ROOM TEMPERATURE FERMENTATION: What does it mean to let bread rise covered with "plastic cloths"?

Fermentation is a crucial process. During this process, the surface of the dough (whether for bread, croissants, etc.) should not dry out, meaning it should not form a "skin," as this could hinder the ideal expansion of the product. 

In professional settings, dough is often placed in a "proofing cell" or "proofing chamber," where both temperature and humidity levels are carefully controlled. As an alternative, covering the dough with a plastic cloth helps to trap moisture. While the moisture in the dough will naturally evaporate (though this process is not noticeable to the naked eye), the plastic cloth prevents this evaporation from escaping, keeping the surface of the dough soft and elastic. 

Another similar method involves using a slightly damp kitchen towel or cloth, though plastic cloths are generally preferred. 

Some bakers also prefer to let larger portions of dough rise in a classic glass bowl (oiled on the bottom) or a wicker basket (lined with a floured cloth), covering it with plastic wrap until the dough has at least doubled in volume before baking. To help with air circulation, some people make small holes in the plastic wrap using a toothpick, allowing a minimal exchange of air during fermentation.