Confectioners' sugar, or powdered sugar, is granulated white sugar that has been crushed into a fine powder and cornstarch is added to prevent caking. It is ideal for icings or as a sprinkle-on dessert topping. Two different grain sizes are available, 6X and 10X confectioners' sugars.

The “X” designations are derived from the mesh sizes of the screens used to separate powdered sugar into various sizes. Thus, 6X would have a larger particle size, whereas 10X would have a smaller particle size.

Store confectioners' sugar in a cool, dry location (not the refrigerator). When it gets moist, it develops lumps. And because of its physical properties, it may absorb strong odors if left unsealed. Confectioners' sugar, however, cannot adequately be restored if it forms lumps, because of the cornstarch used in the sugar.