The unique characteristics of cast iron give it certain advantages over other types of cookware. While the thermal conductivity of iron isn’t as good as that of aluminum or copper, its high density allows it to retain heat much longer than lighter metals. When cold food hits the surface of a hot iron skillet, heat is not lost as rapidly. Cast iron is also relatively inexpensive and, with proper care, it can last a lifetime…maybe two. There’s no reason the cast iron you buy today couldn’t be passed down to your children or even their children.
Perhaps cast iron’s most appealing characteristic is how, over time, it develops a natural nonstick surface. This is achieved through a process known as seasoning, in which fats are baked onto the surface of the pan at high temperatures. The net effect is an inexpensive, long-lasting nonstick pan that doesn’t have the health risks thought to be associated with chemically produced nonstick coatings.
Of course, the operative words here are “over time”. Cast iron pans – even those that are “pre-seasoned” by the manufacturer – do not come out of the box ready to go. It takes time and a little work to build-up an effective nonstick surface, but the payoff is worth the effort.
Getting Off to the Right Start
So you just got a new cast iron skillet and you want to get started? Well, before any food touches the pan, you’ll want to begin the seasoning process. Even if your pan has been pre-seasoned by the manufacturer, you will want to perform this procedure at least once:
Pre-heat your oven to 350°F (176°C). Rinse the pan in warm water only, and towel dry. On the stove top, heat the pan over medium-high heat until all the water has evaporated. Place a tablespoon of vegetable oil or a teaspoon of vegetable shortening in the pan. Heat until the oil begins to smoke.
Using paper towels and a pair of tongs, wipe down the inside of the pan until evenly coated. With a second paper towel, wipe out excess oil. This is important! There should be no pooling or extra oil. The pan should have a thin even coat. Too much oil in the pan will form a tacky film, and you will have to strip the surface and start over again.
On the center rack of the oven, place the pan upside down to allow excess oil to drip. Bake for 30-60 minutes. Turn off the oven and allow the pan to cool completely. If your pan was not pre-seasoned, you should repeat this process 2-3 more times.
Congratulations! You’ve just completed your first seasoning. As I said earlier, the pan will not be ready for prime time. In the beginning, it helps if you reserve your pan for those cooking tasks that involve a lot of oil or grease such as frying chicken or cooking bacon or steaks. These tasks will help to quickly build the nonstick coating.
Cleaning Cast Iron
Nothing – and I mean nothing – will undo your seasoning faster than soap. So from this point forward, you will need to wrap your head around the difficult notion that soap must never again touch the surface of your cast iron pan. This will allow the fats and the oils you cook with to build up over time and create the easy-release properties we’re looking for.
Now before you say “ew gross”, keep in mind that bacteria cannot live at temperatures above 212°F (100°C). You will be heating your cast iron pans well in excess of 350° (176°C). Nothing can live at those temperatures.
Rest assured you will still wash your pan. You just won’t use any soap. Some hot water and a dish rag will usually do the trick. Use a scrub brush to remove any food or debris. You will also want to avoid soaking your pan for long periods. Too much soaking can also eat away at your seasoned coating.
If you end up with a real mess inside your pan that water and a scrub brush can’t fix, don’t give-in and reach for the detergent. There is a better way. Place the pan on the stove top over medium-high heat. Put 2-3 tablespoons of oil in the pan and heat over medium heat until the oil shimmers. Put a generous handful of coarse kosher salt into the pan. With a paper towel and tongs, scrub the inside of the pan using the salt as an abrasive. Rinse out the pan with hot water and repeat, if necessary, until the pan is clean.
Keeping a Good Thing Going
After cleaning your cast iron, give it a quick re-seasoning using this shorter stove top method:
Heat the pan on the stove top until all signs of water are gone. Place a tablespoon of vegetable oil into the pan. With paper towels and tongs, wipe down the inside of the pan and along the top of the rim. Continue to heat the pan until the oil smokes. Remove from the heat and let the pan cool completely.
Once the pan has cooled completely, wipe out any excess oil with a clean paper towel. The pan should have a nice sheen, but it shouldn’t look shiny or be oily to the touch.
Sometimes things go wrong, and something gets on your cast iron pan that no amount of scrubbing will remove. It may become necessary to strip your pan back to its humble origins, and start all over again. If that happens, breakout the dish detergent and a Scotch Brite non-scratch scouring pad. If that’s not enough cleaning power, add some non-bleach non-abrasive scouring powder such as Bon Ami or Bar Keepers Friend. Once you have stripped the surface, begin the seasoning process again, as you would with a new pan.
If your cast iron pan goes unused for a long while, it may develop a little rust. If that’s the case, fear not. Surface rust is superficial and easily removed. Try either of the two cleaning methods described above (water + scrub brush or oil + coarse salt) and the rust should be gone. Just remember to season the pan afterwards using the stove top method.
Follow these basic steps to keep your cast iron well seasoned, and it will soon become one of your favorite and most reliable pans.