Wine Flavour Chemistry Ronald J Clarke Jokie Bakker Ó 2004 by Blackwell Publishing Ltd Editorial Offices: Blackwell Publishing Ltd, 9600 Garsington Road, Oxford OX4 2DQ, UK Tel: þ44 (0)1865 776868 Blackwell Publishing Professional, 2121 State Avenue, Ames, Iowa 50014-8300, USA Tel: þ1 515 292 0140 Blackwell Publishing Asia Pty Ltd, 550 Swanston Street, Carlton, Victoria 3053, Australia Tel: þ61 (0)3 8359 1011 The right of the Authors to be identified as the Authors of this Work has been asserted in accordance with the Copyright, Designs and Patents Act 1988 All rights reserved No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher First published 2004 by Blackwell Publishing Ltd Library of Congress Cataloging-in-Publication Data Clarke, R.J (Ronald James) Wine flavour chemistry/Ronald J Clarke, Jokie Bakker p cm Includes bibliographical references and index ISBN 1–4051–0530–5 (alk paper) Wine—Flavor and odor Wine—Chemistry I Bakker, Jokie II Title TP548.5.F55C53 2004 6630 2—dc22 2004049689 ISBN 1–4051–0530–5 A catalogue record for this book is available from the British Library Set in 10/13pt Times by Integra Software Services Pvt Ltd, Pondicherry, India Printed and bound in India by Replika Press Pvt Ltd, Delhi The publisher’s policy is to use permanent paper from mills that operate a sustainable forestry policy, and which has been manufactured from pulp processed using acid-free and elementary chlorine-free practices Furthermore, the publisher ensures that the text paper and cover board used have met acceptable environmental accreditation standards For further information on Blackwell Publishing, visit our website: www.blackwellpublishing.com Contents Preface x Chapter Introduction 1.1 Scope of the book 1.2 Historical background 1.3 Wine flavour 1.4 Wine colour 1.5 Vinification 1.5.1 Vinification process Pre-fermentation Fermentation Post-fermentation 1.5.2 Red wines Pre-fermentation Fermentation Post-fermentation 1.5.3 White wines Pre-fermentation Fermentation Post-fermentation 1.5.4 Specialized wines Sweet wines Sweet wines from Botrytis infected grapes Sparkling wine in Champagne Sparkling wine by other methods Wines by carbonic maceration Wines by thermovinification Wines matured ‘Sur Lie’ 1.5.5 Fortified wines Port wine Sherry Madeira 1.6 Physiological effects Bibliography 1 8 13 14 17 17 18 18 19 19 20 21 21 21 22 22 23 24 24 24 25 25 27 31 32 34 Chapter Grape Varieties and Growing Regions 2.1 Wine grapes 2.2 Vine plant characteristics 37 37 39 iv Contents Chapter 2.3 2.4 2.5 Soil and climate Grape growing regions of the world Chemical composition of grapes, must and finished wines 2.5.1 Grapes and must 2.5.2 Finished wine 2.6 Quality control and classification of wines 2.6.1 France 2.6.2 Germany 2.6.3 Italy 2.6.4 Spain 2.6.5 Quality control systems in the European Union Bibliography 40 46 48 48 57 58 59 60 62 62 63 64 Basic Taste and Stimulant Components 3.1 Introduction 3.2 Ethyl alcohol 3.2.1 Measurement of ethyl alcohol content in wines 3.2.2 Measurement of sugar content in musts and wines Brix scale Baume´ and Oeschele scales Prediction of alcohol content in the finished wine 3.2.3 Sugar content of grapes and must 3.2.4 Chaptalization 3.3 Acidity 3.3.1 Contents of organic acids 3.3.2 Measurement of acid content 3.3.3 Acid taste 3.4 Sweetness 3.4.1 Chemical structure of sugars 3.4.2 Content/sweetness 3.5 Bitterness, astringency and mouth feel 3.5.1 Basic chemistry Non-flavanoids Flavan-3-ols Flavonoids Anthocyanins 3.5.2 Basic technology Location of polyphenols in grapes Use of the term ‘tannins’ and their classification Quantifying methods 3.5.3 Bitter constituents White wines Red wines 3.5.4 Astringency 3.5.5 Mouth feel 66 66 66 67 68 69 70 70 72 72 73 74 77 78 79 79 84 85 85 85 87 88 89 90 90 90 93 97 97 97 98 99 Contents Chapter v 3.6 Colouring matter 3.6.1 Colour of red wines 3.6.2 Colour of white wines 3.7 Other constituents 3.7.1 Sulphur dioxide Basic chemistry Technical use Taste effects 3.7.2 Carbon dioxide Formation and handling of CO2 Sensory factors 3.7.3 Oxygen Basic chemistry Oxygen content in wines Effect of oxygen on wine 3.8 Changes in maturation 3.8.1 ‘In-barrel’ ageing 3.8.2 ‘In-bottle’ ageing 3.8.3 Oxidation–reduction (redox) potential General Nernst equation Redox potentials in wine Redox potentials during vinification Bibliography 99 99 100 100 101 101 102 102 103 103 104 105 105 106 108 108 109 112 112 112 113 114 115 116 Volatile Components 4.1 General 4.1.1 Partition coefficients 4.1.2 Threshold flavour/odour levels Units Consistency of threshold odour levels Threshold level difference between sniffing and tasting Threshold levels in solutions of dissolved substances in water and in beverages Relationship of threshold values to partition coefficients Volatile compound concentration in the vapour phase 4.1.3 Flavour/odour descriptions Use of word descriptions Intensity of flavour/odour 4.2 Volatile compounds detected in wines 4.2.1 Types of aroma in volatile compounds 4.2.2 Stereochemical effects in aroma volatile compounds 120 120 120 124 126 126 128 128 130 132 134 134 136 137 140 141 vi Contents 4.3 Contents and sensory evaluation