Wine Tasting: A Professional Handbook

By Ronald S. Jackson

Wine Tasting: A Professional Handbook, Fourth Edition presents the latest information behind tasting, including insights on physiological, psychological and physicochemical limitations associated with sensory evaluation. The book's author notes how techniques may guide in achieving improved wine quality and adjusting production procedures to match consumer preferences, occupational hazards of professional wine tasters, and the latest information on types of wine, vineyard and winery sources of quality, and the principles of food and wine combination. Fully updated, this new edition includes coverage of the statistical aspect of wine tasting, including multiple examples to demonstrate the science of wine characteristic measurement and analysis.

With its inclusion of illustrative data and testing technique descriptions, the book is ideal for both those who train members of tasting panels, those involved in designing wine tastings, and the connoisseur seeking to maximize their perception and appreciation of wine through a clear and applicable understanding of the wine tasting experience.

• Presents worked examples of complex statistics applied to wine tasting
• Provides a flow chart of wine tasting steps and production procedures, incorporating course and appreciation practices
• Discusses various types, purposes and organization of wine tastings
• Cautions about design errors that could invalidate data interpretation
• Explains practical details on wine storage and the problems that can occur, both during and following bottle opening

• Language: English
• Publisher: Academic Press
• Release date: Oct 2, 2022
• ISBN: 9780323984508

Ronald S. Jackson

Ron Jackson received the bachelor's and master's degree from Queen's University and the doctrine from the University of Toronto. His time in Vineland, Ontario, and subsequently at Cornell University redirected his interest in plant disease toward viticulture and enology. As part of his regular teaching duties at Brandon University, he developed the first wine technology course in Canada. For many years he was a technical advisor to the Manitoba Liquor Control Commission, developed sensory tests to assess the tasting skills of members of its Sensory Panel, and was a member of its External Tasting Panel. He is also the author of Conserve Water, Drink Wine and several technical reviews. Dr. Jackson has resigned from his position as a professor and the chair of the Botany Department at Brandon University to concentrate on writing. He is allied with the Cool Climate Oenology and Viticulture Institute, Brock University.

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Front Cover for Wine Tasting - A Professional Handbook - Fourth Edition - by Ronald S. Jackson

Wine Tasting

A Professional Handbook

Fourth Edition

Ronald S. Jackson

Cool Climate Oenology and Viticulture Institute, Brock University, St. Catharines, Ontario, Canada

Table of Contents

Cover image

Title page

Copyright

Dedication

Preface

Acknowledgments

Chapter 1. Introduction

Abstract

Outline

Tasting Process

Appearance

In-Mouth Sensations

Finish

Overall Quality

Brandy Tasting

References

Chapter 2. Visual Perceptions

Abstract

Outline

Color

Clarity

Viscosity

Pétillance/Effervescence

Tears

References

Chapter 3. Olfactory Sensations

Abstract

Outline

The Olfactory System

Odorants and Olfactory Stimulation

Sources of Variation in Olfactory Perception

Odor Assessment in Wine Tasting

Off-Odors

Chemical Nature of Varietal Aromas

References

Further reading

Chapter 4. Oral Sensations

Abstract

Outline

Taste

Factors Influencing Taste Perception

Mouth-Feel (Chemesthesis)

CHEMICAL COMPOUNDS INVOLVED

Taste and Mouth-Feel Sensations in Wine Tasting

References

Appendix 4.1

Chapter 5. Quantitative (Technical) Wine Assessment

Abstract

Outline

SELECTION AND TRAINING OF TASTERS

PRE-TASTING ORGANIZATION

TASTING DESIGN

WINE EVALUATION

SENSORY ANALYSIS

INDICATORS OF WINE QUALITY AND CHARACTER

OCCUPATIONAL HAZARDS OF WINE TASTING

References

Appendix 5.1 Aroma and Bouquet Samplesa,b

Appendix 5.2 Basic Off-Odor Samplesa,b,c,d

Appendix 5.3 Response Sheet for Taste/Mouth-feel Test

Appendix 5.4 Off-Odors In Four Types of Wine at Two Concentrations

Appendix 5.5 Minimum Number of Correct Judgments to Establish Significance at Various Probability Levels for the Triangle Test (One-Tailed, P=1/3)a

Appendix 5.6 Rank Totals Excluded for Significance Differences, 5% Level. any Rank Total Outside the Give Range is Significant

Appendix 5.7 Rank Totals Excluded for Significance Differeences, 1% Level. Any Rank Total Outside the Give Range is Significant

Appendix 5.8 Multipliers for Estimating Significance of Difference by Range. Two-Way Classification. A, 5% Level; B, 1% Level

Appendix 5.9 Minimum Numbers of Correct Judgments to Establish Significance at Various Probability Levels for Paired-difference and Duo-trio Tests (One-tailed, P=1/2)a

Chapter 6. Qualitative Wine Assessment

Abstract

Outline

Tasting Room

Information Provided

Sample Preparation

Wine Score Sheets

Sensory Training Exercises

Tasting Situations

References

Appendix 6.1 Sweetness in Wine

Appendix 6.2 Sourness

Appendix 6.3 Phenolic Components

Appendix 6.4 Alcoholic Wine Constituents

Appendix 6.5 Taste Interaction

Appendix 6.6 Wine Appreciation Course

Chapter 7. Styles and Types of Wine

Abstract

Outline

Historical Origins

Naming

Still Table Wines

Sparkling Wines

Fortified Wines (Dessert and Appetizer Wines)

Brandy

References

Chapter 8. Nature and Origins of Wine Quality

Abstract

Outline

Sources of Quality

VINEYARD INFLUENCES

Winery

Chemistry

TASTING PROCEDURE

Postscript

References

Chapter 9. Wine and Food Combination

Abstract

Outline

Introduction

Compatibility

Wine Selection

Historical Origins of Food and Wine Association

Concept of Flavor Principles

Food and Wine Pairing

Uses in Food Preparation

Wine Presentation

References

Glossary

Tasting Term Glossary

Index

Copyright

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Notices

Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary.

Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility.

To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein.

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Dedication

To the memory of Suzanne Ouellet (1940–2010)

My inspiration, constant supporter, and wisest confidant.

Preface

Ronald S. Jackson

The text was originally written primarily as an information conduit for enologists, winemakers, sensory scientists, and students of those endeavors. Correspondingly, the work concentrates on the intrinsic (sensory) qualities of wine, and how the brain integrates and interprets this information. Nonetheless, a significant amount of material has been added for those in the wine trade: wine retailers, wholesalers, sommeliers, those who teach wine appreciation courses, run wine societies, and anyone seriously interested in the sensory qualities of wine.

