Caster Sugar Substitutes

How to make castor sugar illustration

The Spruce / Ashley DeLeon

Caster sugar, also known as castor sugar or super-fine sugar, is frequently used in British baking. It melts and incorporates quicker than regular granulated sugar without the added cornstarch of powdered sugar. It's more expensive than regular sugar and can be difficult to track down in the U.S., but 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 a number of different types of the sweet stuff and names can 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 confectioner's sugar, is simply granulated sugar that has been ground into a fine powder and combined with cornstarch to keep it from clumping. Caster sugar is somewhere between the two. It has smaller crystals for a super-fine but not 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 will depend 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 the melting properties of caster sugar, there is a trick you can use. For cakes and cookies that call for room temperature butter, use butter that is slightly colder (but still mixable) and cream the butter and sugar together for longer, allowing the sugar to better combine.
  • 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. Alternatively, try powdered sugar.
  • For Cocktails: Granulated sugar can be used in shaken cocktails, you'll just need to use a bit of elbow grease and shake the cocktail for longer. Simple syrup is a good substitute that instantly dissolves—keep in mind you'll need 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 at a lower speed to allow the sugar more time to melt. For best results, use caster sugar.
Ingredients for caster sugar
The Spruce / Zorica Lakonic 

How to Make Caster Sugar

If you don't have caster sugar handy and are making a delicate recipe like sponge cake, mousse, or meringue, make your own substitute at home. All you'll need is a food processor (large or small), blender, or coffee grinder and granulated sugar.

  1. Place the granulated sugar in a food processor, blender, coffee grinder, or spice grinder. If you are using a large food processor, you will have to 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 a recipe. If you have any leftover, store in a labeled container for the next time you bake.


Granulated sugar's jagged crystals can scratch the plastic bowl of your 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 yes. Note that the bigger crystals in granulated sugar may affect the texture, making it slightly grainy. When making cocktails, you'll simply need to stir or shake for longer to allow the sugar to dissolve. When making delicate, fluffy items like mousses, meringues, and sponge cakes, a grainy texture will be more noticeable. For best results, use caster sugar in these airy recipes.

Different sugars
The Spruce / Zorica Lakonic

What is Golden Caster Sugar?

Golden caster sugar is made from unrefined sugar cane or sometimes beets and has a subtle buttery flavor. The golden color can help turn baked goods a lovely shade of brown. It is not commonly found outside of the U.K.

Golden Caster Sugar Substitutes

When substituting for golden caster sugar, you have a couple of easy options. Note that we do not recommend using brown sugar since it has more moisture than caster sugar and can have a noticeable effect on the texture.

  • Regular Caster Sugar: The easiest substitution is to use regular caster sugar, whether store-bought or homemade. The sugar will react the same in the recipe, creating the same texture, and the difference in flavor will be minimal.
  • Demerara or Turbinado Sugar: While these sugars have a similar color and flavor to golden caster sugar, they have much, much bigger crystals. When using to make baked goods, run demerara or turbinado sugar through a food processor or blender to make a substitute for golden caster sugar.

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