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Water into whisky

A recently published article from researchers at Linnæus University in Sweden may have identified a scientific rationale for adding water to your whisky. Dr Rob Keyzers from the School of Chemical and Physical Sciences gave his opinion on the findings to Fairfax Media reporter, Thomas Heaton.

The research carried out by Dr Björn Karlsson and Dr Rand Friedman of the Linnæus University Centre for Biomaterials Chemistry focuses on the fact that whisky derives its smokey taste from amphipathic molecules, such as guaiacol. The combination of these guaiacol molecules with water-ethanol mixtures were tested through computer simulations to give atomistic details on the structure of the liquid mixtures. They found that guaiacol was preferentially associated with ethanol, and that at concentrations of ethanol up to 45%, it was more likely to be present at the surface of the liquid rather than further down the liquid column. At concentrations of ethanol greater than 59%, they discovered that guaiacol interacts more strongly with the alcohol and the molecule sinks lower into the solution.

In the context of a glass of whisky, this means that guaiacol would help to characterize the smell and taste of the liquid at the surface of the spirit. The taste of guaiacol and similar compounds in the whisky are enhanced when the spirit is diluted before bottling and similarly the taste may be more pronounced on further dilution in the glass.

The findings of the research were put to Dr Rob Keyzers, senior lecturer in organic chemistry at Victoria by Thomas Heaton, a food reporter with Fairfax Media. Rob stated that flavour and taste were two different things, and the nose had a role to play. 

"That's where we detect flavour," he said. The tongue detected tastes, such as sweet or salty, but the flavours that differ between foods was detected "retro-nasaly", he said. 

That was why wine-tasters put their noses into glasses and are able to recognise certain types of wines, he said. "Adding reasonably small amounts of water to whisky alters, in this case, guaiacol."

"The ethanol helps it stay dissolved, and it's happy there. By adding the water you make it less happy to be dissolved and it wants to release. It's all about changing the distribution really, of how much how much is dissolved and how much is travelling up the back of your nose."

Adding water also had a dilution effect, Keyzers said. "There's a balancing act around how much you can force into the gas stage and how much you get per 100ml or 10ml."

He said this research was a "really good place to kick off experimental research", taking into consideration people's tastes and preferences.

Adding ice was a different story all together, he said. Ice could suppress the "hot" feeling in the mouth and some of the taste, but could melt and add to the flavour. 

"You couldn't put it down to one thing, and ice will have a different effect to water. There's all sorts of subtleties there."

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