An electronic tongue has been developed that can accurately determine the age of wine, the type of barrel it came from, and its overall quality. The aim is to use the device to test wines on an industrial scale to ensure they meet quality standards before they are sold to consumers.

Xavier Ceto and colleagues at the University of South Australia made the tongue out of gold, platinum and carbon electrodes. The device measures the electrochemical signals of sugars, phenolics and other compounds present in wine. These signals are then mathematically processed and converted into a unique fingerprint for each wine.

Unlike conventional sensors, which focus on specific compounds, the electronic tongue can analyse the overall combination. “It mimics the process of tasting, where the different sensations perceived (sweet, bitter, sour, salty and umami) are combined by your brain,” says Ceto.

The researchers recently tested the electronic tongue on 52 red wines from the Catalonia region of Spain. First, they asked eight sommeliers to score the wines out of 10. Next, they calibrated these scores to the fingerprints produced by the electronic tongue, creating a model which could accurately predict the sommeliers’ ratings in other wines by analysing their fingerprint. As well as scoring a wine’s quality, the tongue can also determine the age of a wine and whether it was matured in French or American oak barrels.

The next step will be to test the electronic tongue on a bigger scale, says Ceto. “You can’t have a person tasting 100 wines per day, so this sensor may be able to help screen them,” he says. Although the device is configured for Spanish red wines at the moment, it could easily be retrained to assess other types of wines from different countries, Ceto says. On the other hand, the electronic tongue could not be used to judge wine competitions, he says. This is because it is modelled on the subjective measures of the study’s eight sommeliers, rather than any objective measure of taste.

It is unlikely that electronic tongues will ever be able to perfectly replicate human taste, says Heather Smyth at the University of Queensland, Australia. “The human senses – smell, taste, touch, sound, and sight – all work together in a very complex way to deliver messages to our brain about the qualities of food and beverages we consume,” she says. “Emotion, psychology, past memories and experiences all influence these perceptions and contribute to our perception of flavour – no instrument can possibly replace that.”

Journal reference: Talanta, DOI: 10.1016/j.talanta.2016.09.055

Source: New Scientist