Dr Ronald J. Clarke is a writer and food industry consultant based in Chichester, UK, and is co-editor of Coffee: Recent Developments.

Preface to the Second Edition xv

Preface to the First Edition xvii

1 Introduction 1

1.1 Scope of the book 1

1.2 Historical background 2

1.3 Wine flavour 3

1.4 Wine colour 6

1.5 Vinification 6

1.5.1 Vinification process 8

Pre-fermentation 9

Fermentation 15

Post-fermentation 17

1.5.2 Red wines 22

Pre-fermentation 22

Fermentation 23

Post-fermentation 24

1.5.3 White wines 25

Pre-fermentation 26

Fermentation 27

Post-fermentation 28

1.5.4 Specialized wines 28

Rosé wines 28

Wines made from organically farmed grapes 29

Wines with added resin 30

Wines with low alcohol content 31

Sweet wines 31

Sparkling wine in Champagne 32

Sparkling wine by other methods 33

Wines by carbonic maceration 34

Wines by thermovinification 34

Wines matured Sur Lie 35

1.5.5 Fortified wines 35

Port wine 36

Sherry 38

Madeira 40

1.6 Physiological effects 42

1.6.1 Attributed negative effects 43

1.6.2 Wine ethyl alcohol (ethanol) 43

1.6.3 Effects of phenols 45

Resveratrol 46

Bibliography 48

2 Grape Varieties and Growing Regions 53

2.1 Wine grapes 53

2.2 Vine plant characteristics 56

2.3 Soil, climate and ripeness 57

2.3.1 Soil 57

2.3.2 Climate 58

2.3.3 Ripeness 64

2.4 Grape growing regions of the world 65

2.4.1 World wine production 65

2.4.2 Regions 66

2.5 Chemical composition of grapes, must and finished wines 71

2.5.1 Grapes and must 71

2.5.2 Finished wine 79

2.6 Quality control and classification of wines 79

2.6.1 France 79

2.6.2 Germany 82

2.6.3 Italy 83

2.6.4 Spain 84

2.6.5 Australia 84

2.6.6 USA 85

2.6.7 Quality control systems in the European Union 86

Bibliography 87

3 Basic Taste and Stimulant Components 89

3.1 Introduction 89

3.2 Basic taste perception 90

3.2.1 Role of taste 90

3.2.2 Taste perception mechanism 91

3.3 Ethyl alcohol 92

3.3.1 Measurement of ethyl alcohol content in wines 93

3.3.2 Measurement of sugar content in musts and wines 94

Brix scale 94

Baumé and Oeschele scales 96

Prediction of alcohol content in the finished wine 96

3.3.3 Sugar content of grapes and must 97

3.3.4 Chaptalization 98

3.4 Acidity 99

3.4.1 Contents of organic acids 100

3.4.2 Measurement of acid content 104

3.4.3 Acid taste 105

3.5 Sweetness 109

3.5.1 Chemical structure of sugars 109

3.5.2 Content/sweetness 109

3.6 Bitterness, astringency and mouthfeel 113

3.6.1 Basic chemistry 113

Non-flavanoids 113

Flavan-3-ols 114

Flavonoids 116

Anthocyanins 117

3.6.2 Basic technology 118

Location of polyphenols in grapes 118

Use of the term 'tannins' and their classification 119

Grape tannins 120

Quantifying methods 121

HPLC measurements 122

Other methods 123

Analyses in grapes and during wine-making 124

3.6.3 Bitter constituents 127

White wines 127

Red wines 127

3.6.4 Astringency 127

3.6.5 Mouthfeel 128

3.7 Colouring matter 129

3.7.1 Colour of red wines 129

3.7.2 Colour of white wines 132

3.8 Other constituents 134

3.8.1 Sulfur dioxide 134

Basic chemistry 135

Technical use 135

Taste effects 136

3.8.2 Carbon dioxide 136

Formation and handling of CO 2 137

Sensory factors 137

3.8.3 Oxygen 138

Basic chemistry 138

Oxygen content in wines 139

Effect of oxygen on wine 141

3.9 Changes in maturation 142

3.9.1 'In-barrel' ageing 143

Vats 143

Extraction from barrels 144

Oxidation in barrels 145

3.9.2 'In-bottle' ageing 146

3.9.3 Oxidation-reduction (redox) potential 146

General 147

Nernst equation 147

Redox potentials in wine 148

Redox potentials during vinification 149

Bibliography 150

4 Volatile Components 155

4.1 General 155

4.1.1 Sensory perception 156

4.1.2 Partition coefficients 158

4.1.3 Threshold flavour/odour levels 161

Units 163

Consistency of threshold odour levels 164

Threshold level difference between sniffing and tasting 164

Threshold levels in solutions of dissolved substances in water and in beverages 166