Wine tasting is variously interpreted, depending on the needs of the user. For the consumer it enhances wine appreciation and its association with food. For the winemaker, it permits a wine’s development to be assessed, faults detected, the sensory effects of vineyard or winery practices studied, public awareness augmented, and consumer preferences discovered. In a similar manner, wholesalers and retailers employ tasting to select wines which, hopefully, will pique the interest of their clients. For the sensory researcher, it permits studying the sensory perception of wine, assessing its quality, and investigating the origins of typicity and site uniqueness.

Even the term taste has several interpretations. As a noun, for the sensory scientist, it refers specifically to the gustatory sensations of sweet, sour, salty, bitter, and umami. For most people, taste refers to any sensation that originates in the mouth (be it gustatory, mouth-feel, retronasal odor, or their integrated percept, flavor). As a verb, taste refers to the process of sampling beverages and foods, usually in a deliberate, assessment mode.

The divergent uses of taste underscore a legitimate reality. Although the various oral sensations are initially analyzed individually in distinct areas of the brain, their impulses are subsequently relayed to other interpretative centers, including those associated with memory, language, emotion, and consciousness. With experience, the brain begins to construct archetypical models of different wines. These constructs begin to automate our interpretation of sensory input. Although useful in rapidly assessing wine, these models can modify or even distort perception. A visual example of illogical sensory distortion is the Ames Room Illusion, where people appear to grow or shrink as they walk diagonally across a room (on the learned acceptance that all rooms have parallel sides). Vinous examples of perceptive distortion include the apparent sweetness of fruity wines, the enhanced flavor of wine of intense color, and the influence of extrinsic information (e.g., label, provenance, and price) on perceived quality. Thus it is important to be constantly on guard, and question interpretations, to avoid being misled by experience.

In much of the text, wine tasting refers to the critical analysis of wine. This may involve features such as ranking wine within some concept of quality, cultivar typicity, or appellation prototype; distinctive attributes that delineate its sensory character; or assessment of the origins of its sensory characteristics. To do so, there is an attempt to differentiate between sensation and perception. Because individuals vary considerably in general as well as specific sensory sensitivity, tasting panels are required, and their results submitted to statistical analysis. Typically, tasting panels undergo training to become consistent in term usage and competent assessors. Finally, where the data are to be used as a measure of consumer preference, serious consideration of the data’s relevance is required. Trained panels are unlikely to adequately represent consumer perception and preferences.

Although training helps the professional develop the terminology and wine archetypes necessary to adequately describe and assess wine fragrance, typicity, and quality, similar stress on descriptors can result in consumers focusing on nonessentials. There is evidence that concentrating on odor descriptors can disrupt the ability to recall odor memories. Thankfully, most consumers seem content to focus on appreciating wine for what it is, a salubrious, savory beverage, rather than focus on a vain effort to name every perceived (or illusioned) sensory nuance.

Regrettably, for some, wine is a status symbol, a property that seems to sell most expensive wines. This bias is evident in most trade tastings. Correspondingly, extrinsic factors, such as price, producer, estate repute, or vintage renown are accentuated. However, the principal value of wine for savvy consumers remains the sensory pleasure it provides. Thus it behooves most vintners, retailers, and researchers to emphasize those attributes that consumers seek (and what promotes the majority of wine sales). It is only for certain enophiles that some wines, which are initially unpleasant, have an appeal. They know, or trust, that with proper storage and aging, their patience will be rewarded with special and unique sensory joys, justifying their earlier financial outlay.

It is the potential to provide a better understanding of the underpinnings of wine quality that sensory analysis has its greatest value. However, this information is of limited value without their chemical origins being understood. This is a prerequisite for effectively adjusting the subtleties of grape, yeast, and bacterial metabolism. These are the factors that ultimately impact the sensory uniqueness of varietal, stylistic, and regional wines. This information is also needed to meet the challenges of climate change. Skilled winemakers can do wonders to optimize the qualities of wines, but the process would be more efficient, if not also improved, if the chemical and sensory consequences of most viticultural and enologic procedures were better known.

What also limits efforts in improving wine quality is the absence of a clear, objective, generally accepted, definition of what delineates quality (possibly because none is possible). Quality is the mental construct, based on experience-derived expectation and traditional percepts of a wine’s desirable attributes. For the connoisseur, wine is viewed as an object d’art, produced under the tutelage of highly skilled technician/artisans, and no more amenable to numerical ranking than any other art form. For most consumers, though, purchase decisions are based on a wine’s price, and the absence of unpleasant tastes. Nonetheless, popular wine writers continue to construct commentaries as if people cared, believed, or remembered the florid web of fantasies their fertile minds fabricate. In addition, the proliferation of numerical rankings generates a false impression of precision, potentially diverting consumers from trusting their own judgment. Were it not for the disservice it does to consumers and little known, quality, winemakers, it would matter little. I, too, was once beguiled by reports in the popular press, until I accidentally tasted some astounding wines, unlike the immature, austere wines that columnists recommended. None of their suggestions directed me to wines possessing attributes deserving to be called a gift of the gods.

Tasting techniques are always personal, but the procedure described in the text is designed to maximize sensory detection. As such, it is particularly valuable to those involved in sensory analysis. Although analytical, the process is also useful for anyone desirous of detecting the full range of sensory pleasures a wine may express. As with almost everything, the technique also has potential disadvantages. It equally exposes a wine’s sensory failings. In addition, no one should be under the illusion that it is easy to distinguish (at least initially or consistently) varietal or regional styles. Many factors must be concurrent for clear expression. The wine must be made from grapes grown under conditions conducive to the development of any unique varietal aroma these may possess and fermented and aged under conditions that permit the varietal and/or regional characteristics to be adequately expressed. Although desirable and potentially enhancing the wine’s sensory intrigue, such attributes are not essential for enjoyment. Wine is, after all, a beverage to be enjoyed, not always dissected, or even revered. Most wines do not merit, or benefit from such detailed attention.

Outside research centers, it is unlikely that rigorous sensory evaluation is practiced. Some wineries, possessing highly skilled staff, create superior wines without using any of the elaborate sensory analysis techniques noted in the text. However, other wineries, in less competent hands, produce eminently forgettable wines and would benefit from their use. Large wineries, producing gargantuan quantities of wines, have no option but to use sensory evaluation techniques. Millions of dollars, and shareholder profits, ride on the decisions made by their winemakers, blenders, and evaluation panels.

The text commences by guiding the reader through the process of sampling wine, leading into a discussion of the psycho-physiology of sensory perception. It provides a theoretical understanding for the complexities of valid wine assessment and the intricacies of consumer preferences. What any individual perceives depends not only on their sensory acuity and experience, but also on their cultural upbringing, physical and emotional well-being, and the tasting context.

This is followed by detailing the optimal conditions for wine assessment and evaluation, the selection and training of tasting panels, various sensory procedures, and the analysis of significance. These provide the producer with the tools necessary for assessing wine critically.