data 4.3.1 Esters Structure Presence in wines Flavour characteristics 4.3.2 Aldehydes Presence in wine Flavour characteristics 4.3.3 Ketones Presence in wines Flavour characteristics 4.3.4 Acetals 4.3.5 Alcohols Presence in wines Flavour characteristics 4.3.6 Lactones and furanones Molecular structures Presence in wines Flavour characteristics 4.3.7 Acids 4.3.8 Nitrogeneous compounds 4.3.9 Phenols Presence in wines Flavour characteristics 4.3.10 Terpenes Chemical structure Presence in grapes/wines Flavour characteristics 4.3.11 Pyrazines 4.3.12 Sulphur compounds Chemical structure Presence in wines Flavour characteristics 4.4 Changes during maturation 4.4.1 Storage of wines ‘in-vat (tank)’ and ‘in-barrel (cask)’ 4.4.2 ‘In bottle’ ageing Changes in ester content Substances produced by carbohydrate degradation Sulphur compounds Changes in terpenoids Formation of substances from carotene breakdown 4.5 Aroma detection and quantification 4.6 Chemical structure and physical properties Bibliography 142 142 142 142 143 148 148 149 149 149 149 155 155 155 158 159 159 161 164 164 164 166 166 166 166 168 170 171 172 173 173 174 174 177 177 179 179 180 180 180 181 181 183 184 Contents Chapter Chapter Wine Tasting Procedures and Overall Wine Flavour 5.1 Wine tasting 5.2 Wine-tasting procedure 5.2.1 Reasons for wine tasting 5.2.2 Wine tasting information and analysis 5.3 Factors influencing sensory perception 5.4 Balance of taste sensations in wine 5.5 Wine aromas 5.5.1 Odour/aroma classification 5.5.2 Aroma/odour characteristics of wines from particular grape varieties 5.5.3 Variants in Cabernet Sauvignon wine flavour 5.5.4 Variants of Chardonnay wine flavour 5.5.5 Flavour description of some other commercial wines 5.5.6 Off-odours and taints 5.6 Wine and food flavour 5.7 Aroma indices and statistical methods 5.7.1 Flavour unit concept 5.7.2 Odour activity unit 5.7.3 Multivariate and other statistical procedures Bibliography Sherry and Port 6.1 Introduction 6.1.1 Ethyl alcohol – sensory effect 6.1.2 Ethyl alcohol – chemical effect 6.1.3 Sweetness 6.2 Sherry 6.2.1 Wine producers 6.2.2 Commercial wine styles 6.2.3 Wine writers’ comments 6.2.4 Grapes and must 6.2.5 Base wine 6.2.6 Maturation 6.2.7 Maturation changes under flor 6.2.8 Maturation changes without flor 6.2.9 Maturation with and without flor 6.2.10 Volatile compounds 6.2.11 Changes during maturation in phenolic compound content 6.3 Port wine 6.3.1 Port wine producers 6.3.2 Commercial port wine styles 6.3.3 Wine writers’ comments vii 189 189 191 196 200 202 204 205 207 209 215 216 217 219 221 223 223 225 226 227 230 230 233 233 234 234 235 235 236 236 237 237 238 240 241 241 246 247 247 248 249 viii Contents Chapter 6.3.4 Grapes and must 6.3.5 Fermentation and base port wine 6.3.6 Port wine compared to red table wine 6.3.7 Maturation 6.3.8 Colour changes during maturation 6.3.9 Volatile changes during maturation Bibliography 250 251 253 254 255 258 261 Formation Pathways in Vinification 7.1 Introduction 7.2 Process variables in vinification 7.2.1 Grapes 7.2.2 Yeast strain 7.2.3 Temperature Standard operating temperature Thermovinification 7.2.4 Clarification procedures 7.2.5 Nutrient medium in fermentation 7.2.6 Maceration 7.3 Production of ethyl alcohol 7.4 Production of individual groups of compounds 7.4.1 Esters 7.4.2 Aldehydes 7.4.3 Ketones 7.4.4 Acetals 7.4.5 Higher alcohols 7.4.6 Furanones and lactones 7.4.7 Acids 7.4.8 Amines 7.4.9 Phenols (volatile) 7.4.10 Terpenes 7.4.11 Pyrazines 7.4.12 Sulphur compounds 7.5 Noble rot Bibliography 265 265 266 266 266 269 269 270 271 271 271 272 272 272 273 273 273 274 275 275 276 276 277 277 277 278 279 Appendix I I.1 I.2 I.3 I.4 I.5 Chemical formulae nomenclature Stereochemistry Chemistry of the oxidation of organic compounds Estimation of partition coefficients of volatile compounds in air/water Grape varieties and cultivars 281 281 285 291 301 304 Contents ix Appendix II II.1 Units II.2 Data sources Tables of molecular formulae, weight and physical properties for each group of volatile compounds found in wine –Volatile esters –Volatile aldehydes –Volatile ketones –Volatile alcohols –Volatile furanones/lactones –Volatile acids –Volatile phenols –Volatile terpenes –Volatile methoxy pyrazines –Volatile sulphur compounds 307 307 307 308 308 311 312 313 314 315 316 316 317 317 Index 318 312 Wine Flavour Chemistry Table II.3 Volatile ketones in wines Molecular Name of compound Formula Weight Boiling point ( C) Propanone (acetone) C3H6O 58 Butane-2,3-dione (diacetyl) 3-Hydroxy-butan2-one (acetoin) Pentane-2,3-dione (acetyl acetone) Hexan-2-one (methyl,butyl ketone) Heptan-2-one C4H6O2 86 56.5 22.7/100 25/230 88 C4H8O2 88 148 C5H8O2 100 140.5 C6H12O 100 127 39/10 C7H14O 114 Octan-2-one C8H16O 128 Nonan-2-one C9H18O 142 4-Hydroxy-3methoxy-acetophenone (1-phenyl-1ethanone) b-Ionone C9H10O3 166 151.5 55/10 172.9 61/10 195 72/10 – C13H20O 192 b-Damascenone C13H18O 190 a 271 140/18 – St parts per 100 parts water at 25 or T C Kj,a-w  103 Direct Estimated At 25 C At T C 20 C 1.6a – 1.6d 1:4 (25) 0.72b – – – – – 1:8 (12.50) 1.75%20 1.37b – – – 0.9c 1.7d 0.43%25 5.9 3.1c 2.4d 0.113%25 7.7a 