The debate over whether to add water to whiskey has been going on for about as long as whiskey has been around. But it seems that scientists have finally given us an answer to one whiskey-related question: why does adding water to whiskey enhance it? And as it turns out, diluting a glass of whiskey with water isn’t going to create a ‘watered-down’ effect. Actually, quite the opposite happens.
A study done by a Swedish scientist at Linnaeus University looked at how adding water to whiskey changes the aroma and taste of the drink. Although the water and grain contents of whiskey are relatively simple, the molecules contained in whiskey are quite complex.
Guaiacol is a type of molecule in whiskey that gives the drink its smoky taste. Researchers found that when whiskey had been diluted, the guaiacol molecules rise to the top of the liquid. So when you add in water, the guaiacol molecule is forced to rise to the top of your glass, bringing the smoky flavor of the drink along with it.
“From a molecular perspective, water and alcohol don’t completely mix. Instead, we have clusters of water molecules and clusters of alcohol molecules,” said Ran Friedman, one of the co-authors of the study. “When whisky is diluted, the alcohol is driven to the surface, and many of the taste molecules follow it because they like to be in a slightly less aqueous environment. The taste that we experience is therefore enhanced — but there’s a limit. If we dilute the whisky too much the concentration of the taste compounds is reduced and the drink will be meager.”
Friedman and Co-Author Bjorn Karlsson used computer simulations to test the behaviour of molecules in whiskey. The researchers believe that their findings can be applied to other liquors, including rum, brandy and tequila, which all have similar makeups to whiskey.
“We believe that the principles we describe are true for a long list of taste compounds,” said Friedman. “In that case, one can find an optimal alcohol content for a spirit to taste best for many drinkers. The conclusions may also apply for the food industry, as some extracts that are used in the industry are stored in diluted alcohol solutions.”
So, exactly how much water should you add to a glass of whiskey? Well, that’s largely up to personal taste. To make things even a little more confusing, Karlsson explained that too much water can be a detriment to the taste of whiskey.
“We have receptors on our tongue, in our nose, that are sensitive and depend upon the concentration of the specific components you want to detect with your nose and tongue,” Karlsson told NPR. “So if it’s too diluted there’s a risk that you actually don’t detect it with your nose or your tongue.”
While some whiskey makers provide complicated answers when it comes to how much water to add, you could always go with celebrity chef Anthony Bourdain’s recommendation of one or two ice cubes per glass. No need to do math while drinking your whiskey.