There are three types of molasses, light, dark, and blackstrap, which are categorized depending on how they are processed. After the first boil that removes most of the white sugar the molasses may be boiled several more times to remove additional sugar. This concentrates the molasses and its nutrients, making it darker and thicker. Light molasses has only been boiled once, making it light, thin, and very sweet. Dark molasses has been boiled twice to make it darker, thicker, and less sweet. Finally, blackstrap molasses, the lowest grade, has been boiled three times or more. It is very thick and dark and has a rather bitter taste. High quality kinds of molasses, such as Barbados and New Orleans drip, are light molasses that have been boiled only once.
Molasses is either designated as "sulfured" or "unsulfured" depending on if sulfur was used during the processing of the molasses. Sulfur dioxide gas is used both as a preservative and a bleaching agent. It is thought to remove some nutrients like vitamin A and B from the molasses. The sulfur may also give the molasses an unpleasant odor and cause an allergic reaction in some people. Unsulfured molasses (which I prefer) tends to be lighter and have a cleaner sugarcane flavor than sulfured. Most brands of molasses will indicate whether they are sulfured or not.
Molasses is used in a variety of foods. Light and dark molasses can be substituted for each other in recipes, giving either a light or deep molasses flavor to the dish. Both types are used in savory dishes like BBQ sauce and Boston baked beans. They are also used in sweet dishes like gingerbread, Indian pudding, shoo-fly pie, and molasses cookies. Molasses is acidic, so it is often combined with a base like baking soda to help baked goods rise. Additionally, light molasses is often used as syrup for pancakes and waffles while dark molasses is also an ingredient in rum and some kinds of homemade beer (check out Homebrewing 204: Alternative Sugars). Blackstrap molasses is not normally eaten but instead is used in cattle feed and for making industrial alcohol. Some people think that blackstrap is healthier than the other types of molasses, but the extra nutrients it contains are negligible.
