Researchers refine laser authentication of whisky

Researchers in Scotland have developed a way to test the authenticity of whisky – without opening the bottle – using laser spectroscopy.

The scientists from the University of St Andrew say the new technique can provide a reliable analysis of the contents of a bottle without recording signals from the glass, a factor that previously required the bottle to be opened and a sample removed for testing.

Rather than illuminating the bottle with a standard laser beam, the team used a glass element to shape the light to produce a ring of laser light on the bottle surface and a tightly focused spot within the liquid contents.

As the signal from the bottle and the signal from the liquid are at different positions, a detector can be placed to record only the signal from the liquid, meaning the bottle contents can be assessed without ever opening it. Aside from whisky, the technique can also be used for other spirits like vodka and gin.

Lead researcher Professor Kishan Dholakia said the method doesn’t require complex optical setups and so could be promises to be easily adapted for to screen whisky on a large scale.

“Personally, I hate it when I have to spare a drop of whisky for validation checks,” he said. “I’d much rather drink the whole bottle.

“Laser spectroscopy is a powerful tool for characterising the chemical make-up of many materials, but to use it to characterise alcohol in its original container in this simple way is really exciting.”

Counterfeit whisky is an increasing problem, with a study of rare Scotch whiskies in 2018 at the East Kilbride-based Scottish Universities Environmental Research Centre (SUERC) finding that a third were fake.

The method has been published in the journal Analytical Methods.