Subsequently, wine classification and the origins of wine quality are covered, with a discussion on what can confidently be said about wine and food pairing. The importance of the latter is evident to every winemaker since wine remains the primary food beverage in many parts of the world. Despite this, the best wines usually express their finest qualities when savored alone. For example, the development and finish of a wine are seldom detectable when consumed with food. To facilitate their detection, wines may be assessed prior to eating, or savored slowly and deliberately with minimally flavored food. Equally, aperitif and dessert wines are more amenable to full appreciation when they are taken by themselves. Nonetheless, the social context of a fine meal often enhances a wine’s appreciation. Under such conditions, eating and drinking are elevated to epicurean heights, divorced from the basics of abating hunger and thirst. Even the act of selecting a wine can be tantalizing, providing anticipation of the pleasures to come.

In spite of the emphasis on critical analysis, most vinous epiphanies occur unexpectedly. Truly memorable wines are ineffable, generating the experiences of which aficionados dream. Are such wines necessarily expensive? Typically, no, but usually those about which one knows or expects little, ipso facto, the element of surprise.

Acknowledgments

Without the dedication of innumerable researchers, the complexities of human sensory acuity and perception would remain mysteries and this book would have been impossible.

Many thanks go to my students, participants of sensory panel tests, the Manitoba Liquor Control Commission, and Brock University for providing the opportunity to gain access to both the practical and theoretical sides of wine assessment. I should also express my appreciation to Jean Thurley for volunteering to read most of the text and for her wise suggestions for improvements.

Finally, but certainly not least, I must express my thanks to the assistance provided by staff at Elsevier, notably Nancy Maragioglio. Their help and encouragement have been critical in bringing this book to fruition.

Chapter 1

Introduction

Abstract

Wine tasting refers to a range of procedures, from those intended to enhance appreciation, rank wines relative to their quality, or describe their sensory attributes in relatively objective terms. Thus, wine tasting can vary from actions as simple as a short sniff and sip, to extended sensory analyses lasting up to a half an hour or more. Because of their diversity of purpose, how tastings are conducted can vary extensively. The particular procedure described below assesses the totality of a wine’s sensory attributes. Although most applicable to critical sensory analysis, wine consumers can equally use the procedure to maximize their appreciation of fine wines. The one caveat is that the process highlights not only the wine’s most exemplary sensory qualities but also any sensory deficits and faults the wine may express. This is especially true if the tasting is conducted in a manner avoiding all psychological biases—that is, tasted blind and in black glasses. Correspondingly, most tastings are conducted with the full knowledge of the wine’s origin and often under conditions designed to generate a positive impression.

Keywords

Tasting process; wine appearance; wine flavor; wine taste

Outline

Outline

Tasting Process 1

Appearance 5

Clarity 6

Color 6

Viscosity 7

Effervescence 7

Tears 7

Fragrance 7

Orthonasal (In-Glass) Odor 8

In-Mouth Sensations 10

Taste and Mouthfeel 10

Retronasal (Mouth-Derived) Odor 15

Finish 17

Overall Quality 17

Brandy Tasting 18

Postscript 18

References 19

As befits one of life’s finest pleasures, wine merits serious attention. Nevertheless, no tasting procedure has achieved universal adoption. Most experienced tasters have their own preferred method. Although a detailed method is essential for critical tasting, it is often viewed as unnecessarily complex by most consumers. The difference in approach is somewhat analogous to a conductor analyzing a musical score versus the audience enjoying the performance. Critical tasting compares one or several wines against actual or memory-based archetypical standards. In contrast, wine with a meal is designed to be savored as its liquid accompaniment. Thus, critical analysis is incompatible with the social and epicurean intentions of the dining room. Nonetheless, even here, periodic concentration on a wine’s attributes can reward the diner with sensory discoveries unanticipated.

The detail with which a wine is assessed depends primarily on its intent. These can vary from the purely holistic, to assessing if they are different, to ranking, to generating a sensory profile. Fig. 1.1 illustrates some of the different purposes for which tastings may be conducted.

Figure 1.1 Tasting situations and their respective rationales.

Tasting Process

The procedure outlined in Fig. 1.2 is a synthesis of views, probably going back centuries, as well as experience gained from assessing tasters. The first known recorded description of a detailed assessment of wine is noted in Eiximenis (1384). Interestingly, the commentary is disparaging, comparing the procedure to mediaeval physicians analyzing patients’ urine. Although no procedure is ideal for everyone, and under all situations, Fig. 1.2 provides a reasonable starting point. Probably the most essential requirement is a willingness, desire, and ability to focus on the intrinsic attributes of the wine, with a minimum of extrinsic information skewing perception. Tasting with black ISO glasses (Plate 5.2) is ideal for negating visual aspects that might distort perception (e.g., features suggesting varietal or geographic origin, or wine age). This does obviate appreciation of the wine’s countenance, but it permits the taster to concentrate on its principal sensory qualities: olfactory, taste, and mouthfeel. When attention is separately focused on each, their diverse modalities may be distinguished (becoming progressively more difficult as their number increases, notably with odors at low concentrations) (Ashkenazi and Marks, 2004; Stevenson, 2012). Alternatively, oral sensations may be assessed integratively as flavor. This may partially explain why Rozin (1982) found that of the seven major languages studied, none specifically acknowledged the olfactory component of flavor. In spite of this early integration, flavor is partially divisible into its individual modalities, depending on their component sensations (Small, 2012), expectation (Gottfried and Dolan, 2003), and attention paid (Stevenson, 2012). Thus, it differs from another sensory construct—color, where magenta cannot cognitively be separated into its red and green spectral components. Although focusing separately on individual sensations is valuable in assessing the origin of a wine’s sensory qualities (the central theme of this work), the process misses out on aspects central to most consumers’ appreciation of wine: the tasting’s social context and the pleasure it may provide. Thus, the current interest in the emotional component of wine assessment (e.g., Loureiro et al., 2016; Mora et al., 2018).

Figure 1.2 Sequence of wine tasting.

Before commencing detailed wine analysis, Peynaud (1987) advocated rinsing the mouth with a sample of the wines to be tasted. Where the wines are unfamiliar, this could familiarize tasters to their basic attributes. However, under most circumstances such a practice seems ill-advised, it being preferable to sample each wine unfettered by expectations. Peynaud also cautioned against rinsing the palate between samples. He feels that this could alter sensitivity, and complicate assessment. In this recommendation, he was as at odds with other authorities. Only when the palate seems fatigued does he support palate cleansing. Peynaud’s view assumes that tasters can perceive accurately when their senses have, or are becoming adapted, a dubious supposition. Most data would suggest it is preferable to encourage tasters to cleanse their palate between samples to avoid, as much as possible, adaptation altering and diminishing perception to subsequent wines. Ideally, this should permit each wine to be assessed under similar conditions. Nonetheless, when sampling very complex wines (e.g., vintage ports), olfactory adaptation can be of value. It can result in unmasking aromatic compounds undetectable before adaptation to the more obvious flavorants has occurred (Goyert et al., 2007). Tasting over a protracted period also offers a chance of detecting potential quantitative and qualitative changes in fragrance. This undoubtedly results from dynamic changes in headspace gas composition during assessment. Such changes can occur both in-glass and in-mouth. The understanding of this fascinating phenomena is still in its infancy (Brossard et al., 2007; Baker and Ross, 2014).

