Side by side comparison
Just decided to bake two loaves (the same dough) on the left, cast iron DO, on the right in an unglazed Romertopf. Both pots placed into a cold oven, and bread plopped in after the preheat (475*F). Temperature of cast Iron bread when it hit the cooling rack 208, clay pot 198. I thought that was interesting.
Source: Fresh Loaf