Many think it's a sacrilege to mix water with whisk(e)y, but real connoisseurs know that a few drops of water enhances the taste. They are right - and researchers have discovered why.
True whisk(e)y lovers have known it all along: A few drops of water in the drink and the flavor will come out much better. However, until now nobody knew why this was. Two biochemists solved the mystery: Björn Karlsson and Ran Friedman from the Linnaeus University Centre for Biomaterials Chemistry in the Swedish city of Kalmar discovered that water makes a specific aromatic substance reach its full potential at the surface of the liquid. They published their findings on August 17th 2017 in the journal "Scientific Reports."
The production of whisk(e)y involves several steps: Similar to the brewing of beer, it starts with a mash made of malt. It ferments in a kettle when yeast is added. It is then distilled up to twice. The distillate holds about 70 percent of alcohol in the end.
In the next step, the distillers fill it into wooden kegs, where it sits while the alcohol level gradually drops down to about 55 to 65 percent. In the end, the distillers dilute the whisk(e)y with water to bring the alcohol concentration to about 40 percent for bottling.
The smokey taste comes from the wood
The taste of the whisk(e)y depends on a variety of factors: The malt, the mash, the timing and temperature of fermentation. But probably one of the most important aspects is the quality of the wooden barrels. They are responsible for adding a key flavor to the liquid: A phenol molecule called guaiacol.
This aromatic substance develops in the wood, where bacteria or temperature lead to the reduction of lignin – the material which makes wood sturdy. Also in smoked foods guaiacol is responsible for the flavor - or in fine wines with a specific taste of cork.
Neither too little nor too much
The scientists simulated at the computer how guaiacol, water and alcohol interact at different alcohol concentrations. They found out, that up to an alcohol concentration of 45 percent, the guaiacol moves primarily to the upper level of the glass, close to where the liquid meets the air. There it displays it's fullest flavor and taste.
Too much alcohol in the drink can spoil the flavor: Above 59 percent, the guaiacol will sink in the glass. This is why it is advised to add some water to fine whisk(e)ys.
But be careful and don't overdo it: There is a fine balance between enhancing the taste and ruining it.