Under detailed assessment conditions, wines are sampled using clear, tulip-shaped glasses, such as the ISO Wine Tasting Glass (Fig. 1.3; Plate 5.13 left). The primary exception involves sparkling wines, where flutes permit detailed analysis of the wine’s effervescence (Plate 1.1). Because of the flute’s narrowness, and the habit of filling, concentration of the fragrance above the wine is limited. Although initially reducing the release of aromatic compounds associated with swirling, this may be compensated as bubbles rupture at the surface, dispersing droplets of wine into the air (Plate 1.2; Fig. 7.14). The difference detected will depend on the volatility of the aromatics, the shape of the glass, and the attention of the taster.

Figure 1.3 International Standards Organization (ISO) wine tasting glass. Dimensions are in mm. Source: Courtesy of International Standards Organization, Geneva, Switzerland.

Plate 1.1 Illustration of the effervescence attributes of a sparkling wine in a flute. Notice the cordon de mousse around the edge of the glass. Photo courtesy of R.S. Jackson.

Plate 1.2 The surface discharge resulting from the bursting of bubbles from a flute containing champagne. Photo courtesy of Collection CIVC, copyright Alain Cornu.

All glasses in comparative tastings should be of identical, made of crystal-clear glass, and filled to the same height (about one-quarter to one-third full). This facilitates each wine being sampled under equivalent conditions. Between 30 and 50 mL is adequate for most assessments. These volumes provide enough wine for each wine to be sampled multiple times over the course of a tasting, usually 20 to 30 min. During this period, if the wine shows fragrance development it should become apparent. Correspondingly, the wines should not be allowed to breathe prior to pouring. If the wine shows sensory development, one should not miss this fascinating and glorious aspect. In addition, the duration of the fragrance should also be assessed.

Not only are relatively small volumes economical, but they facilitate holding the glass at a steep angle (for viewing color and clarity). It also permits vigorous swirling, enhancing the release of aromatics from the wine into the headspace (a function of a wine’s surface area to volume ratio, as well as refreshening the aromatics at the wine’s surface). In addition, smaller volumes send a subtle message, if needed, that tasting is not a drinking session. Where color differences amongst the wines are sufficiently marked, the wines should be served in black tasting glasses (or under low-intensity, color-distorting, red illumination), to avoid color potentially biasing assessment.

Tasting in black glasses is a significant challenge. Color is often an integral aspect of odor and wine recognition. Without visual clues, identification can be severely limited. Nonetheless, developing odor memories in the absence of visual clues tends to make them more indelible. For example, the smell of bacon being fried, lilacs, or someone BBQing are instantaneously recognizable, often long before one detects its origin.

Appearance

As noted above, except in situations where appearance might unduly bias assessment, the wine’s visual attributes are the first evaluated. To improve light transmission, the glass is usually tilted against a bright, white background (35–45 degrees angle). This produces a stretched arch along the far side of the glass and varying depths of wine through which its visual attributes can be viewed.

A wine’s countenance is typically a source of visual pleasure but can provide clues as to sensations to follow. Although a harbinger, particular colors do not always correlate with experience-based expectation. Thus, color can be a source of bias, often prejudicing perceptions, depending on personal experience and aplomb. Nonetheless, certain aspects of a wine’s appearance may foretell the presence of particular off-flavors. Albeit an indicator, color should be interpreted with caution, due to its potential undue influence. Assessment should be based on a full and honest evaluation of all sensory attributes.

Clarity

All wine should be brilliantly clear, the only potential exception being barrel samples. Some turbidity can be expected in a still maturing wine. Cloudiness in bottled wine is always considered a fault, despite it seldom affecting the wine’s taste or aromatic character. Because most sources of cloudiness are understood and controllable, crystal-clear clarity is now the expected norm. Even sediment in well-aged red wines is now relatively rare. If present, its disturbance and resuspension can be avoided by careful transport of the bottle to the table, followed by slow and careful decanting.

Color

The two most significant features of a wine’s color are its hue and depth. Hue denotes its shade or tint, whereas depth refers to intensity. Both aspects can provide clues, relating to features such as grape maturity, duration of skin contact, oak cooperage exposure, and wine age. Immature white grapes yield almost colorless wines, whereas fully to overmature fruit can generate yellowish wines. Extended maturation on the vine may, but not consistently, enhance the potential color intensity of both white and red grapes, and correspondingly their wines. The extent to which these tendencies are expressed partially depends on the duration of maceration (skin contact), before or during fermentation, and the incorporation of press wine fractions. Maturation in oak cooperage favors additional color changes, as well as an initial enhancement in color depth. During aging, golden tints in white wines increase, whereas red wines lose color density. Eventually, brownish shades develop in all wines.

Because so many factors can influence color expression, it is difficult to be dogmatic about the significance of any particular shade. Only if the wine’s origin, style, and age are known, may color suggest correctness. An atypical color can be a sign of several faults, but not diagnostic of any. The less known about a particular sample, the less value color becomes in predicting quality.

Tilting the glass has the advantage of creating a gradation in wine depths. Viewed against a bright background, the variation in depth provides a range of hues and density attributes. Pridmore et al. (2005) give a detailed discussion of these phenomena. Tilting can also be used in spectroscopically analyzing a wine’s color (Hernández et al., 2009).

The rim of the wine generated on tilting can provide one of the better indicators of a wine’s approximate age. A purplish to mauve hue is usually an indicator of a red wine’s youth. By contrast, a brickish tint in the same zone is often the first indicator of aging. Comparing the color depth of a series of wines is facilitated by sequentially looking down from the top of each glass.

The most difficult task in assessing wine color is expressing these impressions meaningfully. There is no accepted terminology for wine colors. The Munsell Color System exists but is not readily available nor particularly applicable. CIELAB color coordinates are scientifically useful in comparisons but are essentially meaningless in expressing color in a manner that is applicable to tasting wine. Thus, color terms are seldom noted in a consistent or effective manner. Some tasters place a drop of wine on the tasting sheet. Albeit an attempt at being objective, it does not even temporarily preserve an accurate record of the wine’s color.

Until an effective, practical, wine color standard has developed and been widely accepted, the use of a few simple terms is probably the best that can be achieved. Terms such as purple, ruby, red, brick, and tawny for red wines, and straw, yellow, gold, and amber for white wines tend to have commonly accepted meaning. Combining these hue terms with qualifiers for color depth, such as pale, light, medium, and dark, should provide a suitable range of intensity expressions. Such terms are fairly self-explanatory and provide the potential for some meaningful communication.

