What Is Caster Sugar?

What is caster sugar? Let’s take a look at the different types of sugars often used in baking to understand why we use them, what makes them different, and the substitutions that are available. 

Today we’re taking a break from baking to talk all things sugar. (nerd alert 👩‍🍳)

As an Australian blogger, one of the most common questions I get asked is, ‘What is caster sugar?’ I’ve learnt that while it’s a common baking ingredient here in Australia (I use it in most of my cookies and cakes), it doesn’t seem to be readily available around the world.

So if you’ve been wondering what caster sugar is and what sugar you can use in your baking instead, you’ve come to the right place. I’ve put together the most commonly asked questions about sugar and baking (including ones that I’ve asked myself over the years) to ensure you have success in your kitchen.

What is caster sugar?

Caster sugar is a refined white sugar that is commonly used for baking in Australia and also the UK. It looks like this >

Can I use granulated sugar instead of caster sugar?

Yes. While caster sugar and granulated sugar are not exactly the same, they can be swapped 1:1 in baking recipes. Caster sugar is slightly finer and dissolves more easily, but in my experience, this doesn’t affect most baking recipes if swapped with granulated sugar.

Where can I buy caster sugar?

Here in Australia, caster sugar is sold at all major supermarkets. If it’s not readily available in your country, I suggest you save yourself the headache and just use granulated sugar or similar instead.

Can I make my own caster sugar?

To make your own caster sugar, you can process granulated sugar in a powerful food processor or blender to get a finer texture. I wouldn’t worry though as it won’t make a big difference to the final result in most baking recipes.

Why is caster sugar used in baking?

Caster sugar is often used in baking cookies, cakes, cupcakes and muffins because of it’s light texture and ability to dissolve easily. It is almost always used when baking and is rarely used raw. It is NOT used for icing, frostings or buttercream.

What is golden caster sugar?

Golden caster sugar is caster sugar that has been processed in a way that keeps some molasses (just like brown sugar), therefore giving it a slightly light brown colour and a more buttery, caramel flavour. If you don’t have it, just use regular caster sugar instead.

What is brown sugar?

Brown sugar is a partially refined sugar that has molasses added to it – hence the brown colour. The presence of molasses gives the sugar a distinct caramel flavour.

Can brown sugar be substituted for caster sugar?

This is a tricky one. In some baking recipes yes, in others, perhaps not. Brown sugar and caster sugar are different. They produce different flavours and react differently when baked. More often than not, there’s a reason the recipe writer has chosen to use a particular type of sugar in their recipe.

It’s not to say the recipe won’t work, but bear in mind, it’s likely to alter the look and taste of the final product if you don’t use the sugars that are specified in the recipe.

When a recipe says brown sugar, does it mean light or dark brown sugar?

Good question. Here in Australia, we have a product called brown sugar. It’s most commonly used in baking and is not defined as being light nor dark. However, when compared to American-style light and dark brown sugar, I would suggest it is closer to light brown sugar. It looks like this >

What is icing sugar?

Icing sugar is a very, very finely ground white sugar, that is so fine it resembles a white powder. It is often used to make frostings or buttercream for cakes.

Are caster sugar and icing sugar the same?

No. Caster sugar is NOT the same as icing sugar. Do not substitute these two sugars for each other.

Is powdered sugar the same as icing sugar?

YES. Powdered sugar, confectioner’s sugar and icing sugar are all one and the same. Here in Australia, it’s called icing sugar.

If you have any burning sugar-related questions that I didn’t answer, please leave a comment below.