Gingerbread desserts owe much of their deep, complex sweetness to molasses. True molasses is a byproduct of sugar cane processing. Sugar cane juice is boiled, crystallized, and then centrifuged to separate the crystallized cane sugar from the liquid. That leftover liquid is molasses; it can be refined and processed as is, or it may be boiled up to two more times to produce different grades of sweetness and intensity. Three basic grades exist, but producers use several different terms to refer to them.
Light, mild, Barbados, or robust molasses has been boiled only once. It has a high sugar content and a mild flavor, and it can be used directly on foods as a syrup. Some brands of single-boil molasses haven’t even had any sugar removed from them—they’re simply refined sugar cane juice that’s been reduced to a syrup. A widely distributed brand of this type is Grandma’s Original, and it’s what we used to test the gingerbread dessert recipes.
Dark, full, or cooking molasses has been boiled twice. It’s slightly bitter and less sweet than single-boil molasses. It’s typically used for baking and cooking.
Blackstrap molasses has been boiled three or more times. It has the deepest, most intense flavor of the three. It is generally used for animal feed, although some people prize it for its nutritional value.
The preservative sulphur dioxide is often added to molasses. It alters the flavor somewhat, so use unsulphured molasses when you can.