4.9c 5.1d – 15a – 15 – – – – sl.s – – – – – – – Buttery et al (1969b) b Pollien and Yeretzian (2001) c Calculated from S d Calculated from Pierotti 313 Appendix II Table II.4 Volatile alcohols in wine (alkanols and alkenols) Kj,a-w  104 Molecular Name Formula Propan-l-ol Propan-2-ol C3H8O C3H8O 60 60 Butan-l-ol 2-Methylpropan-l-ol (isobutyl alcohol) (fermentation butyl alcohol) Pentan-l-ol (pentyl alcohol) 2-Methyl butan-1-ol (active amyl alcohol) 3-Methyl butan-1-ol (isoamyl alcohol) Hexan-1-ol (hexyl alcohol) 3-Methyl pentan-1-ol 4-Methyl pentan-1-ol cis-Hex-3-en-1-ol Heptan-1-ol C4H10O C4H10O 74 74 C5H12O 88 C5H12O 88 C5H12O 88 C6H14O 102 C6H14O 102 C6H14O 102 C6H12O C7H16O 100 116 2-Methyl-hexan1-ol Octan-1-ol Octan-2-ol (secondary alcohol) Nonan-1-ol C7H16O 116 C8H18O C8H18O 130 130 C9H20O 144 Decan-1-ol C10H22O 158 Benzyl alcohol (phenyl methyl) 2-Phenyl ethanol [2-(4-Hydroxyphenyl) ethanol] C7H8O 108 C8H10O C8H10O2 122 138 a Weight Direct at 25 C Estimated At T C 25 C a b c d 1 2.8 – – – – – – – (7.4%) 1015 8.1%25 3.5 – 3.6 – 4.3 – 4.5 – 138 45/10 128 2.7 2.20%25 3.620 3.0%25 5.3 – 5.3 6.5 – – – – 132 41/10 214 2.7% – – – – 157 58/10 157 58/10 157 58/10 156 176 86/20 176 86/20 194.5 179–180 0.620 0.6%20 0.59 6.3 7.0 9.1 – – – – 0.59 0.76%25 – 0.1018 0.1725 0.1018 0.1825 0.054%25 0.09626 0.4%25 – – – – – 7.7 – – – 13.2 – – – 213 114/20 230 126/20 206 106/20 219 0.01425 – – – – 0.003725 – – – – 417 0.123%25 1.6 – – – – – – – – St parts Boiling per 100 point ( C) parts 98 82.5 2.4/10 117 108 22/10 Butler (1935) b Buttery (1969) c From solubility data d From Pierotti 9.9 – 10.0 – 9.3 – 11.4 – 9.3 – 11 – 314 Wine Flavour Chemistry Table II.5 Volatile furanones/lactones in wines Molecular Name Formula Weight Boiling point ( C) Sat sol in water St Direct Estimated – – – – – – – Kj,a-w Secondary aromas -Furan-2-one Dihydro-3(H)(g-butyrolactone) Dihydro-3methyl-3(H)(3-methyl-g butyro lactone) Dihydro-5-methyl-3(H)(g-valerolactone) 5-Acetyl-dihydro3(H)- (solarone) 2-Hydroxy-3,3dimethyl-3(H)3-Hydroxy-4,5dimethyl-5(H) (sotolon) -Furan-3-one 4-Hydroxy-2,5dimethyl-2(H)(furaneol; HDMF) C4H6O2 86 C5H8O2 100 204 89/12 – C5H8O2 100 – – – – – C6H8O3 112 102–104/1.2 – – – – C6H8O3 128 102–104/1.2 – – – – C6H8O3 128 – – – – C6H8O3 128 85(subl.) mp 77–78 – – – – C9H16O2 156 93–94 – – – – C9H16O2 156 93–94 – – – – C10H18O2 170 – – – – – C9H7O3 163 – – – – – C7H10O2 126 – – – – – C7H7O2 123 – – – – – Tertiary aromas -Furan-2-one trans/cis 5-Butyl-4methyl-dihydro3(H)- (3-methyl4-hydroxyoctanoic acid g-lactone: (oaklactones) Dihydro-5-pentyl-3(H)(g-nonalone) Dihydro-5-hexyl-3(H)(g-decalone) Hydroxycoumarin (scopoletin) Primary aromas -Furan-2-one 5-Vinyl-5methyl-dihydro- (in Riesling/Muscat) 5-Methyl-3-ethenyl(2-pentenoic acid g-lactone, the raisin lactone) NB: Inadequate or non-available data currently for solubility and vapour pressure Pierotti correlations not available 315 Appendix II Table II.6 Volatile acids in wines (n-alkanoic acids CH3 (CH2)n COOM, also some iso branched chain variants) Kj,a -w  104 Boiling point ( C) St parts per 100 parts at temp T C Molecular Direct at 25 C Estimated a b c d Name Formula Methanoic acid (formic acid, HCOOM) Ethanoic acid (acetic) Propionic acid (propanoic) Butanoic (butyric) 2-Methyl propanoic (iso-butanoic) Pentanoic acid (valeric) 2-Methyl butanoic 3-Methyl butanoic (iso-valeric) Hexanoic acid (caproic) Heptanoic acid (oenanthoic) Octanoic acid (caprylic) Nonanoic acid (pelargonic) Decanoic acid (capric) Dodecanoic acid (lauric) Tetradecanoic acid (myristic) Hexadecanoic acid (palmitic) CH2O2 46 100.6 – – – – C2H4O2 60 118 – – – 0.36 C3H6O2 74 141 – – – 0.4 C4H8O2 88 163 – – – – C4H8O2 88 154 2020 22.8%20 – – – – C5H10O2 102 – – – 102 3.318 2.4%20 – – C5H10O2 184 42/1 187 – – – – C5H10O2 102 176 4.220 – – – – C6H12O2 116 202 – – – – C7H14O2 130 – – – – C8H16O2 144 223o 187/256 240 1.120 0.96%20 0.2518 – – – – C9H18O2 158 253 0.0720 0.08%25 0.03%25 – – – – C10H20O2 172 268 0.00325 – – – – C12H24O2 200 225/100 insol – – – – C14H28O2 228 250/100 0.001220 – – – – C16H32O2 256 271/100 insol – – – – a,b Weight Data not available c Data inadequate d Pierotti correlations 316 Wine Flavour Chemistry Table II.7 Phenols in wines Kj,a-w Name of compound (phenol) Molecular Hydroxybenzene (phenol) 2-Methyl(o-cresol) 3-Methyl(m-cresol) 4-Methyl- (p-cresol) 4-Vinyl-(4-ethenyl) 4-Ethyl 2-Ethyl 2-Methoxy(guaiacol) 2-Methoxy-4ethyl-(ethyl guaiacol) 2,6,-Dimethoxyphenol (syringol) Eugenol C6H6O 94 C7H8O 108 C7H8O 108 C7H8O C8H8O C8H10O C8H10O C7H8O2 108 120 122 122 124 C9H12O2 a,b Bp ( C) St parts or % at 25 C or T C 181 86/20 191 Direct Calculated a b c d 8.220 8.6%25 3.08%40 – – – – – – – – 0.5 2.51%40 2.26%40 – – – 1.715 – – – – – – – – – – – – – – – – – – – – – – – – 152 203 88/10 202 – 218 – 205 53/4 234 – – – – – C8H10O3 154 – – – – – – C10H12O2 164 – – – – – – Formula Weight Data not available c Data inadequate d Pierotti correlations not available Table II.8 Volatile terpenes in wines Molecular Sol in water at T C Kj,a-w Direct Calculated Name Formula Weight Bp ( C) Limonene [1-methyl4-(2-but-1-en)-cyclohex-1-en] Linalool (3,7dimethyl-octa1,6-dien-3-ol) Geraniol (3,7dimethyl-octa2,6-dien-1-ol) -Nerol (isomer of above) a-Terpineol (pmenth-1-en-8-ol) Ho-trienol (3,7dimethyl-octa1,5,7-trien-3-ol) Citronellol (3,7 dimethyl-octa6-en-1-ol) C10H16 136 175 84/40 0.0013825 – – C10H18O 154 198 98/25 v.sl.s – – C10H18O 154 230 142/40 121/17 insol – – C10H18O 154 C10H18O 154 220/27 126/40 insol – – C10H16O 152 – – C10H20O 156 – – 224 108/10 insol 317 Appendix II Table II.9 Volatile methoxy pyrazines in wines Molecular Saturation sol in water St Direct at 25 Ca Estimated Kj,a-w Name Formula Weight Bp ( C) 2-Methoxy-3isobutyl (2-methylpropyl)2-Methoxy-3isopropyl(3-methyl-ethyl-) 2-Methoxy3-sec-butyl(1-methylpropyl) 2-Methoxy3-ethyl- C9H14ON2 166 120 116/61 83/12 –  10À3 – C8H12ON2 152 94–100/61 80/25 – – – C9H14ON2 166 105–115/55 73/10 – – – C7H10ON2 138 – –  10À4 – a Data from Buttery et al (1971) Table II.10 Volatile sulphur compounds in wines Kj,aÀw  103 Molecular Direct at 25 Ca Estimated a c d t Bp ( C) Sat sol S at T C 34 À61 0.125 molar28 – – – CH4S 48 À39/100 2.2% 4.44 – – C2H6S 62 – – 62 1.8% 1.525 2% w/w – C2H6S 35 À13/100 36 25/500 8.46 – – Name Formula Hydrogen sulphide Methane thiol (methyl mercaptan) Ethane thiol (ethyl mercaptan) Dimethyl sulphide (methyl thio methane) 2-methylthiolane-3-ol Ethyl propan-3thiol-oate (ethyl 3-mercaptopropanoate) 4-mercapto 4-methyl-pentan2-one (4MMP) Ethan-2-thio-1-ol (2-mercaptoethanol) Methionol [3(methyl-thio)propan-1-ol)] H2S Weight b C5H6OS 118 – – – – – C5H10O2S 134 162 – – – – 132 – – – – C6H12OS C2H6OS 78 84 – – – – C4H10OS 106 90 – – – – a Pollien and Yeretzian (2001) b No other data cCalculated from St d Calculated from Pierotti.c,dData not available or inadequate Index AC (Appellation Controˆle´e) 5, 59, 197 acetaldehyde 131, 148, 311 binding to sulphur dioxide 253–254, 256 enzymatic reduction 294 flavour/odour 131, 135, 148, 149 formed during ageing 177–178, 239–240, 242, 243, 256, 260 in port wines 253, 255–256, 260 in sherry 239–240, 242, 244 acetals 155, 242, 260, 273–274 acetic acid 315 formed during ageing 111 formed during spoilage 79, 148, 205, 275 limitation 74, 76–77, 80 measurement 77 taste and odour 195, 203 Acetobacter 7, 148 acetoin 154, 244, 312 acidity 57, 73–74, 76–79 and astringency 98 balance with sweetness 205 effect on activity coefficients 123–124 effect of maturation 111 of must 57, 250 reduction under flor 239 see also pH acids organic 74–78, 164, 273, 275–276, 315 in Fino sherry 244–245 flavour/odour 164 activity coefficients 121–122, 123–124, 301–303 aeration 18, 19, 21 ageing and aldehyde development 149 and colour 6, 192 effect of oxygen 105, 107 of fortified wines 27, 31–32, 230–232, 247, 248–249, 254–261 see also under sherry in-barrel 15, 18–19, 109–112, 149, 177–179 in-bottle 17, 19, 21, 109, 116, 149 in oak 92–93, 276 redox potentials 178, 179 in vats 15, 18–19, 109–110, 177–179 see also maturation; storage alcohols 34, 275–276, 282, 313 in Fino sherry 244 flavour/odour 158 in grapes 56–57 in wines 155, 157–158, 273 see also ethyl alcohol (ethanol); fusel oils aldehydes 148–149, 273, 301, 311 chemical changes during vinification 273, 274 flavour/odour 149 formation 108, 111, 177–178, 273, 293–294 in fortified wines 246, 260 in grapes 56–57 partition coefficients 131–132, 133, 311 amines/amides 164, 276 amino acids 266, 275, 289 Amontillado sherry 28–29, 230, 235–236, 241, 246 amyl (pentyl) alcohols 158, 275, 286, 289, 313 anthocyanins 53, 89–90, 92, 94, 99–100 bitterness 98 colour 78, 89, 91, 92, 99 extraction 250–252 in grapes 57, 250–251, 252 oxidation 298 in port wines 255–258 aroma 4, 37–38, 57–58, 120, 196, 205–207 Aroma Indices/Units 126, 223–227 classification 207–209 detection and quantification 181–183 development 178–181 of enantiomers 288–289 primary, secondary and tertiary 58, 120, 140 and terpene content 46 Index threshold levels 136 varietal 140–141, 209–215 see also odour Asti-Spumanti 23 astringency 57, 66, 85, 98, 195 estimation 93–94 auto-oxidation, of lipids 108, 273, 292–294 balance of taste sensations 204–205 barrels/casks 18–19, 109–110 in-barrel ageing 15, 18–19, 109–112, 149, 177–179 Baume´ scale 68, 69, 70, 71 Beaujolais Nouveau grapes/wine 24, 40 beer 129, 223–225, 267–268 benzoic acids 24, 85–86, 96 bicycle pump method for sparkling wine 23 bitterness 57, 66, 85 of red wines 97–98 of tannins 91 and temperature 203 of white wines 97 blending 15, 212–215 of fortified wines 27, 28–29 blind tasting 198, 199 Blue Nun wine 217–218 bodegas 29, 235, 237–238 body 99, 195, 205 Botrytis cinerea 22, 268 effects of infection 1, 22, 24, 278–279 association with sotolon 161, 243, 275, 278 on taste of wine 1, 41, 74 bottles in-bottle ageing 17, 19, 21, 109, 116, 149, 248–249 chemical changes 112, 177, 179 bottling 16–17, 235 bouquet 4, 120, 196, 205–206 oxidative 177 and redox potential 116, 179 reductive 179 brandy 177–178, 179 Brix scale 68, 69–70, 71 browning, oxidative 108, 112, 192, 298–299 prevention 11, 16, 101, 239 Bual grapes 31, 32 bunch rot 22, 41 319 Burgundy wines 60, 72 butane-2, 3-dione (diacetyl) 149–154, 273, 312 butyrolactone 159, 161, 275, 314 Cabernet Blanc grapes 148 Cabernet Franc grapes 42, 76, 173, 210 