EVALUATING A SCOTCH WHISKY
PRELIMINARIES
Scotch whisky, a timeless spirit steeped in tradition and complexity, offers a sensory journey like no other. To truly appreciate its depth and variety, one must approach tasting with reverence, enthusiasm and the exercise of patience. Whether you're a seasoned aficionado or a curious newcomer, understanding how to properly taste and evaluate Scotch whisky can transform your experience from mere drinking to an art form.
At the end of the day, the quality of a whisky is reflected in its volume of sales in the common market. Evidently, buyers look for their own pre-defined parameters. Leaving the budget aside, how else does a buyer judge the whisky he wishes to buy? It obviously starts from the marketing campaign, but that is only a pointer. The buyer first looks, by default, at the packaging and presentation of a whisky, whether all necessary details are printed on the label leaving no doubts about its integrity. He then looks at the colour and strength, having bought it, goes on to check it out.
A whisky is reviewed by assessing its appearance
(colour), aroma (nose), taste (palate), and finish (aftertaste), locating specific notes, complexity, balance, and
overall quality.
The colour is checked for two aspects; whether E150A
Caramel colouring additive has been used or whether it shows chill-filtration.
The former is easy to assess. The latter requires some time. Good indicators
are its strength, generally 46% ABV or more and the appearance of micelles,
i.e., the appearance in that glass of whitish strains floating in the whisky
after a drop of water is added. The label should state both and prominently so.
But then, how would you check the areas that require
the use of your olfactory sensory organs? The nose gives you the aroma, the
mouth the taste, the gullet its smoothness and the sensations as it slides down to the stomach its finish. Actually, a discreet burp would reveal the finish and confirm the taste.
You are your own best judge. Very few people may use
the same terminology-after all, they are different human beings with differing
ideas and actual of aroma, taste and finish. If you described the aromas of a particular whisky to a friend, you may
consider them to be legitimate notes, but what do memories, metaphors and
variables mean to others? What is the meaning of “a classic Speysider or a
classic Islay?” How effective is it to communicate taste by region alone when
there are many unique distilleries, variants or finishes out there, each with
its trademark USP? Medicinal Laphroaig also has its own variants.
What Exactly is Aroma?
The human olfactory system is a complex network of structures
and pathways that enables us to detect and perceive aromas, also known as odours
or smells. It is responsible for processing chemical signals from the
environment, which are detected by specialised cells called olfactory receptors
in the nose. The olfactory system begins with the olfactory mucosa, a thin
layer of tissue lining the roof of the nasal cavity, where odour molecules bind
to olfactory receptors. These receptors are sensitive to specific shapes and
sizes of molecules, allowing us to distinguish between different smells. The
bound molecules trigger a signal that is transmitted to the olfactory bulb, a
structure located in the forebrain, where it is processed and analysed. The
processed information is then sent to other parts of the brain, such as the
limbic system, which is responsible for emotions and memory, and the
hippocampus, which plays a role in memory formation. The olfactory system is
closely linked to our emotional and cognitive centres, which is why smells can
evoke strong emotional responses and memories. Additionally, the olfactory
system is highly sensitive and can detect extremely small concentrations of odour
molecules, making it an essential sense for our everyday experiences.
What Exactly is Taste?
Taste is the perception stimulated when a substance in
the mouth reacts chemically with taste receptor cells located on taste buds in
the oral cavity, mostly on the tongue. Taste, along with the sense of smell and
trigeminal nerve stimulation (registering texture, pain, and temperature),
determines flavours of food and other substances. Humans have taste receptors
on taste buds and other areas, including the upper surface of the tongue and
the epiglottis. The gustatory cortex is responsible for the perception of
taste.
The tongue is covered with thousands of small bumps
called papillae, which are visible to the naked eye. Within each papilla are
hundreds of taste buds. There are between 2000 and 5000 taste buds located on
the back and front of the tongue. Others are located on the roof, sides and
back of the mouth, and in the throat. Each taste bud contains 50 to 100 taste
receptor cells.
