Icing sugar vs. Icing sugar mixture

Q: What is the difference between pure icing sugar and icing sugar mixture?

A: Icing sugar is sold as both pure icing sugar and icing sugar mixture (also called soft icing sugar). The only difference between them is that icing sugar mixture has a little cornflour added to prevent it from forming lumps if it gets moist. This is why pure icing sugar is more likely to form hard lumps on storing.

They are interchangeable but pure icing sugar is the best choice if you are making an icing, such as royal icing, that you want to set as the added cornflour in soft icing sugar will stop the icing from setting.

However, soft icing sugar it’s a great one to use in all other icings or bakes as it easier to sift when preparing a recipe due to its non-lumping nature.