
Brown sugar syrup is a liquid sweetener made by dissolving demerara sugar in water, most often in a rich ratio for a heavier body.
Sweet with a mild caramel and molasses note, and a fuller, heavier body than a plain sugar syrup.
Stirred or shaken into the build as an accent sweetener, it adds both sweetness and body; because the rich ratio makes it more viscous than 1:1 simple syrup, an equal volume delivers more sweetness, so it is dosed sparingly and not swapped one-for-one against plain simple syrup.
Another molasses-tinted cane-sugar syrup built at a rich ratio covers its sweetening, added body, light-brown colour and caramel note; a plain white-sugar syrup matches the sweetness only if a little molasses is added and the ratio raised to rebuild body and colour.
Muscovado syrup
Demerara sugar is a partially refined, large-crystal, pale-brown cane sugar with modest residual molasses; muscovado is an unrefined, fine, dark, moist cane sugar with much higher molasses content, yielding a darker, more strongly molasses-flavoured syrup.
Bartenders dissolve demerara sugar — a partially refined, large-grained cane sugar that keeps some of its molasses — in water, commonly at a richer 2:1 sugar-to-water ratio than plain simple syrup. The retained molasses gives the finished syrup a light-brown colour absent from white-sugar syrup.
As a sugar-and-water solution it can ferment or mould over time; refrigerate and use within a few weeks.

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