The Many Faces of Molasses

It started as a simple question: can you substitute blackstrap molasses for regular molasses in a gingerbread recipe?

In order to reduce our potential exposure to Covid, we are ordering groceries online and having them delivered. Whole Foods (owned by Amazon), delivers free to Amazon Prime customers like us. In our order the other day we included molasses. We are almost out, and I wanted to make a gingerbread recipe this holiday week. The bottle that arrived yesterday along with the rest of our order says “Blackstrap Molasses”. Hmm, I wondered, what is different about blackstrap molasses and can you use it in place of the usual Grandma’s molasses that we have always had in our cupboards?

Once I get reading on a topic, it is hard to stop. It turns out there is much to know about molasses (treacle, in the U.K.). We all know it to be a sweet, flavorful ingredient in baked goods, and in savory dishes like pulled pork and baked beans. Diluted molasses is touted as a hair de-frizzer and hair mask, and there are even claims it can help combat gray hair.

However, there is a decidedly unsavory side to its past. It played a key role in fueling the triangular Atlantic slave trade in the 1700’s and early 1800s. Plantations worked by slaves in the Caribbean would ship molasses to the American colonies, where it would be converted into rum. The rum was shipped to West Africa, to pay for more people to be captured and then shipped to the Caribbean plantations to grow more sugar and make more molasses.

Not to mention the deadly “Great Molasses Flood” in Boston. On January 15, 1919, a 50-ft high storage tank of molasses ruptured, and sent a 15-ft high wall of syrup racing through the street at 35 miles an hour. It crushed and drowned anything and anyone in its path. Buildings were collapsed, and 19 people died. It has a place in the history of litigation as the birthing the modern class action lawsuit.


But I digress. Back to the difference since between types of molasses. Sugarcane is squeezed to extract cane juice. Sugar, the main desired product, starts off dissolved in the juice. The cane juice is boiled to remove water, to precipitate the solid sugar crystals. The liquid that remains after the first boiling (and the removal of the sugar from that stage) is called first or light molasses. That is what has usually been sold in U.S. grocery stores.


That first molasses is subjected to a second boiling, to extract even more sugar. The remaining liquid is called second molasses, or dark or robust molasses. From all accounts, this is pretty similar in properties to the initial light molasses, just somewhat less sweet and more flavorful. Folks say that you can substitute dark molasses for light molasses in most recipes without making a big difference.

To extract the last little bit of sugar, the second molasses is boiled even longer and hotter. After the sugar from that stage has been removed, what is left is the so-called blackstrap molasses. Obviously, this product will have less sugar and less liquid, then the light molasses, with a higher concentration of the other flavoring components. The operational question for me is: Can I take some of that blackstrap molasses and simply re-dilute it with some sugar and some water to get the equivalent of light molasses?


Internet opinion on this matter is mixed. On the one hand, there are those who answer this question in the affirmative. They say that a half cup of blackstrap molasses plus half cup of light corn syrup (or half a cup of a water plus sugar mixture) can readily be substituted for a cup of light molasses.

On the other hand I read counsel such as this:

Blackstrap molasses is what results when regular molasses is boiled down and super-concentrated, This results in bitter, salty sludge that only has a 45 percent sugar content, as opposed to the 70 percent sugar level found in both light and dark varieties of baking molasses. Spoon University warns against using blackstrap molasses as substitute for true molasses in any recipe calling for the latter due to the fact that its bitter flavor will overpower the taste of whatever you’re making.

And this :

Do not use blackstrap molasses as a substitute for light or dark molasses. It has a strong, bitter taste and isn’t very sweet. It’s more likely to wreck your recipe than help it.

But still I (being a chemical engineer by trade) wondered if this “strong, bitter” taste is merely the lack of sugar, which could be cured by replacing the missing sugar. After all, unsweetened chocolate is unpalatably bitter, but we fix that by adding sugar.

I don’t claim the final word on this, but it seems that the severe third boiling that yields the blackstrap molasses does some chemical alterations. It is not merely a matter of removing sugar. It is all well when sugar is lightly heated to form light brown caramel, but when it gets pushed too far, some bitter, dark brown compounds can form. It is not clear that merely adding sugar can undo these flavors, considering that blackstrap still contains a lot (45%) of sugar.

Conclusion: Blackstrap molasses may be fine for your BBQ sauce and as a trendy, mineral-packed low-sugar sweetener for your yoghurt and tea. But that bottle of thick black goo on my counter is going back to Whole Foods, not into my gingerbread.

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