Why would that make a difference? Would the cast iron grates be heavier? Does Weber make cast iron as well as stainless?
Are you not happy with your results?
I mow have a Weber Q and the grate is cast iron....but I know what you have....I think they call them "flavorizer bars" and they are replaceable.
Linda C

I prefer the cast iron cooking grates.

I think the stainless was introduced for ease of cleaning.

I maybe mistaken but I think what they call flavorizer bars are the things that sit immediately over the burner tubes, taking the place of the old lava rock or ceramic briquettes. In that case you certainly want stainless as the porcelain coated metal ones are a pain to clean and you need to clean them or you get flare up.

If you replace the stainless cooking grates with the cast ones, keep the stainless ones...they are valuable. You could sell them on Ebay or Craigslist pretty easy.

I think the thickness of the grill bars will make more difference than the type of metal but I'm not sure in what way. I would like to get nice grill marks on a steak. Maybe a thicker grate which would retain more heat is the answer to that, Aren't the cast iron ones thicker?

I think this is a question for dcarch and his understanding of physics.

Then again, maybe grill marks are just an affectation.

Jim

I find that even when the grill is thoroughly preheated and the thermometer has spun well past 550 deg, I don't get a nice sear very quickly. That's what got me wondering if cast iron, with its ability to hold more heat, would give me better results. I guess I'll just buy one and see.

I also like that the cast iron ones have a closer pattern and are flat rather than wavy. Again, it's aesthetics, but sometimes I don't like the wavy pattern I get when grilling softer foods.

"Then again, maybe grill marks are just an affectation."

Could very well be.

"I think the thickness of the grill bars will make more difference than the type of metal"

Also could very well be. The high-end gas grills I've seen have grates made of relatively thick steel rods.

Grills, stainless steel vs. cast iron.

I don't know how big the differences are.

Cast iron is much heavier, in other words, more material. Therefore it will take longer to heat up but once it is heated it will deliver more heat. I would assume if you take the time to build up the heat, it will do a better job in making grill marks.

Which one will food stick more? I am not sure. Cast iron will naturally develop a seasoned non-stick coating, but cast iron grills tend to have more surface area for food to stick on. A good coat of grease on stainless steel works well for me for non-stick.

What about taste? I don't know. Never have done a side-by-side comparison. I suppose the difference will be from cast iron has about 50% open area and stainless steel 90% open area. More open area will get you more BBQ/ smoky flavor vs. less open area more surface area, which will give you more fried flavor. Meat on hot oiled cast iron surface is similar to frying.

If you look at my blower video, you will notice one thing very interesting, when the fire is very hot it only takes seconds for the grill to be hot enough to sear nice grill marks.

"--maybe grill marks are just an affectation"

One day you may see steaks with pre-printed grill marks.

dcarch

"One day you may see steaks with pre-printed grill marks."

Like fake tatoos. :-)

Actually, that is a brilliant, highly marketable idea.

Jim

They make branding irons that will imprint the diamond pattern on your steak. But if you are going to brand your meat, why not make it a little more fun? Actually, I think I am going to get one for DH - Arkansas of course (Woooooooo. Pig. Sooie!) for Fathers Day.... what a fun way to celebrate an alma mater every time you grill!
\

Alexa

Here is a link that might be useful: Steak Brands