Blackstrap molasses, or simply blackstrap, is the dark, viscous molasses remaining after maximum extraction of sugar from raw sugar cane. This residual product of sugar refining is used in the manufacture of ethyl alcohol for industry and as an ingredient in cattle feed. The term is an Americanism dating to around 1920.
The third boiling of the sugar syrup yields blackstrap molasses. The majority of sucrose from the original juice has been crystallized. The calorie content of blackstrap molasses is still mostly from the small remaining sugar content.[1] However, unlike refined sugars, it contains significant amounts of vitamin B6 and minerals, including calcium, magnesium, potassium, and iron; one tablespoon provides up to 20% of the recommended daily value of each of those nutrients.[2][3]
Blackstrap has long been sold as a health supplement.