
Demerara syrup is a liquid sweetener made by dissolving raw demerara cane sugar in water, usually at a rich 2:1 ratio.
It sweetens with a light molasses note that white syrup lacks, enough to show in rum, whiskey and tiki drinks without making them heavy. At the usual 2:1 it is about 1.4 times as sweet per milliliter as a 1:1 syrup. A recipe written for 1:1 syrup needs less of it.
White 2:1 simple syrup
The easy swap at the same amount. It loses only the light molasses note. If your syrup is 1:1, use about 1.4 times as much.
Light brown sugar syrup
Makes a close syrup at the same ratio.
Homemade demerara syrup
Stir 2 parts demerara sugar into 1 part hot water by weight until it dissolves.
Gum syrup
Works one for one.
Keep it sealed in the fridge, where a month is realistic. A rich syrup keeps longer than a 1:1 because it has less free water for anything to grow in. Clouding or threads mean it has gone.