Brown sugar doesn’t always behave. One day it’s perfectly soft and scoopable; the next, it’s a solid, unyielding block. Why does this happen, and how should you store brown sugar to avoid hard lumps?

We’ve all opened a long-ago purchased box of brown sugar only to find it has turned into a brick. No amount of banging it against the counter will return it to its once supple, wet sand-like texture.