ADD WATER OR NOT?

 SCIENTIFIC ANALYSIS OF HOW WATER DEVELOPS YOUR DRAM

Whisky is a complex and nuanced drink that has developed over centuries and is rich in flavour and aroma. One of the most common questions that whisky enthusiasts ask is whether adding water to their dram is a good idea or not. The answer is not a simple yes or no: There is a scientific rationale behind the story.

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.

Water is a crucial ingredient in the whisky-making process. It is used to dilute the whisky from its cask strength, which can be as high as 70% ABV, to the desired bottling strength. Additionally, water is added during the mashing and fermentation process to create the wort, which is then distilled into whisky. The type of water used can also affect the flavour of the whisky. For example, water from peaty sources can impart a smoky flavour to the final product.

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.

The choice of water is crucial. Filtered or bottled water will ensure purity. You might have great tap water, but most people can’t know what’s in their supply. Tap water can contain chemicals that interfere with the whisky’s profile. Soft water is often recommended, as it can enhance the whisky’s subtle notes without overpowering them.

Room temperature water is typically best for diluting whisky. Cold water can numb your palate, obscuring the whisky’s complexity. Hot water would be even more disruptive and frankly, would be just plain weird.

Using a jug or pipette allows for precise control. A pipette is ideal for adding just a few drops, perfect for gradual adjustments without risking over-dilution. A jug is handy for measuring small amounts, especially when sharing or tasting multiple drams. These tools add a level of control that enhances your tasting experience, letting you focus on the evolving flavours with each sip.

Washington State University has 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, because the experiment was conducted in the USA, 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.

Interestingly, 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 panelists 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 later this year.

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.

Another study asked a panel of trained whisky connoisseurs to test 25 samples of bourbon, rye, single-malt and blended Scotches and Irish whiskies at various dilution levels — 100 per cent whisky, 90 per cent whisky and 10 per cent water, 80 per cent whisky and 20 per cent water, 70 per cent whisky and 30 per cent water, 60 per cent whisky and 40 per cent water, and 50 per cent whisky and 50 per cent water.

As it turned out, the panel decreed that the whisky varieties began to merge at a point starting at 80 per cent whisky and 20 per cent water as the non-hydrophilic molecules were pushed aside and crowded out. Simply put, the 80-20 whisky to water ratio hit the sweet spot, considering that a higher water percentage diluted the distinct flavours of the liquid and made all the different variants taste similar. Fixing up a drink with a water percentage lower than 20 retained its distinct aroma, properties and compositions.

ADDENDUM

Rachel Barrie, when Master Blender at Bowmore Distillery and Camper English, a cocktails and spirits writer, have argued that their experiments have showed that water drawn from the same region in which a whisky was produced seemed to bring out the specific taste qualities associated with that particular whisky. Barrie, who has a chemistry background, including a stint as a research scientist at the Scotch Whisky Research Institute, has documented the following visual and sensory changes that can be observed when water is added to whisky.

• Firstly, something called 'viscimetric whorls' develop - these occur when liquids of differing viscosities are mixed and can be seen as the water penetrates and mixes with the whisky.
• As the alcohol and water combine an exothermic reaction takes place.  This sees the temperature of the whisky rise by around 2ºC and allows it to release more aroma.  It also reduces the strength of alcohol and allows the sense of smell to work better.
• The lowering of alcohol strength gives a cooling effect on the palate and heightens the receptiveness of the tongue, particularly in the salty and fruity spectrum.  It also dampens flavours in the spicy and sweet spectrum.

Nevertheless, it’s interesting that there’s scientific evidence of where the dilution limit lies.