Lasers shed light on counterfeit whisky Published duration 31 October 2011

image caption The test can prove if a whisky is genuine or not using a sample no bigger than a teardrop

A new method to tackle the counterfeiting of Scotch Whisky using laser technology has been developed.

St Andrews University researchers have claimed they can work out a whisky's brand, age and cask by using a ray of light the size of a human hair.

They said the test could prove if a whisky is genuine or not using a sample no bigger than a teardrop.

Counterfeiting is understood to be a major problem for the drinks industry which seeks new methods of detection.

The technique involves researchers placing a tiny amount of whisky on a transparent plastic chip no bigger than a credit card.

Genuine sample

Using optical fibres the width of a human hair, the whisky sample is illuminated by light using one fibre, and collected by another.

By analysing the collection of light scattered from the whisky, the researchers say they are able to diagnose the sample.

The key lies in the ability of the laser to detect the amount of alcohol contained in the sample, genuine whisky must contain at least 40%.

The method exploits both the fluorescence of whisky and the scattering of light and shift in energy when it interacts with molecules, known as its Raman signature.

The research, which has been patented, was carried out by physicists Praveen Ashok, Kishan Dholakia and Bavishna Praveen.

Mrs Praveen said: "Counterfeiting is rife in the drinks industry, which is constantly searching for new, powerful and inexpensive methods for liquor analysis.

"Using the power of light, we have adapted our technology to address a problem related to an industry which is a crucial part of Scottish culture and economy."

Mr Ashok said: "Whisky turns out to be very interesting. We can not only gather information about the alcohol content, but also the colour and texture.

"These are dictated by the manufacturing process, which of course influences greatly the type of whisky people enjoy."

Professor Dholakia said: "Light is incredible and has led to amazing advances in the last 50 years since the advent of the laser.

"It is amazing to think that the technology we are developing for biomedical analysis can also be used to help us enjoy a wee dram and with the minimum of waste."

The research has been published in the journal Optics Express.