[header] How to keep brown sugar soft [title] Store brown sugar in an airtight container. [step] Brown sugar tends to get hard due to air exposure. If you want to keep brown sugar soft, you're best option is to store your brown sugar in a sealable, airtight container as soon as you open it up. 
[substeps] Limit air exposure as much as possible when storing brown sugar. Choose a smaller container and pack the brown sugar to the top.