What is banneton?

couche

A heavy linen cloth used to support shaped dough during the final proof, almost universally for baguettes and similar long loaves. The cloth is floured heavily, then pleated between each loaf so the pleats hold the loaves apart and the floured surface keeps the dough from sticking. The couche solves two problems at once: shape-holding (high-hydration baguettes would spread flat without lateral support) and surface drying (the heavy linen wicks just enough moisture from the dough surface to develop the characteristic dry, flour-streaked exterior that scores cleanly). A clean lint-free kitchen towel rigged in a half-sheet pan is a workable home substitute, though the real linen lasts decades and seasons over time.

pre-shape

A loose, gentle first shaping done after dividing dough but before the final shape — usually a rough round or loose log. Followed by a 15-30 minute bench rest, then the final shape. The point: build just enough surface tension to give the dough structure and let the gluten relax before the final tighter shape, without overworking it. Skipping the pre-shape (going directly to final shape after dividing) produces flatter loaves with weaker structure because the gluten hasn't had a chance to organize. The bench rest between pre-shape and final shape is sometimes called the bench proof — it's where the dough builds final extensibility for clean shaping.