Counterfeit whiskies scotched by artificial tongue

Scottish engineers have built a tiny ‘tongue’, able to differentiate between drams of whisky, in a step towards halting the trade of counterfeit alcohol. A paper published by the Royal Society of Chemistry described how the tiny taster was built, and how it exploits the optical properties of gold and aluminium to test each whisky.

Sub-microscopic slices of the two metals arranged in a checkerboard pattern function as the ‘tastebuds’, approximately 500 times smaller than human tastebuds. Researchers pour samples of whisky over the tastebuds, measuring how they absorb light while submerged. The subtle differences in how the metals absorb light — called plasmonic resonance by scientists — allows scientists to identify different types of whiskies.

The tongue was used to test a number of whiskies from Glenfiddich, Glen Marnoch and Laphroaig, with approximately 99% accuracy, capable of determining subtle differences between the same whiskies aged in different barrels. The taster could also tell the difference between the same whisky aged for 12, 15 and 18 years.

The tongue can’t identify individual chemicals that make coffee taste different to apple juice, but it can differentiate between complex chemical mixtures. The tongue could also be used to ‘taste’ any liquid, making it useful for a variety of applications, including food safety testing, quality control and security.

Dr Alasdair Clark from the University of Glasgow’s School of Engineering is the paper’s lead author.

“We’re not the first researchers to make an artificial tongue, but we’re the first to make a single artificial tongue that uses two different types of nanoscale metal tastebuds, which provides more information about the taste of each sample and allows a faster and more accurate response,” he said.

The paper, titled ‘Whisky tasting using a bimetallic nanoplasmonic tongue’, is published in the Royal Society of Chemistry’s journal Nanoscale.

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