According to a study conducted by Washington State University, adding water to whiskey to “open up” its flavor is a popular belief among whiskey lovers. However, research suggests that adding too much water, especially more than 20%, can ruin the flavor of whisky.
In the study conducted by Washington State University, researchers analyzed the chemical response of volatile compounds from 25 types of whiskeys to the addition of water. Whiskeys included bourbons, ryes, Irish whiskeys, and single malt and blended scotches. Additionally, a trained sensory panel rated six of the whiskeys, including three bourbons and three scotches.
The study by researchers at Washington State University found that adding water to whiskey can alter its aroma and flavor. The researchers analyzed volatile compounds in 25 different types of whiskeys, including bourbons, ryes, Irish whiskeys, and single malt and blended scotches. They also had a trained sensory panel evaluate six of these whiskies. The study found that adding a small amount of water can change the aroma of whiskey, but if more than 20% water is added, whiskeys can start to have the same aroma, which affects their flavor.
According to Tom Collins, an assistant professor at WSU and lead author of the study published in the journal Foods, if someone wants to get the most out of a particular whiskey, they shouldn’t dilute it more than 20%. After this point, the whiskeys begin to have a similar aroma and lose their characteristics, which is undesirable for whiskey lovers. Collins also suggests that adding too much water to whiskey can negatively affect its aroma and taste.
The study found that at a whiskey to water ratio of 60/40, panelists had difficulty telling the whiskeys apart, indicating that the whiskeys had lost their distinct aroma and flavor profiles. The researchers noted that this point of diminishing returns can vary depending on individual taste preferences and the specific whiskeys tested.
The smells of each type of whiskey became more similar when water was added, but Scotch still smelled different from American bourbons and ryes.
The researchers also analyzed changes in the volatile compounds above the liquid, known as “headspace”, when water was added.
Whiskey contains a mixture of compounds that have different levels of attraction to water. When water is added to whiskey, compounds that don’t mix well with water are sent to the space above the liquid, while water-attracting compounds stay behind. It changes the smell of whiskey.
The researchers found that the results of the chemical analysis matched the observations made by the panel of experts. For example, several of the Scotch whiskeys started with a smoky “peat” flavor, but as they were diluted with water, they moved to a more fruity flavor called “apple”.
According to Collins, when whiskey is diluted with water, the compounds that create smoky flavors begin to dissipate and are replaced by compounds that create fruity flavors. This happens because adding water affects what’s in the headspace, which is the area above the liquid.
American bourbons initially smelled of vanilla and oak, but as more water was added, the flavor changed to include flavors of corn and grains that are used in their manufacture.
The results can help whiskey makers better understand how their customers will experience the drink if they choose to add water or have it “on the rocks”.
It also gives some support to the practice of serving whiskey with a single large ice cube.
According to Collins, the study helps explain why large square ice cubes have become popular. As the ice slowly melts, it dilutes the whiskey, allowing it to be enjoyed at a slower pace before it dilutes to the point that it no longer tastes the same.
Collins and his colleagues continue to study the compounds that make Scotch whiskeys smell smoky. They will talk about their ongoing work and this study at a conference in Scotland in May.
In addition to Collins and Tomasino, co-authors of this study include Aubrey DuBois of Michigan State University and first author P. Layton Ashmore and James Harbertson of WSU.
