Long chain esters in the spotlight: analysis of the aroma between traditional whisky and analogous age-accelerated spirit
DOI:
https://doi.org/10.58430/jib.v131i4.83Keywords:
long-chain esters, whisky, accelerated aged spirit, aroma, maturation, barley, ryeAbstract
Why was the work done: Consumer interest in distinctive, high quality alcoholic beverages has driven innovation in whisky production, particularly in ageing techniques. While traditional oak barrel ageing is essential to the legal definition and flavour development of whisky, new approaches such as the Jensen Reactor - an accelerated ageing method combining ultrasound, temperature, oxygenation, pressure, and catalysis - aim to replicate the chemical changes of barrel ageing in one to two weeks. However, how such accelerated methods compare to traditional maturation lasting many years remains unclear.
How was the work done: The study focused on the quantification of medium and long-chain fatty acid ethyl esters in malted rye and barley spirits comparing the new make spirit, accelerated-aged spirit and traditional whisky.
Volatile organic compounds were characterised using stir bar sorptive extraction coupled with gas chromatography-mass spectrometry (SBSE-GC-MS).
What are the main findings: Most C2–C12 ethyl esters increased in concentration during accelerated ageing, often surpassing their sensory thresholds and likely contributing fruity notes. Ethyl acetate, by contrast, was reduced to near or below threshold levels (25-30 mg/L) in accelerated aged samples, while present at 120-300 mg/L in traditionally aged spirits, which presumably contribute a solvent-like aroma. Long-chain esters (C14–C18), commonly linked to waxy characteristics, remained relatively stable across both ageing methods reflecting their initial concentration in the new make spirit. Additionally, ethyl linoleate decreased during traditional ageing, whereas ethyl tetradecanoate increased; the underlying mechanism for this is currently unknown.
Why is the work important: These findings highlight the importance of understanding ethyl ester formation to improve aroma development and quality in whisky or spirit production and maturation.
Downloads
References
Arnold RJ, Ochoa A, Kerth CR, Miller RK, Murray SC. 2019. Assessing the impact of corn variety and Texas terroir on flavor and alcohol yield in new make bourbon whiskey. PLoS One 14:e0220787. DOI: https://doi.org/10.1371/journal.pone.0220787
Autonomous Region of Madeira, 2015. Regional Secretariat of Environment and Natural Resources Ordinance no. 38/2015.
Barnes Q, Vial J, Thiébaut D, De Saint Jores C, Steyer D, Contamin MA, Papaiconomou N, Fernandez X. 2022. Characterization of flavor compounds in distilled spirits: Developing a versatile analytical method suitable for micro-distilleries. Foods 11:3358. DOI: https://doi.org/10.3390/foods11213358
Baxter I, Réveillé A, Conner J. 2024. Guidelines to optimise the sensory detection of 2,4,6-trichloroanisole in neutral spirit and whisky. J Inst Brew 130:112-123. DOI: https://doi.org/10.58430/jib.v130i2.51
Bellut K, Lynch KM, Arendt EK. 2021. Alcoholic beverages: production, trends, innovations, p 19-24. In Lavelle C, This H, Kelly AL, Burke R (eds), Handbook of Molecular Gastronomy, CRC Press. DOI: https://doi.org/10.1201/9780429168703-5
Boothroyd EL, Linforth RST, Cook DJ. 2012. Effects of ethanol and long-chain ethyl ester concentrations on volatile partitioning in a whisky model system. J Agric Food Chem 60:9959–9966. DOI: https://doi.org/10.1021/jf3022892
Buglass AJ. 2011. Handbook of Alcoholic Beverages: Technical, Analytical and Nutritional Aspects. John Wiley & Sons. DOI: https://doi.org/10.1002/9780470976524
