Taste is subjective. That’s why in the wonderful world of whisky you’ll hear many people talk about the different ‘tasting notes’ they get from the same whisky. We know that this can sound a little daunting, especially if you feel like you’re the only one in the room (or zoom) who can’t pick out a specific flavour of ‘pine needles’ or ‘orange’. Although you shouldn’t worry too much (really you just need to know whether you like it or not), there are good reasons behind why some people are able to pick out certain flavours from whisky.
While taste is subjective, flavour compounds aren’t. They’re measurable bits of matter that exist in everything we can taste. Compounds like isoamyl acetate for example, taste like banana sweets. Ethyl caprylate, like pineapples. Cinnamaldehyde, rather unsurprisingly, tastes like cinnamon. There are thousands of these flavour compounds commonly found in your whisky, and using a fancy test (Google “Gas chromatography-mass spectrometry” for a rabbit hole of scientific fun) we can even pretty accurately tell you both what compounds, and how much of each are present in any given bottle.
So how does this objective information turn into subjective deliciousness? To put it simply, it’s all down to you.
How you perceive a whisky and its complex combination of flavour compounds, alcohols and water will vary depending on a whole host of factors. Firstly, in your ability to taste certain compounds. For example, people who think coriander tastes like soap tend to perceive compounds like aldehydes more intensely. Secondly your experience and history with certain flavours has a big effect. One persons vague “citrus” might be another’s “homemade bergamot marmalade”, it all depends on what those flavour compounds trigger in your brain.
There’s a whole host of external factors that can effect how you taste as well. Ever wondered how aeroplane meals can be simultaneously the saltiest and also the blandest thing you’ve ever tasted? The cabin pressure and loud noise of an aircraft will seriously effect your ability to taste, and whilst that’s an extreme example, everything from temperature, lighting, weather, even the colour of the room you’re sat in, can impact how something tastes to you. So when we’re talking about tasting notes, we’re really talking about what we think this tastes like, based off of our personal experience, as well as our general ability to taste and perceive flavour compounds.
Now the big question, where are all these flavour compounds coming from? What makes whisky taste like whisky? The answer, as I’m sure you can imagine, is wildly complicated, so we’ve made it a little simpler to prevent any nodding off!
Here’s where your grain characteristics are going to come from. Compounds like Hexanal and Furan are commonly formed in barley, which taste like citrusy grass and nutty caramel respectively. The malting process for barley can also develop and add more flavour. Reactions when drying barley can cause caramelisation and sweet, toasted flavours, and some distilleries dry with peat smoke, adding smokey and medicinal notes.
Yeast doesn’t just eat sugar and produce bubbles and booze. It also produces a ton of flavour in your whisky, most notably esters. Shorter esters like ethyl acetate taste like green apples, and ethyl lactate like butter. There are also longer esters that effect texture more than they do flavour. Ethyl palmitate, for example, can give whisky a waxy/creamy quality.
Different yeasts, fermentation times and temperatures will all produce different levels of these compounds, which is why we at Nc’nean have two different yeast recipes, designed for different lengths of maturation, and also why we run annual yeast trials, to discover new flavour possibilities in our whiskies.
This is a rather different category, as whilst some flavour compounds are formed here, distillation’s main role is actually to remove a lot of them. More dangerous alcohols like methanol, and undesirable esters and aldehydes are removed in the foreshots and feints (that’s the first and last liquid off the still). Finding the cut point between these and the good “heart” of the run is the skill of a good distiller.
Maturation has a massive effect on the final taste of the whisky. Ageing spirit in oak barrels will add new flavour compounds, like vanillin (vanilla), cyclotene (caramel/maple) and eugenol (clove). The vast majority of Scotch whisky casks will also have been used for a different product beforehand, which will leave its own unique impression on the whisky, like our STR-Red wine casks tasting rich and spicy, and our Ex-Bourbon casks tasting sweeter and softer.
Maturation can also help other compounds develop or break down due to the influence of oxygen. An alcohol molecule can oxidise into an aldehyde, creating a new flavour, which can oxidise further into an acid, creating another new flavour, which can then combine with another alcohol molecule and form a new ester, creating yet another new flavour, yeah science! This constant development, along with more volatile compounds evaporating with the angels’ share is how whisky mellows and matures over time.
The result of all this complex development is a whole world of flavour possibilities in single malt, but also why the basic formula of malted barley, yeast, water and oak creates an unmistakable “Scotch” character. And that, very briefly, is why whisky tastes like whisky.