Temperature: Always keep the pie dough and all ingredients chilled.
Touch: Always use a light touch. Overworking the pie dough while mixing or rolling will activate the gluten in the flour and toughen up your pie dough.
Fat:
Fat is the most critical component of a pie crust. The fat you choose and the way you mix it with the flour determines the taste and structure of your pie crust.
Butter provides a rich flavor and a deep golden color in a pie crust. It cannot be emphasized enough - make sure the butter stays very cold. Butter contains water, and if the butter gets warm, there are reactions with the water and the flour producing glutens, which creates a tough pie dough. Recipes are written for unsalted butter. If you only have salted butter available, omit any salt that might be in the recipe.
Shortening or Lard: Using shortening or lard instead of butter makes an extra-flaky pie crust. Since shortening doesn't contain any water to bind with the flour, the chance of a tough pie dough is minimized. These pie crusts are great for baked-custard pies. Dough made with shortening or lard is easier to work with than all-butter dough, but it's much less flavorful. Most recipes with shortening or lard include some butter to add richness and flavor to the pie crust.
Margarine: Margarine is a water-in-oil emulsion. Margarine is made from any variety of animal or vegetable fats, and is often mixed with skimmed milk, salt, and emulsifiers. During the manufacturing of margarine, some of the unsaturated fats are converted into saturated fats or trans fats in the hydrogenation process in order to give the margarine a higher melting point so that it is solid at room temperature and has the appearance and texture of butter. Nearly all margarine is salted and contains liquids (which produces a tough crust) and various chemicals, which makes shortening or unsalted butter a better choice for baking.
Liquid:
Liquid holds the dough together, but it's imperative to use as little as possible. Too much liquid activates the gluten in the flour, making for dense, chewy dough. Too little liquid and the pie crust falls apart. The key is to find the perfect balance. Acidic liquids, like vinegar, sour cream, yogurt or lemon juice, help relax the gluten and assure a tender crust. But ice water is the most ubiquitous liquid of choice.
Flour:
All-Purpose Flour: When in doubt, use this basic flour; it can be used in most baked goods.
Whole-Wheat Flour: This flour provides a fuller flavor since it contains the wheat germ. If you want to add whole-wheat flour to a recipe, substitute up to half of the all-purpose flour with whole wheat; any more than that and your baked good might be too tough. Also, you may need to add more liquid or fat to compensate.
Cake or Pastry Flour: This finely ground soft-wheat flour is high in starch and low in protein, and is used for baking tender cakes and pastries.
Bread Flour: This flour is higher in gluten, so it gives body to bread and pizza dough.
Self-Rising Flour: This is all-purpose flour with baking powder and salt added. Don't substitute it for other flours because the added ingredients will affect your recipe — only use it if the recipe calls for it.
“In order to make an apple pie from scratch, you must first create the universe."
~Carl Sagan
Sugar:
Adding sugar makes the crust sweet and even more tender. Sugar (along with fat) is what causes baked goods to brown as it carmelizes. Using egg yolks or cream as the liquid makes the crust rich.
Granulated Sugar: Plain white sugar, this is refined from sugar cane or beets and is used in most baked goods.
Superfine Sugar: Since it is more finely granulated than table sugar, it dissolves almost instantly and is useful for meringues and cool liquids.
Confectioners' Sugar: Also called 10X, this is granulated sugar that has been ground into a powder. Confectioners' sugar is commonly used in cake and cookie icings and is often dusted on desserts.
Brown Sugar (Light or Dark): This soft-textured, hearty-tasting sugar is white sugar flavored with molasses. Light and dark are interchangeable (the difference is the amount of molasses); so use whichever you prefer.
Decorating or Coarse Sugar: The granules are about four times larger than granulated sugar and come in a myriad of colors. This is generally only used for decorating.
Molasses: This dark, viscous syrup is the liquid that is left behind from refining sugar. Light molasses is from the first boiling of the sugar syrup; dark is from the second; and blackstrap, the strongest, is from the third and not usually used in desserts. Unsulphured usually has a cleaner flavor.
Honey: The lighter the honey, the more delicate the flavor.
Maple Syrup: Pancake or table syrup is not real maple syrup, so make sure you use pure maple syrup.
Sugar Substitutes: Sugar substitutes are best used in applications when the sugar's primary purpose is to provide sweetness, such as in fruit fillings. Also, keep in mind that sugar substitutes can lose sweetness, and even develop an unpleasant aftertaste, when cooked at high temperatures. When baking with sugar substitutes or recipes very low in sugar and low in fat, food may not brown properly.
Leavener:
Baking Soda (also known as bicarbonate of soda) is used as a leavener to make dough and batter rise. Baking soda has a shelf life of six months once opened, so make sure yours is fresh.
Baking Powder is composed of baking soda, an acid (usually cream of tartar) and a moisture absorber, like cornstarch. Baking powder has a shelf life of six months once opened, so make sure yours is fresh.
Chocolate:
Unsweetened Chocolate is also called baking or bitter chocolate. For convenience,
buy in one-ounce squares.
Dark Chocolate can be labeled bittersweet or semisweet, which can often be used interchangeably when baking.
Milk Chocolate is dark chocolate with milk solids added, making it creamier and mellower.
White Chocolate is technically not chocolate since there is no chocolate liquor, but it does contain cocoa butter along with sugar, vanilla and lecithin.
Chocolate Chips contain less cocoa butter than chocolate bars, which is why they can retain their shape.
Unsweetened Cocoa Powder has a deep chocolate flavor. Dutch-process cocoa powder has been treated with an alkali, which neutralizes its acidity and makes it mellower. Recipes are often written for one type or the other, as they react differently with baking powder. Dutch process is always labeled on the box; if there is no mention, it is natural. Cocoa adds color and flavor to crusts, but it acts like flour, so too much can make dough dry and tough. For a high-impact flavor, use dark, Dutch-process cocoa.
Salt: Use a fine-grain salt, not kosher or coarse, for baking.
Adding nuts to pie crusts contributes richness and flavor. Dough with nuts can be extra sticky, but if it's kept well chilled and manipulated with a little floured parchment, the result is worth the extra effort.