Inverted Baking Dish to Create Steam??

i put my cast iron in the basement storage. I have started using my 1940 granite roasters. Anything that holds heat and steam works. In point of fact I get way better rise and ears with the quick heating of my roasters that I ever got with cast iron. Don’t get me wrong I loved my heated pots but the roasters only need to heat the length of time it takes to preheat the oven so lots of energy saved. 500 degrees is 500 degrees. Your bread  neither knows nor cares how you preheated a stone or pot. It will  get to be 500 no matter if it preheated for 15 min as a thin pot  or an hour for cast iron. Will bake beautifully and the steam will stay in. Turn around time is fast with the granite wear as well, so baking batch after batch is possible in  a short time frame. 

You can look online to see the heating parameters of your particular dishes. You should do so before subjecting to extreme temps. Good luck! Post results

I've baked many batards and other long-ish loaves on a baking stone, covered with an inverted, inexpensive Graniteware roasting pan. Holds the steam just fine, as long as you're careful to make sure the pan doesn't overhang any part of the stone.

Through reading alot of tutorials and YouTube i have seen it done with both large pyrex and stainless steel bowls. Have not tried it myself as i prefer the outcome of fully uncovered loaves

I recall a discussion on this site regarding the use of Pyrex (or other tempered glass) dishes, and comments suggesting that some of the older Pyrex had withstood the heat more successfully than newer products. Try searching for it. A related thought, if Pyrex is used as a pan, rather than as a cover, the dough would allow the material to heat gradually. If used as a lid, the material is exposed directly to the heat. Many years ago, I broke an Anchorware casserole by using it in the broiler with just pork tenderloins in it. The shock was too great and I lost a pan I really liked.

Best of luck! We want pictures!

Cathy

Like a couple of others, I use an old enameled metal roaster body upside down. It's oval and long enough for batards and short baguettes. I've also used my enameled cast iron Dutch oven body upside down for batards, but the roaster is much lighter and thus easier to handle, plus it's a few inches longer, and I haven't noticed any difference in the results, granted I've never compared side by side. 

... works quite well, without the risk of breakage.

but what happens after you take it out.  I have busted plenty of them by putting them on a cold surface like the stove top when they are 450 F.  If you put them on a wood cutting board no problem for some reason and you can get all you want of either at Goodwill for next to nothing.  A stainless steel mixing bowl and stone works better than a dutch oven for boules if you ask me and the long breads a stone and inverted granite-ware is tough to beat

I've used my cast iron frying pans covered with steel bread bowls for stubby 'chubbs' (not boules, but not baguettes either). I've covered loaves baking directly on the stones with upturned foil roasting pans too. Both worked fine. I also sometimes bake rye bread in bread pans covered with steel steam table inserts from a restaurant supply shop (used, $5 each). I think a deep roasting pan lid would probably work best as it has a handle on it. The problem with the pyrex baking dish is getting hold of it properly to take it off halfway through the baking (when it's really hot) and then putting it somewhere safe.

of the Average Joe Artisan Bread kit.  Anyone could use enamelware of the size and shape that suits their baking, without having to buy the kit.

Paul