To maintain a cast-iron skillet’s seasoning—the key to its nonstick quality—we recommend coating the cleaned skillet with oil and then heating it briefly after every use. But how much oil is needed? Is it like skin moisturizer, where a little is good but more is better? We set up an experiment to find out.
We heated two cast-iron skillets and added 1 tablespoon of oil to each skillet. We used a wad of paper towels to wipe the oil from one skillet, leaving behind a thin but visible layer of oil (we used our kitchen scale to confirm that 3 grams of oil remained). We then used a wad of paper towels to thoroughly wipe the other skillet until we could see no trace of oil (just 1 gram of oil remained). We heated both skillets until they smoked, a sign that the oil was breaking down and bonding to the pan to create a nonstick coating. To evaluate the level of seasoning achieved, we let the skillets cool and then scrambled eggs in each, noting how much egg stuck to each pan.
The oil remaining in the first skillet beaded up when heated. Once cooled, this pan was shiny and its surface felt tacky. The oil remaining in the second skillet did not bead up when heated. Once cooled, this pan had the semimatte appearance of a well-seasoned pan and felt slick. Large patches of eggs stuck to the first pan’s surface, while only a few small bits of egg remained in the second pan.
When oil is applied with a too-generous hand, the excess oil (as evidenced by beading) can’t break down completely and therefore doesn’t completely bond to the pan. Plus, the byproducts of this partially polymerized oil make the surface of the pan feel tacky.
Apply only a thin, uniform layer of oil to cast-iron cookware to ensure the proper seasoning. We recommend using a wad of paper towels to smooth the oil over the surface of the pan. Then, use a clean wad of towels to wipe away as much oil as possible. If you notice oil beading up when the pan is heating, stop and wipe out this excess before continuing. Too much oil will only gum up the pan.