Viscosity

Viscosity refers to a liquid’s resistance to flow. Factors such as the sugar, glycerol, and alcohol content can all affect wine viscosity. Typically, though, humanly distinguishable differences are detectable only in dessert or highly alcoholic wines. Because these differences are minor, and of diverse origin, they are of little diagnostic value. Viscosity is ignored by most professional tasters.

Effervescence

Bubbles occasionally form along the sides and bottom of glasses of still table wines, potentially inducing a slight prickling in the mouth. Typically this is of little importance, being a consequence of early bottling (before excess carbon dioxide sorbed during fermentation has dissipated). Infrequently, slight bubbling can also result from late, in-bottle malolactic fermentation. In the past, slight pétillance could have been caused by the activity of spoilage microbes, but currently this is exceedingly rare. Active and continuous effervescence is usually found only in sparkling (or artificially carbonated) wines. In either case, the size, number, and duration of the bubbles are considered important quality features.

Tears

Tears (alternatively called rivulets or legs) often develop and flow down the sides of the glass following swirling. They are little more than a crude indicator of a wine’s alcohol content. Other than the intrigue they may generate, tears are sensory trivia. Nonetheless, the film of wine that forms along the sides of the glass favors the liberation of aromatics, enhancing detection of a wine’s fragrance.

Fragrance

A wine’s fragrance is critically important in evoking memories and eliciting emotional responses. Thus, it is the aspect given most attention by aficionados. When assessing a wine’s fragrance, focus should involve all its aspects (qualitative, quantitative and temporal).

Odor quality refers to the unique attributes of the sensation, usually denoted in terms of resemblances to specific aromatic objects (e.g., roses, apples, truffles), their categories (e.g., flowers, fruit, vegetables, wood, mold), experiences (e.g., barnyard, hayfield, East Indian store), or emotional/esthetic connotations (e.g., elegance, subtlety, refined nature, complexity, perfumed aspect). Quantitative aspects refer to the intensity of the perception, be that of a particular odor quality or the overall sensation. Temporal aspects refer to how the fragrance fluctuates or develops in quality and intensity, both in the glass and in the mouth during repeat samplings.

Because of the concentration often demanded in assessing a wine’s fragrance, it is not uncommon for the taster to close their eyes. This helps exclude extraneous influences from interfering with focusing of the fragrance, hopefully allowing the detection of attributes that will trigger odor memories and their associated terms. By a sequential contemplation or elimination of aromatic possibilities, a wine’s origin may be divined. Where origin is not a concern, attention can solely focus on attributes indicative of the wine’s esthetic qualities.

Orthonasal (In-Glass) Odor

Assessment of a wine’s fragrance usually begins with sniffing above the mouth of the glass, prior to swirling. This permits an initial investigation of the wine’s most volatile aromatics. In comparing several wines, it is often easier to position the glasses close together and near the edge of the table or counter, assessing the fragrance of each sample at the rim, rather than raise each glass in sequence to the nose. An alternative procedure, preferred by some assessors is to sweep aromatics toward the nose by waving a hand over the rim of the glass. Subsequently, inserting the nose deeply into the bowl permits comparing these sensations with those detected at the rim.

Effective swirling, although simple, usually takes some practice. For those unfamiliar with the practice, it is safer to begin by slowly rotating the base of the glass on a level surface. The action involves circular shoulder movements, while the wrist remains stable. Holding the glass by the stem assures a good grip and permits progressively more vigorous swirling. Once comfortable with this action, commence swirling with wrist action, and slowly lift the glass off the surface. Occasionally, some tasters hold the glass by the edge of the base, between the thumb and index finger. While it works, its awkwardness seems designed as an affectation, appearing pretentious. More secure is the normal habit of holding the glass jointly by its stem and base.

Because aromatics are released only at the wine’s air interface, swirling favors their release. It increases this interface by generating a thin film of wine on the inner surfaces of the glass. In addition, it mixes the wine, replenishing its surface with aromatics. By comparison, diffusion of aromatics to the surface is slow, and only slightly improved by convection currents (Tsachaki et al., 2009). Swirling is particularly important for highly volatile compounds, where the surface rapidly becomes depleted in these constituents. The process does enhance oxygen uptake by the wine, but there is no evidence of any significant sensory benefit (other than in the distant past, expediting the oxidation of any resident hydrogen sulfide). The now popular wine aerators are a poor substitute for swirling. Even more nonsensical is pouring wine back-and-forth between decanters. Although it does facilitate volatilization, it reduces one’s likelihood of observing the opening of the wine’s fragrance, something best sensed in the glass. One of joys of slow-motion videos is seeing in a few minutes what takes hours or days to occur in real time. This is not a situation with wine, where aromatic equivalents can occur in minutes. Accentuating aroma escape, before having an opportunity to detect its occurrence, can result in much sensory pleasure being missed.

The incurved sides of tulip-shaped ISO glasses help not only concentrate released aromatics in the headspace above the wine, but also permit vigorous swirling. Other factors influencing the dynamics of aromatic release are the equilibrium between dissolved and weakly bound odorants in the wine.

The different concentrations of aromatics detected during successive samplings can generate distinct perceptions. With considerable attention, involving both inductive and deductive reasoning, it may be possible to recognize varietal, stylistic, vintage, age-related and regional attributes. Where possible, this usually requires several attempts, extensive experience, and that most illusive of all skills, intuition. As the primary source of a wine’s unique character, analyzing the wine’s fragrance merits all the attention it requires and deserves. Murphy et al. (1977) consider that as much as 80% of the sensory significant information about what we drink or eat comes from olfaction. For wine, this involves about 0.6% of a wine’s constituents.

When tasting under laboratory conditions, covers are often placed over the mouths of the glasses. These may be tightly-fitting plastic Petri dish covers (see Plate 5.1), small pieces of plexiglass (see Plate 7.9), or watch glasses, even coffee-cup lids can suffice. The covers serve several purposes. With highly fragrant wines, covers limit potential aromatic contamination of the tasting room, especially those with inadequate ventilation. Such contamination could complicate the assessment of mildly aromatic wines. If the wines are poured in advance of tasting, the covers guard against fragrance loss during the interval between pouring and sampling (Wollan et al., 2016). In addition, the cover permits vigorous swirling (if the lid is held on tightly). This can be particularly useful when the wines are only delicately fragrant.

No special inhalation technique is deemed necessary for effective odor sleuthing (Laing, 1983). A single sniff is often adequate for olfactory identification (Laing, 1986), at least with simple aromatic solutions. Typical whiffs tend to last about 1.6 s, have an inhalation velocity of 27 L/min, and involve approximately 500 cm³ of air (Laing, 1983). The duration and vigor are usually instinctive, and inversely correlated to odor intensity, unpleasantness, and ease of identification (Frank et al., 2006). Thus, although smelling for more than half a second rarely improves odor identification, at least for single compounds under laboratory conditions (Laing, 1982), extending the duration the sniff may be helpful with aromatically mild wines. However, prolonged inhalation runs the risk of adaptation and loss of sensitivity to some aromatics. Thus, a combination of short sniffs and more prolonged inhalations might be optimal. Experimentation with each wine is the only way to tell.

