The Fermentation process yields ethanol and other alcohols and pot still distillation, in particular, reveals this note. Column still distillation separates the notes extremely efficiently and so the column still process typically produces a lighter, less characterful, liquid. Fusel Oil is associated with the “tail” of the distillation and some Rum blenders add back these fusel notes to the lighter mix in the first stage in the column to give more character and body. However this does not always integrate smoothly and therefore becomes a prominent note as compared to the pot still distillation of rums where the fusel note is more diffused into the mix and is therefore less prominent.
The full rum aroma story is actually more complex as the Fusel Oil also contains minute quantities of exceeding powerful key impact odorants (KIOs) which also nuance the aroma profile.
This is an important aroma in the Rum Aroma Kit as we often are asked – What does a typical Fusel Oil aroma actually smell like?
See our Rum Aroma Kit for more information.