Demerara sugar
Large, hard, pale-brown crystals that do not dissolve readily — which makes it a topping sugar rather than a baking sugar.
Also called raw sugar (US); turbinado sugar (US); golden granulated (UK); can you bake with demerara sugar (UK)
Demerara is a partially refined cane sugar with a thin film of molasses left on large, hard crystals. It is often shelved beside soft brown sugar and behaves nothing like it.
SOFT BROWN SUGAR is fine-crystalled and moist, with molasses distributed throughout. It creams, it dissolves, and it brings acidity and moisture into a mixture.
DEMERARA is coarse and dry. The crystals resist dissolving, and they are hard enough to survive a bake intact — which is exactly why demerara is used on top of things: a crunchy, glittering crust on a loaf cake or a biscuit that would be lost with any other sugar.
Used INSIDE a mixture it is usually a mistake rather than a substitution. In a creamed cake it does not aerate well and can leave gritty patches; in a shortbread it gives an uneven crunch. Where a formulation is wet enough and cooked long enough to dissolve it — a syrup, a wet fruit cake — it works and contributes a mild toffee note.
Turbinado and most sugars sold as 'raw' are the same class of product under other names.
What changes if it is left out
For a crunchy topping there is no good substitute — every finer sugar dissolves. Inside a mixture, soft brown sugar gives the flavour and behaves far better, which is usually what the recipe wanted.
Follows from the crystal-size and dissolution behaviour described above and from the brown sugar record.
RecordedFollows from evidence recorded elsewhere on BakeHQ
Related
What it does
Flavour contribution
A thin film of molasses on a hard crystal, giving a mild toffee note — and crystals hard enough to survive a bake, which is what it is really for.
Covered in
The sugars, and when the difference matters
Hard crystals that survive a bake, which is what makes it a topping sugar.
Compared in
One side of the comparison.