"Dunder" and "funk" may be two of the most misused terms in rum, and I'm afraid we have years to go before these are understood. It's like "rhum agricole" which is nothing more than rum made from cane juice, and which should properly be referred to as "cane juice rum". For all practical purposes "cane juice rum" was born in Haiti nearly 200 years ago. Back then the rest of the French Islands - including Martinique - made rum just like everyone else, from molasses.
It was not until sugar beets killed the cash cow of Caribbean sugar, that Martinique - very reluctantly - turned to cane juice out of financial pressure - an act which had nothing to do with quality or artistry. And it wasn't until the early 1990's - little more than 20 years ago that they cooked up the marketing ploy of creating the term "Rhum Agricole AOC Martinique" under the pretense that sugar cane actually had a terroir, and secondly that rum made by voluminous regulations was somehow superior to all others.
The truth? "Rhum Agricole" is a marketing invention, and a recent one at that. Back to "dunder".
Regardless of the this term being thrown around like a frisbee at a dog park, the real, honest and historical term emanates from the style of rum pioneered in Jamaica and which used "dunder". The real stuff. And just what is that "stuff"? It's the leftovers from distilling that were dumped in large open pits called "dunder pits" and left there for many years. These dunder pits were often over 30 years old, and over that long time and exposure to the elements became very, very nasty - but - also incredibly rich in flavor compounds and precursors as the contents combined and recombined. The magic?
The magic was that the Jamaicans uniquely decided to dip out some dunder to be added to new ferments, and thus introduce hundreds upon hundreds of new and potential esters to their rums. How many? Most of what you think is rum may have between 30 to 50 esters. A Jamaican rum? Think a thousand. In fact this whole process of dunder produced esters was so important that Jamaica legally classified their rums by the number of esters, another subject.
No other country or producers did this. And "this" is dunder from the dunder pits. Kindly ignore any other frisbees that fall nearby. This is the real dunder, and this is what you should be thinking when you use the term. What "dunder" is not, is Lost Spirits tossing an overripe banana into their ferment for 2 days. That my friends, is a very bad and misleading joke. Now - a quick word about "funk".
What is funk? Some mistake it for an extension of the word "funky" - like taking a whiff of yesterday's jock strap. Funky! But before you think I'm kidding, I've seen the word used by any number of sweet bomb loving rum drinkers who run across a rare unaltered rum that lacks added sugar and vanilla. To them such a rum is dry, leathery, perhaps with a bit must or tar that then gets described as "funk". If not true then just what is real "funk".
Dunder-produced Jamaican rums. What "funk" really describes is the tremendous complexity of a dunder-based rum, with not just 30 esters, but perhaps a thousand. Because of their number, age, and unexpected qualities these rums exhibit what is called "funk", but which would better be called "dunder". In fact, this complex aroma is so distinctive that its presence is easily noted, and indeed almost defines Jamaican style.