Brown sugar is a mixture of granulated white sugar and liquid molasses. The more molasses you have the deeper your color will be. Keep in mind that it will also be less sweet. The moisture from molasses causes sugar granules to swell slightly, so a cup of brown sugar contains fewer plumper sugar crystals than a cup of granulated white sugar. Since it is the sugar crystals, not the molasses that gives brown sugar its sweetness, brown sugar is typically packed into a measuring cup to give it a similar number of sugar crystals along with the sweetness, as the same volume of white sugar.
Light brown sugar is about 10% molasses, and dark brown sugar is closer to 20% molasses. If you don’t have brown sugar you can make some by stirring molasses into granulated white sugar.
•To make light brown sugar, stir 1 1/2 tablespoons molasses into 1 cup granulated white sugar.
•To make dark brown sugar double the amount of molasses.
•Turn light brown sugar into dark brown sugar by adding 1 tablespoon molasses to 1 packed cup light brown sugar.
•Turn dark brown sugar into light brown sugar by blending equal amounts dark brown sugar and granulated white sugar.