Caldeira M, Rodrigues F, Perestrelo R, Marques JC, Câmara JS. 2007. Comparison of two extraction methods for evaluation of volatile constituents patterns in commercial whiskeys. Elucidation of the main odour-active compounds. Talanta 74:78–90. DOI: https://doi.org/10.1016/j.talanta.2007.05.029
Canas S, Caldeira I, Anjos O, Belchior AP. 2019. Phenolic profile and colour acquired by the wine spirit in the beginning of ageing: alternative technology using micro-oxygenation vs traditional technology. LWT 111:260–269. DOI: https://doi.org/10.1016/j.lwt.2019.05.018
Canas S, Danalache F, Anjos O, Fernandes TA, Caldeira I, Santos N, Fargeton L, Boissier B, Catarino S. 2020. Behaviour of low molecular weight compounds, iron and copper of wine spirit aged with chestnut staves under different levels of micro-oxygenation. Molecules 25:5266. DOI: https://doi.org/10.3390/molecules25225266
Conner JM, Paterson A, Birkmyre L, Piggott JR. 1999. Role of organic acids in maturation of distilled spirits in oak casks. J Inst Brew 105:287–291. DOI: https://doi.org/10.1002/j.2050-0416.1999.tb00522.x
Conner J. 2014. Maturation, p 199–220. In Russell I, Stewart G (eds) Whisky: Technology, Production and Marketing. 2nd ed. Amsterdam: Elsevier. DOI: https://doi.org/10.1016/B978-0-12-401735-1.00011-8
Carrithers AD, Brown MJ, Rashed MZ, Islam S, Velev OD, Williams SJ. 2020. Multiscale self-assembly of distinctive weblike structures from evaporated drops of dilute American whiskeys. ACS Nano 14:5417–5425. DOI: https://doi.org/10.1021/acsnano.9b08984
Chemat F, Rombaut N, Sicaire AG, Meullemiestre A, Fabiano-Tixier AS, Abert-Vian M. 2017. Ultrasound assisted extraction of food and natural products. Mechanisms, techniques, combinations, protocols and applications. A review. Ultrason Sonochem 34:540–560. DOI: https://doi.org/10.1016/j.ultsonch.2016.06.035
Christoph N, Bauer-Christoph C. 2007. Flavour of spirit drinks: raw materials, fermentation, distillation, and ageing, p 99–239. In Berger RG (ed), Flavours and Fragrances, Springer.
Code of Federal Regulation. 2024. Title 27 Alcohol, Tobacco Products and Firearms.
Cordero C, Cagliero C, Liberto E, Nicolotti L, Rubiolo P, Sgorbini B, Bicchi C. 2013. High concentration capacity sample preparation techniques to improve the informative potential of two-dimensional comprehensive gas chromatography–mass spectrometry: application to sensomics. J Chromatogr A 1318:1–11.
Dabija D, Nastase CE, Chetrariu A, Dabija A. 2024. Multi-criteria analysis in circular economy principles: using AHP model for risk assessment in sustainable whisky production. Computation 12:206.
Delgado-González MJ, Sánchez-Guillén MM, García-Moreno MV, Rodríguez-Dodero MC, García-Barroso C, Guillén-Sánchez DA. 2017. Study of a laboratory-scaled new method for the accelerated continuous ageing of wine spirits by applying ultrasound energy. Ultrason Sonochem 36:226–235.
Demyttenaere JCR, Sanchez Martínez JI, Verhé R, Sandra P, De Kimpe N. 2003. Analysis of volatiles of malt whisky by solid-phase microextraction and stir bar sorptive extraction. J Chromatogr A 985:221–232.
European Union. 2008. Regulation No 110/2008 of the European Parliament and of the Council.
European Union. 2019. Regulation 2019/787 of the European Parliament and of the Council of 17 April 2019 on the definition, description, presentation and labelling of spirit drinks.
Gao W, Fan W, Xu Y. 2014. Characterization of the key odorants in light aroma type Chinese liquor by gas chromatography-olfactometry, quantitative measurements, aroma recombination, and omission studies. J Agric Food Chem 62:5796–5804.
