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gh ANALYZING BRANDY: AN ‘ELECTRONIC TONGUE’ INSTEAD OF A COOPER?

St. Petersburg , St. Petersburg State University, Faculty of Chemistry
22.02.2008
Researchers from St. Petersburg have developed a brandy analyzing device. A new variant of an ‘electronic tongue’ quickly and confidently tells not only young brandy from seasoned brandy but also distinguishes between various types of the drink.
Send mail Scientist: Alisa Mikhailovna Rudnitskaya, research assistant, , Andrey Vladimirovich Legin, leading research associate, andrew@kl13930.spb.edu , St. Petersburg

For additional information: alisa.rudnitskaya@gmail.com
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Researchers from St. Petersburg State University have designed a brandy analyzing device, which is able to significantly lighten the work for manufactures of the drink popular with many people, which is based on ethyl alcohol seasoned in wooden casks. The device, which represents several sensors and the most complicated hardware and software complex for processing the results obtained by the sensors, enables to confidently tell the ‘young’ drink from the seasoned one and even to distinguish among variants of brandy. This is of great help both to the ones who manufacture the drink and to those who are duty-bound to reveal counterfeit, which, alas, exists in the market. Certainly, such an ‘electronic tongue’ is unable to replace the cooper of the highest class. But it suits best of all for the routine work – as it is unbiassed, acts quickly, does not fall ill, does not give trouble, and the analysis outcome is expressed not in the feeling (well-bad-that’s the thing- that’s not the thing) but in figures and diagrams.

It should be noted that the notion of ‘electronic nose’ and an ‘electronic tongue’ has become widespread. Certainly, not everywhere but in analyst circles. It means the device intended for determination and/or identification of the objects of complicated composition. Most importantly, this device works on principle of ‘human’ noses and tongues – that is, unlike ordinary analytical instrumentation it is not obliged to separate all components of a complicated raciness of the object’s taste or aroma so that to analyze them later individually. The electronic tongue determines the taste ‘as a whole’ like a good cooper who faultlessly remembers and recognizes gustatory sensations, but, as a rule, has no idea about exact chemical composition of the product. And the electronic nose deals with scents in the same manner – it does not break them down into components but remembers and then determines at once as a whole – by the bouquet.

However, all these devices have one but a very significant drawback. They are never multi-purpose. For each task (should it be identification of rare earth elements in spent fuel or analysis of coffee, tea, juice, vodka, or dairy produce), an individual set of sensors should be developed to enable accurate reveal and identification of the aroma in question without ‘digressing’ to other foreign tastes and scents. Therefore, in this case, when the problem was posed to the St. Petersburg chemists by brandy manufactures from South Africa (the highest professionalism of Russian scientists, who create electronic tongues, is known all over the world), the chemists had first to think which sensors would allow to solve the problem, to select appropriate software and then to ‘train’ the selected sensors on real objects – on samples of brandy with known characteristics.

As the South-African brandy somewhat resembles cognac (both drinks are aged in oak casks after distillation), the task was to ‘teach’ the device, firstly, to distinguish the ‘young’ unseasoned drink from the seasoned one. The St. Petersburg ‘electronic tongue’ has coped with this task more than successfully. This is quite obvious – the seasoned brandy contain tannin, the presence of which fundamentally changes chemical composition the drink. Then there came a task to teach the device to distinguish variants of the drink, and to tell the brandy produced in laboratory environment from the one produced via industrial process. They have also succeeded in this task although not that brilliantly – expectancy of ‘hitting’ made approximately 3 out of 4. This is not that bad in principle – coopers also make mistakes.

“It is not for the first time that we worked with brandy, says Andrey Legin, the leader of investigation, Doctor of Chemistry. Prior to the South African Republic we dealt with, for example, the French from the famous town of Cognac (Martell, Remy Martin), so we worked with cognacs. By the way, wooden cask are necessarily made of oak (in France, the oak timber should come from a certain forest), and ethyl alcohol is very romantically called eau-de-vie in French (the juice of life). In general, we have worked a lot with wines. Besides France and the South-African Republic, we dealt with Italy, Portugal, New Zealand, Australia. We have published about 20 articles, devoted to developments of electronic noses and tongues for similar ‘tasty’ objects.”

In any case, it can be said for sure that the South-African brandy manufactures are happy with the results of cooperation with the St. Petersburg scientists, although such a device would prove useful to wine-makers and those who are fighting counterfeit all over the world.

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