Unlike flour, which you should never pack, brown sugar should always be packed firmly into the measuring cup. This is one of the few cases in baking where "compressed" measurement is intentional and correct.
Why Brown Sugar Is Measured Packed
Brown sugar contains molasses, which makes it moist and sticky. Unlike granulated sugar, it does not pour freely — it clumps together, leaving large air gaps if spooned loosely. Packing it down removes these air gaps and gives you a consistent, repeatable measurement.
When a recipe says "1 cup packed brown sugar," it means pressed firmly enough that it holds the shape of the cup when turned out. This is what recipe developers used when they tested the recipe.
How to Measure Brown Sugar
- Scoop brown sugar into the measuring cup.
- Use your fingers, the back of a spoon, or the bottom of another cup to press it down firmly.
- Add more sugar and press again until the cup is full and level at the top.
- When you turn it out, it should hold the cup's shape momentarily before crumbling.
Packed vs. Unpacked: How Much Difference Does It Make?
Packing brown sugar significantly increases its density. Loosely spooned brown sugar weighs about 160–170g per cup, while firmly packed brown sugar weighs about 220g. That's a 30% difference — more than enough to noticeably affect a recipe.
The Scale Solution
To avoid all ambiguity, use a kitchen scale. Recipes that provide gram weights for brown sugar always mean packed. 1 cup packed brown sugar = 220g.
Soft vs. Hardened Brown Sugar
If your brown sugar has hardened into a rock, place a slice of bread or a few apple slices in the bag and seal it overnight. The sugar absorbs moisture and softens. Alternatively, heat it in a microwave-safe bowl covered with a damp paper towel for 20–30 seconds at a time.