Whiskey is distilled in several different varieties and each is linked to its country of origin. For example, scotch whiskey is made in Scotland, Irish whiskey in Ireland, Canadian whiskey in Canada, and Bourbon whiskey is made in America.
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Manufacturing American bourbon whiskey involves the use of specific grain types, and unique barrel wood for aging. While bourbon is made primarily in Kentucky, Bourbon can be distilled anywhere in the US.
On the other hand, Scotch whiskey is distilled in Scotland and involves the use of barley and a distinct barrel wood type.
But Scotch and Irish whiskeys are also chemically distinct from American whiskeys and according to PopSci, researchers are attempting to determine exactly how.
So food science researchers at the University of California at Davis have been studying different whiskeys to determine whether they can scientifically distinguish them from one another.
“Right now, we can do a pretty good job of separating, for example, Scotch whiskeys from bourbons and other American whiskeys and also Canadian and Irish whiskeys,” said research director Thomas Collins during a talk at the American Chemical Society’s annual meeting.
“When you narrow it down into whiskeys from a particular region, the process gets a little more difficult because they’re more similar to each other.” The researchers are looking into the data more closely to try to distinguish chemically between American whiskey types, Collins said.
Collins and his team analyzed 60 American whiskeys using two common chemical techniques — high-performance liquid chromatography and high-resolution mass spectrometry.
These techniques separate compounds in a mixture and reveal compound characteristics such as weight and structures. Researchers then used other data to identify the different compounds, and performed statistical analyses to determine differences between the concentration levels of different chemicals in various whiskeys.
The major chemicals used to distinguish different whiskeys include some that originate from the grain, the fermentation process, and the wood barrel in which whiskey ages.
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“Ethanol is a good solvent and it will extract a number of things from the barrel,” Collins said, and added that it is the relative concentrations of about 30 to 50 chemicals that distinguish any two given whiskeys from one another.
“Those chemicals include terpenes and terpenoids, which may come from either the barrel or the grain; fatty acids, which may come from either yeasts or plants; and polyphenols, such as tannins, which come from the aging barrels and vary by both distiller and a whiskey’s age.”
Collins hopes his work will be able to help distillers determine what practices are required for the most flavorful whiskey. For example, Collins suggested he could ascertain whether whiskeys taste different if they’re aged in different parts of the same warehouse.
And the chemical composition of whiskey can enable people to identify whether particular bottles of whiskey are genuine.