Cabernet Sauvignon grapes 42, 76, 95, 139, 140–141, 277 Cabernet Sauvignon wines 149, 178, 210, 215–216 caffeic acid 86, 91 caftaric acid 97, 108, 112, 298 carbon dioxide 103–105 carbonation of sparkling wines 23 carbonic maceration 24 Carignan grapes/wines 39, 211 carotene breakdown 181, 273 casks see barrels catechins 87–88, 94, 96, 97, 98, 100 oxidation 297–298 Chablis wines 216–217 Champagnes 22–23, 104–105, 266 chaptalization 11–12, 71, 72–73 Chardonnay grapes/wines 22, 25, 44, 178, 213, 306 chemical nomenclature 280–284 Chenin Blanc grapes/wines 22, 44, 141, 180, 181, 213 chirality and enantiomerism 141, 282, 285–289 cinnamic acids 86, 96, 246, 276 citric acid 56, 73, 79, 80, 278 citronellol 169–170, 180, 245, 316 clarification 14, 15–16, 20, 21, 23, 271 clarity 6, 192 closing up of port wines 255, 256 coffee aroma/flavour 128, 136, 225–226, 265 constituents 91, 154, 161, 172, 225–226 sniffing 206 cold stabilization 16 Colombard grapes/wine 141, 180 colour 5–6 colour of wine 78, 89, 91, 92, 99–100 and acidity 78 assessment 192 and grape skins 6, 37 320 Index colour of wine (Continued ) port wines 5–6, 27, 247, 252–253 sherry 29 sulphur dioxide effects on 100, 101, 257 Concorde grapes 37 corks 16–17, 116, 219 Coˆte d’Or wines 216, 217 coumarins 86, 110, 246 crushing of grapes 11, 17, 20, 108, 115–116 cyanidin 3-glycoside 89, 250, 298 b-damascenone 154, 171, 181, 225, 273 decantation 192 delphinidin glycoside 89, 250 diacetyl (butane-2, 3-dione) 149–154, 273, 312 1,1-diethoxyethane (diethylacetyl) 242, 243, 244, 274 diethyl succinate 148, 260, 310 dihydroquercitin (taxifolin) 88 dimethyl sulphide (DMS) 180 DO, DOC and DOCG 62 Douro valley 25, 247–248 drinkability 19 dryness 218 EC quality control systems 63–64 Electronic Noses 183 enantiomerism and chirality 141, 282, 285–289 enzymes in flavour production 265 and Noble Rot 57, 278 oxidation by 293–294, 298–299 in yeasts 268–269, 272, 277 esters 142–148, 272, 282, 302–304, 308–310 benzoic 86 changes during ageing 179–180, 181, 243 effect of fermentation temperature 269–270 flavour/odour 143–148, 224 in fortified wines 244, 245, 260 estufagem process 31–32, 231 ethyl acetate 123, 124, 272, 308 flavour 143–148, 205 partition coefficients 123, 303–304, 308 in sherry 243, 244 threshold levels 123, 130, 205 ethyl alcohol (ethanol) content in wine 1, 59, 66–68, 70–71, 192–193 effect on flavour 205, 233–235 effect on threshold levels 219 enzymatic oxidation 294 formation by fermentation 66–67, 272 in fortified wines 27, 232, 233–234 physiological/sensory effects 32–34, 66, 203, 233 ethyl butanoate (n-butyrate) 121, 122, 130, 308 ethyl hexanoate (caproate) 122, 124, 308 ethyl lactate 143, 148, 243, 244, 310 extraction of head-space samples 182–183 of volatile compounds by maceration 271 fermentation 7, 13–14, 18, 20–21, 143, 265–269, 271 carbon dioxide production 103 of Champagnes and sparkling wines 22–23 chirality of products 289 of fortified wines 26–27, 31, 237, 251 of monosaccharides 67 redox potentials 116 and temperature 143, 269–270 under flor 239 ferulic acid 86, 276 filtration of wine 16 fining 15–16 Fino sherry 232, 235–236, 243 nose 239–240 production 28–31, 230, 237, 238 volatile compound content 244–245, 246 flavanoids 33, 87, 90, 93–95, 96, 98 flavanols 87–88, 90, 92, 94, 97–98 determination 94 oxidation 296–297 in port wines 255 furanones 275 flavonoids 88 flavonols 88, 96, 246 flavononols 88, 90, 97 Index flavour 3–5, 189, 196, 219 assessment 194–195 classification 207–209 contributing factors 57–58, 212–215 description 134–137, 217–219, 236, 249–250 development during ageing 177–181 effect of fermentation temperature 269–270 effect of malo-lactic fermentation 14 effect of oxygen 105, 108 enhancers and modifiers 195 enzymatic production 265 Flavour Index system 94 Flavour Units 137, 223–225 of fortified wines 231, 232, 233, 234 of grapes 46 history interactions 129, 195, 203, 221–222, 224 sensations/perception 136–137, 189, 190, 194–196, 233 statistical analysis 226–227 threshold levels 122, 124–126, 128–130, 223–225 varietal 209–217 see also odour; taste flor yeasts 238–239, 240 and maturation of sherry 28, 29, 230, 236, 237–240, 241 volatile compounds produced under 241–245, 242–245 Folin–Ciocalteu phenol determination 93, 95 fortification of Madeira 31 of port wines 25, 231 of sherry 29, 238, 241 fortified wines see Madeira wines; port wines; sherry French classification systems 59–60 fructose 51, 79, 83, 84, 286 fermentation 66–67, 272 furans/furanones 159, 160, 275, 314 in fortified wines 245, 260–261 see also lactones Furmint grapes 22 fusel oils (higher alcohols) 34, 155–158, 260, 270, 274–275, 313 321 galacturonic acid 74, 81, 276, 279 gallic acid 81, 93, 110 Gamay grapes/wine 24, 37, 42, 210 gas chromatography (GC) 132, 181–182 gentisic acid 86 geometric isomerism 289–290 geraniol 169, 171, 180, 278, 316 German classification systems 60–61 Gewu¨rztraminer grapes/wine 22, 45–46, 45, 141, 174, 214 gluconic acid 74, 81, 276, 278 glucose 51, 79, 82, 84, 286 fermentation 66–67, 272 glucuronic acid 74, 81, 276 glycerol, in sherry 239, 240, 242 glycosides 86, 89–90 grapes 37, 40 composition 72, 90, 92, 95, 