Irish or Scotch, blended or single malt? While a whisky aficionado might be able to differentiate a good drink from a mediocre one just by smelling it, most drinkers depend on the label.
Whisky is one of the most sought-after alcoholic beverages internationally and, with some top brands costing five or six figures, it is also a choice target for deception.
To fight this, scientists have created an electronic nose (e-nose) that can differentiate between various brands, styles and origins by “sniffing” the alcohol.
The study was headed by Associate Professor Steven Su with Ph.D. students Taoping Liu and Wentian Zhang, from the University of Technology Sydney (UTS), in partnership with chemists Dr. Maiken Ueland and Professor Shari Forbes.
Up until now, detecting the differences between whiskies has required either a trained whisky connoisseur, who might still get it wrong, or complex and time-consuming chemical analysis by scientists in a lab. So to have a rapid, easy to use, real-time assessment of whisky to identify the quality, and uncover any adulteration or fraud, could be very beneficial for both high-end wholesalers and purchasers.
Associate Professor Steven Su, Study Lead, University of Technology Sydney
The researchers employed a new e-nose prototype (called NOS.E), created at UTS, to recognize the variances among six whiskies by their brand names, styles and regions in under 4 minutes.
The experiment took samples of three single malt whiskeys and three blended malts, including Chivas Regal, Ardberg, Johnnie Walker Black and Red label whiskey, and a Macallan's 12-year-old whisky.
The study has recently appeared in the journal IEEE Sensors. It demonstrated the e-nose achieved 100% correctness for identifying the region, 96.15% correctness for the brand name, and 92.31% correctness for the style.
NOS.E is engineered to imitate the human olfactory system, with eight gas sensors to identify odors in a container of whisky. The sensor array produces the exclusive signal matrix according to the various odor molecules it is exposed to.
It then transmits the information to a computer for examination, with a machine learning algorithm programmed to identify whisky features.
The scientists verified the NOS.E findings using advanced laboratory tests on the whisky samples: time-of-flight mass spectrometry coupled with two-dimensional gas chromatography, which produced similar outcomes.
This technology not only sees use in the alcohol sector, with beverages like cognac and wine besides whisky, but also for other products that are faced with counterfeiting such as top-class perfume.
The e-nose technology has also been employed to identify prohibited animal parts traded on the black market, for example, black rhino horns, and has considerable potential for disease detection and health applications.
Zhang, W., et al. (2022) The Use of Electronic Nose for the Classification of Blended and Single Malt Scotch Whisky. IEEE Sensors. doi.org/10.1109/JSEN.2022.3147185.