Esters and Jamaican Rum
In our prior post, Where Does Rum Flavor Come From, we learned that the aromas and tastes in a rum originate from numerous organic compounds touching our olfactory sensors. Among the compounds are many permutations of acids, alcohols, and aldehydes, but it’s esters that make a rum geek’s heart beat faster, especially when it comes to Jamaican rum. To understand the particularly strong connection between esters and Jamaican rums, we must go back several centuries.
Marks/Marques
When European blenders started importing Caribbean rum in the 1700s, they purchased rum from many distilleries and assembled them into blends that customers enjoyed. The blenders referred to specific rums from a distillery as a mark or marque. Each mark was named with a short sequence of letters and symbols, for example, “VRW” or STC♥E. Blenders trusted that two casks with the same mark tasted similar, even if made years apart. Certain marks were particularly favored by blenders and commanded a higher price.
By the 1830s, rum made at the Jamaican estates of the Plummer and Wedderburn families became particularly popular. These “Plummer rums,” or “Wedderburn rums,” commanded prices substantially higher than other Jamaican rums.
Common Clean / Continental / German Rums
Fast forward to the late 1800s when chemists had proven that a rum’s esters contributed a substantial portion of a rum’s flavors. Naturally, they used lab testing to measure the quantity of esters present in various rums, and to no surprise, Jamaican rums had much higher ester levels than rums made elsewhere. Thus, two more classes of Jamaican rum joined Plummer and Wedderburn rums in the rum trade. The first was Common Clean rum, lighter than Plummer or Wedderburn rums but still with more punch than rum made elsewhere.
The final category of Jamaican rum resulted from economic reasons due to an unlikely source: German tax laws. By the 1880s, German blenders were avoiding high import taxes on foreign spirits by importing the most flavorful Jamaican rums to adulterate with inexpensive neutral spirits. Jamaican rums with higher ester levels could be blended with more neutral spirits, up to 20 parts neutral spirit to one part of Jamaican rum. These adulterated rums were known as rum verschnitt.
Rums with the highest ester levels commanded higher prices from German blenders, so some Jamaican distilleries focused exclusively on making high-ester rum for the German market. Such rums were known as flavoured rum, German rum, or continental rum. Due to significant scientific research, Jamaican distilleries could make rum with astronomically high ester levels, as high as 7000 gr/hlAA. (See our previous story for an explanation of gr/hlAA.) Nobody drank these rums neat; they were for blending purposes only.
Mark Ester Ranges
By 1947, the above four categories of Jamaican rum were associated with ester level ranges. The Jamaican chemist J. R. McFarlane noted them as follows:
● Common Clean: 80-150 gr/hlAA
● Plummer: 150 — 200 gr/hlAA
● Wedderburn: 200 — 300 gr/hlAA
● Flavoured: 700 —1600 gr/hlAA
The above ester level ranges are for newly distilled, unaged rum. While aging can increase a rum’s ester levels, it won’t make a common clean rum into a Plummer rum. In 1935 the Jamaican Spirits Pool established a maximum ester level of 1600 gr/hlAA to prevent only certain distilleries from receiving all the rum orders. This limit remains in effect today.
Modern Times
Today, nobody uses Plummer, Wedderburn, or the other categories other than for marketing purposes. Instead, each Jamaican distillery has its own unique set of marks, each with a designated ester range. For example, Hampden Estate is famous for its HLCF (500-600) and DOK (1500-1600) marks, while Long Pond is famous for its VRW (150-250) and STC♥E (550-700) marks. While distilleries rarely disclose their full set of marks or what the initials mean, Cocktail Wonk’s mark page contains background information on the several dozen marks used by Jamaica’s six operating distilleries.
