Dark brown sugar is sugar which contains at least six and a half percent molasses. It has a distinctive dark brown color and rich molasses flavor, and it is also very high in moisture. In cooking, dark brown sugar is used in recipes where a deeper sugar flavor is desired, and some people also enjoy the flavor in tea, coffee, and other drinks. Many markets sell dark brown sugar, along with its closely related cousin, light brown sugar, which contains three and a half percent molasses.
There are two ways in which a sugar refinery can produce dark brown sugar. In the first case, the refinery adds molasses to processed white sugar until the correct percentage is reached. The sugar may also be amended with stabilizers to make it easier to pour, and to reduce clumping. The technique of adding molasses can also be used at home by cooks who need brown sugar, by adding one and a half tablespoons (22 milliliters) of molasses for every cup (190 grams) of white sugar.
Other refineries make dark brown sugar by simply minimally refining their sugar so that all of the molasses is not taken out. Natural brown sugar is made by saving the first pressing, producing a dark brown crumble which is high in molasses, while minimally refined forms may be rinsed so that they are encouraged to crystallize, making them easier to work with.
When working with brown sugar, it is important to be aware of the higher moisture content. Swapping brown and white sugar in a recipe can have undesirable consequences, because the change in moisture content may throw the recipe off. Recipes which call for brown sugar may turn out dry if white sugar is used, while white sugar recipes can turn overly moist if brown sugar is used. It is also critical to store dark brown sugar in a cool dry place in an airtight container so that it does not meld into a solid mass.
Some recipes call for a mixture of brown and white sugar, tempering the intense flavor of the brown sugar with the more neutral white sugar. People who like a more intense brown sugar flavor can use dark brown sugar in these recipes, while light brown sugar can be used for a milder effect. Dark brown sugar will also cause baked goods to darken, as people who have experimented with different types of sugar may have already noted.