Cast Iron Re-seasoning
I came into possession of a tiny three-inch diameter cast iron pan while on vacation during high school. It was caked in oils, rust and deeply engrained dust, and I did not feel up for cleaning it out by hand if I planned to cook with It in the future. My stepfather allowed me to use the sandblaster at his auto shop, with which I blew off the old layer of hardened oil along with all the dust, rust and congealed oil.
On google I found many ways to season a cast iron pan, but the one that I settled on insisted that flaxseed oil would produce the best, hardest, most even, and longest lasting final product. They claimed, in fact, that you could wash it in a dishwasher if you chose to, and the finish would not be damaged. I never tried doing that because in general cast iron pans should not encounter soap. Bits of food, oils and seasonings are expected to work themselves into the porous finish of the pan and enhance the flavor and cooking ability of subsequent meals cooked with it. Tarnishing that with soap would only have negative effects.
I believe that I applied nine separate very thin layers of flaxseed oil to the pan and baked it in the oven at 500 degrees for an hour between each layer, allowing it to cool to room temperature after each bake cycle. The finish that it produced was hard and quite even, however, on a camping trip, I discovered that it had been left in a bag which for some reason had water in it, and the pan began to rust through the finish. With a good thick finish this is generally not easy to do, so I figured that my first attempt at producing a thick non-permeable coating had failed.
I left that pan the way it was for a while and only came back to it when my Aunt gave me a full-sized cast-iron pan full of rust with barely any black finish remaining to see if I could repair it. I told her that I’d be able to restore it to its original state and would love to cook with it, so she let me give it a shot. I brought it again to the auto shop and sandblasted it, along with my mini-pan, leaving only the bare iron surface behind. I began my third year of college that same year and seasoned both pans with Crisco in my apartment, only putting on 5 slightly thicker layers than those used in the flaxseed oil-finish. This pan, sporting its new seasoning surface, was used nearly every night that year to cook dinner, and it quickly became my favorite pan.
Over the summer following that schoolyear, a few friends from Boy Scouts and I went on a trip to our old summer camp location that had been shut down and emptied two years prior, to see how things had changed there. While we explored I encountered a large cast iron pan which we were very familiar with from the many years that we spent at that camp. It had rusted all the way through the layer of finish on the underside after years of weathering, and clearly nobody intended to return for it, so I brought it home, sandblasted and finished it with Crisco in the house I lived in during my senior college year. My housemates and I used it and my other smaller pan for many meals that year. I am very fond of my pans, and plan to keep them in good, usable shape for as long as I can.
Flaxseed oil applied in thin layers did produce a more even and official look, but even after nine separate layer-applications and firings, the finish was still too thin to fully function and keep water out of the pores in the iron. Around 6 layers of Crisco was all that I ended up needing for my pans which produced solid, thick black layers, which lasted a long time.
I found that spreading the Crisco onto a slightly preheated pan by hand was the most consistent application-method. I was able to get an even coat of oil on the surface, thick enough that it would produce a distinct layer, but thin enough that it would not run and drip while baking. Using any cloth or paper towel to spread the oil led to bits of fiber getting stuck on the surface and baked into the oil. While this wasn’t a huge issue in terms of edibility, it did make the surface rougher and function more poorly as a non-stick surface. Heating the pan beforehand to a temperature that would melt the Crisco but would still allow the pan to be held in bare hands greatly simplified spreading the Crisco evenly across the whole surface and helped when searching for areas where it would drip if placed in the oven.
Broiling the pan brought certain areas of the pan to excessively high temperatures, which rather than baking the oil on would literally oxidize and it and burn it off as smoke. I found instead that the highest possible evenly-distributable temperature that an oven can produce, which is usually 500 degrees, is more than enough when the pan is left in for an hour and allowed to cool slowly.