Cordero C, Cagliero C, Liberto E, Nicolotti L, Rubiolo P, Sgorbini B, Bicchi C. 2013. High concentration capacity sample preparation techniques to improve the informative potential of two-dimensional comprehensive gas chromatography–mass spectrometry: application to sensomics. J Chromatogr A 1318:1–11. DOI: https://doi.org/10.1016/j.chroma.2013.09.065
Dabija D, Nastase CE, Chetrariu A, Dabija A. 2024. Multi-criteria analysis in circular economy principles: using AHP model for risk assessment in sustainable whisky production. Computation 12:206. DOI: https://doi.org/10.3390/computation12100206
Delgado-González MJ, Sánchez-Guillén MM, García-Moreno MV, Rodríguez-Dodero MC, García-Barroso C, Guillén-Sánchez DA. 2017. Study of a laboratory-scaled new method for the accelerated continuous ageing of wine spirits by applying ultrasound energy. Ultrason Sonochem 36:226–235. DOI: https://doi.org/10.1016/j.ultsonch.2016.11.031
Demyttenaere JCR, Sanchez Martínez JI, Verhé R, Sandra P, De Kimpe N. 2003. Analysis of volatiles of malt whisky by solid-phase microextraction and stir bar sorptive extraction. J Chromatogr A 985:221–232. DOI: https://doi.org/10.1016/S0021-9673(02)01471-1
European Union. 2008. Regulation No 110/2008 of the European Parliament and of the Council.
European Union. 2019. Regulation 2019/787 of the European Parliament and of the Council of 17 April 2019 on the definition, description, presentation and labelling of spirit drinks.
Gao W, Fan W, Xu Y. 2014. Characterization of the key odorants in light aroma type Chinese liquor by gas chromatography-olfactometry, quantitative measurements, aroma recombination, and omission studies. J Agric Food Chem 62:5796–5804. DOI: https://doi.org/10.1021/jf501214c
Jeleń HH, Majcher M, Szwengiel A. 2019. Key odorants in peated malt whisky and its differentiation from other whisky types using profiling of flavor and volatile compounds. LWT 107:56–63. DOI: https://doi.org/10.1016/j.lwt.2019.02.070
Jensen PA, Trinh NT, Lundgaard Christensen R, Dam-Johansen K, Bech N. 2015. Rotor for a pyrolysis centrifuge reactor. Patent No. WO2015150265.
Jensen TE, Byzdra A. 2024. A process for accelerating aging of spirits. Patent No. WO2024079347A1.
Johnsen LG, Skou PB, Khakimov B, Bro R. 2017. Gas chromatography–mass spectrometry data processing made easy. J Chromatogr A 1503:57–64. DOI: https://doi.org/10.1016/j.chroma.2017.04.052
Karlsson BCG, Friedman R. 2017. Dilution of whisky – the molecular perspective. Sci Rep 7:6842. DOI: https://doi.org/10.1038/s41598-017-06423-5
Kelly TJ, O’Connor C, Kilcawley KN. 2023. Sources of volatile aromatic congeners in whiskey. Beverages 9:64. DOI: https://doi.org/10.3390/beverages9030064
Kim S, Chen J, Cheng T, Gindulyte A, He J, He S, Li Q, Shoemaker BA, Thiessen PA, Yu B, Zaslavsky L, Zhang J, Bolton EE. 2025. PubChem 2025 update. Nucleic Acids Res 53:D1516–D1525. DOI: https://doi.org/10.1093/nar/gkae1059
Krüger RT, Alberti A, Nogueira A. 2022. Current technologies to accelerate the aging process of alcoholic beverages: a review. Beverages 8:65. DOI: https://doi.org/10.3390/beverages8040065
Kyraleou M, Herb D, O’Reilly G, Conway N, Bryan T, Kilcawley KN. 2021. The impact of terroir on the flavour of single malt whisk(e)y new make spirit. Foods 10:443. DOI: https://doi.org/10.3390/foods10020443
Lee M, Paterson A, Piggott JR, Richardson GD. 2001. Origins of flavour in whiskies and a revised flavour wheel: a review. J Inst Brew 107:287–313. DOI: https://doi.org/10.1002/j.2050-0416.2001.tb00099.x
Li H, Ming X, Liu Z, Xu L, Xu D, Hu L, Mo H, Zhou X. 2021. Accelerating vinegar aging by combination of ultrasonic and magnetic field assistance. Ultrason Sonochem 78:105708. DOI: https://doi.org/10.1016/j.ultsonch.2021.105708
