Fat

Shortening. Butter. Lard. Oil. Each of the three solid fats will yield reliably tender, flaky crusts, so long as you combine them with the flour using the correct technique. An oil crust will be more tender than flaky.

• Vegetable shortening yields a crust that holds its shape well in the oven. For a pie with the sharpest-looking crimp, use shortening. It is downside? Shortening lacks flavor, and an all-shortening crust may taste flat.
• Butter makes a flaky crust that’s packed with wonderful flavor. Due to its water content, it also makes a “loftier” crust; as the butter melts it gives off water that turns to steam, which in turn separates the layers a bit, yielding a slightly puffy crust. We prefer unsalted to salted butter, as it’s generally fresher; it also lets us control the level of salt in the crust more precisely.
• Lard, rendered from pig fat, has a higher melting point than butter or shortening; thus it yields an extra-flaky crust (though the flakes are small in size, rather than large). It also gives pie old-fashioned diner-style flavor.
• Vegetable-based oil, including olive oil, makes a crust that’s somewhat hard to handle; without the “plasticity” of solid fat, it tends to crumble as you roll it. Also, an oil crust will be only marginally flaky — but very tender.

Which fat should I choose?

If you choose a solid fat, make sure it’s cold! Chunks of cold fat in pie crust dough are your ticket to a flaky crust.

We find that a combination of butter and shortening, like that in our Classic Double Pie Crust and Classic Single Pie Crust recipes, makes crust that’s easy to handle: flaky, tender, and full-flavored.

Salt

Salt is added to pie crust dough for one chief reason: flavor. While it does strengthen the flour’s gluten just a touch, making the dough easier to roll out, its basic role is heightening the flavor of the flour and fat, and thus the crust overall.

Does it matter if you use sea salt, kosher salt, or table salt? Only to your measuring spoon. The coarser the salt, the more space it takes up. All of the pie recipes on our King Arthur Flour site are written for plain table salt. If you use a coarser salt, you’ll want to add more than the recipe calls for, to taste. You’ll also want to dissolve coarse salt in some of the water from the recipe, to make sure it’s fully dispersed throughout the dough.

Ice water

Water mixed with flour gives pie crust dough the structure it needs to hold together. The amount of water you use is critical; too much, and you’ve made a sticky mess. Too little, and the crust won’t hold together, or will crack around the edges as you roll.

You’ll notice that there’s usually very little water in pie crust. Your goal is to use just enough to create a flour/water matrix that’ll hold its shape, but not enough to potentially make the crust tough. In addition, using ice water helps the fat remain cold and solid; and the colder the fat when you put the pie into the oven, the greater the chance for flakiness.

Other Ingredients

You may have seen pie crust recipes calling for an egg, milk, buttermilk, vinegar, lemon juice, or sugar. All of these add-ins have their own minor effect on the dough.

Egg, milk, and buttermilk add protein, which enhances browning and tenderness. Egg also makes a sturdier crust, one with more body; bakers will often use an egg in pies they want to serve outside the pan.

We used to think that lemon juice or vinegar “tenderized” the gluten, encouraging it to remain un-elastic and making the dough easier to roll. As it turns out, the small amount of these acidic liquids added to pie crust dough doesn’t really do anything one way or the other — though there’s no harm in using either, if that’s what you’re used to.

Sugar enhances both flavor and browning when added to pie crust dough. When sprinkled atop the oven-ready pie, it offers a bit of crunch, as well as pretty shine.