Liquid

First, pastry dough must contain the right amount of liquid. If the dough is too dry, it will be impossible to roll out—at best it will crack as you try to place it in the pie dish. If it’s too wet, it will be too sticky to roll out. Because different brands of flour absorb different amounts of liquid, and butter contains varying amounts of water, it’s hard to provide an exact recipe. The first time you make the pastry dough, you’ll need to experiment a little to get the amount of liquid just right. The next time you make it, you’ll know exactly how much liquid to use, provided you continue to use the same brands of butter and flour. To judge the amount of liquid, you’ll have to watch the consistency of the pastry as you’re adding the liquid by pinching a piece to see if it comes together or falls apart in your hand. If it crumbles, it needs more liquid. If the pastry dough is too wet, you can incorporate extra flour as you roll it out by constantly flouring the work surface. If the pastry dough ends up too dry, it’s more problematic. You can chill it, cut it into chunks, and process it with a tablespoon or two of cold liquid, but at the risk of overheating the dough. It’s better to err in the direction of too wet than too dry.