Brown sugar gets its distinctive color and flavor from the presence of molasses. It may be either unrefined or partially refined, so that it naturally retains molasses, or it may be produced by adding molasses to refined white sugar. The latter method is more common in commercial brown sugar. In addition to its brown color and rich flavor, brown sugar differs from white sugar in its consistency, which is finer, softer, and moister.

Natural brown sugar, or raw sugar, is unrefined and minimally processed, produced from the first crystallization of sugar cane juice. It gets its color and flavor from the sugar cane itself, rather than from any additional ingredients. Natural brown sugar is often darker and has a stronger molasses taste than other types of brown sugar, and it also contains more minerals. Raw sugar from different parts of the world often takes on the unique taste of the plants it is extracted from.

Most brown sugar for sale in supermarkets is simply refined sugar with molasses added. The amount of molasses determines whether the sugar is light brown sugar or dark brown sugar - consisting of 3.5% and 6.5% molasses respectively. The type of brown sugar used in a recipe is usually a matter of personal preference.

Brown sugar is notorious for clumping after the package is opened and has been on the shelf for a while, as it begins to dry out. This can be prevented by keeping it in an airtight container. However, if your brown sugar is hard as a brick, you can restore it to a usable consistency by placing it in a tightly sealed container with an apple wedge for one to three days. Alternatively, you can purchase a terracotta disk at many kitchen supply stores that will keep your brown sugar free flowing, or you can liquefy brown sugar in the microwave before adding it to a recipe. If all these methods are too much trouble for you, you can now buy brown sugar in granulated or liquid form, neither of which will ever clump.