My guess is that you should heat it longer....I have a n old gas cooktop and 2 cast iron flat griddles....one heavier than the other....and after1 5 minutes the heavy one is uniform....maybe your griddle isn't heavy enough?

Cast iron doesn't conduct heat well so it pretty much heats right where the heat is applied so under the burners is always hotter than in between. I get around this with my sauce pan by rotating it back and forth every few minutes but the griddle is obviously too big to move. Since it is always cooler in the middle between the burners. I just incorporate this cooler area into my cooking and rotate the foods that are thinner or more cooked into the middle and rotate the middle ones to the edges to finish cooking.

Cleo, thanks for your reply....

Will I do better with a aluminum double griddle? Any recommendations?

Yes....I had an aluminum one....but tossed it when I got the iron one.....dummy me!

Aluminum is a good thermal conductor, that can be good or bad. Unless the griddle is thick enough, heat from the fire will heat up the metal right above the fire much quicker than it has a chance to even out.

Try this trick with your cast iron griddle, assuming you have a four burner stove.

Take the other two grates and stack them on the two burners under your griddle. Your griddle will be lifted higher above the fire, and the fire will spread out wider to give you more even heating.

dcarch

The best griddle that I ever had before I got a range with a built in griddle was a cast aluminum one. It wasn't terribly thick--probably about 3/16". Heated pretty evenly across two burners; cooked like a dream.

Aluminum is a much better conductor of heat than cast iron is so I would stay away from the cast iron ones.

What are you cooking on this griddle? If I am cooking pancakes on mine, I just center them over the burners - the space in between never gets as hot, but with pancakes, this is not necessarily a problem, as I can move them around and turn them twice. If you are trying to cook a bunch of vegetables, you will just have to move them around a lot.

I had not heard of aluminum griddles before - I will have to look into that. You should be aware that the melting point of aluminum is 1,221°F, and my BGE gets hotter than that. I've melted aluminum in it!

I have a collection of griddles including one perhaps like ci_lantro mentioned that is almost 3/16 inch thick aluminum by WearEver. ci_lantro: was yours a non-stick, or was it plain aluminum like mine? I thought that I had used mine without serious issues (except storage because it had stuck out handles), but testing mine today, found that pancakes stuck severely. I cleaned and oiled it just before use. Does anyone know how to prevent sticking on plain aluminum?

I had stopped using them and instead have been using electric griddles for the convenient temperature control, but I decided to check them out for even heating after extended heating like lindac suggested. I have the aluminum one, a light non-stick Nordic Ware one, and a very heavy cast iron one (slightly bumpy, non-branded but like current Lodge). They all appeared to heat evenly enough to cook pancakes to similar conditions in the same times. Unfortunately, the Nordic Ware 'non stick' surface was compromised and the pancakes stuck almost as badly as the plain aluminum. The heavy cast iron did not stick, although one of my cast iron better seasoned frying pans that happened to be used earlier on the stove, did better for absolutely no stick.

Chas, it wasn't non-stick but was well-seasoned when I got it second hand. Always used a bit of oil or bacon grease for pancakes. Main use for it was grilled cheese sandwiches back when I had young'uns at home so that contributed to the seasoning. When I got the new Wolf with a built in griddle, I stood back and let DSII have at it w/ grilled cheese sandwiches. He had it nicely seasoned in no time! (I didn't even try to use it until he had it 'ready' to go!)

The best dual burner griddle I've found is one made by Demeyere, called a Teppanyaki or Plancha. It's about 4 mm thick of aluminum wrapped in stainless steel. Unfortunately, the US distributor no longer has any more stateside. It's not nonstick but the specialized SS finish releases pancakes and grilled cheese with only a minimal rub of butter required.

I also had the All-Clad version, in hard anodized Aluminum with a non-stick coating. It was thick but not quite as even as the Demeyere. I think a lot companies make simliar ones -- I would search out the thickest. The downside, of course, is that you have to watch your temperature and damage with non-stick. I also had a Lodge, which was woefully uneven, even with extensive preheating.