The product has been doing the rounds for a short while now, however many people initially expected the stones to go the way of most drinks fads and into the history and hazy memory books of people who thought them novel. Well they haven't if anything they seem to be growing in popularity. They do however seem to be drawing a line in the sand when it comes to opinion though.
The vast majority of bartenders and whisky purists are firmly of the opinion, single malts should be enjoyed either neat or with a splash of water. Dale DeGroff is even quoted as saying "It's idiotic" he carries on to point out the fact that zero bars, unless in an ironic manner, are using the stones.
Some argue the stones are trying to fix a problem that doesn't really exist. When was the last time someone sent back a scotch with the complaint "the temperature to dilution ratio is completely off. I want it X degrees in temperature but with only X amount of dilution." An odd complaint to say the least.
Once you start to look at who is actually buying the stones, you realise bars and bartenders aren't the market they're aimed at. The stones have become a gift for 'tough to shop for' Dads, or Uncles. They're for friend's Husbands who you don't know too well, however you do know they're a fan of scotch. The suppliers say they are breaking into younger markets. Young professionals who enjoy the drink but not the stigma. This simple addition creates an identity for them as the forward thinking Scotch drinkers not bound by the choice of simply neat or rocks.
What the stones do not cater for is the fact that dilution AND lowering temperature actually releases more flavours within whisky that you wouldn't be able to taste without it. The classic phrase, "water opens up whisky" is actually completely true. The simplest way of understanding this effect is via the diagram below, (courtesy of khymos). Essentially alcohol over 20% forms micelles which are so tight they actually trap flavour within them. Add dilution and cooling, the whisky becomes more soluble and a lower % of alcohol. This loosens the chains and increases the release of flavour.
It seems the stones have a high novelty value and make a great gift, however when it comes to flavour their purpose appears to be lacking. It's unlikely many bars will be serving up whisky with rocks anytime soon however thinking outside the box for a second, how many other drinks are ruined by dilution or loose desirability as their temperature rises..... A martini that stays cold for an hour, or a long drink that you can sip on slowly without it becoming a watery mess by the time you hit the bottom of the glass….. Not so good for whisky but potential in other areas maybe?