If you've ever sauntered up to the bar and

ordered a whiskey neat,

you probably looked really cool doing it.

But… sadly, you ordered a sub-par drink.

Because it turns out a little water can make your whiskey more flavorful.

It's all thanks to the weird chemistry of alcohol solutions.

Whether it's an aged Glenfiddich or your standard Jack Daniels, whiskeys can all be

boiled down to three basic components.

Alcohols, especially ethanol, to get you tipsy; water, to keep you from dying; and some yummy

carbon-containing compounds to add flavor.

In scotches, for example, one of the key flavor compounds is guaiacol, which essentially looks

like a ring of carbon atoms with a couple of oxygens attached.

It's largely responsible for that distinctive, smoky flavor.

But what's most important about guaiacol is that it's amphipathic: part of it interacts

with water, while another part repels water.

And that means it behaves differently depending on the concentration of water it's dissolved

in.

To figure out what this all means for your glass of whiskey, a team of researchers carried

out a set of computer simulations that modeled various combinations of water, ethanol, and

guaiacol.

They already knew that water and ethanol never really fully mix.

And the shape of alcohol molecules means that they tend to collect at the liquid's surface,

a state that minimizes the mixture's overall energy.

But while guaiacol can form relatively strong hydrogen bonds with both water and ethanol,

the computer data suggested that its carbon ring forms an additional interaction with

the alcohol.

And that meant that, at moderate alcohol concentrations, it followed the ethanol up towards the drink's

surface—putting it in a prime position to hit your tongue when you take a sip.

The scientists found this concentration effect happened up to about forty-five percent alcohol-by-volume,

which, in whiskey terms, would be ninety proof.

And that might explain why whiskeys and scotches, which are distilled at one hundred thirty

to one hundred fifty proof, are usually diluted down during the bottling process.

They literally taste better that way, like you can taste them better...

Annnnd that wasn't all the researchers found.

As the simulated whiskey continued to be diluted past the forty-five percent mark, the guaiacol

in it became less and less bound to ethanol.

So not only was it at the surface, it lost some of its connections to the liquid around

it.

That's key because the surface of a liquid is also where evaporation happens.

And the flavor you experience when you drink something isn't just what you taste with

your tongue.

A lot of it depends on the compounds you smell.

While the time period studied was too short to actually see evaporation happen, the authors

said diluting from forty-five percent to just twenty-seven percent alcohol would likely

increase the amount of guaiacol that becomes part of the whiskey's smell—and therefore,

a bigger part of its flavor.

And all that means that if you want the most flavorful whiskey experience, you probably

want to add in some water instead of drinking it neat.

You might even consider watering down other boozes.

Lots of flavor-causing substances are amphipathic molecules, so the authors speculated that

the tasty components of other drinks could behave a lot like guaiacol.

Of course, taste is a complicated, personal thing and some ways of adding water — like

dropping in an ice cube — might have other, unexpected effects.

So, really, just do what tastes best to you.

And drink responsibly!

And before I go, I want to lift a glass to our wonderful community of patrons who support

SciShow on Patreon.

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