Should You Add a Splash of Water to Your Whiskey?

Distillers, whiskey experts, and bartenders have been advising whiskey consumers for decades to add a bit of water to their whiskey, whether by a splash or by an ice cube. The reason behind this advice is that distillers claim a touch of water allows the flavors to open and improves the taste. But what does "open" mean? 

The Controversy

Let's open the door to this potentially controversial topic. 

But should it be controversial? This stems from whiskey consumers who believe that adding water is a form of dilution that no serious whiskey drinker should entertain. 

These whiskey connoisseurs overlook science that shows the process of measured dilution can enhance whiskey. In an interview with Popular Science, Jimmy Russell, Master Distiller at Wild Turkey reflects on the tradition of adding water to whiskey. While some bourbon makers historically opposed the idea, he acknowledges that adding water or ice can subtly alter the drink's profile, particularly as the ice melts, releasing new flavors. However, there's an exception. Per Russell, whiskey straight from the barrel is best enjoyed in its natural state, no water no ice. 

The Chemistry

Let's look into the chemistry of the addition of water to whiskey. 

A study in the journal Scientific Reports by Ran Freidman of the Linnaeus University Center for Biomaterials Chemistry in Sweden has utilized a computer simulation model to demonstrate that diluting whiskey brings flavor molecules to the surface, thereby improving the aroma and taste. 

This project began during his trip to Scotland, where Ran observed that all Scots added water to their Scotch regardless of the whiskey's proof. 

The reason is guaiacol, an aromatic oil that gives the liquor its signature flavor. Guaiacol is present in guaiacum, a kind of slow-growing shrub with purple flowers, and as relates to whiskey, the compound is also present in something called wood creosote. 

The Creosote

If we look at the whiskey process, the distiller begins by creating mash, which is then fermented, and the fermented mash is distilled. Following distillation, we have ethanol, which is the alcohol we commonly think of. Then the alcohol is aged in charred oak barrels. Charring wood creates wood creosote, so as the liquid interacts with the barrel’s walls, some guaiacol migrates into the liquor.

Ran Friedman used computational models investigating the distribution of guaiacol in water-alcohol mixtures of varying concentrations. Their research revealed that alcohol doesn't readily mix with water. 

At lower alcohol levels, alcohol tends to rise closer to the top of the glass. However, as alcohol concentration increases, alcohol molecules are in larger, denser clusters, and alcohol gravitates towards the bottom of the drink, away from the palate. 

When we sip whiskey from a glass, there is a liquid-to-air interface. However, when whiskey contains more than 50% alcohol, guaiacol tends to remain deep in the glass. 

Adding a bit of water moves guaiacol closer to the surface, for an improved tasting experience. 

The Centuries-Old-Practice

In conclusion, the centuries-old practice of adding water to whiskey finds validation in modern scientific understanding. The interaction of molecules within a glass of whiskey reveals why water improves the whiskey experience. 

Through computational simulations and observations, researchers like Ran Friedman have highlighted the role of water within whiskey's flavors. 

So, the next time you raise a glass of whiskey, consider the intricate interplay of molecules within, and perhaps, a touch of water will allow the spirit to reveal its hidden depths, inviting you on a journey of flavor and discovery. 

Cheers to the art and science of whiskey appreciation!