Taste receptors in the mouth sense the five basic
tastes: sweetness, sourness, saltiness, bitterness, and savoriness (also known
as umami). Scientific experiments have demonstrated that these five tastes
exist and are distinct from one another. Taste buds are able to tell different
tastes apart when they interact with different molecules or ions. Sweetness,
savouriness and bitter tastes are triggered by the binding of molecules to G
protein-coupled receptors on the cell membranes of taste buds. Saltiness and
sourness are perceived when alkali metals or hydrogen ions meet taste buds,
respectively.
The basic tastes contribute only partially to the
sensation and flavour of food in the mouth—other factors include smell,
detected by the olfactory epithelium of the nose; texture, detected through a
variety of mechanoreceptors, muscle nerves, etc.; temperature, detected by
temperature receptors; and "coolness" (such as of menthol) and
"hotness" (pungency), by chemesthesis.
In one line, it is the detection of a set of chemicals
that define Aroma and Taste.
Now that we know what we are looking for and how we find them, let us proceed to The Tasting Wheel. The Council of Whisky Masters recommends the official Tasting Wheel published by Whisky Magazine, also known as Delmarter's Tasting Wheel.
On this page, I will break down the hard-to-read wheel
details, for practical use in daily leisure tastings as well as analytical
tastings. The categories and descriptors shown on this page are part of the
official vocabulary for all assessors.
The 6 categories starting clockwise from the 12 o’clock
position through the wheel show categories that arise mainly from malting,
fermentation and distillation:
Cereal
Fruity
Floral
Peaty
Feinty
Sulphury
The 2 categories in the upper left quadrant of the
Tasting Wheel (7&8) cover categories that arise mainly from the wood maturation
process of the whisky:
Woody
Winey
Category 1: Cereal Flavours
These flavours are related to malted barley or other
grain types.
Cooked Mash: porridge, bran, mash tun draff, cooked,
potato skins
Cooked Veg: mashed potato, boiled corn, baked potato
Husky: dried hops, mousy, ale, iron tonic
Malt Extract: malted milk, cattle, cake
Yeasty: pork fat, sausage, gravy, meaty
Category 2: Fruity Flavours
Appealing aspects from the production process, sweet
& fragrant.
Citric: oranges, tangerine, kiwi, nectarines, lemon,
kinu
Fresh Fruit: apples, pears, peaches, apricot, fruit
salad, lychees, custard apple, chikoos
Cooked Fruit: stewed apple, marmalade, jam, candied
fruits, barley sugar
Dried Fruit: raisins, figs, dates, prunes, fruit cake,
mince pies
Solvent: nail varnish remover, bubble gum, paint, soda,
pine essence
Category 3: Floral Flavours
Scents associated to fresh grass and hay, or leaves.
Fragrant: perfume, fabric softener, barber’s shop,
coconut, lavender
Green House: geraniums, green tomatoes, florist’s shop
Leafy: green leaves, lawn clippings, pea pods, fir,
pine nuts
Hay: mown hay, dry hay, barns, heather, herbal, sage,
mulch, mown lawn
Category 4: Peaty Flavours
In Scotch, peat flavours join the malt during the
kilning process.
Medicinal: iodine, carbolic, hospitals, lint, tar,
diesel oil, sea-weed
Smoky: bonfire, burnt sticks, incense, peat reek
Kippery: sea shells, dried shellfish, oysters, smoked
salmon, anchovies
Mossy: moss water, birchy, earthy, turf, hemp rope,
fishing nets
Category 5: Feinty Flavours
Feints enter the picture in the end of the spirits run,
and they become milder during wood maturation.
Honey: clover honey, heather honey, mead, beeswax,maple syrup
polish
Leathery: leather upholstery, libraries, new cowhide,
biscuits
Sweat & Plastic: buttermilk, cheese, yeast, shoe
polish, old gym shoes, plastic rope
Tobacco: dried tea, fresh tobacco, tobacco ash
Category 6: Sulphury Flavours
Mostly developing during distillation, these
problematic flavours are moderated through the fluid interaction with copper.