96, 266 terpene content 38, 45–46, 140, 170–171 cultivation conditions 3, 6, 8, 39, 40–42, 215 diseased 268 see also under Botrytis cinerea for fortified wines 232 harvesting 7, 8–11, 19 juice see must pre-fermentation treatment 8–13 skin 6, 37, 52, 95, 251 transport 11 varieties 5, 37–39, 42–57, 250–251, 304–306 and acidity 74–77 and wine flavour 46–47 see also Vitis genus and wine colour 6, 37 Grenache grapes wines 43, 148, 211 harvesting of grapes 7, 8–11, 19, 40, 250 head-space concentrations 120–121, 233 sample preparation 182–183 hexanal and hexenals 148, 273 hexanol and hexenols 158 histamine 33–34 Ho-trienol 170, 277, 316 HPLC determination of phenolic compounds 94–95 322 Index inoculation of must 268 invertase 73 a and b-ionones 154, 171, 181, 273 isoamyl (isopentyl) acetate 144, 224, 269–270, 309 isomerism 141, 285–291, 289–290 Italian classification systems 62 Jerez de la Frontera 27, 28 ketones 149, 149–155, 150–155, 273, 312 Kloeckera yeasts 268 LA method of phenol determination 93 labelling of wine 17, 59–64 laccases 24, 101, 270, 278 lactic acid 14, 73, 80, 285, 287, 289 from malic-lactic fementation 74, 79 see also malo-lactic fermentation lactones 159–164, 242–243, 275, 314 lagar fermentation of port wines 251 Landwein 61 Liebfraumilch wine 217–218 Likens–Nicholson extraction–distillation apparatus 182–183 linalool 169, 171, 172, 180, 245, 278, 316 lipids, auto-oxidation 108, 273, 292–294 maceration of grapes 12–13, 17, 18, 20, 108, 271 for thermovinification 24, 270 Madeira wines 1, 31–32, 195, 231, 232 Maillard reaction 265 Malbec grapes/wine 43, 76, 95, 211 malic acid 14, 56, 73, 79, 80 content in wines 74, 76 measurement 77 see also malo–lactic fermentation Malmsey grapes 31 malo-lactic fermentation 14, 18, 22, 116, 237, 269 and ester content 143 stabilization by 63 malvidin glycoside and derivatives 89, 90, 99, 100, 298 in port wines 250–251, 252, 256, 257 Manzanilla sherry 235, 236, 238 masking of odour 204 mass spectrometry 182 Mateus Rose´ wine 218 maturation 15, 17, 108–112 of Champagnes 23 chemical changes 177–181 of red wines 18–19, 107, 108–109 Sur Lie 24–25 of white wines 21, 109 see also ageing; storage Melon du Bourgogne grapes 24–25, 45 p-menthene-8-thiol 177 mercapto compounds 173–177, 277, 317 4MMP 177, 317 Merlot grapes/wine 42, 161, 210 2-methoxy-3-isobutylpyrazine 122–123, 277, 317 methyl alcohol (methanol) 34 Mourve`dre grapes 43, 56–57, 139, 142 Mourve`dre wines 143, 155, 164, 211 mouth feel 85, 99, 195 Mouton Cadet wine 218 Mu¨ller-Thurgau grapes/wine 37, 44, 214, 306 Muscadelle grapes 45, 76 Muscadet wine 24–25, 218 Muscadine wine 141 Muscat grapes 38, 44, 45, 161, 174 terpene content 140, 170–171, 277 Muscat wines 214 must 6–7, 50–57, 75–76 effect of oxygen 108 inoculation 268 musty odour in wine 219 for port wines 250–251 sugar content 50–51, 56, 68–70, 72 naringin 97 Nebbiolo grapes/wine 37, 43, 211 Nernst equation 113–114, 299–300 noble grapes 37–38 Noble Rot see Botrytis cinerea nonenals 141, 149 nosing 4, 120, 128, 190, 193, 194–195, 205–206 Electronic Noses 183 see also sniffing Index oak aroma/flavour 177, 178–179 barrels/vats/casks 18–19, 109–110, 178–179, 247, 276 lactones 161, 164, 178, 179, 243, 260–261, 275 oaking 219 odour 196 assessment 190–191, 193–194 classification 207–209 description 134–137, 204 of enantiomers 288–289 interactions with flavour 129, 195, 203 musty 219 odour activity 223 Odour Activity Units 225–226 off-odours 219–220 sensitivity/perception 193, 195, 202–204 threshold levels 122, 126–127, 128–130, 136 determination 124, 128–129, 132–133, 135 varietal 209–215 see also aroma Oeschele scale 68, 69, 70, 71 Oloroso sherry 28–29, 230, 235–236, 237 composition 242, 246 production 238, 240 optical activity 283, 286 oxidation 106, 111, 291–299 during ageing 111, 112, 177–178, 255 formation of aldehydes 108, 177, 256, 260 redox potential 112–116, 178, 179, 299–301 oxygen 100–101, 105–108, 291–292 content in wines 106–107 effect on flavour 105, 108, 111 exclusion 7, 11, 19 exposure of wine before serving 192 supply to flor 239 palate-aroma 120, 206 Palomino grapes/wine 28, 230, 236–237, 242 partition coefficients 120–124, 130–132, 183, 307–317 estimation 301–304 323 pasteurization 16 Pays d’Oc wines 218 pectin-hydrolysing enzymes 57 pectins 52 pentanols (amyl alcohols) 158, 275, 286, 289, 313 peonidin glycoside 89, 250 Petit Verdot grapes/wine 43, 76, 212 petunidin glycoside 89, 250 pH 74, 78, 90, 111, 203 see also acidity phenolic compounds 53, 85–90, 110, 166, 276, 316 as anti-oxidants 293 and colour of white wine 100, 255–256 colouring reactions 295 determination 93–97 effect of maturation 111 extraction 95, 252, 270, 271 organoleptic properties 85 oxidation 294–298 physiological effects 33 see also anthocyanins; polyphenols; tannins photosynthesis by vines 40 Phylloxera Piat d’Or wines 218 Pinot Meunier grapes 22 Pinot Noir grapes 22, 42, 76, 95, 270, 305 Pinot Noir wine 96–97, 211 Pinotage grapes/wine 43, 141, 212 pKa 78 polarography 114–115 polyphenoloxidase 108, 298–299 polyphenols 90, 109, 166, 295, 296–298 polysaccharides 278 port wines 1, 25–27, 231, 247–249, 258–261 colour 5–6, 27, 254, 255–258 