What does it mean if dough has not fully proofed?

If dough has not fully proofed, it means it has not completed the fermentation process where yeast produces gas and causes the dough to rise. For properly proofed dough, one of the key indicators is that it has doubled in size. This signifies that the yeast is active and has produced enough carbon dioxide to expand the dough. When the dough has not reached this stage, it may lack the necessary volume and texture for optimal baking.

While temperature, kneading, and texture can all impact dough development, the defining characteristic of full proofing is the increase in size due to fermentation. This is why the correct answer emphasizes that the dough has not doubled in size during the proofing stages.