Add too much water and your expensive malt turns into cheap brand whisky, study says

On the rocks, a few drops of water, neat or mixed are some of the ways whisky can be enjoyed.

Now, a study has found that adding too much water or ice makes a 21-year aged single malt taste the same as a cheap knock-off.

Three drops of water, or a single large ice cube, is the optimum way to serve a whisky, according to researchers. Dilution of more than 20 per cent however, ruins the drink, data show. A two-inch square ice cube contains slightly more than 100 ml of water. According to the study, this is ten times too much water to dilute a double measure of 50ml, which needs a maximum of 10ml water to preserve the whisky's flavour.

Nevertheless, scientists say the key to avoid watering down the drink beyond recognition is to use as large an ice cube as possible and sip regularly, to slow the melting rate down as much as possible.

Adding water changes the chemicals released from the drink, previous studies have found, with the air directly above the surface, known as headspace, influencing aroma. Too much water, however, and these chemicals dissipate quickly, altering sensory perception.

American researchers assembled a panel of smell experts who sniffed 25 different samples, ranging from ryes and single malts to Scotch and Irish drams.

The panel tested the samples neat, and then diluted by 10, 20, 30, 40 and 50 per cent. All of the whiskeys and whiskies could still be distinguished from one another up to a 20 per cent dilution, with their distinctive scents still discernible.

However, dilution beyond the 20 per cent cut-off means the identifying factors, carefully crafted by expert distillers, are lost. After this point, all the samples blur into one pungent, vaguely whisky-flavoured aroma.

“If you want to enjoy a specific whisky, this suggests that you don't want to dilute it by more than about 20 per cent,” said Dr Tom Collins, senior author of the study from Washington State University. “By the time you get to 60/40 whisky to water, the whiskies are not differentiated by the panellists; they begin to smell the same, and that’s not really what you're looking for.”

The team found that the loss of nuance in flavour occurred within individual types of whisky, but not across them. For example, excess dilution makes a high-end Scotch indistinguishable from a low-cost alternative, and a luxury single malt the same as a cheaper alternative.

But defiling a fine Scotch with large amounts of water will not make it taste like an American bourbon, the study found, as the different groups are varied enough to still be detectable even at 50 per cent dilution. The smoky aromas of a Scotch were found to disappear quickly in the presence of water, the study’s follow-up chemical analysis found, being replaced with generic fruity scents.

For bourbons, the identifying vanilla and oak notes are replaced with corn and grain odours from the crop used to make them. The findings lend some support to the practice of enjoying whisky not with several clumps of ice, but one large ice cube.

“This study helps to understand why those large, square ice cubes have become so popular because you can actually enjoy the whisky before it gets diluted to the point that it's not the same whisky,” said Dr Collins.

Mark Reynier, chief executive and founder of Waterford Whisky, an Irish distillery which has applied the French winemaking science of terroir to whisky, says that diluting drink is often seen as taboo, but can play a key role in enjoying the drink.

“There is often a certain fear, within whisky circles, of adding water to whisky – as though diluting somehow breaks a kind of unwritten purity law,” he told The Telegraph. “That can be the case if too much is added. But adding a few drops – usually no more than three – can make the unique flavours of a whisky all the more rewarding.

“When drops of water are added, ‘viscimetric whorls’ form – these are those mesmerising spirals you can see in the glass. They allow the spirit to breathe: the whisky literally ‘opens up’ as compounds unclench, and complex aromatic potential – derived from different barley flavour sources – can be fully realised.

“Of course, not all whiskies are created equal and because of Waterford’s unusual technological set-up and higher bottling strength, people are able to add a touch more water to their glass than they can with whiskies that have been filtered or artificially coloured.”

He also warned that adding ice makes the drink colder, and this can also inhibit flavours  because it "closes down flavour profiles rather than opening them up”.

The study is published in the journal Foods.

Make sure your ice is large - and make sure it's quality too!

by Joel Harrison and Neil Ridley

It is no secret in the drinks industry that the addition of a little water opens up the flavour and aroma of a whisky. We sit on various spirits awards judging panels, and our fellow judges who hold roles as master blenders and whisky makers for various globally famous brands will always add a little water to their drams.

For professional assessment, we would suggest that adding a little H2O is a great way to explore the flavours hidden in a dram. However, if you are drinking simply for pleasure, then whatever way you feel whisky is best enjoyed, should be the way that you drink it. And we would wholly advocate adding ice, if that’s your serve of choice.

Drinking whisky on the rocks has distinct benefits. Where a dash of water will open a whisky, ice chills too, and the overall effect will result in a whisky that is more viscous, changing the mouthfeel and texture. As ice melts, it also dilutes. Too much dilution can drown a whisky, but the right piece of ice can melt slowly -  to open the dram up as you drink.

This is best seen in the high end bars where a large ice ball has become the choice to serve for many bartenders. This trend is rooted in the highly technical bar scene in Japan, where the very best bartenders learn, over generations, to hand carve tennis ball-sized, perfectly clear, spheres of ice which have the quality of chilling down the whisky, hardly melting at all.

Herein lies the key to adding ice to your whisky: make sure it is large, and make sure it is of quality.

Those tiny cubes from a small tray at the top of your freezer won’t do. Try and buy ‘good’ ice, the clear sort in bags from your supermarket. And try and get the biggest cubes possible. One decent sized - the size of a golf ball - of quality ice, will do for a good double measure of your favourite Scotch, Irish or Bourbon.

It is fantastic to consume whisky neat, if you like it strong and straight. Adding a little water is great, as it will reveal greater depth in your dram.

And ice? Go ahead. There is a reason the letters ‘i-c-e’ appear in ‘choice’. Just make sure it is quality ice, in quality whisky!