Influence of the Production Process on the Key Aroma Compounds of Rum: From Molasses to the Spirit

The production of rum consists of fermentation, distillation, and aging. To check the influence of each step on the final rum aroma, molasses, mash, distillate, and the final rum were analyzed using the sensomics concept. The changes in key aroma compounds were determined by application of aroma extract dilution analysis (AEDA) in combination with gas chromatography-mass spectrometry for identification and by stable isotope dilution assays (SIDAs) for quantitation. Odor activity values (OAVs; ratio of concentration to respective odor threshold) were calculated for the compounds determined in the rum and, finally, the rum aroma was successfully simulated by recombination. (E)-β-Damascenone showed by far the highest OAV (3280) in rum. Although this compound was determined already in molasses, its concentration increased significantly during distillation, indicating a thermolabile precursor. Vanillin, 4-ethylphenol, 2-methoxyphenol, 4-ethyl-2-methoxyphenol, and 2-methoxy-4-propylphenol are well-known compounds mainly stemming from the wood barrels used for aging and showed an OAV ≥ 1. Another important group of aroma-active compounds in rum were ethyl esters, for which a significant increase was determined during fermentation but also to a lesser extent during aging. Altogether, the concentrations of 68% of the aroma-active compounds increased during the process, demonstrating its influence on the overall rum aroma.