Granulated sugar is ground to different consistencies for assorted baking and cooking applications. To smoothly combine with icing and frosting ingredients, it is reduced to a fine powder. There is no difference between icing sugar and icing sugar. The various names for the ingredient come from the geographic regions in which it is used.
Names by Country and Uses
In the United States, pulverised granulated sugar is called either icing sugar, based on its powdery texture, or confectioner's sugar, because confectioners or candy makers use it for its superior mixing ability. The former name is most commonly used in the northern states and the latter in the southern regions. In Canada and the United Kingdom, the same ingredient is referred to as icing sugar, as it is a main ingredient in many icings.
Icing sugar is made through grinding granulated sugar to a soft powder, sifting it and adding around 3 per cent cornstarch to prevent it from lumping and caking. It comes in three grades, based on fineness. The packaging indicates how many times the sugar was ground, with 10 times being the finest grade. This is the type sold in supermarkets, and it cannot be ground finer by home food processors. The two other coarser grinds are used only by industrial baking companies.
Using Icing Sugar
Use icing sugar in icing, frosting, candy, confections and whipping cream as it dissolves quickly and completely in fats and liquids, and the cornstarch helps the sweets thicken and maintain their form. Sift icing sugar over the top of bundt and pound cakes to add a decorative touch. Use stencils to create flourishes on top of sheet cakes, tarts, pastries or baked cream or custard pies. For an elegant dessert presentation, sift the sugar over the entire surface of the serving plate and create a design on top with trickles of chocolate, caramel or raspberry syrup before placing the dessert in the centre.
If necessary, you can create a reasonable icing sugar facsimile by pulverising a cup of granulated sugar with a tablespoon of cornstarch on high speed for a few minutes in a blender. The consistency may be a bit different from commercially produced icing sugar, so for best results, purchase the real thing for large baking or cooking projects. Do not substitute icing sugar for granulated sugar in recipes, as the final consistency of the dish will be compromised. A product called snow white sugar is a special type of icing sugar that does not melt. It is appropriate for sifting on top of pastries or cakes but cannot be used in recipes in which icing sugar is combined with wet or fatty ingredients.