Adding Water To Whiskey? Here's Why Temperature Matters

While many assume that adding water to whiskey will weaken its taste and its strength, this couldn't be further from the truth. In fact, adding a few drops of water can elevate the drink and reduce the whiskey's burn, and is often recommended if the liquor has an ABV above 55%. "Adding water can open up aroma, soften alcohol heat, and make flavors easier to identify, especially in higher-proof whiskey," says Chris Blatner, an executive bourbon steward and the executive director at Bourbon Charity. "A small amount of dilution can release volatile compounds that are otherwise masked by alcohol. It's less about weakening the whiskey and more about reshaping how it presents itself."

However, there are many variables at play when adding water, including temperature. While one might figure that cold water would be best for the job, Blatner says room temperature is ideal. "Cold water suppresses aroma and flavor, while hot water can exaggerate alcohol and throw the balance off entirely," he said. "If the goal is exploration and clarity, room temp gives you the fullest picture of the whiskey."

There are some instances when combining hot water with whiskey is common — whiskey, hot water, honey, and lemon juice make a hot toddy, one of the best warm whiskey cocktails for cold weather. However, if your focus is on making as few modifications to the whiskey as possible, sticking to room temperature – specifically between 60 and 65 degrees Fahrenheit — is absolutely vital. 

Both the water's quality and amount are pivotal for having a great glass of whiskey. While some say the difference between using tap water and bottled water is purely a matter of personal preference (though many recommend avoiding this bottled water brand), Chris Blatner noted that the best fluid for the job should meet one specific requirement. "It's best to use some type of filtered water when possible," he said, noting that chlorinated or heavily mineralized water could impact your whiskey's flavor drastically.

As for how much water to use, while it does depend on the type of whiskey, Blatner noted that being conservative with the added ingredient is your key to success. "Start with just a few drops, not a splash," Blatner said. "You can always add more, but you can't take it back out." With this in mind, the whiskey expert also advised giving your whiskey a try before altering it. "Not every whiskey benefits from water," Blatner said. "Some are already balanced right out of the bottle, and forcing dilution can actually ruin the experience." This is often the case for whiskeys with an ABV between 40% and 46% that may come balanced, like the immensely popular Jack Daniel's Old No. 7.