I think the problem with olive oil and cast iron is that in many, if not most cases, you want to heat the iron up to well beyond olive oil's smoke point. This kind of science isn't my thing, but I suspect that if the majority of the season in your pan is composed of olive oil, then that matrix can cause issues with the season, and the iron itself, if constantly heated beyond tolerance. I seem to recall reading something about how it opens up the season and will allow water to seep in more readily when rinsing it out, then leading to internal rusting after time.
Though maybe if you have a healthy mix of substances it isn't such a big deal. Or maybe it really doesn't behave that way once it's baked in. I dunno, but it is something I have read. I always use canola oil and other fats--I used to apply crisco liberally to older pans at first, but I don't do that with my current one.
I do prefer Kenji's treatise on cast iron, though: removes all of the pretense and stress over maintaining that hunk of metal.
Perhaps, but that doesn't sound right at all.
When you take the oil past its smoke point, what you're doing is causing a few reactions, one of which is to polymerize the oil, which is the same goal of seasoning a pan in the first place. Another is oxidation (which aids all of these steps I think), and creation of a carbon-rich layer which won't exist if you don't take it past the smoke point. Polymerization for certain oils will occur under the smoke point, but you won't leave the carbon-rich layer which helps create the strength and luster/shine.
Burning olive oil should essentially just be adding a layer of polymer and carbon, though it may be likely that if there was a previous seasoning that was impenetrable already, that extra seasoning might not actually stick nearly as well and might be scrubbed off. At the very least I cannot imagine it causing any harm.
The thing you definitely want to avoid, however, is smoking olive oil, or any other oil for that matter, when you are actually cooking. All those great properties of polymerized and oxidized fat that create that incredibly strong bond and barrier, are the very same properties that make it unhealthy to consume fat in that state.
Fats, when burned, oxidized, and polymerized, essentially turn into very different chemicals, and they can be potentially carcinogenic, and I believe some have been identified as just that. They can also otherwise promote certain unhealthy reactions in the body IIRC.
Yeah, burning food on the grill and smoking and curing foods can be just as bad for our health in the long-run, but it is too easy to limit that possibility by not smoking fats, which are almost certainly the worst things we could introduce into our body that are a product of burned consumables.
Summary: won't someone think of the colons?!
:biggrin: