Combining art and science
When appreciating the bouquet and taste of fine whisky, the experts rely on art as much as pure science. It is undoubtedly true that whisky stimulates the senses. However, appreciating all the characteristics of a sample of amber spirit involves more than sensory pleasure – important as the latter is.
As well as enjoying the bouquet or nose and the finish on the taste buds, it is necessary to take a few moments to analyse the aromas. Doing so helps one to understand the uniqueness of a particular vintage. That said, a premium scotch might well represent more than the mere sum of those components which it is possible to perceive at a first sip – or even to analyse in a laboratory.
There again, other factors come into play at tasting time. Every individual has differing perceptions. Their experience and expectations will likely influence their impression of the essence and qualities of any given vintage.
To some extent, cultural aspects could be relevant. For instance, Japanese collectors or Spanish enthusiasts may opt for blended whiskies with sweet notes. In contrast, connoisseurs in northern climes could well prefer full-bodied peated scotches to subtle, rounded Speyside malts.
Selecting the right type of whisky tasting glass
Later, we will cover the essentials of judging the appearance before noting the nose, palate and finish of the liquor. Firstly, however, the selection of a suitable tasting glass is vital.
Contrary to popular conception, tumblers are not the best type of glass to appreciate whisky’s concentrated aromas. They became popular in American bars mainly for reasons of convenience. The cups of ice and soda shakers fit with ease over the mouth of this broad, sturdy design.
However, oxygenation occurs quickly in tumblers; it results in an off taste that much sooner than in a narrower vessel. Instead, to gain the most representative and best possible impression during tastings, tulip-shaped stemmed glasses are best.
Because tulip-shaped glasses tend to concentrate the aromas more, they enable tasters to perceive them more fully. In contrast, with a whisky tumbler, one can usually detect only the most noticeable and aggressive, ethereal notes.
Significantly, there are two more advantages to using stemmed glasses. Firstly, the heat from one’s fingers and palm will not affect the contents. Secondly, distancing one’s hand from the mouth of the glass will ensure that any natural skin odour, fragrance or soap does not influence the perceived smell and taste.
In all cases, the best glasses have thin lips and are free of irregularities or bulges around their rims. Ideally, the bowl of the glass should not be too shallow. However, it should not be too deep; otherwise, the heaviest of the volatile aromas will not be able to rise to the top.
A final consideration: when comparing two or more whiskey vintages, identical glasses are a good idea. That way, the results will be as objective as possible.
Adding water to the whisky
Next, there is a decision to make: whether to add water. Usually, the consensus is that adding just a few drops of pure spring water will transform both the nose of the liquor and its finish on one’s palate.
On adding a small quantity of water, perhaps carefully controlled with a pipette, the composition in the glass changes. Fatty alcohols recombine to accentuate some of the aromas while masking others. Notably, these changes do not make a whisky better or worse. Instead, they open up the bouquet while reducing the alcohol continent slightly.
Optimally, we should serve whisky at room temperature, i.e. between 18 and 22 degrees Centigrade. The adage that quality trumps quantity is as accurate as ever if we want to appreciate the bouquet and flavours to the maximum. Around a single measure, between 20 to 40 centilitres (one fluid ounce) is usually sufficient.
Next, as we critique the appearance of a whisky, we ought to consider three essential factors: its colour, clarity and viscosity.
Primarily, the colour of a finished spirit depends on the type of cask in which it aged and how long it matured in contact with the oak interior. Quite legally, some producers opt to add a colouring agent such as caramel (E150). However, a liquor without any artificial additives will not be subject to unnecessary effects on its aroma.
At cold temperatures, whisky with an alcohol concentration of less than 46 per cent by volume tends to become cloudy. This phenomenon could be especially notable when adding water, such as during tasting or when serving. Thankfully, this cloudiness does not have any effect on the quality. Simply, it occurs because certain fat-soluble compounds dissolve only in high concentrations of alcohol.
Typically, bottled whisky contains 40 to 44 per cent alcohol by volume, except for less common editions of cask-strength liquor. For aesthetic reasons rather than for flavour, some producers use a process of chill filtration before bottling. This extra step removes those fatty acids, esters and proteins, which, if left in, often cause opaqueness at low temperature.
