Brown sugar syrup is a simple syrup made by simmering brown sugar with water (often in a 1:1 ratio) until the sugar dissolves into a smooth, pourable sweetener. Thanks to the molasses in the brown sugar, it brings warm caramel and toffee notes—sometimes boosted with a hint of cinnamon and vanilla—making iced coffees, milk teas, and specialty lattes taste deeper, cozier, and more “dessert‑like” than regular simple syrup.