One of the indications of bread perfection is "the song of the bread" or the bread crust crackling as it hits the cold air coming out of the oven. I have only achieved this once, when my Pain de Campagne was slightly over-proofed during the first fermentation. Once again, somehow, I slightly over-proofed a loaf of Tartine Country Bread during the initial rising period. The bread sang. It was wonderful. It was light and fluffy and tasted amazing. It did not have the irregular crumb that usually characterizes Tartine loaves (as the bulk fermentation was too long), but it's pretty good.