How to Properly Season and Maintain a Cast Iron Skillet
Cast iron has been used for cooking for centuries, and for good reason: it holds heat exceptionally well, it goes from stovetop to oven without complaint, it lasts essentially forever if treated properly, and a well-seasoned pan rivals any non-stick surface for most cooking tasks. The problem is that most people either mistreat their cast iron through ignorance or are so afraid of ruining it that they barely use it. Neither approach serves the pan well.
What seasoning actually is
Seasoning is not a coating that you apply once and preserve carefully. It is a layer of polymerised fat that has bonded to the iron surface through repeated cycles of heat. When fat is heated to its smoke point in the presence of iron, it undergoes a chemical reaction that converts it from a slippery liquid into a hard, slick, non-reactive surface. The more times you repeat this process, the thicker and more durable the seasoning becomes.
A new cast iron pan from the factory has a thin factory seasoning that is adequate for immediate use but not robust enough to be truly non-stick. Building proper seasoning takes time — not effort, but time and regular use.
How to season a new pan
Start by washing the pan with warm soapy water and a stiff brush. Yes, soap. The no-soap rule is a myth perpetuated by people who misunderstand what seasoning is. Modern dish soap is not strong enough to remove polymerised seasoning — it will remove fresh oil, but not cured seasoning. Rinse thoroughly and dry completely. Any residual moisture will cause rust.
Preheat your oven to 230°C. Apply a very thin layer of a high-smoke-point fat — flaxseed oil, grapeseed oil, or Crisco are all good choices — to every surface of the pan, inside and out, including the handle. Then wipe off as much as you possibly can with a clean cloth. The layer should look almost dry. Too much oil produces a sticky, gummy seasoning that never fully cures.
Place the pan upside down on the oven rack with a foil-lined sheet beneath it to catch drips. Bake for one hour. Turn the oven off and leave the pan inside until it cools completely. That is one seasoning layer.
For a new pan, repeat this process three to five times before using it for cooking. Each layer adds depth and durability to the seasoning.
The fastest way to build seasoning: cook with it
The oven seasoning method produces a controlled, even base layer. But the most effective way to build seasoning over time is to cook fatty foods in the pan regularly. Bacon, sausages, fried chicken, and pan sauces with butter all contribute to seasoning with every use. The fat penetrates the existing seasoning, bonds with the iron, and adds another layer.
This is why a family cast iron pan that has been used daily for thirty years is often more non-stick than any modern PTFE surface. The seasoning built through decades of cooking is a fundamentally different material from a single oven-applied layer.
Cleaning without destroying the seasoning
For everyday cleaning, a stiff brush or chainmail scrubber and hot water is all you need. If food is stuck, add water to the pan and heat it on the stovetop — most stuck food will loosen within minutes. Then rinse, dry immediately and completely (leave it on a low burner for a minute or two to be sure), and apply a very thin layer of oil to the cooking surface. Wipe off the excess. This habit takes thirty seconds and keeps the seasoning in excellent condition.
If you need to use soap for particularly strong smells or flavours, do so. Rinse, dry, and re-oil. The seasoning will not be harmed by occasional soap use.
What will harm seasoning: soaking in water, dishwashers, leaving wet, and highly acidic foods cooked for extended periods. A quick tomato pan sauce will not damage well-established seasoning. Simmering tomato sauce for an hour in a brand-new pan will strip it.
Dealing with rust
If you find rust on your cast iron, it is not ruined. Scrub the rust off with steel wool or a metal scourer and water, wash, dry completely, and re-season from scratch. Cast iron can come back from almost any state of neglect. The pan your grandmother left in the shed for a decade can be restored to cooking condition with an afternoon of work.
What cast iron does best
Understanding where cast iron excels helps you use it properly. It is exceptional for searing meat, because it holds high heat without temperature drops when cold food is added. It is excellent for baking — cornbread, skillet cookies, and frittatas all benefit from its even heat and ability to go from stovetop to oven. It is ideal for frying, because it maintains consistent oil temperature.
Where it is less suited: tasks requiring rapid temperature adjustment (the pan retains heat for a long time, which is a disadvantage for delicate fish that needs to come off heat quickly), acidic braises and sauces over long periods, and any application where weight is a constraint.
The most important thing: use your cast iron regularly. Pans that sit unused develop rust and dull seasoning. The best cast iron care is to cook in it, wash it promptly, dry it completely, and oil it lightly before storing. Nothing else is required.