Lin JY, Wu YJ, Hsiao YT, Wang CY. 2021. Acceleration of the ageing process in mei (Prunus mume Siebold) liqueur by high hydrostatic pressure treatment. Int J Food Sci Technol 56:2030–2040. DOI: https://doi.org/10.1111/ijfs.14835
Madrera RR, Valles BS, García YD, Argüelles PdV, Lobo AP. 2010. Alternative woods for aging distillates – an insight into their phenolic profiles and antioxidant activities. Food Sci Biotechnol 19:1129–1134. DOI: https://doi.org/10.1007/s10068-010-0161-4
Miller GH 2024. Maturation, p 377-478. Distillation Theory. In Whisky Science: A Condensed Distillation Springer Int Pub. DOI: https://doi.org/10.1007/978-3-031-50687-1_8
Mirza-Aghayan M, Zonoubi S, Molaee Tavana M, Boukherroub R. 2015. Ultrasound assisted direct oxidative esterification of aldehydes and alcohols using graphite oxide and oxone. Ultrason Sonochem 22:359–364. DOI: https://doi.org/10.1016/j.ultsonch.2014.05.012
Morgan N. 2022. Master of Malt blog. Accelerated ageing, in search of whisky’s Holy Grail.
Nguyen DT, Pham QT. 2020. A theoretical and experimental study on esterification of citric acid with the primary alcohols and the hydroxyl groups of cellulose chain (n = 1–2) in parched condition. J Chem 2020:8825456. DOI: https://doi.org/10.1155/2020/8825456
Niu Y, Yao Z, Xiao Z, Zhu G, Zhu J, Chen J. 2018. Sensory evaluation of the synergism among ester odorants in light aroma-type liquor by odour threshold, aroma intensity and flash GC electronic nose. Food Res Int 113:102–114. DOI: https://doi.org/10.1016/j.foodres.2018.01.018
Piggott JR, Conner JM. 1995. Whiskies, p 247-274. In Lea AGH, Piggott JR (eds) Fermented Beverage Production. Boston, MA: Springer. DOI: https://doi.org/10.1007/978-1-4757-5214-4_10
Piggott JR, Conner JM, Paterson A. 1995. Flavour development in whisky maturation. J Inst Brew 101:327–335. DOI: https://doi.org/10.1016/S0167-4501(06)80261-X
Poisson L, Schieberle P. 2008a. Characterization of the key aroma compounds in an American bourbon whisky by quantitative measurements, aroma recombination, and omission studies. J Agric Food Chem 56:5820–5826. DOI: https://doi.org/10.1021/jf800383v
Poisson L, Schieberle P. 2008b. Characterization of the most odor-active compounds in an American bourbon whisky by application of the aroma extract dilution analysis. J Agric Food Chem 56:5813–5819. DOI: https://doi.org/10.1021/jf800382m
Quintanilla-Casas B, Bro R, Hinrich JL, Davie-Martin CL. 2023. Tutorial on PARADISe: PARAFAC2-based Deconvolution and Identification System for processing GC–MS data. Protocol Exchange h DOI: https://doi.org/10.21203/rs.3.pex-2143/v1
Quintanilla-Casas B, Hinrich JL, Schneide PA, Bro R. 2025. Automated correction of saturated peaks in untargeted GC-MS: a chemometrics approach. Pre-print. DOI: https://doi.org/10.1016/j.chemolab.2025.105582
Rodríguez-Olvera MG, Rodríguez-Rodríguez LI, Qian MC, Qian YP, Vazquez-Landaverde PA. 2019. Implementation of stir bar sorptive extraction (SBSE) for the analysis of volatile compounds in tequila. ACS Symp Ser 1321:311–324. DOI: https://doi.org/10.1021/bk-2019-1321.ch019
Russell I, Kellershohn J. 2018. Advances in technology and new product development in the beer, wine, and spirit industry, pp. 89–104. In Panda SK, Shetty PH (eds), Innovation and Trends in the Global Food Systems, Springer. DOI: https://doi.org/10.1007/978-3-319-74820-7_5
Saerens SMG, Delvaux F, Verstrepen KJ, Van Dijck P, Thevelein JM, Delvaux FR. 2008. Parameters affecting ethyl ester production by Saccharomyces cerevisiae during fermentation. Appl Environ Microbiol 74:454–461. DOI: https://doi.org/10.1128/AEM.01616-07
Salo P, Nykänen L, Suomalainen H. 1972. Odour thresholds and relative intensities of volatile aroma components in an artificial beverage imitating whisky. J Food Sci 37:394–398. DOI: https://doi.org/10.1111/j.1365-2621.1972.tb02647.x
Stitzel F. 1880. Rack for tiering barrels. US Patent RE9175E.
