It seems a bit odd. Purchasing a fine single malt Scotch whisky, a spirit aged over many years in highly specific conditions under tender care, cracking open the seal, pouring a dram and then … adding some water to it. Sounds like sacrilege to the uninitiated. But it can actually be a key to unlocking the spirit’s true character.

“By adding water to a whisky, you are bringing down the alcoholic strength,” explains Simon McGoram, national whisky ambassador for Diageo. “As you do, different flavours and aromas are released, as different molecules dissolve with the alcohol at different strengths.”

Adding water to Johnnie Walker Black Label, for instance, can help release aromas that give the spirit notes of fruit, citrus and grass. “Adding water will help you see another side of a whisky,” he says.

How much water?

“When we're talking about adding water, I'm not talking about drowning it,” says McGoram.

He suggests first trying a new whisky neat. Then start with adding just a few drops. Proceed cautiously until you reach the whisky to the level where you feel your palate can better appreciate its flavours.

The amount of water you add also depends on personal preference and the particular whisky’s characteristics. Cask strength whiskies, like the Lagavulin 12-year old cask strength single malt Scotch whisky, tend to have a higher alcohol content than bottled varieties. So adding water can help unlock flavours hidden under the alcohol.

“You might be looking at a whisky that's over 50 per cent alcohol, or even up to 60 per cent alcohol by volume,” says McGoram. “They can be delicious on their own, but some people might also try adding water to bring them down to a strength more enjoyable for their palate.”

Water vs. ice

Temperature has a dramatic impact on our perception of sweetness, says McGoram. “A really great example for this is, if you have an ice-cold can of cola, it's quite refreshing,” he explains. “But if that same can of cola has been sitting out in the sun and you were to drink it warm, it wouldn't be refreshing at all.”

Just like a cooler temperature can dampen cola’s sweetness, adding ice to whisky can make whisky’s sweetness more subtle, allowing other characteristics like smoky, earthy, and bitter notes to shine.

The shape and quality of the ice can also affect the whisky’s flavour. “If you use very small cubes, then you've got a greater surface area of liquid to the cube,” says McGoram. “It means each cube will melt faster and dilute your whisky very quickly.”

While diluting is a personal choice, if you’re using small ice cubes you don’t have control over the dilution. This is why many whisky bars serve a single large block of ice with a dram ordered on the rocks. “They melt much slower, and you've got a bigger surface area of ice in contact with the liquid than you would with a smaller cube,” says McGoram.

Another option is to simply serve a glass of chilled water on the side. This is suitable for high-end whiskies like the prestigious Johnnie Walker Blue Label. “You don't want to compromise that without a reason,” says McGoram.

Flavour and aroma notes

What sorts of flavours and aromas should you expect to find in whisky after adding water? McGoram uses the Talisker 10-year-old Scotch Whisky, a medium-peated whisky from the Isle of Skye that’s rich with “smoky and maritime” characteristics as an example.

Add a few drops of water, says McGoram, and “you would start to get more of those rich, toffee notes coming through.” Notes of crystallised ginger and tropical fruits like grilled pineapple will become present also.

If you choose to add ice, you’ll suppress some of those sweeter characteristics and allow notes of campfire smoke and spice to come through.

Ultimately McGoram says how you drink your whisky comes down to personal preference. With such complex flavours at play, “it’s hard to say one will be better with water, one will be better with ice and one will be better neat.” But any reason for experimenting is half the fun.

This article is produced by Broadsheet in partnership with World Class.