Relationship of threshold values to partition coefficients 168

Volatile compound concentration in the vapour phase 170

4.1.4 Flavour/odour descriptions 173

Use of word descriptions 173

Intensity of flavour/odour 175

4.2 Volatile compounds detected in wines 175

4.2.1 Types of aroma in volatile compounds 178

4.2.2 Stereochemical effects in aroma volatile compounds 180

4.3 Contents and sensory evaluation data 180

4.3.1 Esters 180

Structure 181

Presence in wines 181

Flavour characteristics 182

4.3.2 Aldehydes 189

Presence in wine 189

Flavour characteristics 190

4.3.3 Ketones 190

Presence in wines 190

Flavour characteristics 190

4.3.4 Acetals 196

4.3.5 Alcohols 197

Presence in wines 197

Flavour characteristics 201

4.3.6 Lactones and furanones 201

Molecular structures 201

Presence in wines 205

Flavour characteristics 207

4.3.7 Acids 207

Presence in wines 207

Flavour characterisitcs 208

4.3.8 Nitrogeneous compounds 208

4.3.9 Phenols 209

Presence in wines 209

Flavour characteristics 209

4.3.10 Terpenes 209

Chemical structure 209

Presence in grapes/wines 213

Flavour characteristics 215

4.3.11 Pyrazines 216

Chemical structure 216

Presence in grapes/wines 216

Flavour characteristics 216

4.3.12 Sulfur compounds 219

Chemical structure 219

Presence in wines 219

Flavour characteristics 220

4.4 Changes during maturation 221

4.4.1 Fermentation and storage of wines 'in-vat (tank)' and 'in-barrel (cask)' 221

Fermentation 221

Storage 222

4.4.2 'In-bottle' ageing 224

Changes in ester content 225

Substances produced by carbohydrate degradation 225

Sulfur compounds 225

Changes in terpenoids 225

Formation of substances from carotene breakdown 226

4.5 Aroma detection and quantification 227

4.5.1 Gas chromatography 227

4.5.2 Sample preparation 228

4.5.3 Olfactometry 230

4.6 Chemical structure and physical properties 231

Bibliography 231

5 Wine Tasting Procedures and Overall Wine Flavour 239

5.1 Wine tasting 239

5.2 Wine tasting procedure 241

5.2.1 Tasting glass 241

5.2.2 Serving 243

5.2.3 Visual 243

5.2.4 Smell 244

5.2.5 Flavour 246

5.2.6 Interactions 247

5.2.7 Astringency 248

5.2.8 Judging the wine 249

5.2.9 Reasons for wine tasting 250

Sensory analysis 250

Quality tastings 251

Identifying wines by tasting 251

Sensory analyses used in research 252

Consumer tasting 252

Analytical tasting 253

5.2.10 Wine tasting information and analysis 254

Statistical analysis 254

5.3 Factors influencing sensory perception 256

5.3.1 Threshold and sensitivity 257

5.3.2 Vocabulary 258

5.4 Balance of taste sensations in wine 258

5.5 Wine aromas 259

5.5.1 Odour/aroma classification 261

5.5.2 Aroma/odour characteristics of wines from particular grape varieties 262

5.5.3 Variants in Cabernet Sauvignon wine flavour 270

5.5.4 Variants of Chardonnay wine flavour 271

5.5.5 Flavour description of some other commercial wines 273

5.5.6 Off-odours and taints 274

Cork taint 275

Mousiness 278

Ethylphenols 279

5.6 Wine and food flavour 279

5.7 Aroma indices and statistical methods 282

5.7.1 Flavour unit concept 282

5.7.2 Odour activity unit 284

5.7.3 Multivariate and other statistical procedures 285

Bibliography 288

6 Sherry, Port and Madeira 291

6.1 Introduction 291

6.1.1 Sherry introduction 291

6.1.2 Port introduction 292

6.1.3 Madeira introduction 292

6.1.4 Comparisons between fortified wines 293

6.1.5 Ethyl alcohol - sensory effect 294

6.1.6 Ethyl alcohol - chemical effect 295

6.1.7 Sweetness 295

6.2 Sherry 295

6.2.1 Wine producers 296

6.2.2 Commercial wine styles 296

6.2.3 Wine writers' comments 297

6.2.4 Grapes and must 297

6.2.5 Base wine 298

6.2.6 Maturation 299

6.2.7 Maturation changes under flor 299

6.2.8 Maturation changes without flor 301

6.2.9 Maturation with and without flor 302

6.2.10 Volatile compounds 302

6.2.11 Changes during maturation in phenolic compound content 309

6.3 Port wine 311

6.3.1 Port wine producers 311

6.3.2 Commercial Port wine styles 312

6.3.3 Wine writers' comments 313

6.3.4 Grapes and must 314

6.3.5 Fermentation and base Port wine 315

6.3.6 Port wine compared to red table wine 317

6.3.7 Maturation 318

6.3.8 Colour changes during maturation 318

6.3.9 Volatile changes during maturation 322

6.4 Madeira 327

6.4.1 Madeira wine producers 327

6.4.2 Commercial Madeira wine styles 327

6.4.3 Wine writers' comments 328

6.4.4 Sensory properties 328

6.4.5...