flavour 232, 249–250, 254 production 25–27, 247–248, 250–254 and red table wines 253–254 ruby 231, 248, 254 tawny 27, 231, 248, 254, 258 vintage 27, 231, 248, 249 white 27 post-fermentation treatments 7, 14–17, 18–19, 21 324 Index pre-fermentation treatments 7, 8–13, 17, 19–20, 107 pressing of grapes 13–14, 20 price, and wine quality 198 procyanidins 92, 93, 96, 297–298 Proof 67–68 protocatechuic acid 86 pruning of vines 41 pumping over 12 pyrazines 172–173, 277, 317 QbA and QmP 60–61 quality assessment 197–200, 218 classification 58–63 quality control 57–64, 101 quality wines 37–39, 60–61 quercetin 89, 94, 270–271, 293 quinta wines 247 racking 14, 21, 255, 256, 271 ranking tests 200 red wines 98, 195, 205 colour 5–6, 92, 99–100, 258 composition of must 50 of wine 56, 96, 111–112 grape varieties 42–43, 210–212 maturation 18–19, 107, 108–109 and port wines 253–254 production 8, 9, 10, 17–19, 24 fermentation 18, 143, 269–271 maceration process 12, 17, 18 redox potentials 115–116 reduction 106, 294 redox potential 112–116, 178, 179, 299–301 refractive index 69 regional wines 46–48, 59–63 Riesling grapes 22, 44, 45, 97, 154, 161, 170 Riesling wines 139, 174, 180, 181, 213 Rioja wines 178 ripening of grapes 40, 41–42, 46 rose´ wines ruby ports 231, 248, 254 Saccharomyces genus 3, 239, 266–269 S cerevisiae 3, 101, 265–269, 277 Sangiovese grapes/wine 37, 43, 211 Sauvignon Blanc grapes 44, 76, 173 Sauvignon Blanc wine 141, 174–177, 177, 213, 277 Scheurebe grapes/wine 45, 214, 306 Se´millon grapes/wine 22, 44, 76, 213 sensory perception 189, 191, 193, 195–196, 202–204, 233 Sercial grapes 31, 32 serving of wine 192 settling, cold 20 sherry 1, 25, 29, 230–232, 234–235 ageing (maturation) 27–28, 29, 230, 234, 237–240 composition 234, 238, 241–245 production 27–31, 234–235, 236–246 varieties see Amontillado sherry; Fino sherry; Oloroso sherry sinapic acid 86 sniffing 4, 120, 128, 190, 193, 206, 233 to determine threshold levels 128–129, 135 see also nosing solera system 29–31, 238–239, 241 sorbic acid 64 sotolon 164, 243, 275 in Noble Rot infections 161, 243, 275, 278 sourness 203 Spanish classification systems 62–63 sparkling wines 22–23, 104–105, 268 champagne see Champagnes specific gravity 68–70 spoilage 79, 148, 195, 269, 275 prevention 7, 12–13, 17, 241 by sulphur dioxide see under sulphur dioxide statistical analysis, of flavour 226–227 stereochemistry 283, 285–291 and flavour 141–142 storage 14–15, 18–19 chemical changes 177–181 of fortified wines 27, 29, 238 history 2–3 see also ageing; maturation succinic acid 73, 80, 276 sucrose 57, 67, 79, 83, 84, 123 for chaptalization 11–12, 72–73 Index sugars 84, 195, 234, 286 in must 50–51, 56, 68–70, 72, 79, 84 in wine 79, 84, 193 see also fructose; glucose; sucrose sulphur compounds organic 173–174, 277, 282–283, 317 changes during ageing 180 in coffee 225 flavour 174–177 sulphur dioxide 101–103 addition to must 57, 237 binding to acetaldehyde 253–254, 256 effects on colour 100, 101, 257 protective action 7, 11, 16, 101, 237 as antimicrobial 101, 102, 237 as antioxidant 7, 16, 101, 177–178, 237 quality control of content 21, 63–64 Suppleness Index 204–205 surface tension 192–193 Su¨ss reserve 73 sweet wines 21–22 sweetness 57, 61–62, 79, 84–85, 234 Syrah grapes/wine 42, 139, 142, 210 taint 166, 219–220, 276 tanks in-tank storage 14, 177–179 tank fermentation of port wines 251 Tannat wines 148 tannins 53, 90–93, 95, 110, 111–112 determination 93–94 effect of maturation 111–112, 205 tartaric acid 52, 73, 79, 80 as acidifier 12, 111 determination 77 isomerism 111, 287–288, 289 removal 16 in wine 56, 76 tartrates 239 taste 196, 218–219 and acidity 73–74, 78, 79 of Botrytis-infected wine 1, 41, 74 from chaptalization 73 description 199–200, 206–207, 236 effect of carbon dioxide 104 effect of organic acids 74, 75 effect of sulphur dioxide 101, 102–103 325 sensations/perception 4, 66, 190, 191, 194, 195–196, 202–203 balance 204–205 see also flavour tasting 4, 189–191, 196–200, 218 analytical 199–202 procedures 190, 191–196 to determine threshold levels 128–129, 136, 200 tautomerism 285, 290–291 tawny ports 27, 231, 248, 254, 258 taxifolin (dihydroquercetin) 88 tea, tannin content 92 temperature effect on nose 194 effect on partition coefficients 123, 301–304 effect on sensory perception 203 of fermentation 7, 13, 18, 21, 269–270 of maceration 20 for serving wine 19 Tempranillo grapes/wine 37, 43, 211 terpenes and terpenoids 166–170, 277, 316 changes during ageing 180–181 extraction 271 flavour 38, 45–46, 140, 171–172 in grapes and wines 38, 45–46, 140, 170–171 metabolism in Noble Rot infections 278 thermovinification 24, 270–271 thiols 173–174, 177, 277, 282–283 threshold levels 94, 122–132, 136, 203–204, 219 determination 124–130, 135–136, 200 tongue map 194 transfer process for sparkling wine 23 transport of grapes 11 of wine 2–3, 247–248 2,4,6-trichloroanisole 219 1,1,6-trimethyl-1, 2-dihydronaphthalene (TDN) 181 tyrosol 86, 97 vats 15, 18–19, 109–110, 177–179 VDQS 59 Verdelho grapes 31, 32 vineyards 38, 60 326 Index vinification 5, 6–17, 115–116, 265–271 vintage years 19, 215 for Madeira wines 32 for port wines 27, 231, 248–249, 253 