What is 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.