Caramel and Molasses Aren't the Same Thing
I frequently come across social media discussions where it’s clear the poster and/or commenters aren’t clear on the distinction between molasses and caramel. Usually, these discussions are in the context of sweetening rum, notably the tradition of some producers lining their cask’s internal walls with caramel before adding rum for aging. Shaun Caleb of Demerara Distillers (El Dorado) discusses this practice and their recent move away from it in my 2019 interview with him.
It is true that molasses and caramel are somewhat related, but they are not the same, nor are they interchangeable.
Molasses is what remains after heating cane juice until sucrose crystals form and are removed. The thick, brown liquid contains several forms of fermentable sugars and other organic compounds.
Caramel results from heating sugar crystals to around 160°C (320°F), turning them dark. However, there are additional steps beyond that before it becomes spirit caramel, and not all spirit caramels are created equal.
In the context of distilled spirits today, most people think of spirit caramel as E150a, which is industrially manufactured in very exacting conditions. A minuscule amount adds significant coloring to a spirit with very little flavor impact. Producers use E150a only as needed to adjust the color of each batch to have a consistent color.
Long before there was E150a, rum makers made their own spirit caramel for coloring. The raw material (sugar) was usually available a few steps away at the on-site sugar mill.
In historic texts this coloring is often referred to as “burnt sugar,” and many note the importance of not overcooking it until it becomes bitter. Alexander McRae’s 1856 book, A Manual of Plantership In British Guiana, includes a great description of how it was made:
The proper manufacture of good colouring matter for rum is very important. For this purpose the best sugar should be selected and placed in sufficient quantity in a pan on an independent fire. The sugar must be constantly stirred with a wooden paddle during the action of the fire on the pan, in order to prevent its getting a singed taste or flavour ; and when it comes to a consistency, making it difficult to keep it in motion with the paddle, the fire must be withdrawn, and high wines gradually added to it under the agitation of the paddle, until it comes to a consistency of thick cream, so that the whole will be perfectly dissolved. After this, it should be put into a cask placed on end, with two cocks, one about six inches from the bottom of the cask, the other about two inches from the bottom, and allowed to remain undisturbed, in order to its depositing the sediment left in it, until it runs off from the upper cock entirely free of sediment. It may then be used for colouring the rum…
High wines in the above context essentially means high strength rum. The burnt sugar was blended with alcohol, then allowed to rest in a cask until all the sediment fell to the bottom. The liquid higher in the cask was clear and free of sediment, so suitable for coloring purposes.
Simply put, this traditional spirit caramel that rum makers made wasn’t E150a. It was less burned, which meant two things:
It had less coloring power per unit volume
Some amount of residual sugar remained
Noël Deer, in the 1911 book Cane Sugar: a text-book on the agriculture of the sugar cane, notes the above points:
When caramel is used for colouring rum, two points have to be considered; the caramel should reduce the strength of the spirit as little as possible, and give to the rum a sugary flavour. To obtain the latter effect the molasses or sugar syrup should not be burned too far, but in this case the amount of caramel required to give the necessary depth of colour so much increases the density of the spirit that there is a large apparent loss.
Deer’s reference to “reduce the strength of the spirit as little as possible” means the effect of the sugar content on the alcoholic strength as measured by a hydrometer, i.e., obscuration. The higher the sugar content, the lower the hydrometer measured strength. This was well understood; old rum purchase contracts typically allowed up to two degrees of obscuration.
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House-Made Caramel Today
Most Caribbean rum distilleries use E150a, although a few, such as Demerara Distillers Ltd. and Trinidad Distillers Ltd., continue to make their own caramel to use in certain circumstances. In fact, Trinidad Distillers, aka Angostura, make two types of caramel; one for rum and the other for their bitters.
An important point to ponder for those interested in the sugar content of rum: if a rum maker puts their house-made spirit caramel into a cask, adds rum, then ages it for several years, the rum will get sweeter over time. How so?
Sugar molecules aren’t a volatile substance, so they don’t evaporate to the angels like ethanol and water do. Consider a newly filled, caramel-lined cask with a hypothetical sugar content of 3 grams/liter. That cask then ages for 15 years with a 7% angel’s share rate. Our online calculator indicates that around 33% of the liquid remains. However, all the original sugar remains, making the sugar content 9 grams/liter.
Molasses and spirit caramel aren’t the same thing and should not be confused with one another. I’m unaware of any historical practice of adding molasses to aging casks—if you have a reference, let me know! Nor am I aware of any current rum brand adding molasses to their rum other than Cruzan Black Strap. Hopefully, the above sets the record straight and creates a reference for future discussions. Let me know your thoughts in the comments!