With powdered sugar, confectioners' sugar and 10X sugar, the differences are all in name only — the products are all the same. In Great Britain, you'll see the same sugar labeled icing sugar and in France, it's sucre glace. While powdered sugar and granulated sugar can substitute for one another in a pinch, your dishes will come out with better texture and taste when you use powdered sugar only for certain recipes.
Different Regional Names
As is the case with some mayonnaise and ice cream brands, different brands of powdered sugar come with different names. Although they come from the same parent company, one brand of sugar in Eastern U.S. markets says Confectioners Sugar in large letters on the package, with 10X powdered sugar in smaller letters underneath. In Western U.S. markets, the word Powdered is prominent, and in products produced in Florida but sold nationwide, the bag says 10X Powdered Sugar on the front.
How They're Produced
Powdered sugar begins as regular granulated sugar, but sugar manufacturers grind it to an extra degree of fineness—4 times and 6 times as fine for industrial bakers; and 10 times, or 10X, as fine for commercial products bought by home cooks. Some cooks use the term confectioners' sugar for the powdered sugar that is more ground to the 10X level, but manufacturers use the terms interchangeably. All grinds of powdered or confectioners' sugar have 3 percent of cornstarch added as an anti-caking ingredient so the sugar doesn't clump together.
When to Use Powdered Sugar
Confectioners' sugar melts easily in liquid or in creamed, soft butter, making frostings and sauces come together quickly. And it gives a professional look to cakes, cookies or muffins when you dust it over their tops. Some recipes recommend sifting the powdered, or confectioners', sugar before using it to reduce lumps, but that isn't really necessary since a minute or 2 of extra stirring also dissolves any lumps.
When to Avoid Confectioners' Sugar
You can substitute about 1 3/4 cups of packed powdered sugar for 1 cup of granulated sugar in any recipe, but the cornstarch in the sugar will produce a slight thickening in your dish. Confectioners' sugar doesn't work well in syrups and beverages. When dissolved in cold water for iced tea or lemonade, the cornstarch in the sugar gives an off-putting taste; in hot drinks, cornstarch causes thickening.