Coal Gas: spent fireworks, burnt matches, matchbox
Rubbery: pencil eraser, new tires, electric cables,
burnt rubber
Sandy: fresh laundry, starch, linen, beach, sulphur
Vegetative: brackish, cabbage water, turnips, stagnant,
marsh gas
Category 7: Woody Flavours
Partially directly from the oak, partially related to
aging, wood maturation increases complexity and balance, and adds colour.
Toasted: rice pudding, burnt toast, coffee grounds,
fennel, liquorice
Vanilla: custard, crème caramel, sponge, madeira cake,
toffee
Old Wood: musty, cardboard, cellars, pencils, cork,
ink, metallic
New Wood: resinous, cigar box, sandalwood, cedar,
ginger, pepper, nutmeg
Category 8: Winey Flavours
If casks were filled with a type of wine before using
them for whisky, some of the wine flavours can become part of the whisky
profile.
Sherried: white or red wine, sauternes, fino, oloroso,
armagnac, madeira, port
Nutty: walnuts, hazel nuts, praline, almonds, marzipan,
betel
Chocolate: cream, butter, milk chocolate, cocoa, bitter
chocolate
Oily: linseed oil, candlewax, suntan oil, olive oil
The roundness of a Tasting Wheel indicates that flavor
categorisation represents a circular continuum:
One type of flavour may blend into the next, often
absent of clear borders. When present in moderation, most of the above tasting
descriptors are perceived as positive. However, presence of some flavours
usually fall into the category “nasty”, e.g., metallic, musty, vegetal, cheesy,
very meaty, sulphury.
FROM DESCRIPTION TO EVALUATION
While the above Tasting Wheel discussion assists during
the description of whisk(e)y, other categories and criteria are used during a
professional and comparative evaluation of the spirit:
Assessing a whisky’s Complexity, Balance and
Expressiveness may help the taster to arrive at an overall quality assessment. Further, assessing a sample’s Type and Character—its
expression of a regional or traditional style alongside the distillery’s unique
characteristics—may provide further insight into the product’s identity and
relative positioning in the marketplace.
APPEARANCE AND COLOUR
All Scotch whisky is aged in oak casks and picks up
colour from the maturation process. The final colour will depend on the length
of the aging, the kind of barrel used, and its prior contents. There are a
variety of colour classifications and recognised gradations that are used,
though the specific subdivisions identified will vary by author.
Begin your evaluation of a Scotch whisky by first
assessing the colour. Pour in a measure of whisky—about an ounce or so. Hold
the glass to the light and assess its colour, depth or intensity, and its
clarity. New spirit is gin-clear; 20 years in sherry wood may turn the whisky
the colour of molasses. Between these poles is a spectrum of hues. The
classification shown here recognises seventeen different colour hues.
The first step is to ask yourself, how would you
describe the colour of the whisky you are evaluating? How does it appear? Is it
clear or hazy? Are there any other distinctive elements of its appearance that
are worth noting?
NOSE OR AROMA
The second step in the sensory evaluation of whisky is
to identify its principal aromas. This is done largely with the nose and this
step in the evaluation process is typically called nosing.
The type of glass used to evaluate or enjoy whisky can
have an enormous impact on its sensory appreciation. Fortunately, the choice of
glassware is usually under one’s control. The shape and volume of the glass
have a distinct effect on taste, both by concentrating the aromas and directing
them to your nose, and by directing the Scotch to specific parts of the tongue.
A Glencairn or a Riedel whisky glass is recommended. A sherry copita can also
be used. Like wine, gently swirl the contents of the glass. The shape of the
glass, the volatility of the aromatic compounds in the whisky activated by a
gentle swirl will release the whisky’s aroma. Swirling the glass vigorously often
results in increasing the amount of evaporated alcohol and will actually desensitise
the nose, making it less able to distinguish the aromas present.
What condition is the whisky in? Are there any obvious
off notes? Typically these would be feinty such as plastic, sweat, or cheese
and would indicate a poor distillation process or a wash contaminated with
undesirable yeasts or bacteria. If a bottle has been stored on its side and has
had prolonged contact with its cork there could be cork taint resulting in a
musty, wet cardboard aroma. Whisky that has been aged in casks that have sulphur
taint could exhibit the burned match smell typical of sulphur dioxide. The most
commonly encountered fault is oxidation resulting from a bottle that has been
opened too long and has had excessive exposure to air. Oxidation will result in
the loss of the lighter, more volatile aroma elements in a whisky, resulting in
a whisky that seems bland, less intense, and one dimensional.
The second factor to consider is the intensity and
characteristics of the aroma. Are the aromas intense or subdued? Lowland malts
and whiskies that have undergone triple or quadruple distillation often exhibit
lighter, less intense aromas. Heavier highland malts, especially heavily peated
whiskies, will typically exhibit stronger, more robust aromas. Does the aroma
seem harsh or spirity, as is typical of young whiskies, or does it have the
well-integrated rancio aromas of old wood and leather that we associate with
extended aging?
The best time for a sensory evaluation is before lunch.
Add a little water, especially if there is a nose prickle indicating a high
ABV, as this will release additional aromas. Do the aromas change and if so
how? Is there a progression of aromas, especially after you add some water, or
does the initial aroma just gradually fade away? The addition of water also
makes it easier to hold the whisky in your mouth. Swirl the whisky within the
mouth so that it reaches all parts of it. Finally, let the whisky trickle down
your throat slowly rather than swallowing it in one gulp.
The addition of water to whisky has become a
controversial issue of late. Historically, the addition of a small amount of
water, typically one half of the volume of the whisky in the glass, was
recommended to release some additional aromas in the whisky, a practice
sometimes referred to as “releasing the serpent.” The noted whisky critic and
author Jim Murray, on the other hand, insists on reviewing whiskies “neat” on
the basis that any added water would create a different experience for his
readers unless they were able to use the exact water that he did.
The matter is further complicated by findings of research by
Rachel Barrie when Bowmore Distillery’s Master Blender, and cocktail and spirits
write Camper English, which they believed showed that the addition of water from
the same locale where a whisky was made tended to intensify the basic character
of that whisky. In other words, the addition of water from Islay will make a
heavily peated Islay whisky taste even more peated.
Whyte & Mackay master blender Richard Paterson,
renowned for his ability to assess single malts and blends is picky about the
glass. It must be tulip shaped with a stem—he likes to hold his glass only by
the stem. As for adding water, he believes that 35% ABV is the best ABV for
tasting young whiskies, i.e., 12 YO or less. For 15 YO whiskies, he sips it
neat. If it bites, he adds water until it mellows. For him, ice is taboo, as it
subdues most flavours by reducing their volatility, thereby suppressing its
aromatics. For tasting, he takes a small amount of whisky and keeps it on and
under the tongue for a few seconds and assesses the flavours, then lets it go
down while he savours the flavours for the following 20 to 30 seconds. His tip:
always take a second taste. “Different layers will start to open up to you with
the second taste,” says Paterson.
I recommend you base your decision on the nose burn
felt, if at all, during nosing. Have a small sip first, add five to six drops
of water, a gentle swirl, pause a minute and sip again. The water is free H2O. It will react with free molecules of volatile compounds floating in the glass and add another flavour or two.
PALATE: TASTE, MOUTH FEEL,
AND FINISH
The third step consists of the primary tastes
associated with the whisky and its body or mouth feel. In reality what we call
taste is a combination of the five primary tastes as well as aromas that we
perceive while the whisky is in our mouth and that we add to the taste profile.
Many of the flavours that we associate with “taste” are
in actuality aromas. These are perceived by the olfactory receptors in the
olfactory epithelium. This organ is a mass of epithelial tissue located on the
roof of the nasal cavity about three inches above and behind the nostril and is
directly responsible for detecting odours.
