Serious whiskey drinkers insist that it tastes better on the rocks — that is, diluted with a little water — and, with the help of computer simulations, scientists now know why.
The distinctive taste of whiskey is largely caused by a molecule called guaiacol, which has one section that likes water and one section that doesn’t like water. In a study published today in the journal Scientific Reports, researchers simulated what happens to guaiacol when there are different concentrations of water, and which combination makes the molecule most potent.
Of course, the liquid in the Jack Daniels bottle isn’t pure alcohol to begin with. By the time whiskey is in the bottle, it’s usually already about 40 percent alcohol, though this can vary. The simulations showed that at the range of 40 percent to 45 percent alcohol, guaiacol is likely to be floating around at the top of the glass, which enhances both the smell and taste. So adding just a little bit of water can improve the taste of the drink because it pushes the molecule to the surface instead of having it dispersed weakly in the rest of the mixture.
But when there’s more than 59 percent alcohol in the drink, the lack of water means that the molecule gets driven away from the surface. It floats around in other parts of the glass, which makes the taste work — and proves that people are right when they say don’t drink your whiskey neat.