We all know that sugar is essential for baking—after all, it’s what makes sweets taste sweet. But thanks to its unique chemical nature, sugar also performs many other essential functions in cookies, cakes, and other baked goods.
Just to be clear, I’m talking about the kind of sugar we use most in baking: the dry, crystalline sugars that are collectively referred to as table sugar. (It comes in several forms, such as granulated, brown, powdered, and turbinado.) When you understand how this ingredient behaves in recipes, you’ll be on your way to becoming a better baker, because many baking disasters can be traced to one little mistake: tinkering with sugar. Using less (or more) sugar than a recipe calls for (or even substituting honey for table sugar) can really affect your results.
Sugar stabilizes meringues
Whip egg whites with sugar and what do you get? Meringue. More than just a fluffy, white pie topping, meringue gives lightness and loft to mousses, sweet soufflés, angel food cakes, and even some frostings.
Sugar stabilizes meringue in two ways. First, it protects the egg whites from being overbeaten. As you whip air into egg whites, the egg proteins bond and form thin, strong sheets that stretch around the tiny air bubbles, creating foam. Adding sugar slows down this foaming, so you’re less likely to overbeat the egg whites.
Second, sugar protects the foam from collapse. The sugar dissolves in the water in the bubbles’ walls, forming a syrup that surrounds and supports the bubbles.
Sugar affects texture
When sugar molecules meet water molecules, they form a strong bond. This union of sugar and water affects the texture of baked goods in two important ways.
It keeps baked goods soft and moist. The bond between sugar and water allows sugar to lock in moisture so that items such as cakes, muffins, brownies, and frostings don’t dry out too quickly.
It creates tenderness. Baked goods get their shape and structure from proteins and starches, which firm up during baking and transform soupy batters and soft doughs into lofty muffins and well-formed cookies. But because they build structure, proteins and starches can potentially make baked goods tough, too. The sugar in a batter or dough snatches water away from proteins and starches, which helps control the amount of structure-building they can do. The result? A more tender treat.
It is here that tinkering with a recipe’s sugar can have a dramatic effect. When, for example, a loaf of pound cake has a nice shape and an appealing texture, the sugar, proteins, and starches are in balance. But if you tip that balance by using more or less sugar than the recipe calls for, the result could be so tender that it lacks the structure to hold its shape, or it could be shapely but too tough.
It’s best to dust moist cakes with confectioners’ sugar right before serving, because over time the sugar will attract even more moisture and become sticky.
No doubt you’ve noticed that cake and quick bread batters rise during baking. Well, sugar helps make this happen.When you mix up a cake batter and beat sugar into fat, eggs, and other liquid ingredients, the sugar crystals cut into the mixture, creating thousands of tiny air bubbles that lighten the batter. During baking, these bubbles expand and lift the batter, causing it to rise in the pan.
Sugar deepens color and flavor
Thank sugar for the appealing golden-brown color of many baked desserts. As sugar gets hot, it undergoes a cascade of chemical reactions called caramelization. In this process, sugar molecules break down into smaller and smaller parts and begin to turn deeper shades of brown and develop more complex flavors.
Sugar adds crunch
In the heat of the oven, moisture evaporates from the surface of baked goods, allowing dissolved sugars to re-crystallize. This creates the crunchy, sweet crust that you’ve probably enjoyed on such items as brownies, pound cakes, and some kinds of muffins and cookies.