Dilution of Whisky -- the Molecular Perspective (nature.com)

From a new published paper in Scientific Report by Bjorn C. G. Karlsson and Ran Friedman: Despite the growing knowledge of the nature of water-alcohol mixtures on a molecular level, much less is known on the interaction of water, alcohol and small solutes. In particular, the nature of the interaction between the solvent and taste-carrying molecules, such as guaiacol, is not known. To address this gap, we used MD simulations to study the distribution of guaiacol in water-alcohol mixtures of different concentrations. Our simulations revealed that guaiacol is present at the air-liquid interface at ethanol concentrations that correspond to the alcohol content of bottled or diluted whiskies. Because the drink is consumed at the interface first, our findings help to understand why adding water to whisky helps to enhance its taste. A molecular understanding of the nature of taste compounds in water-alcohol mixtures allows for optimizing the taste of alcoholic spirits. [...] Overall, there is a fine balance between diluting the whisky to taste and diluting the whisky to waste.

Comments

Whisky != Whiskey

[lophophore]

The authors of the article don't understand that "whisky" (from Scotland) is not the same as "whiskey" (from anywhere else.)

The discussion that the water opens the whisky up and makes the guaiacol more aromatic does not apply to whiskey that does not have a lot of this chemical in it, that is to say NOT SCOTCH.

Adding water to Irish Whiskey, or good ole American Bourbon Whiskey, is not going to have the same effect. Adding a couple teaspoons of cool water to your delicious smoky single malt from Islay will make a noticeable difference and open op the "nose" of the whisky.

True "whisky snobs" know the difference.

Re:Whisky != Whiskey

[Sumus Semper Una]

The authors of the article don't understand that "whisky" (from Scotland) is not the same as "whiskey" (from anywhere else.)

Isn't that why Scotch exists as a word used to describe a specific kind of alcoholic beverage? Also, did you even read the article? Ok, this is Slashdot, that was a silly question to ask. Anyway, here's an excerpt from the introduction stating that they are well aware of the differences in guaiacol content:

Guaiacol is a small and mostly hydrophobic molecule that is able to interact with polar solvents via hydrogen-bonding and polar-aromatic interactions. Higher concentrations of guaiacol have been found in Scottish whiskies than in American and Irish ones. The concentration of guaiacol was found by GC/MS to be 3.7–4.1mgL1, or about 3.2105M in two undisclosed Scottish whiskies5. It is likely that the concentration of guaiacol in Isley whiskies is even higher.

And, more specifically, they point out in their conclusions that dilution with water is only helpful to cask-strength whiskey to bring out its flavor:

Dilution of cask-strength whisky improves its taste by increasing the propensity of taste compounds at the liquid-air interface... ...It is therefore reasonable to assume that the taste of guaiacol (and other amphipathic, semi-volatile compounds) is less pronounced at high alcohol concentrations, which explains why dilution of cask-strength whiskies results in a change in the sensory effects of the whisky.

So diluting some off-the-shelf Jack Daniel's likely won't enhance its whiskey flavor. But adding a little water to some Scotch or cask strength Maker's Mark will enhance it.

Re:Whisky != Whiskey

[pz]

Having been in and around both audiophiles and whisky aficionados, I can most certainly say that the latter are far less ... ah, annoying ... than the former. Whisky lovers, after all, like to drink. That alone eliminates most of the peccadillos.

And, really, when it comes down to it, there are substantial differences between the various amber liquors. Just because something alcoholic is aged in wood does not mean it is like everything else that is.

Also, importantly, the differences that audiophiles talk about are often minute and difficult to discern. The differences that whisky aficionados talk about are readily perceived by the ordinary palette.

And while the audiophile realm is filled with snake oil salesmen who want nothing more than to separate you from your hard-earned wages, providing you with products of highly dubious value, whisky is largely --- and I do say this in the over-all sense, understanding that there are occasional exceptions --- value-based. The more you spend on a bottle, generally speaking, the better it will taste. By comparison, wire is largely wire no matter how expensive it is.

Cask strength -v- Bottle strength

[seoras]

As lophophore correctly points out this only applies to Scottish Whisky, but I'd go further by adding that it only applies to cask strength Whisky not your off-the-shelf bottle strength (~40%) which has already been watered to taste.

I got my education in Whisky in the early 90's living in Edinburgh where there was a private club in Leith called the Scotch Malt Whisky Society. 4 times a years the owners would tour the distilleries sampling casks and purchasing the ones they liked best which they then bottled and sold in the club rooms directly from the cask (hence cask strength). The distilleries allowed them to do this on the condition they numbered the bottles protecting the anonymity of each distillery which has it's own unique (blended) flavour.
They'd organised guided tastings which I went to a number of. You'd get 3 Whisky's and be told to taste a tiny amount un-watered and then slowly add water to taste until you felt the flavours had come out. The results are dramatic and the taste of that Whisky is unlike anything you've ever tried or known about Whisky.
They've since been bought out by a large company and are now a global franchise. If you can find one near you then I recommend trying them out.

If you can't find them near by the I'd recommend by favourite Whisky Lagavulin.
It comes as a standard 16 year old which is regular strength and also as a 12 year old cask strength. I always go for the cask strength one.
Whisky's don't improve much after 12 years.

Final tip. Try to use distilled water to dilute. As clean and neutral as you can get.