Brown sugar is brown because it contains molasses , which coats the sugar crystals and gives them their dark color, deeper flavor, and slightly sticky texture.

Quick Scoop

So… what makes brown sugar brown?

  • Brown sugar starts as regular white sugar, then molasses is added back to it, which gives it that caramel color and taste.
  • In unrefined or partially refined sugars, some of the natural molasses from sugarcane is simply left in, which also creates a brown color.
  • The more molasses present, the darker and more flavorful the sugar becomes.

Light vs dark brown sugar

  • Light brown sugar has less molasses (around 3.5% by weight), so it’s milder in color and flavor.
  • Dark brown sugar has more molasses (around 6.5% by weight), so it looks darker and tastes more like toffee or caramel.
  • Natural types like muscovado can look almost black because they retain a high level of molasses.

What does the molasses actually do?

  • Molasses gives brown sugar its richer, more complex, caramel-like flavor compared to plain white sugar.
  • It makes the sugar more hygroscopic (better at holding onto water), which helps baked goods stay moist and chewy.
  • Because of the molasses, brown sugar also browns and caramelizes more readily, deepening the color of cookies, cakes, and sauces.

A quick kitchen example

  • Stir a spoonful of white sugar into hot oatmeal and you mostly get sweetness.
  • Stir in brown sugar instead and you’ll see a deeper color and taste notes of caramel or toffee—that’s the molasses talking.

TL;DR: When you ask “what makes brown sugar brown,” the answer is simple: it’s the molasses —either left in during less processing or added back to white sugar—that provides the color, flavor, and extra moisture.

Information gathered from public forums or data available on the internet and portrayed here.