Nevertheless, chill filtering has an impact on the aromatic qualities of the liquor. While it can improve the quality of a slightly deficient whisky, it can also result in a less balanced bouquet – or even slight aromatic defects. Most experts take the view that chill-filtration can lessen the quality of an outstanding vintage.
Viscosity involves observing the speed at which, after swirling the glass, the legs or tears of a whisky return to the body of liquid. This observation technique uses the Marangoni effect, a principle based on the different surface tensions of the two fluids. Visibly, the trails vary because of the difference in the evaporation rates of ethanol (alcohol) and water in the glass.
To a trained eye, the watery trails indicate the strength of the scotch. The slower the legs or tears return to the body of the whisky, the higher the alcohol content. Experts will also observe that fatty acids cause thicker legs, while ageing in a cask for longer means that the legs will be thinner and further apart.
After observing the colour tone, degree of clarity and viscosity of the whisky, one should leave the glass upright. After a short interval, the aromas will settle and concentrate immediately above the surface of the liquid.
Nosing a whisky
To sniff, whiff or smell? Those in the know use the expression to nose a whisky. While sight is entirely physical, smell detects the sometimes subtle difference between aromas and the chemicals which make them up. Initially, the molecules of these compounds pass into the nasal tract, which some clinical specialists term the orthonasal pathway.
In contrast, the other sense of olfaction comes via the retronasal pathway, which picks up smells and tastes as we chew, eat, swirl a liquid around our mouth or swallow. The retronasal route adds to the perceived flavours of food and drink.
In healthy humans, the sense of smell is surprisingly sensitive and can differentiate between thousands of different volatile stimuli. While some aromas are characteristic of the base compound, such as vanilla, others might merge with other substances to produce a more complex note. A well-known example is the familiar smell of fresh baking. In the case of whisky, casks previously used to age sherry or bourbon spirit have distinct sensory signatures.
When we perceive the aroma of a whisky, the primary influences come from the type of barley, grain or malt. Next, the variety and soil type or location might be noticeable to a refined palate. The malting process also influences the taste of the finished liquor, especially when the malt dries over smoking peat.
In turn, secondary aromas arise from the fermentation and distillation and processes. Milky elements from the cereal base, yeasty mashes and metallic stills could affect the final characteristics and taste.
Later, as the new-make spirit ages in casks, tertiary aromas arise: wine, wood, vanilla and spice being the main influences. Apart from the initial milling of the barley and drying of the mashed malt, smokey aromas can also come from heavily toasted casks. Similarly, those casks that previously stored heavily peated maturing whisky will transfer natural smoky notes to the finished liquor.
Finally, for the scientifically minded, whisky production is an example of the redox phenomenon, which involves oxygen reduction and changes in chemical composition due to oxidation.
Now for the ten stages of tasting.
Tasting a whisky
To achieve uniformity from the tasting, some experts advocate the use of non ventilated rooms. In contrast, others might prefer to taste the spirit outside in the open air, as is possible on some tasting sessions during tours of certain distilleries on the Hebridean islands.
The same person could perceive different aroma and tastes if sampling the same whisky in a city tavern, remote countryside pub or seaside bar.
First stage: allow the lighter aromas to rise
The first stage involves helping the glass upright but slightly above your nose. Positioning the glass this way allows one to experience the first volatile aroma while allowing the nose enough time to adjust to the alcohol concentration. If you are tasting cask-strength whisky, this gradual adaptation is crucial.
Second stage: sense the heavier aromas
Angle the glass towards you so that it is almost on its side and perpendicular to your face. Without spilling the contents (of course!), raise the glass upwards in a straight line so that you can sense the various strata of the aromas.
As you do so, you will probably notice that the first notes are fruity and floral. After these light, volatile aromas come the spicy, wine-like notes. Lastly, the heavier compounds with earthy, woody and smoky notes reach the rim of the glass.
