Pour whiskey out of the bottle in whiskey glass in the bar

Laser could help verify authentic whiskies

Image credit: fotoknips/Dreamstime

Scientists have developed a technique using lasers to accurately measure the authenticity of exclusive whiskies without removing the cap.

Iconic bottles of whisky have been known to sell for prices over £1m. Yet owners of such whisky cannot tell whether or not the contents of the bottle is the genuine product. According to a 2018 study by the European Union’s Intellectual Property Office, counterfeit drinks cost the UK economy more than £200m in lost revenue per year.

New research by University of St Andrews scientists has seen the development of a method using lasers which can see through the bottle to analyse the contents. The team used the method of laser spectroscopy, a process that shines laser light into a substance of interest and the sample scatters the light into different colours.

“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,” said Professor Kishan Dholakia, who led the study. 

Colours of the scattered light depend on the chemical make-up of the substance and can be used to identify materials ranging from bacteria, food and drink, through to the paint on sculptures and explosive powders.

The researchers demonstrated a decade ago that laser spectroscopy could be used to identify counterfeit whisky. Their previous method was hampered by the fact that the alcohol is not the only material to scatter light: the glass of the bottle can create an even bigger signal which dwarfs the signal produced by the contents. Therefore, previous setups required the removal of a small quantity of the liquid for testing.

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

To tackle this issue, 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 the bottle.

According to the team, the approach doesn’t require complex optical setups and therefore promises to be easily manufactured for widespread use. They have also demonstrated the method using vodka and gin.

In August 2019, researchers in Scotland developed an artificial ‘tongue’ that can taste subtle differences between drams of whisky - a tool which could help cut down on the trade in counterfeit alcohol.

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