Molasses is a byproduct of the process of refining sugar cane into sugar. It is a thick syrup, dark in color, with a very strong sweet and somewhat bitter flavor. It is frequently used in baking and it is particularly popular in recipes for spice cookies and cakes, where it adds a lot of brown sugar flavor without making a recipe too sweet. Like honey, molasses attracts moisture and recipes that use it will tend to stay more moist for longer periods of time. This is an especially great feature for spice cookies and cakes, where the flavors of the spices will develop more over time when a recipe can be prepared a day or two in advance.
When sugar cane is processed into sugar, the sugar cane is pressed to extract all of the sugar-juice from the plants and this syrup is boiled to promote the formation of sugar crystals. There are three types of molasses – light, dark and blackstrap – and the boiled liquid from the first press of sugar cane is light molasses. It is sweeter and less dark in color than the other two. Dark molasses is formed when the boiled sugar cane juice is boiled again. Blackstrap molasses is the result of the third, and final, boiling of the sugar cane juice. It is the thickest, darkest and least sweet molasses. Molasses can be sulphured or unsulphured, as sulphur was often added to molasses as a preservative in the past, as well as to kill unwanted bacteria and to help whiten the resulting sugar crystals, although it is uncommon now.
Most molasses used in baking is unsulphured, light molasses – even if the labels don’t specifically say (like the molasses above). Dark molasses and blackstrap molasses are usually labeled as such, or are described as “robust” to emphasize the fact that they have a stronger flavor. The three are interchangeable in baking, although most recipes that call for molasses (unless otherwise specified) assume that you will be using the sweeter, milder light molasses. Feel free to experiment with other molasses varieties in your baking and cooking if you’re looking for a darker flavor. If you’re looking for an even lighter flavor, maple syrup and agave syrup can often be substituted for part of the molasses called for, as well.