Yes, shortcrust pastry dough should be rested in the refrigerator for at least 30 minutes, and preferably longer, before shaping. This allows the gluten to relax and the fat to firm up, resulting in a more tender and less shrunken pastry.
Resting shortcrust pastry dough is a crucial step in achieving a flaky and tender result. When you mix flour and water, gluten develops. Gluten is a protein that provides elasticity and structure to dough. However, too much gluten development in shortcrust pastry leads to a tough and chewy texture, which is undesirable. Resting the dough allows the gluten strands to relax, preventing them from becoming overly elastic.
Furthermore, shortcrust pastry contains a high proportion of fat, usually butter or shortening. During mixing, the fat warms up. Resting the dough in the refrigerator allows the fat to solidify again. This is important because when the pastry is baked, the solid fat melts and creates steam, which separates the layers of dough and results in a flaky texture. If the fat is too soft, it will simply melt into the flour, resulting in a greasy and dense pastry.
The resting period also allows the flour to fully hydrate, which contributes to a more even baking process and prevents the pastry from shrinking excessively during baking. A minimum of 30 minutes is recommended, but longer resting times, even overnight, can further improve the texture of the pastry.
If you're short on time, you can rest the dough for a shorter period in the freezer (about 15-20 minutes). However, be careful not to freeze it solid, as this can make it difficult to roll out.