Olfaction And The Science Behind Nosing A Whisky - The Whiskey Wash

Olfaction And The Science Behind Nosing A Whisky

The next Diploma we are launching at the Edinburgh Whisky Academy, which I founded a few years back, is the Diploma in the Art of Tasting Whisky.  This is quite clearly a sensory focused course with a key focus on flavour creation, oak and olfaction.  It is the olfactory system that I would like to write about today, as this is a subject area that is still reasonably misunderstood, and yet is the most vital of senses when it comes to nosing whiskies.

Olfaction (the ability to detect and discriminate between different odours) is the most ancient of our senses, being the first one in evolutionary history to develop.  Nearly all air, water and land-dwelling creatures have a sense of smell, and it plays a significant role in nutrition, safety and maintaining our quality of life.

Essentially, the sense of smell is a chemical detection system that allows creatures, including ourselves, to discriminate between chemicals in the environment that could be either harmful or beneficial.  It originally developed as a way for our most primitive of sea dwelling ancestors to follow a chemical gradient away from a dangerous source or towards a nutritional source, and this original discrimination, developed over 400 million years ago, remains with our sense of smell today.  We are attracted to smells that we find pleasant and repelled from odours that may do us harm.

Whisky ready to be examined (image via Edinburgh Whisky Academy)

However, our sense of smell is one of the most downplayed and misunderstood senses.

One of the reasons for this could be that it interacts very differently with our memory compared with our other senses.  For example, if you try and conjure up the odour of freshly cut grass, you cannot. Yet, if presented with a sample associated with this aroma you will immediately identify it. Furthermore, you will be able to recall events/moments associated with that odour from many, many years ago.  Effectively, due to the way our olfactory system works with our brain, we cannot recall an odour to our conscious mind without some external olfactory stimulus.

Any expert in the flavour of whisky must know how the sense of smell works, otherwise it will become difficult to build up an appropriate sensory memory and use that to discriminate between different whiskies. So, for those of us who do not have detailed knowledge of the anatomy and physiology of smell detection, how can we build up our sensory memory to allow us to hone our whisky nosing skills?

Firstly, we must touch on olfactory cognition.  This is the mental action or process of acquiring knowledge and understanding through the sense of smell.  Historically, this was poorly understood.  However, a number of recent studies have looked at the sense of smell between experts and non-experts, throwing light on the way we acquire and process olfactory information.

Odour sensitivity and discrimination

The above-mentioned studies found no difference in sensitivity between experts and untrained subjects in odour sensitivity. The reason behind this is that our sense of smell is not designed to detect single odours, but rather to discriminate complex odours made up of many individual odour molecules.

If you look at odour discrimination in mixtures of single compounds, each with an individual smell, the maximum number of individual compounds that an individual can distinguish is three or four at most (this is the same for experts and non-experts). When mixtures get more complex than this, like with a whisky, we tend to classify the smell into types (i.e. floral, peaty or feinty).  Where experts score more highly is in their ability to be more accurate in naming single individual compounds.

Perceptual learning

Perceptual learning in odour discrimination is also very important.  The more smells we are repeatedly exposed to will enhance our ability to discriminate between smells.  The old adage of practise makes perfect rings true with this as well – training our nose will make us better at discriminating between different whiskies, as well as discriminating between different whiskies we have not previously been exposed to.

Odour memory and identification

We now know that odour familiarity will increase with repeated exposure.  However, whilst we might possess perfectly good odour detection and discrimination systems (through practise), smell is the most difficult sense to verbalise, and we have to learn how to identify a particular smell and communicate it in non-personal terms for general understanding (most odours are explained in terms of personal experience).   Doing this in a group or classroom setting, with other people who are learning how to verbalise smells, is good practice.

This is where experts excel as they are able to verbalise their olfactory experience and identify odours in a way that is repeatable and identifiable both to themselves and to others. The industry has reacted to this by producing specific terminologies used to describe and classify different whiskies, usually assisted with a version of a flavour wheel.

So, with training and the development of olfactory memory, one can describe the whisky in a more analytical manner, whereas the novice taster will describe a flavour in a manner which stresses the enjoyment and richness of the flavour.

In essence, there is no reason why we cannot all become whisky tasting experts through repeatedly nosing whiskies and learning to verbalise our findings.  Once a whisky is recognised through smell, then the expectation of whisky characters and traits are much easier to find.