Berry sugar, also called bar or caster sugar, is a more finely granulated sugar than the white table sugar that is commonly used in home kitchens. It dissolves instantly, making it preferred for sweetening cocktails and for certain baking projects.
Thanks to its small, finely granulated crystals that dissolve quickly, berry sugar is often used in recipes where larger granules of sugar would not deliver the same results, such as meringues, custards and mousses. Berry sugar is also ideal for sweetening beverages or cocktails and making candies. Superfine sugar should not be confused with confectioner's sugar, or powdered sugar, which is typically used in making icing. Powdered sugar has a different appearance and texture, feeling more like flour than sugar crystals.
If superfine sugar is not readily available, a food processor with a metal blade allows cooks to create a viable substitution. The cook can use the same amount or a bit more granulated sugar than what the recipe requires, and put it into the food processor for about five minutes, allowing the dust to settle after agitation. The result is a superfine sugar that dissolves as needed for many recipes. Superfine sugar can be stored the same way as regular granulated sugar.