When you have a cold, your nose loses much of its
ability to distinguish aromas. This is why food doesn’t taste as appetising
when your nose is congested. There are only 9,000 taste buds on the surface of
the tongue, the roof of mouth, and in the throat. The human nose, on the other
hand, has millions of epithelial cells and can detect more than ten thousand
aromas.
TASTE
There are five primary tastes: sweet, sour, bitter,
salty, and umami.
The first four tastes are straightforward and are
familiar to most everyone, although it should be noted that individual
sensitivity to each of those tastes can vary widely. Umami, the fifth taste, is
an Indian word that is typically translated as savoury. It represents the taste
of glutamate. The tongue has specialised taste cells, or specific taste
sensors, for each of these tastes. These sensors, or taste buds, are located
throughout the mouth and throat but are especially concentrated in particular
areas of the tongue.
The first tastes discerned by the mouth are sweet and
salty. The taste receptors for these two tastes are particularly concentrated
at the tip of the tongue. The receptors for sour are located about halfway up
the tongue on either side, while the receptors for bitter are at the back of the tongue. A few taste buds for Umami are in the central half of the tongue but most are at the back of the mouth and in the upper throat. Paradoxically, the
centre of the tongue has very few taste buds.
Order of Taste
Salt, the primary cooking flavour, is first tasted at a
concentration of about 0.025 percent. It is a strong flavor stimulant that can
“round off” sweetness. Sugar is tasted at around 0.5 percent sucrose
concentration and is associated with warm and pleasant feelings. Sour is the
taste that detects acidity. It will register at a concentration of 0.000135
percent. Bitter is tasted at a minuscule 0.00005 percent concentration. It is
the slowest taste to register, taking up to ten seconds or more.
Bitter becomes enticing to the palate as we age and
actually stimulates appetite. Umami records the presence of glutamate and
indicates the presence of amino acids. It is tasted through monosodium
glutamate (MSG), first extracted from soup seasoning made from seaweed. MSG is
discerned at 0.03 percent concentration and enhances the flavour of meats. The
taste of glutamate is often described as that of asparagus.
MOUTH FEEL
Mouth feel is also referred to as body. It is a measure
of weight, richness, or viscosity of the whisky when it is in one’s mouth.
Sugar, flavour compounds and alcohol will add to the sensation of “body.” Fusil
alcohols, while a fault in excessive quantities, can, in small amounts, create
a sensation of richness and greater viscosity. Tannins extracted from wood will
have a similar effect. Whiskies that have been aged will typically exhibit more
body than a young whisky. In older whiskies the alcohol is better integrated
with the flavour components and this also adds to the sensation of a heavier
mouth feel.
FINISH
As the whisky is swirled around in one’s mouth there
are additional “flavour components” that are being released. These too are
simply additional aromas that are being perceived by the taster. The finish, or
length, refers to the length of time that these additional aromas linger in the
mouth after the whisky has been swallowed. A long, lingering finish is
typically associated with an older, well-aged, well-integrated whisky, and is
considered a sign of quality. Although even a young whisky can exhibit a
lingering finish. Anything peaty will often exhibit a long finish regardless of
the age. Is the finish long or short? Are the flavours in balance? Is the
finish excessively spirity and harsh? Do you experience a complex succession of
multiple flavours.
Based on this threefold evaluation, a reviewer can make a determination of quality. Is it faulty, poor, acceptable, good, very good, or outstanding? How is the balance, length, and complexity? Is it a good example
of its type? Whiskies where one particular flavour component dominates can make
a malt seem boring and one-dimensional and is usually considered a fault, on
the other hand if you are evaluating “peat monsters”, that intensity of flavour
is precisely what you are searching for.
THE ROLE OF OAK CASKS
The major constituents of oak are the three building
blocks of all woody plants - cellulose, hemicellulose and lignin - plus tannins
and small amounts of lipids (oils, fats and waxes). An exception, which applies
mainly to American white oak, is the oak lactones. The small amounts of lipids
give rise during the coopering process to oak lactones. These have a profound
effect upon flavour.