Viognier grapes/wines 38, 45, 214 viscosity of wines 192–193 Vitis genus 2, 3, 37, 304–306 V lambrusca 37, 141, 161 V vinifera 1–2, 37, 39, 306 composition 90, 99, 250–251 cultivation conditions 3, 6, 8, 39, 40–42 varieties see under grapes vitisins 100, 257–258 vitispirane 260 volatile compounds 120, 137–140, 142–177, 183, 307–317 aroma/flavour 140–142, 233 assessment 193–194 concentration in vapour phase 120–121, 132–133, 233 extraction by maceration 271 in fortified wines 232, 233, 234, 238, 241–245, 258–261 in grapes 53, 56–57 partition coefficients 120–124, 130–132, 183, 301–304 and shape of wine glass 190–191 whisky 179 white ports 231 white wines champagne see Champagnes colour 5, 100 composition 50, 56, 96 fermentation 20–21, 143, 269–270 grape varieties 44–45, 213–214 production 19–21 maturation 21, 109 wine history 2–3, 33 and its constituents 63–64, 307–317 transport 2–3, 247–248 wine glasses 191–192 yeasts 13, 266–269 Brettanomyces 276 in flor see flor yeasts flor see flor yeasts Saccharomyces see Saccharomyces genus [...]... the flavour of the wine is being judged The flavour of wine originates from (1) the grapes, (2) the treatment of the must (grape juice) and its fermentation and (3) the maturation process of the wine The chemistry of the flavour compounds 4 Wine Flavour Chemistry derived from these three sources will be discussed in some detail for both non-volatile (Chapter 3) and volatile (Chapter 4) compounds Wine. .. fall into three groups (1) white wines, which include most sparkling wines, (2) red wines, including 6 Wine Flavour Chemistry most fortified port wines and (3) rose´ wines, essentially an intermediate between white and red wines A wine s colour is determined by the choice of grape and the vinification process White grapes, which usually have pale yellow skins, give white wines, while black grapes, which... the wine information available In 1994, Jackson in Canada published his excellent and wide-ranging book, Wine Science, with a second edition in 2000 This was followed in 2000 by the equally excellent Handbook of Enology from Ribe´reau-Gayon and his colleagues in France This new book on the chemistry of wine flavours draws together aspects of wine making pertinent to wine flavour, and tries to link chemistry, ... sweetening wine, or to colour a wine, by adding some specially prepared colouring wine However, in many wine- making industries, highly skilled blending experts prepare blends to ensure a consistency of wine character Blending is also done to improve the wine flavour The character of wines such as Champagne, fortified port and sherry depend heavily on the preparation of blends, often drawing on wines from... the wine industry in Europe started to recover Ironically, Phylloxera eventually attacked vines in California around 1980, damaging many vineyards 1.3 Wine flavour The smell and taste of a wine are directly associated with the chemistry of the entire wine- making process The word flavour usually indicates the combination of smell (or odour) and taste However, when assessing the sensory properties of wine, ... hand with generally vastly improved wine production skills, have given an array of wine flavours from grapes, which wine- makers in the past could barely have believed possible The cultivation and production of single variety/cultivar wines have given consumers an insight into the many flavours possible in wines Of course, the technological advances in viticulture and wine making have been based upon the... dealt with the subject of wine flavour Some texts are aimed at the marketing aspects of wine, and emphasize the opinions of expert wine tasters Other texts are more critical, such as Barr (1988) Of course, there are also numerous texts in French and German, dealing with all aspects of wine The number of technical texts which directly relate the flavour of the wine to its chemistry is much more limited,... clarity of the wine are assessed entirely by eye, usually before the tasting Next, our sense of smell and taste are used to assess the flavour of the wine The depth of intensity and the multicomponent detection of flavour notes in wines (usually described in terms of flavour notes from other fruit/vegetable/mineral/ animal sources) that are used to describe wine attributes by many expert wine Introduction... in subsequent chapters Current wine- making practice is outlined in Section 1.5 to give a better understanding of the background in which chemical changes related to flavour occur Formation pathways of flavour compounds during vinification are discussed in Chapter 7 Some physiological aspects of wines related to wine chemistry will be described briefly 1.4 Wine colour Wines are primarily distinguished... consumers with an inquisitive mind about wine, and to all those involved with the production of and trade in wines with an interest in the chemical and technical aspects of wine flavour A considerable amount of threshold flavour/ odour and other flavour compound information has been recently compiled by Flament in his comprehensive book, Coffee Flavor Chemistry (2002) Many wine odour compounds, now known to