A pair of Swedish chemists are blinding the drinking world with science. The duo claims to have ended the old barroom debate about adding water to whisky (and whiskey). Their new study, published in Scientific Reports, offers proof that ethanol concentration is directly linked to guaiacol’s dispersement. In English, that means that diluting your Scotch with water will increase the flavor. Check out our rundown of the details.
The Players: Ran Friedman of the Linnaeus University Center for Biomaterials Chemistry was touring Scotland when he became fascinated by the custom of adding water to whisky. Upon his return to the institute, Friedman enlisted his colleague Bjorn Karlsson and the two set out to finally determine whether whisky tastes better with water.
The Setup: Basically, whiskies are comprised of hundreds of compounds. Karlsson and Friedman decided to focus on three most essential to flavor: water, ethanol, and guaiacol. Water is simply the H2O that we all know and love. C2H6O or ethanol is what we normally just call “alcohol.” Guaiacol is known in the chemistry world as C6H4(OH)(OCH3). It is a naturally occurring compound that is responsible for contributing flavor to favorites such as coffee and vanillin. In the case of whiskies, guaiacol adds that beloved smoky, peaty flavor.
The Study: Friedman and Karlsson set up computer simulations to measure the effects of adjusting each compound. The scientists theorized that the flavorful guaiacol is attracted to the ethanol. Unfortunately, that attractions also allows the ethanol molecules to surround and trap the guaiacol. Confined in these molecular prisons, the guaiacol is unable to deliver all of their coveted flavor to the drinker. Our intrepid researchers set out to discover how to release break the smoky compound free from these ethanol cages.
The Results: The simulation showed that when whisky has an ABV of 59% or higher, the guaiacol and the alcohol have an extremely strong attraction and the flavor is pushed away from the surface. However, using water to reduce the alcohol content changes everything. At around 45% ABV, those ethanol cages start to break up and float to the surface dragging the guaiacol along for the ride. In layman’ terms, your drink becomes more flavorful. The effect is only increased with additional dilution; around 27% ABV, the ethanol starts aerosolize, releasing even more of the guaiacol.
So, yes Virginia, adding water to your whisky does enhance the flavor.
The Rub: Of course, if you add too much water to your whisky, it will just start to taste like, well, water at some point. So, balance is necessary. Also note, those special, barrel proof whiskies are even more undiluted (often around 59% ABV). That means, less, not more flavor.
Fun Fact: Friedman and Karlsson chose Islay Scotches to use for their study. Clearly, these chemists have good tastes.