Valcárcel-Muñoz MJ, Guerrero-Chanivet M, García-Moreno MV, Rodríguez-Dodero MC, Guillén-Sánchez DA. 2021. Comparative evaluation of brandy de Jerez aged in American oak barrels with different times of use. Foods 10:288. DOI: https://doi.org/10.3390/foods10020288
Wanikawa A. 2020. Flavors in malt whisky: a review. J Am Soc Brew Chem 78:156–167. DOI: https://doi.org/10.1080/03610470.2020.1795795
Wu J, Liu Y, Zhao H, Huang M, Sun Y, Zhang J, Sun B. 2021. Recent advances in the understanding of off-flavors in alcoholic beverages: generation, regulation, and challenges. J Food Compos Anal 103:104117. DOI: https://doi.org/10.1016/j.jfca.2021.104117
Wu Y, Chen H, Huang H, Chen F, Hong J, Zhao D, Zhang C, Zhao Z, Wang S, Ao R, Sun B. 2023. Revelation for the influence mechanism of long-chain fatty acid ethyl esters on the Baijiu quality by multicomponent chemometrics combined with modern flavor sensomics. Foods 12:1267.
Wu Y, Chen H, Huang H, Chen F, Hong J, Zhao D, Zhang C, Zhao Z, Wang S, Ao R, Sun B. 2023. Revelation for the influence mechanism of long-chain fatty acid ethyl esters on the Baijiu quality by multicomponent chemometrics combined with modern flavor sensomics. Foods 12:1267. DOI: https://doi.org/10.3390/foods12061267
Xia Y, Liu Y, Wang J, Shuang Q. 2020. Assessment of key aroma compounds in fresh jujube brandy by GC-O-MS and odor activity value. J Food Process Preserv 44:e14494. DOI: https://doi.org/10.1111/jfpp.14494
Zhang B, Cai J, Duan CQ, Reeves MJ, He F. 2015. A review of polyphenolics in oak woods. Int J Mol Sci 16:6978–7014. DOI: https://doi.org/10.3390/ijms16046978
Zhang Q, Wang D, Liu X, Li Y, Sun J, Meng N, Ji Z, Lan Y, Cao X, Sun B, Li J. 2025. Flavor characteristics and formation mechanisms in spirits: a case study in whisky. Food Res Int 178:115901. DOI: https://doi.org/10.1016/j.foodres.2025.115901
Zheng X, Zhang M, Fang Z, Liu Y. 2014. Effects of low frequency ultrasonic treatment on the maturation of steeped greengage wine. Food Chem 162:264–271. DOI: https://doi.org/10.1016/j.foodchem.2014.04.071
Zhao YP, Zheng XP, Song P, Sun ZL, Tian TT. 2013. Characterization of volatiles in the six most well-known distilled spirits. J Am Soc Brew Chem 71:161–169. DOI: https://doi.org/10.1094/ASBCJ-2013-0625-01
Published
Versions
- 27-01-2026 (2)
- 18-12-2025 (1)
How to Cite
Issue
Section
License
Copyright (c) 2025 Journal of the Institute of Brewing
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
This is an open access article which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed or built upon in any way.
Permission will be required if the proposed reuse is not covered by the terms of the License. In this event, email the Editor in Chief - david.quain@cibd.org.uk - with details of your request.
