Joanne Chang On Flaky

The most common example of the importance of chilling ingredients is making flaky pie dough. Most recipes instruct you to start with butter that is straight from the refrigerator. Be honest now: Do you do that? You will once you understand why. To make pie dough, you mix butter into flour and then add liquid. If the butter is from-the-fridge-cold, it won't completely mix into the flour and some will remain in pieces, ideally the size of grapes. As you roll out your dough, these grape-sized pieces of butter get elongated by the rolling pin and you end up with long flat sheets of butter within your dough.

Most butter contains about 15 to 17 percent water. When the pie dough goes into the oven, the water turns to steam, which is what helps create layers in your dough. In other words, it is the sheets of butter that make your pie dough flaky. If your butter is somewhat warm, then you end up with something that is more like cookie dough than flaky pie dough. Not the end of the world by any means—and a tender, crumbly pie dough is still a good dough—but for a pie crust that flakes and shatters and impresses with its many layers, keep your butter cold, cold, cold.