Conscious smelling activates the brain’s olfactory centers (Sobel, 1998), similar to tasting activating the gustatory cortex (Veldhuizen et al., 2007). In addition, the intensity of a sniff can affect the efficiency with which various odorants are deposited along the olfactory mucosa (Kent et al., 1996; Buettner and Beauchamp, 2010). Odorants adsorb onto, and diffuse through, the overlaying mucous layer at different rates. Thus, this may be another reason to vary the intensity/duration of smelling during assessment (Mainland and Sobel, 2006). Longer inhalations appear to equalize odorant detection on both sides of the nasal septum (Sobel et al., 2000), negating any potential effects of the typical differences in flow rate between nostrils (Zhao et al., 2004).

Although extended inhalation induces adaptation to most aromatic compounds, adaptation can be informative with some aromatically complex wines, notably vintage ports. As certain olfactory receptors become adapted, detection of otherwise unnoticed compounds, or their combined influences, may become apparent.

When beginning concerted odor assessment of a series of wines, each sampling should be separated by about 30 to 60 s. Most olfactory receptors appear to take this long to reestablish their intrinsic sensitivity. In addition, measurements of the rate of wine volatilization suggest that the headspace takes a minimum of 15 s to replenish itself (Fischer et al., 1996). Thus, assessment is best conducted at a leisurely pace. This may be an aromatic example of haste makes waste.

In comparative tastings, the wines’ attributes should ideally be assessed both sequentially and repeatedly over 20–30 min. Although this may seem excessive, considerable effort is required in making a detailed assessment and recording its sensory features. In addition, aspects such as development and duration may take several minutes to express themselves. Development and extended duration are highly regarded attributes, characteristics that should be expressed by any premium wine. The higher cost of these wines is justifiable only if accompanied by exceptional sensory endowments. Sequentially concentrating on the fragrance, taste, and flavor of a series of wines also diminishes the likelihood of sensory fatigue developing during tasting.

Regardless of how assessments are conducted, it is important to record olfactory impressions as clearly and precisely as possible. This is easier said than done and is difficult for everyone. This may be because we are not trained from an early age to develop verbal-olfactory associations. The difficulty even applies to naming common odorants in the absence of associated visual clues. The situation has been aptly dubbed the the-tip-of-the-nose phenomenon (Lawless and Engen, 1977).

One of the advantages of recording olfactory perceptions is it focuses attention on the central aromatic features that distinguish wines. Except in technical sensory evaluations, the actual terms used are less important than their relevance to the user. Dissecting a wine’s sensory attributes is essential for the winemaker or sensory scientist but does not necessarily enhance sensory appreciation. Wine enjoyment is not the equivalent of the sum of its sensory parts, any more than a poem’s merit is denoted by the number of similes, alliterations, metaphors, analogies it possesses, or its adherence to a particular rhyming pattern.

Most complex flavor perceptions are cerebral creations, just as color perception. Odor perception starts with the activation of nasal receptor neurons, but soon involves interactions with other related neurons, often in several distinct brain centers. These connect with odor memories, the totality of which generates the perceptions we consciously detect. Thus, most recognizable fragrances, be it wine, coffee, lilacs, or fried bacon, are a unique combination of multiple neuronal interactions, coordinated in the frontal regions of the brain (Figs. 3.12 and 3.40).

For detailed sensory analysis, tasters are usually trained using samples specifically designed for particular research projects. Reference samples for the various terms are commonly provided during tastings (Appendices 5.1 and 5.2). Fragrance and off-odor charts (Figs. 1.4 and 1.5) can assist in developing and maintaining a common wine lexicon. Terms help codify the uniquely distinctive aromatic attributes of particular groups of wines, similar to the characteristic note and harmonic patterns that embody the music of specific composers. However, without directed and extensive training, precise use of the most detailed tier of descriptors (e.g., violet, blackcurrant, truffle) is difficult. In general, middle-level terms (floral, berry, vegetal) seem more applicable, and are more effectively used by the majority of people. At the same time, it is important that consumers realize that odor analogy, as illustrated in such charts, should not be construed as accurately describing a wine’s aromatic features. They, at best, only suggest some of a wine’s more distinctive sensory characteristics. This is analogous to the difference between a house and its architectural drawings. At worst, obsessive concern with descriptors can convince some consumers that, because they cannot recognize features supposedly present, they are inherently incapable of appreciating wine. Analysis may enhance appreciation, like recognizing the names of plants in a garden, but it is not essential to enjoying being in a garden.

Figure 1.4 Wine fragrance chart. Source: From Jackson, R.S., 2000. Wine Science: Principles, Practice, Perception, second (ed.) Academic Press, San Diego, CA, reproduced by permission).

Figure 1.5 Wine off-odor chart (column at right notes examples of causal chemicals). Source: From Jackson, R.S., 2000. Wine Science: Principles, Practice, Perception, second (ed.) Academic Press, San Diego, CA, reproduced by permission.

Thus, undue emphasis on descriptive terms by consumers can be counterproductive, especially in wine appreciation courses. Charts should be used only to encourage focusing on a wine’s fragrance. Once the importance of a wine’s olfactory traits is realized, description in terms of specific fruits, flowers, vegetables, etc. is of limited or negative value. Inventing fanciful terms, in a vain attempt to be informative, is superfluous as well as disingenuous. This potential is aggravated by the legitimate difficulty people have in verbalizing olfactory sensations. It is generally more advantageous for consumers to concentrate on learning to recognize (develop a memory trace for) the sensory differences that exemplify varietal aromas, production styles, an aged bouquet, and other features, than articulate these in words. No one expects people to verbally describe the facial features that distinguish their friends, but this does not inhibit them from recognizing them. Except for research purposes, collections of descriptive terms are best left for the purposes for which they were initially developed, descriptive sensory analysis.

In recording olfactory sensations, both positive and negative aspects should be noted. For this, use of an appropriate tasting sheet can be invaluable. Fig. 1.6 provides an example of a general tasting sheet for wine appreciation courses. Designed for reproduction on 11″ × 17″ sheets, the circles indicate the placement of six wine glasses. Where desired, photocopies of wine labels can be inserted, as illustrated in Figure 6.3. Alternatively, a simple hedonic tasting sheet, such as illustrated in Fig. 1.7 may be appropriate. Tasting sheets are discussed in greater depth in Chapters 5 and 6. In addition to static verbal descriptions, similar to a composite photo, a line drawn on a rough time–intensity scale can effectively illustrate the dynamic, evolving nature of a wine’s characteristics, equivalent to a montage (Fig. 1.8). Vandyke Price (1975) seems to have been the first to demonstrate this graphic method of recording both a wine’s quantitative and qualitative attributes over the course of a tasting. The process easily and succinctly expresses the most noticeable and varying impressions. It may be the forerunner of a more codified and precise sensory procedure termed temporal dominance of sensations (Pineau et al., 2009) (see Chapter 5).

