new vs old cast iron on a glass cooktop?
I'm a cast iron cooking virgin. This past weekend my project was to strip my 10" Wagner, 2 - 8" Wagners, and 6.5" unbranded skillets to prepare them for lard seasoning. However, I thought I remembered reading somewhere that for a glass cooktop newer CI may be better? Something to do with the ring around the bottom of older CI, I'm thinking...? Aesthetics are a concern as my husband tries to keep our 1.5 year old Kenmore looking new. So I could probably easily eBay my Wagners, buy Lodge, and still come out ahead. I have read this thread (http://chowhound.chow.com/topics/762368) and this thread (http://chowhound.chow.com/topics/417089) but I didn't see anything mentioning that newer may be better. Thoughts? TIA! :)
I got rid of my Lodge Logic CI 12' skillet when I replaced my dysfunctional gas cooktop with a glass-cooktop electric range - but that was mainly because I hadn't been using it anyway. I do still own 2 CI Dutch ovens, but they mostly get used in the oven, not on the cooktop. My range's manufacturer (Crosley) warns against using CI at all, however. I love having the unused burners on the cooktop as an extra work surface; however, I am VERY careful not to drop or bang any cookware (whether CI or not) on that cooktop. (Now if I could just get other family members to wipe up spills & boilovers on the cooktop ASAP!)
"Better" invokes several issues:
Thick vs. thin... Older tends to be thinner and so will be more responsive. But thinner tends to hotspot more than thick.
Ring v. No-ring... Older is more likely to have a flame ring, and so most of the pan will sit a tiny fraction of an inch off the glass. The difference in heat between the ring touching the glass and the rest of the pan is *claimed* to stress the glass more, making it more prone to crack. HOWEVER, I've used a Descoware skillet with ring on my glasstop for many years with no problems.
My opinion is that if your electric hob is even and your pan is sized properly to it (i.e., an 8" pan on an 8" hob), a thinner (ergo, older) pan is better, because there is no hotspotting *and* it's more responsive. But if you're planning on *finishing* food off of the heat, you might want the increased thermal mass of a newer, thicker pan. They cost so little, you should be able to have both and compare.
A minor concern is warping of the pan. Pans without the ring tend to warp a bit more easily, and usually if a pan warps, the bottom goes *convex*, which will make it dervish all over on your dead-flat glass.
I say keep the old stuff, but buy one new one and experiment. Just be a little careful moving the old ones around--the rings can scratch/abrade the applied patterns on the glass.
I used old CI on my cooktop for a number of years. Really I had no problem using it, and I thought my cooktop did a good job in general.
The problem might be with really old CI. Some of the old pans seem to have been designed for use on woodstoves, and they had raised rings around the bottoms to elevate the pots. You will do fine if your CI is completely flat. CI actually does well on glass cooktops because the weight of the pan holds it in place. Lighter weight pans slip around a bit.
I stripped my pans in the dishwasher, and used high heat with flax seed oil to apply successive coats. There are multiple threads on this topic.
I got good and less than good results on my pans. But the pan that really took is a beautiful pan to use for anything.