Choosing Your Sugar

• Not all sugar can be blended to make powdered sugar. Made with molasses, brown sugar contains too much moisture and won't turn into a powder when blended. Both granulated beet and cane sugar are processed to make powdered sugar, but beet sugar can behave differently in recipes, requiring the sugar to be cooked to a particular temperature or stage. Check the label of your sugar to determine whether it’s made from beet or cane.

Adding Cornstarch to the Sugar

• Cornstarch is added to prepared powdered sugar to absorb excess moisture and prevent the sugar from clumping in the bag. Cornstarch also serves as a thickening agent for frostings, icings and puddings. To make a substitution from your granulated sugar, add 1 tablespoon of cornstarch per cup of granulated sugar before blending. If you don’t have cornstarch or prefer not to add a grain-based thickener, blend your granulated sugar by itself and use it immediately. Store your homemade powdered sugar in an air-tight container and don’t refrigerate to avoid moisture getting into the sugar.

Processing Granulated Sugar

• Use a food processor or coffee grinder and measure out the amount of sugar you need for your recipe. Spoon the granulated sugar and the cornstarch into the processor and pulse on high for about one minute, or until you have a fine powder. To measure your powdered sugar, place a measuring cup in the bottom of a bowl and pour your powdered sugar into a sieve or sifter, holding it over the bowl until the desired amount of sugar falls into the cup.

Using Powdered Sugar

• Even though powdered sugar is made from granulated sugar, because it has been ground, it doesn’t stand up to heat the same way granulated sugar does. Use powdered sugar as a decorative garnish for rolling donuts or sprinkling over sweet treats or for thickening unheated frostings or desserts. Use granulated sugar for cooked frosting and candy confections where the sugar must be heated to a certain temperature or stage. When substituting powdered sugar for granulated sugar in a recipe, use 1 3/4 cups of powdered sugar for each cup of granulated.