How to season a steel baking plate

What seasoning actually is

Seasoning is not a coating that sits on the steel. It is oil that has been heated past its smoke point until it breaks down and bonds to the metal as a hard, dry film. The technical name is polymerisation. The practical result is a dark, slightly slick surface that releases dough and keeps air and moisture off the bare iron.

This is the same process that makes an old cast iron pan non-stick. Carbon steel behaves identically, and a baking plate has the advantage of a completely flat surface, so the film builds evenly.

Which oil to use

Any cooking oil will polymerise. What differs is how hard the resulting film is and how much smoke you produce getting there.

• Flaxseed oil forms the hardest film but is brittle and can flake. It is popular online and disappointing in practice.
• Sunflower oil has a high smoke point and gives a durable, forgiving layer. This is what we season with in the workshop, and what we would use at home. Grapeseed behaves much the same way if that is what you have.
• Regular olive oil works and is what most people already have. It smokes earlier, so open a window.
• Skip butter and anything with milk solids. They burn rather than bond.

The method

This takes about ninety minutes, most of it unattended. Do it once when you feel the surface getting dull, not on a schedule.

1. Wash the plate with hot water and a stiff brush. No soap. Dry it completely with a towel, then put it on a low burner or in a warm oven for a few minutes so the last of the moisture leaves.
2. Pour about a teaspoon of oil onto the warm plate and spread it over every surface, edges and underside included, with a lint-free cloth.
3. Now wipe it all off. This is the step people skip and it is the one that matters. The plate should look almost dry, with only the film the steel has absorbed. A visible pool of oil bakes into a sticky patch, not a seasoning layer.
4. Put the plate in a cold oven, set it to its maximum temperature, and leave it for one hour once it reaches temperature. Your kitchen will smell of hot metal and there may be some smoke as the oil passes its smoke point. That smoke is the process working.
5. Turn the oven off and let the plate cool inside it. Pulling a plate from a hot oven into a cold kitchen is unnecessary thermal stress.
6. Repeat the oil-and-bake cycle if you want a darker layer. Two or three rounds gets you a deep, even black.

Keeping it, day to day

The best seasoning comes from baking, not from seasoning sessions. Every pizza and every tray of flatbread adds to the layer. What you need to avoid is undoing it.

• Wash with hot water and a brush while the plate is still warm. Detergent strips the film you have built.
• Dry it immediately and completely. Carbon steel is not stainless, and standing water is what starts rust.
• Wipe on a very thin film of oil after washing, then wipe it back off.
• Never run cold water over a hot plate. Thermal shock is bad for the seasoning and, over time, bad for the steel.
• Store it dry, and not stacked under something damp.

If it has gone patchy, or rusted

Neither is a disaster. Carbon steel is the one cooking surface you genuinely cannot ruin.

For patchiness, just do a full oil-and-bake cycle. The new layer evens out the old one.

For surface rust, scrub the orange off with steel wool or coarse salt and a little oil until you reach clean grey metal. Wash, dry thoroughly, and then run two or three full seasoning cycles. The plate comes back looking better than it did before.