Whisky fans are possibly the most particular spirit drinkers in the world. Debates have raged over the right way to consume whisky, with mixers or ice being either wholeheartedly welcomed or vehemently rejected by aficionados everywhere.
However, if you’re not drinking neat, the most commonly agreed upon method of enjoying whisky is with water. It’s long been known that adding water to a dram can open up the whisky to reveal new aromas and flavours. A recent study has now determined the optimal whisky to water ratio for drinkers.
Washington State University have conducted a two pronged experiment. Firstly, they studied the chemical composition of the headspace (the area between the top of the liquid and the top of the glass) in a range of different whiskies - including both single malt and blended Scotch, Irish whiskey, and American ryes and bourbons -, and then analysed the differences that occurred during dilution.
The second element of the study featured a trained panel of 20 experts assessing the aromas of six different whiskies as they were diluted. These whiskies were three Scotch whiskies and three bourbons.
Undiluted, the experts were easily able to distinguish between the whiskies in the two categories, and this continued up to around 20% dilution. In this zero to 20% water range it was noted how the aromas of all six whiskies changed.
However, 20% seemed to be the maximum dilution level that had this benefit; any more than this, then the differences became less pronounced. By the time the spirits reached a 60:40 whisky-water ratio, the panellists were unable to distinguish between the various whiskies in each category (although they could still determine a difference between the Scotch and the bourbon).
In terms of flavour, the panel noted that the Scotch whiskies started off with a distinctly peaty and smoky aroma initially which subsided with dilution to reveal notes of pome fruits. The scientific analysis of the headspace went some way to explaining this.
Whisky is composed of chemical compounds that are either hydrophilic or hydrophobic, meaning attracted to or repelled by water. Adding water to whisky will in essence release these hydrophobic compounds into the headspace in the glass. Acetic acids contained within whisky are known for their ripe fruit aromas and are hydrophobic, explaining why the experts noticed sweeter, fruity aromas after dilution.
Compounds run from hydrophilic to hydrophobic on a scale, so adding different volumes of water will release different compounds and therefore reveal different aromas. Because the senses of smell and taste are so closely related, the researchers conclude that dilution will affect a whisky’s flavour as well as its aroma to a similar degree.
Those behind the study hope that their findings will help whisky makers better understand what their customers’ whisky drinking experience, particularly with water or ice, and also aim to explore reasons behind drinking trends.
For example, their research backs up the reason why serving whisky with a single large ice cube (rather than multiple smaller cubes) has become increasingly popular. Large cubes melt slower and therefore dilute the whisky less quickly, so drinkers can then enjoy their chosen whisky at a cooler temperature before it becomes too diluted.
The research is still ongoing, and the researchers hope to reveal more of their work at the Worldwide Distilled Spirits Conference in Edinburgh later in May.
Of course, the findings from this study probably won’t come as too much of a surprise to most whisky drinkers. At some point we’ve all experienced how an otherwise uninspiring dram can flourish with just the lightest hint of dilution, or gone the other way and accidentally killed a whisky by adding a little too much water.
Nevertheless it’s interesting that there’s scientific evidence of where the dilution limit lies. Now if scientists could get to work on figuring out the perfect volume of lemon juice to add to a whisky sour that would be great.