Not all loaves will be perfect. I cannot stress this enough. Baking bread, especially sourdough, is influenced by a seemingly infinite amount of variables that can vary by the hour such as oven temperature, prooving temperature, gluten development, flour type, humidity, and yes, even the weather. Overprooved loaves, especially ones with not enough gluten development will become droopy and fail to expand in the oven, resulting in a flattened dense mess. Look for signs of overprooving in the crumb—large gas bubbles or even a gap between the top crust and crumb, indicating a large upper gas bubble. Even if overproved, these loaves can still be delicious and flavorful! Cut them into crostini and bake in the oven or halve the loaf horizontally for a great panini base.