Third stage: sip the whisky
Take a sip and then lower the glass so that it is horizontal. Your nose should be about a centimetre directly above its upper rim. As the air circulates within, it will dispel the lighter elements to the top of the outer edge so that you can appreciate the floral notes. These are fleeting moments; the more powerful and full-bodied aromas will return before long.
Fourth stage: vary your breathing rate
With the glass in the same position, vary your inhalation and exhalation rate. First, breathe slowly, then quickly, while noting the different aromas. This technique isolates the fast-binding molecules from those which adhere to the olfactory mucus at a slower rate. Varying one’s breathing enables the detection of different smells from the same glass of liquor.
Fifth Stage: alternate between nostrils
Again, without moving the glass, sniff the whisky using one nostril before changing to the other. In most individuals, the flow capacity of each nostril alternates throughout the day in phases that usually last for two to three hours. This natural variation in the nasal passage means that aromatic molecules bind to the sensing membranes at different rates. Thus, changing between nostrils will give a different olfactory perception.
Sixth stage: consult an aroma wheel
Now, it is time to note the aromatic groups experienced, using the aroma wheel. This diagram groups aromatic compounds by similarities. It consists of three concentric circles, divided into the following ten flavour categories and separated by colour:
- Cereal. Barley is the base crop used to distil malt whisky. In contrast, most Canadian and American whiskies use grain such as corn, rye or wheat. Nonetheless, grain whiskies usually* contain some malted barley for the necessary enzymes.
- Floral. Blossom notes vary from honey through to lavender.
- Fruity. Thanks to the use of bourbon or sherry barrels, tasters might pick up hints of figs, raisin, peach, plum or apricot, among others.
- Vegetable. This category covers earthy notes of peat and forest soil through to herbal, grass and hay overtones.
- Roasted. Flavours include smoky, chocolate, and nutty hints such as almond, walnut and hazelnut.
- Spicy. Vanilla, liquorice and pepper notes are some typical notes which might present themselves at a tasting.
- Winey, particularly sherry or port.
- Off-flavours, preferably notable for their absence. Causes include microbiological, technological or chemical sources.
- Taste. Possibilities here include sweet, sour, bitter, astringent, burning or stinging.
The inner circle further divides the above into several sub-categories.
Usefully, the aroma wheel provides tasters of all levels with a standard grammar to document the characteristics noted during whisky tastings. It also offers novice tasters an intuitive method to compare the descriptions, focus their observations and train the palate through deduction.
Whisky derives its flavours from its sapid molecules in solution. When imbibed, the perceptions of taste result from identifying the substances present via the stimulation of chemo-receptors on the tongue. These receptors are sensitive to sweet, sour, salty, bitter, savoury, astringent, spicy, fatty, mineral (calcium) and metallic inputs.
So that the taste buds can start from a reasonably uniform point of reference, we rinse the palate during the next step.
Seventh stage: drink some water
Drinking some soft neutral water at room temperature beforehand is essential to ensure that temperature and acidity variations do not affect the outcome. Also, before tasting sessions, it is a good idea to avoid spicy or highly-seasoned foods.
Eighth stage: sip and swirl
Take a series of tiny sips to adjust the pallet gradually. Next, move the whisky round inside the mouth; this stimulates the salivary glands and sensory receptors. At this point, the sapid molecules will release the aroma and flavour into the oral cavity, thus accentuating the taste. Remember to place the sample at the front, centre and back of the tongue to optimise the various aromatic effects.
Ninth stage: the finish
When tasting the finish on the palate, retro-olfaction plays a vital role as the whisky in question stimulates the sensory receptors between the mouth and the back of the throat. After swallowing a small amount, exhale deeply to maximise the effect. A series of sips superimposed on each other lengthens the aromatic impact.
Tenth stage: seal the glass
As it dries, an emptied glass will still contain dry whisky extract. After the liquids have evaporated, a brown deposit relates to the woody elements. You might also note a thin, opaque coating of oxidised resin on the sides.
Finally, cover the glass hermetically to concentrate the non-volatile residual aromas, which will continue emerging for minutes or hours after the tasting. Later, sniffing the resulting scent will give one a final appreciation of the base notes in addition to the richness and woodiness of the liquor.
*always in Scotland and Ireland, due to regulatory requirements.