What is the purpose of docking a prebaked pie crust?

Docking a prebaked pie crust involves puncturing small holes in the dough before baking. The primary purpose of this technique is to allow steam to escape during the baking process. When liquid in the pie crust turns to steam, it can create air bubbles that cause the crust to puff up or become uneven. By docking, the steam has an outlet, leading to a flatter and more uniformly baked crust. This technique helps maintain the intended texture and appearance of the pie crust, ensuring that it provides a stable base for the filling.

Other options mention concerns like shrinkage and drying out, which are not directly addressed by the docking process. Docking specifically focuses on preventing undesirable air bubbles from forming, which is crucial for achieving the desired visual and structural qualities of the baked pie crust.