
Brown sugar syrup is brown sugar dissolved in water, usually at a rich 2:1 ratio for extra body.
It sweetens like plain syrup and adds a molasses depth, which is why it suits rum, whiskey and spiced drinks, hot or cold.
Demerara syrup
The closest swap at 2:1, one for one. It keeps some of its own molasses.
Plain 2:1 sugar syrup
It carries about 0.89 g of sugar per milliliter. Works in the same amount but loses the molasses note.
Plain 1:1 sugar syrup
It carries about 0.62 g of sugar per milliliter. Use about 1.4 times the measure to replace a 2:1 syrup, or about 70% going the other way.
Carries slightly less sugar per milliliter than 2:1 and can take its place, though it tastes of maple.
Refrigerated, sealed, a couple of weeks. A richer syrup keeps longer because there is less water in it, and any syrup that has clouded or thrown threads has gone.
Hot Toddy (brandy)
Cognac