If you’ve ever been to a whiskey tasting, you’ve likely been encouraged to add a few drops of water to your glass to “open up the palate.” This technique has long been employed in the single malt scotch whisky world, but the amount of water you should add is often open to interpretation. That is until now, thanks to a new study from Washington State University that reveals how much water is too much water.
Of course, add as much water as you want to your whiskey—or Coke or Dr. Pepper or whatever— because it’s meant to be enjoyed however you like it best. That being said, if you are interested in knowing at what point you are diluting your whiskey and not allowing the palate to bloom, the WSU researchers have capped it at 20 percent. In other words, if you have a 60-ml glass (about two ounces) of single malt whisky in front of you and would like to add some water, don’t add more than 12 ml or the equivalent of 20 percent of the whiskey’s volume. According to Thomas Collins, WSU assistant professor and senior author of the study (which was published in the journal Foods), adding more than this homogenizes whiskey and makes it all kind of start to smell and taste the same.
For this study, WSU researchers analyzed the volatile compounds of 25 different whiskeys across many categories, including bourbon, rye, scotch, and Irish, as well as having a sensory panel analyze six samples, to find out what the right amount of water is. Specifically the researchers looked at what they called the “headspace” above the liquid where the volatile chemicals can be found. Some are attracted to water and others are repelled by it, so when you add water the smell and flavor will change. According to Collins, peated whiskies shifted from smokey to fruity after adding water, and bourbon from vanilla and oak flavors to a more grain-heavy profile. At a 60/40 whiskey to water ratio, panelists had trouble telling one whiskey from another.
Show this study to any scotch distiller or blender and he or she would likely mutter “I told you so” in a thick brogue. When you are encouraged to add water to a glass of whiskey, usually just a few drops are recommended which is enough to unlock new flavors without totally diluting the spirit. According to Collins, this research might also help encourage people to use one large ice cube if they want to drink whiskey on the rocks instead of filling your glass with smaller cubes—that way the dilution slows down and you can finish it before the 20 percent water threshold is reached. Kudos to this important work in the world of helping us better enjoy our whiskey, but maybe scientists and researchers can get back to curing cancer now.