Scientists find why whiskey tastes better with water

A new study has found that a little water goes a long way in enhancing the taste of whiskey.

The combination does not at first strike as a particularly a happy one which was one of reasons researchers wanted to look at the molecular chemistry behind what goes on in your whiskey glass.

Though whiskey is mostly grain and water that goes through a specific process, but from a chemistry standpoint, whiskey also comes with a complex variety of molecules that contribute to its unique taste. Among these is a compound called guaiacol, which lends itself to the smokiness associated with some whiskeys.

Björn Karlsson and Ran Friedman from the Linnaeus University Center for Biomaterials Chemistry in Sweden studied the molecule and reported their findings on Thursday in the journal Scientific Reports.

The researchers used both bottled and cask-strength whiskey in the study. Bottled whiskey has been diluted to about 40 per cent alcohol by volume, down from 70 per cent after distilling, while whiskey is stronger, at about 55 per cent to 65 per cent alcohol by volume, even if some alcohol evaporates as it matures in barrels for at least three years.

The researchers found that guaiacol is most present at the surface of diluted whiskey, which accounted for whiskey with added water tasting better, as taste molecules are at the top of the glass.

Karlsson and Friedman found that guaiacol was more likely to be present at the ''liquid-air interface'' of a whisky with concentrations of ethanol up to 45 per cent.

''This suggests that, in a glass of whisky, guaiacol will therefore be found near the surface of the liquid, where it contributes to both the smell and taste of the spirit,'' said Freidman.

''Interestingly, a continued dilution down to 27 per cent  resulted in an increase of guaiacol at the liquid-air interface. An increased percentage, over 59 per cent, had the opposite effect, that is to say, the ethanol interacted more strongly with the guaiacol, driving the molecule into the solution away from the surface.''