ASSESSING SCOTCH WHISKY

 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 stomach sensations 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.

Enter 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

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: boiled pork, 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 recent research by Rachel Barrie, Bowmore Distillery’s Master Blender, and cocktail and spirits write Camper English, which they believe shows that the addition of water from the same locale where a whisky was made tends 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 and sip again. 

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.