Add acid to the dough in the form of lemon juice, vinegar, or sour cream. Acid breaks long gluten strands. A little acid helps keep crusts tender. Adding acidic ingredients to the dough will break apart long gluten strands, making the crust more tender. For this reason, many pie crust recipes call for a few drops of lemon juice or vinegar.
Flaky pastry has many thin, crisp layers.
This pastry was made with cold butter cut into small pieces and then quickly rolled out with flour and ice water. Soft fats grease proteins more easily. Shortening is softer than cold butter and therefore easier to blend with flour. In the 1930s, a popular recipe for pie crust called for combining warm vegetable oil with the flour. This recipe produced a crust that was fall-apart tender without a single flake.