Figure 1.6 General wine tasting sheet (usually enlarged to 11×17–in. paper).

Figure 1.7 Hedonic wine tasting sheet for quality assessment. Source: From Jackson, R.S., 2014. Wine Science: Principles, Practice, Perception, second (ed.) Academic Press, San Diego, CA, reproduced by permission.

Figure 1.8 Example of a graphic representation of the development of a wine’s fragrance during a tastings. Specific observations can be applied directly to the point on the graph where the perception was detected.

In-Mouth Sensations

Taste and Mouthfeel

After an initial assessment of the fragrance, attention switches to taste and mouthfeel. As with odor, several attributes are evaluated. These may include their quality, intensity, duration. Quality refers to the various expressions of a modality (e.g., the different expressions of astringency). Intensity refers to the perception of their relative strengths. Temporal characteristics relate to how the quality and intensity of each modality change while the sample is in the mouth. The spatial pattern concerns the site(s) (tongue, cheeks, palate, throat) where the modality is detected. The time–intensity and spatial pattern can be useful in differentiating between each modality.

Tasting commences with sipping about 6 to 10 mL of the sample. As far as feasible, the volume sampled should be kept identical, to permit valid comparison between samples of a single wine and among different wines. Sip volume also affects the relative release of volatiles in the mouth, and thus, potentially the wine’s flavor (Genovese et al., 2015). Active churning (chewing) or aspirating the sample (see below) brings the wine into contact with all oral surfaces.

The detection of a wine’s taste modalities typically occurs in a specific temporal sequence (Fig. 1.9). The first taste modality typically detected, if present, is sweetness, followed by acidity (sourness). The sensation of sweetness is most evident on the tip of the tongue. In contrast, sourness is more evident along the sides of the tongue and insides of the cheeks, depending on the individual. The sharp aspect of acidity typically lingers longer than that of sweetness. Because bitterness begins to be detected slightly later, its increasing intensity often coincides with a decline in perceived sweetness, except in dessert or sweet fortified wines. In fortified wines, sweetness helps to diminish any bitterness the wine may possess (e.g., ports). This is equivalent to the mollifying effect of sugar on the bitterness of coffee or tea. Bitterness can take upwards of 15 s before peak intensity is reached. Thus, to fully assess this attribute, the sample should remain in the mouth for at least 15 s. Bitterness is usually more prominently detected over the central, posterior portion of the tongue. Subsequently, or during this period, the taster should also focus on mouthfeel sensations, notably the dry, chalky, rough, dust-in-the-mouth or velvety qualities of astringency. Additional mouthfeel sensations that may be present include the burning sensation of alcohol and the prickling/pain aspect of carbon dioxide. These and other tactile sensations are dispersed throughout the mouth, without specific localization.

Figure 1.9 Assessment of a wine’s taste perceptions over time (s) using the Temporal Dominance of Sensations procedure. Source: From Frost, S.C., Harbertson, J.F., Heymann, H. 2017. A full factorial study on the effect of tannins, acidity, and ethanol on the temporal perception of taste and mouthfeel in red wine. Food Qual. Pref. 62, 1–7, reproduced by permission.

As noted, the sequence, location, and temporal dynamics of each modality can be useful in their identification (Kuznicki and Turner, 1986; Marshall et al., 2005; Laing et al., 2002). This capacity is, however, partially dependent on the taster’s approach (Prescott et al., 2004). That is, analysis (conscious attention to each modality) versus synthesis (holistic integration of all in-mouth sensations). In contrast, the duration of each sensation is not particularly diagnostic. Persistence reflects more the concentration and maximum perceived intensity of the tastant than its modality (Robichaud and Noble, 1990).

Although significant in some critical tastings, noting and recognizing individual sapid sensations is less important than on how they integrate to form holistic perceptions (e.g., balance, body, complexity), and combine with retronasal odor to generate flavor. An example of integration is the creaminess of dairy products, being dependent not only on mouthfeel and fat-particle size, but also aroma (Kilcast and Clegg, 2002).

Sensory integration develops instinctively, as a consequence of experience, without the need for conscious participation (Hollowood et al., 2002). Wine-related examples of such unconscious integration include the illusion of sweetness often considered to be present in fruity, but dry, white wines, and the apparent greater flavor intensity of deeply colored wines. Nonetheless, this integration seems reversible. Actively concentrating on a complex sensation can often separate its component sensory aspects (van der Klaauw and Frank, 1996; Prescott, 1999). Thus, it may be up to the individual to decide whether the more inherently natural (integrated/holistic) approach, or a more analytic (dissective) approach, is desired. Perceived reality often depends as much on experience as on the context in which the sensation is detected.

Because wine tasting means different things to different people, there are differing opinions on whether the initial or subsequent taste and mouthfeel perceptions are the more representative. Tannins react with saliva proteins in the mouth, diminishing their ability to activate bitter and astringent perceptions. Although tannins induce enhanced saliva production, it is insufficiently marked or rapid to compensate for its dilution and precipitation during sampling. Thus, subsequent samplings of red wines often appear more astringent and bitter than during the first sip. If the purpose of the tasting were to suggest food compatibility, then the first taste would provide a better equivalent (several food constituents react with tannins, reducing their sensory impact). Otherwise, data from the second and subsequent samplings are likely to provide more accurate and comparable data with a series of wines.

In an attempt to minimize carry-over effects, from one wine to another, cleansing the palate between samples is recommended. Due to the importance of palate cleansers in food and wine sensory analysis, the effectiveness of different palate cleansers have been repeatedly investigated. For example, Colonna et al. (2004) found that a weak solution of pectin (1 g/L) was more effective than several traditional palate cleansers. Pectins (Hayashi et al., 2005) and ionic carbohydrates, such as xanthans and gum arabic (Mateus et al., 2004), appear to have their cleansing effect by limiting tannin-protein polymerization, much in the same manner as grape polysaccharides (rhamnogalacturonans) mollify wine astringency (Carvalho et al., 2006). This effect is marked with galloylated flavonols (Hayashi et al., 2005), but becomes less effective as polymer size increases (Mateus et al., 2004). In a study by Brannan et al. (2001), the use of 0.55% carboxymethyl cellulose was recommended, due to its low residual effect in the mouth. In another study, crackers were assessed to be most effective in reducing the residual effects of red wine (Ross et al., 2007). Water, a commonly provided palate cleanser, has universally been found ineffective.

