[BAKENOTE] Recipe: Sour Sour Dough | Bake temp: 475°F → 450°F | Bake time: lid on ~19-27min + lid off ~19-33min COLD RETARD 48 HOURS OR MORE in the refrigerator -- this is the key change from the standard overnight retard. Extending the retard well past the usual ~12-13hrs is the single biggest lever for a more sour, tangier loaf (extended cold time lets acetic-acid-producing bacteria keep working long after yeast activity slows).