
Caramel syrup is a sweet syrup whose flavor and color come from caramelized sugar.
Making it takes ten minutes: melt sugar to a deep amber and stop the cooking with hot water, off the heat, at arm’s length. Demerara or dark cane syrup gives a molasses sweetness instead of a burnt one, which is close and not the same. Maple is warmer and more distinctive.
Caramel sauce
Thickened and usually enriched with butter or cream, so it coats instead of dissolving; in a cold drink it stays in strings.
Butterscotch syrup
Brown sugar and butter rather than caramelized white sugar: softer, sweeter, faintly dairy. The drink reads as dessert where caramel read as roast, and it wants about a third less.
A commercial bottle keeps for months and wants the fridge once open. Homemade lasts a couple of weeks refrigerated and may crystallize, which a gentle warming reverses.