Confectioners' sugar is a term used in cooking to refer to any of a variety of refined sugars that have been finely ground into a powdery form.
It's simply another name for powdered sugar. In other words, confectioners' sugar (aka powdered sugar) is nothing but ordinary sugar. The only thing different about it is that it's been ground to a much finer consistency than table sugar, also called granulated sugar. (If sugar is called for in a recipe, it means granulated sugar. If the recipe needs powdered sugar, it will specify that.)
It does behave differently, however. Confectioners' sugar is easily dissolved in liquid, which makes it ideally suited for making icings and frostings. Additionally, confectioners' sugar can be used decoratively by lightly dusting it over desserts, baked items, and even fruit.
The word "confectioner" means someone who makes candies and other sweets. Confectioners' sugar is widely used in candy making and baking, and that's where the name comes from. (It's also sometimes referred to as 10X sugar.)
Confectioners' sugar is not the same as superfine sugar or bakers' sugar. These products are finer than granulated sugar but not as fine as confectioners' sugar.
Substituting Sugar for Powdered Sugar
You can use granulated sugar when the recipe calls for powdered sugar in certain situations.
Candy making is one area where making random substitutions isn't a good idea unless you're certain you know what you're doing. So if you're making candy, you really should use whatever type of sugar the recipe calls for.
Beyond that, recipes that call for powdered sugar instead of granulated sugar usually do so for a reason.
- Icings and frostings use confectioners' sugar because it dissolves easily and provides a smooth consistency.
- Powdered sugar is sometimes used for dusting the tops of desserts. Granulated sugar won't give you the same effect.
- Some cookie and cake recipes call for powdered sugar, and in general, it's because the goal is a denser consistency. Because of its larger crystals, granulated sugar incorporates more air into doughs than confectioners' sugar.
In cases like this, you could substitute granulated sugar, and even though the recipe won't turn out exactly as intended, it will have the proper sweetness as long as you use the same amount of sugar.
But this is important: You must substitute the sugars on a weight basis, not a volume basis. So if a recipe calls for a cup of powdered sugar, and you want to use granulated sugar, you can't just use a cup. You have to know how much a cup of powdered sugar weighs, and then use that much granulated sugar.
A cup of confectioners' sugar weighs about 4 ounces (113 grams). So you would use 113 grams of granulated sugar.
Make Your Own Confectioners' Sugar
Because it's made from granulated sugar, you can make your own confectioners' sugar. All you need is a coffee grinder. Simply place some ordinary granulated sugar in the coffee grinder and pulse until it's a fine powder. Commercial confectioners' sugar contains about 3 percent cornstarch to prevent it from clumping up, but if you're grinding your own and using it right away, clumping shouldn't be an issue.