The photo shows that Uwe Bunz (L) and doctoral student Jinsong Han look at a row of the glowing dyes used in the whiskey-distinguishing "tongue". (Credit: Sebastian Hahn)
WASHINGTON, June 8 (Xinhua) -- Scientists have developed an artificial "tongue" that can tell if you are drinking fake whiskies, a new study said Thursday.
The artificial "tongue," or sensor arrays, can not only distinguish between two nearly identical whisky samples, but also identify some of the whiskies' key qualities, such as malt status, age, and country of origin, according to the study published by the U.S. journal Chem.
Whisky was first produced in Scotland, where the oldest distillery was licensed in 1775. Since then, Scotch and other whiskies have been popular, and today, countless whiskies of different origin, age, brand, blend status, taste, and price range are available.
"For high-end whiskies, asking prices range from 10,000 to 135,000 euros per bottle. For this type of price, one might worry about counterfeits, but that could also apply at the low end of the quality spectrum, where large amounts of cheap alcoholic beverages and low-quality counterfeits are sold as branded Scotch," the study wrote.
"Because it is difficult to obtain bona fide counterfeit whiskies, discriminating different whisky brands and sub-brands is a closely related and perhaps even more challenging and important task."
As a result, Uwe Bunz, an organic chemist at Heidelberg University in Germany, and colleagues introduced an artificial "tongue" that is made up of a series of solutions each containing a unique glowing sophisticated dye.
When a droplet of whisky is added into the solutions, it will cause a slight change in the brightness of each chemical's glow, leading to a unique signature pattern for each whisky.
"If you have three, four, or five elements on the tongue, you get three, four, or five different intensity changes, and these intensity changes form a pattern. And the pattern is unique," Bunz said.
"Each single polymer's response to the whisky would not be very useful, but if you combine them, they form a really unique pattern."
The device looks nothing like a traditional tongue, but it operates on some of the same principles, Bunz argued.
"Our human tongue consists of six or seven different receptors -- sweet, salty, bitter, sour, umami, and hotness -- and they're able to identify food by differential reactions of those elements," he said. "The combination of differential receptors gives you an overall taste impression of what you eat."
These synthetic "tongues" can be used to spot counterfeits of expensive luxury whiskies, but they can't identify an unknown whisky from scratch, he said.
"You start with a sample that you know is the real McCoy. Then you look at another sample, and you can say whether it's the same sample or it's not."
The researchers said their method could in principle work well for other beverages and even for biological materials, which are also complex mixtures.