Caster Sugar (UK) substitutes
The best substitute for caster sugar (uk) is blitzed granulated sugar: Blitz granulated sugar in a blender or food processor for 10 to 20 seconds, then let the dust settle before opening. This is exactly what caster sugar is. Do not over-blitz, or you drift towards icing sugar, which behaves quite differently.
Why it matters. Sugar milled finer than granulated but coarser than icing sugar. The small crystals dissolve fast, which is what lets a meringue turn glossy and a creamed sponge hold air. Granulated will work but leaves grit in delicate mixtures.
BestBlitzed granulated sugar
●●●●●Blitz granulated sugar in a blender or food processor for 10 to 20 seconds, then let the dust settle before opening
Keeps the sweetener, texture and tenderizer roles.
This is exactly what caster sugar is. Do not over-blitz, or you drift towards icing sugar, which behaves quite differently.
Superfine or baker's sugar
●●●●●1:1
Keeps the sweetener, texture and tenderizer roles.
The American name for the identical product. A naming difference rather than a substitution.
Golden caster sugar
●●●●●1:1
Keeps the sweetener, texture and tenderizer roles.
Unrefined, so it carries a faint caramel note and tints pale bakes cream. Behaves identically in every other way.
Granulated sugar
●●●●○1:1 by weight
Keeps the sweetener, texture and tenderizer roles.
Larger crystals that dissolve more slowly. Cream it an extra minute or two and most cakes are fine, but a meringue stays gritty and is more likely to weep.
Blitzed coconut sugar
●●●○○Blitz it fine, then use 1:1 by weight
Keeps the sweetener, texture and tenderizer roles.
Darker, drier and slightly less sweet, so it browns the bake and leaves a sandier crumb. No good where you need a pale colour.
Light brown sugar
●●●○○1:1 by weight
Keeps the sweetener, texture and tenderizer roles.
Adds moisture, caramel flavour and a little acidity, so a soda-leavened bake rises more and the crumb is chewier and darker. Wrong for meringue or a pale sponge.
Icing sugar
●●○○○1 3/4 cups icing sugar per 1 cup caster sugar, or match by weight
Keeps the sweetener and tenderizer roles; loses texture.
Contains cornflour and dissolves instantly, so a creamed batter traps far less air and the crumb turns dense. Meringues made with it come out soft rather than crisp.
Other sugar substitutes
Measuring by weight instead? Use the kitchen converter.