Stone vs Sheet Pan

I have always felt guilty using a baking stone and try to reduce the time for the pre-heat. Simple physics tells us that this is probably worse that baking on a sheet pan as energy is sucked up by the stone. Despite my using a baking stone and copius steaming, the results I get for those on the stone were no different from those on the sheet pan. 

For this bake, I preheated the stone for a longer period and the results speak for themselves. Those baked on the stone had a more pronounce grigne. It showed that my previous preheat was insufficient. The 3 shorter loaves were baked on a stone and showed great oven spring.