Retronasal (Mouth-Derived) Odor

As with fragrance, the relative intensity and qualitative aspects of retronasal odor should be noted repeatedly over the course of a tasting. Two interrelated events affect retronasal detection (Normand et al., 2004): punctuated surges of air from the throat (immediately following swallowing), and the more tranquil upward flow during breathing (Fig. 1.10). Flow can be regulated by adjusting swallowing (Fig. 1.10C), varying the breathing pattern, and tilting the head forward. These actions affect the movement of the velum (soft palate), epiglottis, and uvula. During swallowing, the velum and epiglottis block passage to the lungs, and the uvula forms a tight seal at the back of the nasopharynx, preventing passage to the nasal cavities (Buettner et al., 2001). After swallowing, the velum, epiglottis and uvula return to their normal positions, allowing volatiles to again enter the nasal passages from the mouth, and airflow to and from the lungs. Intentional focus on deliberate expiration apparently enhances retronasal identification (Pierce and Halpern, 1996).

Figure 1.10 Flavor release from a solution of menthol sampled by three different subjects: Each large peak corresponds to a swallow, smaller peaks to breathing. Panelist 3 was a flavorist who made many small swallows. This behavior clearly prolongs flavor release. Source: Reproduced from Normand, V., Avison, S., Parker, A., 2004. Modeling the kinetics of flavor release during drinking. Chem. Senses 29, 235–245, by permission of Oxford University Press.

Because swallowing is discouraged during professional tastings (due to alcohol’s reduction of taster accuracy), the importance of swallowing in retronasal odor detection, and thereby the perception of wine flavor, is of concern. Without swallowing, perceived aroma complexity can be both reduced and modified (Déléris et al., 2014). Thus, aspiration and focus during expiration take on increased importance during research-based assessments.

Movement of aromatics from the mouth into the nasal cavities is facilitated by aspirating the wine. It can involve tightening the jaws, pulling the lips slightly ajar, and slowly drawing air through the wine. Alternatively, the lips can be pursed, before drawing air through the wine. Either procedure favors volatilization by increasing contact between the wine and air (analogous to swirling wine in the glass), as well as atomizing some of the wine. Vigorous agitation (mastication or chewing) of the wine in the mouth has a somewhat similar effect (de Wijk et al., 2003), but is less effective. Aspirating wine in public, unless done discretely, can be interpreted, by those unfamiliar with the process, as uncouth.

Wine fragrance perceived retronasally can be qualitatively different from that detected orthonasally (Negoias et al., 2008). This distinction is well known, relative to the difference often detected between the smell and flavor of cheeses. This phenomenon probably has several origins. The concentration of aromatics reaching the olfactory patches via the oral cavity is considerably less than via the nose, the volume of airflow coming from the oral cavity being much less. As a result, some constituents may retronasally be below their detection thresholds. Other factors may involve the increased temperature in the mouth (selectively modifying the relative volatility of aromatic compounds) and the action of both salivary and microbial enzymes. These could either degrade, generate, or facilitate the liberation of volatile compounds in the mouth. In addition, the perceived quality of a compound may be affected by the reversed airflow (Small et al., 2005). This may relate to the spatial positioning of different receptors along the olfactory patches, and, correspondingly, the temporal sequence with which they respond to aromatic compounds. This may be analogous to playing a short segment of music backward, or the interpretation of faces viewed upside down (Murray, 2004). More significant may be the almost immediate integration of these olfactory impulses with those of taste and mouthfeel from the mouth, generating the multimodal percept, flavor. Without the retronasal component, most foods and beverages lose most of their identifiable characteristics, an experience well known to anyone having had a head cold. Pinching the nose has a similar effect. A similar integration of orthonasal odor detection with gustatory perceptions also can occur (Pfeiffer et al., 2005), but is rare due to their asynchronous timing.

At the end of oral sampling, tasters may complete their assessment with a prolonged inward aspiration. After swallowing the sample, or expectoration, vapors are drawn into the lungs, then slowly, but forcefully exhaled. Any perception so derived is referred to as the after-smell. The aromatics that induce this perception originate from both the lungs and the oral cavity. While occasionally informative, the procedure is typically of value only with complexly aromatic wines.

An adjunct, near the end of an assessment, is to refrain from sampling for several minutes. During this period, aromatics accumulate in the bowl (the effect being enhanced by placing a cover over the opening of the glass). After this interval, it can be astonishing how the intensity of the fragrance has augmented (to the joy of the taster).

In contrast to wine sensory analysis and competitions, samples are typically consumed in wine appreciation courses, at wine society tastings, and the like. Because the number of wines being tasted during such events is often small, and the assessments only for personal edification and enjoyment, consumption is unlikely to negatively affect tasting skill or results. However, when twenty or more wines are sampled, as in wine competitions or technical tastings, consumption must be avoided. Expectoration limits any significant increase in blood-alcohol content (Scholten, 1987). Nonetheless, sufficient tannic material may be consumed to cause a headache. This may be avoided by taking a prostaglandin-synthesis inhibitor (e.g., acetylsalicylic acid, acetaminophen, or ibuprofen) about an hour before tasting. This and other occupational hazards of wine tasting are discussed at the end of Chapter 5.

Finish

After assessing the wine’s individual sensory attributes, concentration switches to the finish. Finish refers to the lingering sensations in the mouth after the sample had been swallowed or expectorated. These arise from the thin film of wine that coats the mouth and throat, as well as compounds that have sorbed onto the mucous layer lining of the throat (Bücking, 2000) and nasal passages. In addition, only those compounds that persist in, and subsequently escape from the saliva and/or mucus are potentially detected. Although tending to be subtle and fleeting (like a sunset), a delicate lingering finish is considered by many oenophiles as a sine qua non of a quality wine. It may last from a few seconds to minutes. Occasionally its duration is measured in terms of caudalie (each unit being equivalent to one second). There have been few studies of this phenomenon, but examples are Goodstein et al. (2014) and Baker and Ross (2014).

The finish is influenced by features such as the volatility and polarity of individual aromatic compounds, and how these properties are affected by the wine matrix and conditions in the mouth (see Buettner, 2004). Matrix features include aspects such as the changing alcohol content of the wine in the mouth, or the presence of binding compounds such as mannoproteins. Finish is also likely a function of the rate of adaptation to individual compounds in the nose, their degradation by enzymes in the mucous lining of the nose, as well as dilution and degradation in the mouth. Finally, how food constituents are modified by salivary enzymes and interact with wine constituents further affect the dynamics of aromatic release in the mouth.

Although most table wines possess a relatively short finish, fortified wines, possessing more intense flavors, typically exhibit a much longer finish. Although a prolonged finish is usually viewed as desirable, features such as a persistent metallic sensation, the presence of off-odors, or excessively acidic, bitter, and astringent sensations are clearly not interpreted positively.

Overall Quality

After individually assessing a wine’s sensory attributes, attention shifts to overall quality. As noted by Amerine and Roessler (1983), it is far easier to detect a wine’s quality than define it. Wine quality