theory, and that the polymerized oil from a drying oil is a coating that would flake off, rather than the desired bonding with the cast iron.
100% Tung oil, and (not boiled) linseed oil are the ones I'm aware of.
I have no information using them on cast iron.
There are a couple other drying oils, but my understanding is that they're more used in oil painting than wood finishing [0].
Also note that modern boiled linseed oil is not the same as the historic product, which as I understand it, was made by boiling linseed oil with white lead. The modern stuff is partially polymerized by heating it in the absence of oxygen.
Disclaimer: I am not a chemist or finish chemistry expert. I'm just a woodworker who sometimes reads about this stuff. Bob Flexner is an excellent author for anybody interested in further reading.
Matfer Bourgeat and De Buyer both recommend frying up a batch of potato peels in plenty of oil and too much salt, until the peels are very dark. Doesn't matter which kind of oil, salt or potatoes. Move them around and scrub them on the pan with your spatula while frying. When done, clean the pan with hot water.
Then just use the pan. The only things you really shouldn't do are soaking it or putting it in the dishwasher. Simmering acidic foods like tomato sauce is not great, but also not the end of the world.
The biggest contributing factor to make food not stick is to properly preheat the pan and not be afraid of oil/butter.
Yep, even a standard stainless steel pan will not stick to much if you get it up to temp beforehand and use some fat.
I also have a De Buyer carbon-steel pan, which I tried to season the same way; total failure. I had to strip off the failed seasoning. I now just use it with fat, clean it with hot water and detergent, and dry it carefully. All is good.
I seasoned the pan exactly as recommended: Very clean pan, stripped of previous seasoning, super thin layers of oil, barely visible on the surface, heat for 1 hour, cool for 1 hour, then repeat oil and heat/cool. And I used high-quality fresh flaxseed oil, not some old oxidized stuff.
It's a complete waste of time, when frying up some potato peels takes ~15 minutes and gives a sturdier result. It may not be as pretty or uniform, but it works, and how cast iron/carbon steel pans are prepared in every professional kitchen I know of. They don't have time to faff about, seasoning pans doesn't pay the bills. Cooking does.
The other myth is that the pebbly surface is non-stick. I used to work at a casting plant, that's the natural finish from sandcasting. That doesn't mean it's functional. Sanding down the casting surface to a smooth working surface takes less than an hour and lasts a lifetime.
Heating while you do it makes a convection pattern that hinders the process. Air drying for a few days between coats works better but, again, traditional seasoning by regularly oiling (using) the pan is more trad for iron / steel.
For oak though, drying oils that produce a polymerised surface make a fantastic finish. Add thistle oil, sunflower oil and soya oil to your flaxseed (linseed) oil, or just buy this:
But they have been used routinely: They seasoned themselves just by being used and they never saw strong detergents. "Iron rusts" was obvious to everyone because one was confronted with it every day and thus the drying for the night or oiling/greasing to protect against humidity was a natural task.
Nowadays, when we don't use our one cast iron pot every day, we need to replace the routinely usage with a maintenance routine.
You are exactly right on this. Ours get, scrubbed, wiped, soaped, and cleaned as needed but just use and constant reseasoning is all it takes to make them look and cook gorgeously.
Our parents (in particular) are terrified of the damn pans. Of caring for them of using them. They have this trope in their heads that is just a feedback loop… they see them as fragile so they treat them as fragile so they become fragile.
Just cook at home more, preferably bacon. Lots of mechanical things are meant to be used, pans, cars, homes. Letting them sit unused causes more decay
In my experience even the inside bottom will at times rust in places. Likely where the seasoning broke or was tore through in scraping.
We did an initial oil (sunflower or rapeseed) or two, either on the flame or more likely in the oven, and my partner cooks with a lot of oil. No expert at all so maybe we have just been lucky so far, but it works.
If you can stay on top of it, you can usually just wipe it down with oil cloth while it's hot, and presto, like new.
If you run it too hot and dry and start burning something, and let it sit and cool...get the hammer and chisel.
I usually don't preseason my pans, as just cooking will take care of it over time. I do however take an angle grinder to the inside to get it glassy when new. Much easier to cook eggs on than that sandpaper Lodge gives you.
Modern conveniences such as a dishwasher coupled with a focus on healthy eating (less fat) result in poorly taken care of cast iron pans.
Dishwashing soap these days are also a lot more efficient than they use to be. More and better surfactants eat away at any pantina that develops.
Yes you can drop a cast iron and nothing will happen to it. But to get eggs not to stick to it takes a bit of upkeep.
putting cast iron in the dishwasher seems insane to me though.
Please don't put your pans in the dishwasher, not matter what they're made of.
Why shouldn't I?
Dishwasher soap is a whole different story. It contains abrasives, among other things.
Cleaning with water and not-too-abrasive tool plus initial and periodic long heating with oil aren't complicated, they are just different from the convenient methods applied for more modern cookware.
A blow-torch works just great too, just the kind you'd use for a creme brulee to carbonize the stuck stuff (usually cheese for me) and scrape it off.
As long as you don't leave it sitting wet there should really be no problem with them.
Depends on what you plan to cook though, probably wouldn't add it if I was planning on cooking pancakes or something. But a stirfry or anything like that.