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

Counterfeit drinks cost the UK economy more than £200 million in lost revenue each year, according to a 2018 study published by the European Union’s Intellectual Property Office.

New research by University of St Andrews scientists has seen the development of a method using lasers to analyse the whisky without opening the bottle. Scientists previously had to take a sample of the contents as the glass caused interference with the readings.

Professor Kishan Dholakia, who led the study, said: “I hate it when I have to spare a drop of whisky for validation checks. 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.”

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The team used the method of laser spectroscopy, a process which shines laser light into a substance of interest and the sample scatters the light into different colours. Different chemical components will scatter the light differently, so this technique can be used to determine exactly what is in a sample.

Laser spectroscopy can be used to identify materials including bacteria, food and drink, the paint on sculptures and explosive powders.

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 signals from the bottle and 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.

The research has been published in the Analytical Methods journal.

Why does a drop of water make whisky taste better?

Asked by: Gus Mitchell, Hemel Hempstead

Whisky is predominantly water and ethanol. One end of the ethanol molecule is hydrophilic (water-loving) and the other hydrophobic (water-hating). As a result, the ethanol tends to form a thin layer at the surface of the whisky, with the hydrophobic ends pointing up into the air. Elsewhere in the tipple, it clumps together, forming a so-called micelle, with the hydrophilic ends shielding the other parts of the molecule from the water.

Many of the flavours in whisky dissolve better in ethanol, and therefore get locked away in the micelles. When water is added, this disrupts some of the micelles allowing more of the ethanol to migrate to the surface of the drink, along with the volatile flavours. Scientists and whisky connoisseurs agree that to get maximum flavour enhancement, you need more than a drop of water – diluting the whisky to about 25 per cent alcohol is ideal.

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Sara RigbyOnline staff writer, BBC Science Focus

Sara is the online staff writer at BBC Science Focus. She has an MPhys in mathematical physics and loves all things space, dinosaurs and dogs.