Identification of Rotundone as an Important Contributor to the Flavor of Oak-Aged Spirits

Elizabeth Genthner-Kreger, Keith R. Cadwallader

Research output: Contribution to journalArticlepeer-review


Experiments were conducted to identify a compound responsible for a spicy, woody, incense-like odor note in oak-aged spirits. The target compound was extracted from oak wood and various oak-aged spirits and analyzed by multidimensional (heart-cut) gas chromatography–mass spectrometry–olfactometry (MD–GC–MS–O), and was unambiguously identified as the sesquiterpene ketone, 5-isopropenyl-3,8-dimethyl-3,4,5,6,7,8-hexadydro-1(2H)-azulenone (rotundone). Quantitation of the trace-level target compound was done by stable isotope dilution analysis (SIDA) in a variety of oak-aged spirits, including bourbon, rye, Tennessee whiskey, scotch, rum, and tequila. The content of rotundone was found to increase as a function of years of barrel aging for 4-, 8-, and 12-year-old bourbons obtained from the same manufacturer, thus confirming its origin to be from oak. In addition, odor-activity values (OAVs) were compared for selected potent odorants, including rotundone, in the same 4-, 8-, and 12-year-old bourbons, which indicated the relative importance of rotundone in the overall flavor of oak-aged spirits.
Original languageEnglish (US)
Article number4368
Issue number14
StatePublished - Jul 2021


  • flavor
  • stable isotope dilution
  • gas chromatography–olfactometry
  • whiskey
  • rotundone
  • Stable isotope dilution
  • Rotundone
  • Whiskey
  • Flavor
  • Gas chromatography–olfactometry

ASJC Scopus subject areas

  • Drug Discovery
  • Analytical Chemistry
  • Chemistry (miscellaneous)
  • Molecular Medicine
  • Physical and Theoretical Chemistry
  • Pharmaceutical Science
  • Organic Chemistry


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