When fans of exquisite whiskey talk about their favorite drink, it is often associated with a far greater than average use of all sorts of adjectives. Woody, mossy, smoky or peaty should be the single malt, which naturally comes from Scotland. At times, experts taste notes of malt, vanilla, fruits of all kinds, even chocolate, caramel or pepper.
The layman wonders about such opulent descriptions, fights with the sharpness in the mouth – and prefers to order coke and ice cream. This brings the whiskey lover tears in the eyes, possibly water is allowed to the drink.
Some connoisseurs add dropwise selected spring water from Scotland to the noble distillate by pipette. But even this behavior is controversial in the whiskey scene. Many swear by pure enjoyment. Who makes it better? A clear case for science.
Analysis of the flavor guaiacol
How to tickle out at least one flavor best from the whiskey, now researchers may have fathomed. Björn Karlsson and Ran Friedman from the Linnaeus University Center for Biomaterials Chemistry in Kalmar, Sweden, wanted to know how the chemical interaction of alcohol, water and whiskey flavors works.
In fact, the alcohol content of whiskey, which is mostly made from cereal mash, can vary considerably. After distillation, it comes into the cask with values around 70 percent by volume of alcohol. However, during storage over several years, the alcohol content drops – depending on the storage period, it is usually between 65 and 50 percent. It is diluted before being bottled – and then reaches levels around 40% alcohol by volume. However, many manufacturers also market cask-powered bottles under the name "cask strength".
In their analysis, the researchers focused on the substance guajacol, which has long been known as an important whiskey flavor carrier. This phytochemical is found in wooden tars and gets into the drink through its storage in the barrels for several years.
Lots of ethanol, less taste
The researchers did not work with real whiskey in the lab. They used molecular computational simulation to develop models of ethanol (alcohol), water and guaiacol on the computer and then calculated the chemical behavior of guaiacol at different levels of dilution.
They found out that up to an alcohol content of about 45 percent, the guaiacol is more at the boundary layer between liquid and air and there is released more. As a result, the substance can directly influence the smell and taste of the whiskey, the researchers write in "Scientific Reports".
If the alcohol content rises to 59 percent or more, the flavor-enhancing substance rather decreases – the guaiacol is surrounded by more ethanol molecules, the taste could be less intense. This is an explanation that the dilution of a noble whiskey with higher alcohol content could well be worthwhile. "We assume that flavorings such as guaiacol unfold less well at higher ethanol concentrations," the researchers write.
In addition, her model also explain why the dilution with water in whiskey in cask strength could cause a change in taste. However, one must be very careful with this procedure: The degree between pleasure and rejection is very narrow. Therefore, the use of pipettes should not be exaggerated when it comes to the perfect taste.
Whiskey or whiskey?
However, the researchers themselves note that their study was only concerned with investigating chemical behavior at the molecular level. Other factors could exert an influence on a person's individual taste perception.
In addition, the researchers have generally designed their model for a solution with the basic ingredients ethanol, water and guaiacol. It does not refer to the many different ways of production and countries of origin of whiskey – and to other flavorings.
After all: The researchers write "whiskey" in the study only with y – on the spelling "whiskey" with an e renounce it. This suggests that mainly products from Scotland, the motherland of whiskey, could be meant. Whiskey comes from Ireland or bourbon – it is also made from corn and comes from the USA.
By the way, a good single malt, which may only be made from malted barley for this predicate, has long since ceased to be from Scotland. Even in Germany, India or Taiwan, fine wines are produced. And experts from the past rated whiskeys from Japan.