Scotch whisky can be very expensive. While testing for suspected fraud or adulteration of such pricey drinks, contactless sensing without opening the bottles would be preferable.
Researchers have developed a process to detect any adulteration in Scotch whisky and other distilled alcoholic drinks, without opening their containers. The method developed by physicists from the University of St. Andrews in Scotland, leverages laser. It is simple and low-cost way to examine expensive drinks while being non-destructive and contactless.
Scotch whisky can be very expensive, with the price usually increasing with the drink’s maturation age. While testing for suspected fraud or adulteration of such pricey drinks, touchless sensing without opening the bottles would be preferable. This would preserve the original value of these products.
The team at St. Andrews demonstrated a method called Raman spectroscopic analysis to examine the liquids in the bottle. Raman spectroscopy is a powerful and popular method to gain information at the molecular level, the method having a wide range of applications in biomedicine, cultural heritage, and defence.
In the context of whiskey, a laser beam is focused on the bottle. This generates Raman signals from the alcoholic spirit inside the bottle. However, glass is a highly Raman active substance, often masking regions of interest within the bottle. Unwanted signals originating from the glass bottle itself can significantly interfere with signals from the bottle’s contents, reducing their effectiveness. This is a major obstacle with the method, researchers said.
The team used a cone shaped lens in the process to cope with this issue, excluding any undesired signals from the glass bottle while maintaining a strong signal from the contents. They examined 11 different commercially available spirit drinks, in their original bottles. The branded spirit drinks included a range of vodka, whisky, and gin spirits which were purchased from national retail outlets.
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The St. Andrews scientists chose these spirit beverages due to their high economic value. They believed that non-destructive touchless analytical process will prove valuable to examine them. Food and drink adulteration leads to serious health risk and is also an economic issue. This is of particular concern for alcoholic spirits such as Scotch whisky which are often targeted for fraudulent activity, they say.
Whiskey, a chemically complex mixture, comprises thousands of compounds which contribute to the colour, taste and aroma of the beverage. Researchers have used infrared rays as well as processes that do not include the use of light to detect the purity of such drinks but those studies required direct analysis of the sample.
