Caster Sugar Substitutes

How to make castor sugar illustration

The Spruce / Ashley DeLeon

Caster sugar, also known as castor sugar or superfine sugar, is finer-grained than regular granulated white sugar. Frequently used in British baking, it incorporates into food more quickly without adding cornstarch or powdered sugar. Superfine sugar is also often used in drink recipes because it dissolves so well. While caster sugar is more expensive and can be challenging to track down in the US, it's easy to make a quick substitute at home.

Fast Facts

  • Other Names: castor sugar, superfine sugar, baker's sugar, berry sugar
  • Uses: baking, cocktails
  • Types: white, golden
Caster sugar
The Spruce / Zorica Lakonic

What Is Caster Sugar? 

The world of sugars can be a bit confusing since there are several different types and names that differ from country to country. Caster sugar is very popular in British baking but less common in American recipes.

Granulated sugar always refers to white sugar in the U.S. It has a somewhat gritty texture and is the most common type of sugar stateside. Powdered sugar, also known as confectioners' sugar, is simply granulated sugar that's ground into a fine powder and combined with cornstarch to prevent clumping. Caster sugar is somewhere between the two; it has smaller crystals but not a powdery consistency.

Caster sugar incorporates more easily than granulated sugar into delicate, airy recipes like sponge cake, mousse, meringue, and soufflé. It's also used to sweeten fresh berries since it dissolves quickly. Many bartenders use caster sugar for shaken or stirred cocktails instead of simple syrup.

Fruit and sugar
The Spruce / Zorica Lakonic

Caster Sugar Substitutes

Whether or not you can use a substitute for caster sugar depends on the recipe. Here are some common substitutions:

  • For Cakes and Cookies: If the recipe calls for white caster sugar, most recipes will work just fine with white granulated sugar. To better mimic caster sugar's melting properties, use slightly colder butter than room temperature (but still mixable) and cream the butter and sugar longer, or until the sugar and butter are better combined.
  • For Berries: Regular granulated sugar will work just as well. It will just take longer to dissolve. Allow the berries to sit a few extra minutes, tossing occasionally, or try powdered sugar.
  • For Cocktails: Granulated sugar works in shaken cocktails; you'll just need to shake the cocktail longer. Simple syrup is a good substitute that is pre-dissolved, though you'll want to use slightly more syrup than straight sugar, and it will water down your drink very slightly.
  • For Meringues: For meringues or cakes that call for beating egg whites with sugar, use granulated sugar and mix it more slowly to allow the sugar more time to melt.
Ingredients for caster sugar
The Spruce / Zorica Lakonic 

How to Make Caster Sugar

Make a substitute at home if you don't have caster sugar handy and are making a delicate recipe like sponge cake, mousse, or meringue.

  1. Place granulated sugar in a food processor, blender, coffee grinder, or spice grinder. When using a large food processor, add enough sugar to cover the blades. A well-cleaned spice or coffee grinder is perfect for making small batches of caster sugar.
  2. Pulse until it reaches a super-fine but not powdery consistency. You're aiming for a crystal size directly between granulated sugar and powdered sugar.
  3. Let the sugar settle for a few minutes. Otherwise, you'll end up with a dust cloud when you open the top.

Use your homemade caster sugar in place of store-bought caster sugar in any recipe. If you have leftovers, store them in a labeled container for the next time you bake.

Tip

Granulated sugar's jagged crystals can scratch the plastic bowl of a food processor. The effect will likely be minor if noticeable at all, but if this concerns you, try using a coffee or spice grinder instead.

Can I Substitute Granulated Sugar for Caster Sugar?

Whether or not you can substitute granulated sugar for caster sugar depends on the recipe. If you're making a standard cake or cookies, then it should be fine. Note that the bigger crystals in granulated sugar may affect the texture, making it slightly grainy. A grainy texture will be more noticeable in delicate, fluffy items like mousses, meringues, and sponge cakes. For best results, use caster sugar in these airy recipes.

When making cocktails, stir or shake for longer to allow the sugar to dissolve.

Different sugars
The Spruce / Zorica Lakonic

What Is Golden Caster Sugar?

Most commonly found in the UK, golden caster sugar is made from unrefined sugar cane and sometimes beets. It has a subtle buttery flavor and gives baked goods a lovely shade of brown.

Golden Caster Sugar Substitutes

When substituting for golden caster sugar, you have a couple of options. Brown sugar is not recommended since it has more moisture than caster sugar and can affect the texture.

  • The easiest substitution is white caster sugar, whether store-bought or homemade. The sugar will react the same in the recipe, creating a similar texture with a minimal flavor difference.
  • Demerara and turbinado sugars have similar colors and flavors to golden caster sugar but significantly larger crystals. When used to make baked goods, run these sugars through a food processor or blender for a golden caster sugar substitute.
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