“Brown sugar was apparently a brick in a previous life, and it keeps trying to revert back to that state,” says small h. But what do you do about petrified brown sugar?
For a quick fix, 20 to 30 seconds in the microwave will do the trick, says Emme. This is just a temporary fix, though—the sugar must be used immediately after heating, or it will revert back to its rock-hard state.
For a more permanent answer, moisture must be added back into the hardened sugar. Seal hard sugar with something moist, like a slice of apple, a piece of bread, or even a damp paper towel. The sugar will suck all the moisture out of the wet item, and be good as new in a day or two, says mcsheridan.
kchurchill5 offers a low-tech solution: “I usually just whack it with my meat mallet and it is fine.”
Board Link: Brown Sugar
Just seal the bag of commercial brown sugar and keep it in the humid part of your frig. You will never have a problem. I promise.
The apple slice works fine for me. Just don’t leave it in there too long. The brown sugar I buy from the farmer’s market seems to stay soft longer on its own than the commercial, grocery store brands.
i've seen people put a piece of terracotta (they make disks specially for this) in their brown sugar to keep it soft.