How to season an iron griddle on an induction hob

First, there is no difference between seasoning and re-seasoning, unless you need to do some extra work to remove rust (see instructions below). In fact, for new cast iron, scouring is also usually a good idea since you need to get off whatever wax or protective oil the manufacturer or seller may have put onto the cookware. (They don't use cooking oil for that sort of thing, believe me.)

1. If you need to remove rust: use a mixture of salt and oil and scrub that hard into the rust, then rinse thoroughly in hot water. Use steel wool if necessary.

2. Next, scour the pan completely under hot water. Do this for several minutes or until the water runs clean. I've heard varying things about whether soap or an SOS pad is OK at this step. My personal opinion is that it's OK, but you must wash the soap completely off before continuing with the seasoning so that your seasoning doesn't taste like soap!

3. Coat the cookware with grease or oil. (I do this with the whole pan, not just the cooking surface, to reduce the possibility of external rust.) Crisco, vegetable oil, and lard all work well. Don't pick something with a low smoking point, or too strong a flavor. Make sure it's a light coating... you shouldn't have pools of oil anywhere on your cookware.

4. Bake your skillet in a 250 - 350 °F (121 - 178 °C) oven for an hour. If you used liquid oil, you may want to put the cookware in upside down so excess oil drips off. But it's good to put a cookie sheet or something underneath the cookware to catch the drips if you do!

5. Let the cookware cool, and wipe off any excess oil.

6. For best results, do this two or three times, though a skillet can be satisfactory after a single treatment.

To keep the seasoning happy:

• Don't let the cast iron sit too long without using it (you may notice a rancid smell or flavor if the seasoning turns bad; I'm not sure at what point this happens, but it's happened to me before).

• Don't cook anything acidic (e.g. tomatoes) during the first or second use of your pan.

• Don't use dishwashing liquid or soap on the pan (hot water and scrubbing only).

• After cleaning the pan after each use, wipe it lightly with another bit of oil, using simple vegetable oil.

Another trick sometimes used to season Chinese woks: rub Chinese chives over the surface of the cookware when the oil is being heated (this works best on a stovetop, not in the oven). The juice of the chive has sulfur compounds that help remove remaining flavor from the previous coating of the cookware. Be aware that this technique really kicks up a lot of steam and smoke. I've never tried it on cast iron skillets, but I'd be curious if anyone out there has.

Induction cooking works by generating an electric current in the metal cooking vessel and converting that current into heat, which requires a resistive material (i.e. a poor conductor).

It's a bit of a catch-22, because you need a good conductor to actually distribute that heat. This is why some of the best induction cookware is clad metal - two layers of (magnetic) steel around an inner layer of highly-conductive aluminum or sometimes copper, sometimes layered multiple times this way. The thick magnetic sheets generate heat, and the thin conductive sheets transfer it.

Thicker metal means that the surface is slightly farther away from the magnetic field source, but also has significantly more resistance (since resistance is proportional to length, and we are talking about doubling or even tripling that), so theoretically it should be much more effective at converting the electric current to heat, and heat up faster.

The disadvantage of a thicker metal - assuming that there is no additional heat transfer material - is hot spots. This doesn't matter at all for a skillet, but if you're trying to cook with, say, a cast-iron stock pot or dutch oven, you'll find that the hot spots are even worse on an induction cooktop than an electric or gas cooktop, since the surface heat is generated very rapidly but takes forever to spread.

Carbon steel is a pretty good compromise, which is why it's generally the material of choice for woks, and that's the material I'd choose for an induction cooktop for any vessel other than a skillet or frying pan (assuming I had to choose a single material; again, copper/aluminum-clad stainless steel works better). For pans/skillets, you want the heat to stay focused on the surface, which makes heavy/thick cast iron a better choice.

I can't honestly say that I've had much experience with forged iron, but all my instincts are telling me not to bother with it because it would be combining the worst of both worlds - lower resistance at the surface but still relatively high resistance up the sides. The only caveat to this would be a possibly significant difference between the magnetic susceptibility/permeability of forged vs. cast iron, but this is likely going to vary from vessel to vessel anyway (not all cast/forged iron is the same) so I think your best bet there is to try sticking a magnet to it. If it sticks much harder to the forged than cast iron (doubtful) then it might be good for surface cooking; I still wouldn't choose it for a larger pot.