Whisky stones are an unusual little tool to put in whisky glasses. They are intended to replace ice cubes, with the added benefit of not melting and diluting the whisky.
There is unanimous agreement that over-diluted whisky ruins its flavor. The mechanism of action is easy to understand, as diluting any drink weakens its flavor. I can remember drinking cordial on a hot day as a child and gradually losing the sugary taste as the ice in it melted.
Heavily diluting whisky, however, may alter the nose of the whisky significantly. It can make some smells more prominent and push others in to the background. This probably qualifies as ‘interesting’ rather than good or bad. Personally, I prefer to taste all but cask strength whiskies at their full strength.
The other issue that whisky lovers raise when they recommend against adding ice is the issue of temperature. By lowering the temperature of the whisky, it is supposed that the chemical content changes or the ability of the taster to perceive released flavors (to nose the whisky) is altered when the liquid is a lower temperature. The theory goes that cooling the liquid slows the release of aromatic compounds. So a cooler liquid will reduce the aroma of the whisky, but not the taste.
Enter Whisky Stones
From the paragraphs above we have established that whisky stones may reduce the capacity to nose whisky but won’t ruin the flavor. Truthfully, whisky stones lower the temperature of whisky much more slowly than ice does, and they heat back up more quickly too. They tend to stay cool for around 20 minutes or so in my experience.
Whisky stones are actually a traditional method of cooling whisky. The Scots would go to a riverbed, pick up some pebbles and drop them in to their glass to cool them. Basically identical to what we do now. Legend says that this is where the phrase on the rocks comes from when we order whisky with ice at a bar.
Problems With Whisky Stones
Some users of whisky stones report tasting a distinct flavor when using stones. The taste, appropriately, is somewhat ‘stoney’. Whether this is real or imagined is hard to say. I personally did not find them to add extra flavor to my whisky.
To ensure that they do not add flavor, before using your stones you could boil them. Store them in the freezer in a sealed bag so that they do not ‘pick up’ the flavors of your freezer. I’ve not heard of many distillers hoping for a hint of frozen veg in their whisky!
Conclusion
Whisky stones are best used on a hot day to maintain or slightly cool whisky. Alternatively, they can be used with blends or ‘daily drinkers’ that are being sipped gradually rather than fully appreciated. Taking whisky neat provides the most optimal flavor in my and many others’ experience.