The final rise of shaped bread dough before baking. It refers to a specific rest period within the more generalized process known as fermentation. Over-proofing occurs when a fermenting dough has rested too long. Its bubbles have grown so large that they have popped and tunneled, and dough baked at this point would result in a bread with poor structure. A bread that is properly proofed will balance gas production with the ability of the bread's gluten structure to contain it, and will exhibit good oven spring when baked. A bread that is under- or over-proofed will have less oven spring and be more dense. An over-proofed bread may even collapse in the oven as the volume of gas produced by the yeast can no longer be contained by the gluten structure.