Shortcrust pastry shrinks during baking primarily due to gluten development and fat melting, both of which cause the dough to contract. Relaxing the gluten and chilling the dough before baking can minimize shrinkage.
Detailed Explanation:
Several factors contribute to shortcrust pastry shrinkage:
- Gluten Development: Overworking the dough develops gluten, the protein in flour that makes it elastic. When heated, gluten contracts, pulling the pastry inwards.
- Fat Melting: Shortcrust pastry relies on solid fat (butter or shortening) to create its characteristic flakiness. As the fat melts during baking, it releases moisture and leaves air pockets. The dough then collapses into these spaces, causing shrinkage.
- Moisture Loss: The evaporation of water in the dough also contributes to shrinkage. As the water turns to steam and escapes, the pastry loses volume.
- Incorrect Handling: Stretching the dough when placing it in the pan can cause it to snap back during baking, leading to shrinkage.
Pro Tip:
To prevent shrinkage, blind bake your pastry with pie weights or dried beans to help it retain its shape while the gluten sets and the fat melts. This provides support and minimizes the dough's ability to contract.