Back last year, Stuart Williams, professor of mechanical engineering at the University of Louisville in Kentucky, discovered the "spider-web" effect for whiskey. It manifests itself if you evaporate a drop of this drink, after which an imprint with a pattern resembling threads of a cobweb is left. Williams suggested that this could be an interesting identifier for different whiskeys, and has since gone a long way in exploring this unusual phenomenon.
First, he was able to identify the mechanism of the formation of the track. Evaporation at the edges of the droplet occurs faster than in the center, so the liquid moves and carries with it the solids dissolved in it, which form a trace. But this is observed only for drops with a diameter of no more than 1 mm, in solutions with a strength of more than 10%, but below 30%, therefore, whiskey must be prepared for analysis by diluting with water. Otherwise, instead of a clear pattern, a homogeneous uninformative film is obtained.
During the experiments, Williams' team studied about a hundred varieties of whiskey, of which 66 are American, mostly bourbons. They easily managed to deduce the patterns that distinguish the spider-web trail of Scotch whiskey from a product from Kentucky. And within the product line of one brand, make a list of patterns in order to identify the drink by its trace with an accuracy of 90%. Any addition of impurities, traditional flavors, also causes obvious changes in the pattern structure, which makes it possible to use the method for detecting counterfeits.
Professor Williams is ready to take on the development of a method for identifying old and young (aged and regular) whiskey. And even create a quick test as a smartphone app with a USB microscope that only needs a few drops of a drink. But at the same time he admits that the main task, the determination of the chemical composition of whiskey by the spider's trail, has not been solved - it is too complicated for such primitive methods of study.