I’ve been wanting to do that experiment for a while because preheating the oven at 375°F for 30-45 minutes wastes electricity; that obviously also add to the cost of the loaves.
The baking procedure is mostly the same as when baking with a preheated oven, as outlined in the French boule recipe, with the following differences:
- The first step: Put loaves into cold (not preheated) oven. Pour 1 C of hot water (more than 200°F) into tray of quarry tiles. Turn oven on to 375°F. Bake for 25 minutes (instead of 15 minutes).
- Add 8 minutes to the last step: 23 minutes instead of 15 minutes.
The loaves had the same golden hue and same amount of nice oven spring when baked starting with a cold oven. The end result looks and tastes just as good.
Overall, starting with a cold over reduces hot-oven time by 12 minutes, or 20%: not a lot, but meaningful enough.