Molasses is a viscous by-product of the processing of sugar cane or sugar beets into sugar. The word molasses comes from the Portuguese word melaço, which ultimately comes from mel, the Latin word for "honey". The quality of molasses depends on the maturity of the sugar cane or sugar beet, the amount of sugar extracted, and the method of extraction. Sweet sorghum syrup is known in some parts of the United States as molasses, though it is not true molasses.
Sulfured molasses is made from young sugar cane. Sulfur dioxide, which acts as a preservative, is added during the sugar extraction process. Unsulfured molasses is made from mature sugar cane, which does not require treatment with sulfur. There are three grades of molasses: mild or barbados, also known as first molasses; dark, or second molasses; and blackstrap. These grades may be sulfured or unsulfured.
To make molasses, the sugar cane plant is harvested and stripped of its leaves. Its juice is extracted from the canes, usually by crushing or mashing; it can also be removed by cutting. The juice is boiled to concentrate it, which promotes the crystallization of the sugar. The result of this first boiling and of the sugar crystals is first molasses, which has the highest sugar content because comparatively little sugar has been extracted from the source. Second molasses is created from a second boiling and sugar extraction, and has a slight bitter tinge to its taste.
The third boiling of the sugar syrup makes blackstrap molasses. The majority of sucrose from the original juice has been crystallized and removed. The calorie content of blackstrap molasses is still mostly from the small remaining sugar content. However, unlike refined sugars, it contains trace amounts of vitamins and significant amounts of several minerals. Blackstrap molasses is a source of calcium, magnesium, potassium, and iron; one tablespoon provides up to 20% of the daily value of each of those nutrients. Blackstrap, often sold as a health supplement, is also used in the manufacture of cattle feed and for other industrial uses.