Should you add water to whisky? Don’t listen to the experts.

Science is largely still confused on how whisky "tastes" best.

Over the last decade, whisky tastings have changed dramatically. If the crowd is older, you’ll often find pipettes and distilled water as part of the tasting experience. Younger whisky drinkers, though, often prefer cask strength varieties and wouldn’t dream of watering down their lower proof (45% ABV) whiskies. 

When writing The Whisky Cabinet, I had no intention of telling people how to enjoy their whisky. What I did want to do, though, is provide an explanation of what happens to whisky when modifiers are added (ice, water, or even warming the glass in the palm of the head). 

Excerpt from The Whisky Cabinet

However, a study from 3 years ago changed conventional thinking. Forbes declared Yes, You Should Put Water In Your Whisky. The Washington Post all but declared the study found the best way to drink whiskey, according to science (spoiler: it’s water). Bigger spoiler—that’s not the conclusion to draw from the study. 

NPR went as far to conclude one should add a little bit of water to whisky. 

The study didn’t prove this either. The study did suggest more flavor is found when whisky is diluted to at but below 45% ABV. Most popular whiskies already coming at this proof point. Further, this was based on the study one one (and only one!) flavor molecule. That’s kind of ridiculous. 

So what did that one study show? 

Much of the science is purely speculative. Yes, even that one study that “proved” whisky tastes better with water is based on one assumption—guaiacol. This organic molecule is produced when lignin (polymers found in plant life) get heated. That’s a fancy way of saying char. Guaiacol is seen as the flavor molecule in coffee (toasted coffee beams produce guaiacol) and in whisky (similarly, charred oak barrels produce guaiacol). 

The study that “proved” whisky tastes better:

Computer simulations of water/ethanol mixtures in the presence of guaiacol discovered that, in mixtures with an ethanol concentration of up to 45%, guaiacol was more likely to be present at the liquid-air interface.

The conclusion, then, is with 45% ABV or under guaiacol is more detectable and thus the whisky tastes better. At above 59% ABV, guaiacol becomes heavily loaded with alcohol molecules and it becomes (theoretically) muted on our senses. 

What if you don’t like guaiacol? There are all sorts of studies that suggest whisky has ten, twenty or even fifty different compounds that provide flavor. Why all this focus on one flavor molecule? This one compound comes from charred barrels and nothing else (when it comes to whisky) and there are plenty more compounds found in barrels. 

I’m not arguing the validity of the research, only that it trivializes the taste of whisky to one flavor component. That’s a mistake. 

When adding water, what type of water should we add? 

The topic of water gets (accurately) more ridiculous. Important reading includes this article about the type of water:

However, by adding that water we are subtly altering the taste beyond simply releasing that ‘something’ already in the whisky. All drinkable water contains combinations of minerals with distinct flavours – and that inevitably can affect our whisky in various ways and to varying degrees.

Therefore, we should take our choice of water seriously: I firmly believe that the whisky tasting experience can be compromised through a poor choice of water.

This article by Felipe Schrieberg raises terrific points. I think they’re absolutely true. But I also think that once we start needing to measure the mineral content of the water we add, it’s added another complexity to our whisky drinking experience we potentially don’t need. 

So what actually happens when we add water to whisky?

A lot. In What Happens When You Add Water to Whiskey, Matthew Hartings explains much of the conventional thinking around water and whisky (thinking that I, personally, believe): 

And then water comes in like a bomb and destroys that tranquil balance. “When you take a drop of water and put it in a glass of whiskey, you can see all these ripples and all these convection currents. That’s the water you’re adding disrupting that balance,” Hartings says.

We love whisky because its pure chaos. Wine is settled and soft, and its low ABV means less is happening in the glass. That’s why one swirls the wine glass—it’s to excite alcohol molecules and provide more aroma (bouquet). In whisky, we have a volatile drink already, and we can influence that chaos. 

water radically rearranges the molecules inside. Hartings explains, “It’s kind of like playing pool. You start off with the racked balls. When they’re sitting in that rack, they’re happy being there. And even when you pull the rack away, they’re going to sit there. But you throw in that cue ball and it disrupts everything. Everything kind of moves around and has to find a new place to be.”

From my personal experience, I find a few drops of water release lighter acidic notes, especially with richer sweeter whiskies. However, it really does depend on the whisky: 

Water doesn’t affect all flavors equally, though. Some flavor molecules interact more strongly with water molecules than others. Picture again that kid holding a balloon, now picture him joined by an entire field of kids holding balloons of different colors—some blue, some green, some purple, all representing different flavors and smells. 

It should be noted, that some of these changes are temporary. By adding water, you shock the glass. Eventually (30 seconds to a minute), though, the glass will calm. 

Can you just tell me how to drink my whisky? 

I like Davin de Kergommeaux’s answer:

For rare whiskies, I prefer to start straight up. I guess this works for shooters too, but I never do shooters. For a casual dram while chatting I like to add ice. I HATE those whisky stones, discs, whatever. Slow dilution is part of the benefit of using ice cubes. A few drops of water often improve the whisky by making it more approachable and by releasing a lot of hidden flavours. ...I prefer to focus on the people I am drinking with and not be distracted by analyzing the whisky. Analytical tastings, I do in private and they are not all that much fun.

I rarely add water to whisky. I almost never do it when I’m casually drinking, and I rarely do it when analyzing tasting notes. There are times where I can’t quite get a tasting note, and I start to heat up the glass in the palm of my hand and/or add water to see what happens. Those times, through, are rare. That’s me, though, and that answer won’t be right for you.

We don’t all love spicy food. Some of our palates are more or less sensitive to spice. There’s no right or wrong answer to how much sriracha we should put into our food. Whisky, water, and alcohol content is a similar conversation. 

Drink whisky the way it tastes best for you.