When considering oak’s influence on wines and spirits
during maturation, it is important to remember that oak barrels, chips or tank
staves do not consist of oak as such, but as oak which has been modified by
seasoning and heat treatments - toasting or charring.
Approximate composition of American and European oaks
|
Species
|
% Cellulose
|
%
Hemicellulose
|
%
Lignin
|
%
Extractives
|
|
European
oak
|
38
|
29
|
25
4.
|
4
0
|
|
English
oak
|
39-42
|
19-26
|
25-34
|
3.8-6.1
|
|
American
oak
|
44
|
24
|
24
|
5.4
|
1. Cellulose : Cellulose
is the most abundant natural polymer on Earth and consists of linear chains of glucose
units. It plays no part in maturation other than to help hold the wood
together. However, there is some evidence that it can play a role in bacterial
action in wine maturation, but not whisky maturation.
2. Hemicellulose
: Hemicellulose is a two-dimensional polymer which consists of several simple
sugars. Whereas cellulose consists purely of glucose sugar units, hemicellulose
can be broken down into several simple sugars. These include glucose, xylose,
mannose, rhamnose, arabinose and galactose. Although two-dimensional in
structure compared to the single dimensional chain-like structure of
cellullose, hemicellulose is less abundant and less stable. Upon heating it
breaks down into constituent sugars and these rapidly break down further into
caramelization products. This aspect of toasting and charring of oak wood is extremely
complex but is clearly of great importance in the development of toasty
flavors. The breakdown of hemicellulose by heat begins around 140°C (284°F) and
stops at 220°C (430°F).
Toasting yields furfural, hydroxymethyl furfural,
maltol, cyclotene and a host of other sugar condensation products en route to
the highly condensed structures which give the brown color of caramel. Acetic
acid and methyl alcohol are also formed. Thus the breakdown of hemicellulose
yields wood sugars which add to the body of the matured product, toasty flavors
and color. With the exception of furfural these compounds have sweet-associated
burnt sugar or caramelized aromas and flavors. In addition there are numerous
other compounds released during toasting which have similar characteristics.
3. Lignin : Lignin
is a three-dimensional polymer. Oak lignin - i.e., hardwood lignin - consists
of two building blocks, the guaiacyl and syringyl structures. In matured drinks
these two building blocks give rise to two groups of compounds. These are
coniferaldehyde, vanillin and vanillic acid in one group and sinapaldehyde,
syringaldehyde and syringic acid from the syringyl structure in the other. The
structure and aroma detection thresholds of these compounds (in 20% alcohol :
water) reveal that the application of relatively gentle heat or mild acid
attack releases the compounds listed above, collectively known as phenolic
aldehydes. But when extra heat is applied the lignin complex can break down
into much simpler structures - the steam volatile phenols. These are
responsible for the smoky aroma and flavors often found after barrel
maturation.
Oak tannins are described as hydrolysable because they
can be broken down into simpler parts in the presence of water and acidity. Ellagitannins
are formed when glucose combines with ellagic and sometimes gallic acid. Resulting
compounds are both astringent and bitter and they are clearly unattractive to
potential distillers. It is a major part of the process of seasoning and
toasting (or charring) to break down the tannins and render them more
acceptable. At the same time they also play an essential role in maturation by
enabling oxidation and the creation of a delicate fragrance in spirits. Three
steps are involved in this mechanism. The first two are common to both wines
and spirits. The third is largely restricted to spirits.
In Step 1, the wood tannin reacts with oxygen in the
presence of a transition metal - e.g., iron, copper or manganese - to release
activated oxygen which can be represented by hydrogen peroxide. In Step 2 the
activated oxygen is able to oxidise alcohol to acetaldehyde. In the third step
more alcohol combines with the acetaldehyde from Step 2 and creates a new
compound in the drink. This is diethylacetal, often just called acetal. This
compound has a strongly ethereal influence on the product giving it delicacy
and top-note. Without this step matured spirits are dull and flat.
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