How do you taste whisky?

A tulip-shaped glass with an opening narrower than the bowl concentrates the aroma above the liquid and therefore works better than a straight glass.

ISO standard 3591 from 1977, titled Sensory analysis, Apparatus, Wine-tasting glass, describes exactly that glass: an elongated egg shape on a stem with a foot, with an opening narrower than the bowl so that the bouquet collects. The standard was confirmed in the 2022 review and is therefore still valid.

In its tasting guide the Scotch Whisky Association works with the Glencairn glass, designed in Scotland. The tulip shape captures the aromas, and the rounded base acts as a lens with which you can judge the colour well.

First look at the colour, then smell calmly, take a small sip and finally pay attention to how long the flavour lingers.

The tasting guide of the Scotch Whisky Association works with five steps: hearing, seeing, smelling, tasting and feeling. The first is literally the sound of the cork, as a marker that the tasting begins.

When looking, you swirl the glass and look at the traces along the wall: the higher the alcohol content, the more of those legs you see. Smell calmly, because master distillers judge a whisky on the nose alone. Then let a sip coat the mouth, because the taste differs from what you smelled. In the last step you assess the mouthfeel and whether the flavour lingers or fades quickly.

Keep a glass of water at hand while tasting.

Water lowers the alcohol content and raises the temperature slightly, releasing more aroma compounds.

A 2017 study by Karlsson and Friedman in Scientific Reports shows what happens at the molecular level. Guaiacol, the compound behind smoky notes, stays mainly at the interface between liquid and air up to about 45 percent ethanol by volume, precisely where smell and taste pick it up. Between 45 and 59 percent by volume that picture tips, and above 59 percent by volume guaiacol moves into the liquid, surrounded by ethanol molecules.

Diluting a mixture that starts at around 59 percent by volume therefore increases the chance that guaiacol ends up at the surface. The Scotch Whisky Association recommends still water that has not been chilled.

The label states the actual alcohol content by volume to at most one decimal, followed by % vol, determined at 20 degrees Celsius.

Annex XII of Regulation (EU) 1169/2011 allows a deviation of 0.3 percent vol for drinks with more than 1.2 percent vol alcohol, other than beer, wine, cider and fruit wine. A bottle stating 46.0 percent may therefore lie between 45.7 and 46.3 percent.

Scotch must be bottled at a minimum of 40 percent. For tasting, the strength matters: the further you go above 45 percent by volume, the less guaiacol stays at the surface.

Tasting calls for clean glassware, still water within reach and, in the Netherlands, the age limit of 18.

NIX18 is de campagne van het ministerie van Volksgezondheid, Welzijn en Sport met één regel: geen alcohol voor kinderen onder de 18. Niet kopen, niet krijgen, niet drinken.

It also helps to know what is in the glass. The colour says something about the maturation, and an age on a Scottish label always refers, under rule 12 of the Scotch Whisky Regulations 2009, to the youngest whisky in the bottle, expressed in years.