I baked a couple Norwich Sourdough  loaves last night. They had bulk fermented for 24+ hours in the fridge, and also proofed 24 hours in the fridge.
Unfortunately I made the mistake of proofing seam-side down in the baskets! I realized my mistake just after popping them in the fridge.
The seams were barely visible when I turned them out onto the peel, but even with some slashes they still split at the seams. In the oven they rose into a sort of deformed alien spaceship looking shape.
But I'm not complaining! This was BY FAR the best oven spring I've gotten from sourdough, heck from any loaf I think. And the crumb is nice too:
I'm kind of glad I found out what happens when you proof seam-side down (and thus bake seam-side up), I don't think I'll make that mistake again! Although it is possible the oven spring was helped by the seam opening up, I do think proper slashing can achieve the same thing, while controlling the shape & look better. (You can see some evidence of the slashes I made in the darker sections of the crust but they couldn't compete with the seam I guess.)