Shelling on french loaf
I am working on a type of French bread called Po-boy bread in New Orleans. I am very pleased with crumb, crust, flavor and color etc but one last minor problem hes me stumped. At some point during the bake I get what Rose Levy Beranbaum calls shelling. Down along one or both SIDES of the loaves there in an intentation. Imagine that you put a ruler up against the loaves during baking so instead of getting a long, almost perfectly round loaf I get this indentation about 1/2 inch deep by 14 inches long. I bake with steam and the loaves are proofed and baked in a double baguette pan. Sorry I can't post a photo. P.S. I am NOT talking about the crust coming up and away from the loaf. Oh yeah, one other thing, the sides of the loaves are MUCH lighter color than the rest of the loaf. Any thoughts on this? Thank you.
Without photos I am just guessing, but possibly a little over proofed then the top springs when the steam hits it, then the bottom heat expands the rest of the loaf, but the top is ahead of the game and the indentation left by the edges of the pan are fixed in place and never fill in. Light sides could be from a light colored pan (possibly aluminum?) or insufficient bottom heat. Others will have to chime in with their hypotheses. I have had tall loaves when I used a double baguette pan but not an indentation such as you describe.