Brown sugar is simply white sugar to which a molasses syrup has been added. The darker the sugar, the more molasses has been added. Molasses is a byproduct of the sugar refining process that is originally removed. In brown sugar, the molasses just coats the outside of the sugar crystals so it is like a moist sticky glue that surrounds each and every grain of sugar. This is why brown sugar can be packed together and will hold its shape somewhat.
Why Does Brown Sugar Get Hard?
It is the moisture in the molassses that keeps this ‘glue’ soft. But, when brown sugar is exposed to air, the moisture evaporates and the molasses syrup hardens and sticks together a bit like hard candy. This forms a rock-hard lump that can be almost impossible to completely break up.
Keeping Brown Sugar From Hardening
To prevent brown sugar from drying out and hardening, it has to be stored in an airtight container. A sealed plastic bag is best, but any airtight container is fine. As long as you can keep the moisture in, the brown sugar will not harden. Storing brown sugar in the refrigerator, which is a moist environment, can help keep it soft, but this is not necessary if you have a good container.
If your brown sugar does harden, the way to soften it again is to get moisture back into it. Fortunately, sugar crystals attract moisture to themselves so this is absolutely doable. The first two methods given here take longer, and are for fixing brown sugar that you aren’t in a big hurry to use. The last method is a quick fix for immediate, or almost immediate, use.
1. Wet Towel Method to Soften Brown Sugar
One good method for getting moisture back into hardened brown sugar is to drape a moistened towel or paper towel over the sugar container and leaving it there fro about 12 or so hours. The sugar will draw the moisture in from the towel and soften back up. Once the sugar is softened again, seal it up good and tight.
2. Slice of Bread Method
Place a nice fresh slice of bread in the sugar container and seal it in with the sugar. The moisture from the bread will be drawn into the sugar so the brown sugar will soften back up. For a large amount of sugar you might want to use more than one slice. Fresher bread has more moisture, so don’t use an old stale slice.
3. Heating in Oven Method
Unlike the other methods, this quick-fix method is only temporary. Place the sugar in a heat-proof container and heat it in 250 to 300° F oven (121 to 149° C) for a few minutes, until soft. You can also heat it briefly in a microwave. This will soften up your brown sugar but try not to overheat it. The first two methods are preferred. Heating the sugar does not put moisture back into it but rather begins to melt the molasses syrup that is binding the sugar together, temporarily making it pliable again. Once it cools back down it will begin to harden up again.