As an applied science, enology is a collection of knowledge from the fundamental sciences including chemistry, biochemistry, microbiology, bioengineering, psychophysics, cognitive psychology, etc., and nourished by empirical observations. The approach used in the Handbook of Enology is thus the same. It aims to provide practitioners, winemakers, technicians and enology students with foundational knowledge and the most recent research results. This knowledge can be used to contribute to a better definition of the quality of grapes and wine, a greater understanding of chemical and microbiological parameters, with the aim of ensuring satisfactory fermentations and predicting the evolution of wines, an7thd better mastery of wine stabilization processes. As a result, the purpose of this publication is to guide readers in their thought processes with a view to preserving and optimizing the identity and taste of wine and its aging potential.
This third English edition of The Handbook of Enology, is an enhanced translation from the 7h French 2017 edition, and is published in print as individual themed volumes and as a two-volume set, describing aspects of winemaking using a detailed, scientific approach. The authors, who are highly-respected enologists, examine winemaking processes, theorizing what constitutes a perfect technique and the proper combination of components necessary to produce a quality vintage. They also illustrate methodologies of common problems, revealing the mechanism behind the disorder, thus enabling a diagnosis and solution.
Volume 1: The Microbiology of Wine and Vinifications addresses the first phase of winemaking to produce an "unfinished" wine: grading grape quality and maturation, yeast biology then adding it to the grape crush and monitoring its growth during vinification; and identifying and correcting undesired conditions, such as unbalanced lactic and acetic acid production, use of sulfur dioxide and alternatives, etc.
Coverage includes: Wine microbiology; Yeasts; Yeast metabolism; The conditions for the development of yeasts; Lactic acid bacteria, their metabolism and their development in wine; Acetic bacteria; The use of sulfur dioxide in the treatment of musts and wines; Products and processes acting in addition to sulfur dioxide; Winemaking; The grape and its maturation; Harvesting and processing of grapes after harvest; Vinification in red and white wine making.
The target audience includes advanced viticulture and enology students, professors and researchers, and practicing grape growers and vintners.
Table of Contents
Foreword xi
Preface to the Second Edition xiii
Preface to the First Edition xv
Remarks Concerning the Expression of Certain Parameters of Must and Wine Composition xix
Part I Microbiology of Wine 1
1 Yeasts 3
1.1. Introduction 3
1.2 . The Cell Wall 5
1.3 . The Plasma Membrane 9
1.4 . The Cytoplasm and Its Organelles 15
1.5 . The Nucleus 18
1.6 . Reproduction and the Yeast Biological Cycle 19
1.7 . The Killer Phenomenon 23
1.8 . Classifi cation of Yeast Species 27
1.9 . Identifi cation of Wine Yeast Strains 49
1.10. Ecology of Grape and Wine Yeasts 57
References 67
2 Yeast Metabolism 73
2.1 . Introduction 73
2.2 . Sugar Degradation Pathways 74
2.3 . Regulation of Sugar-Utilizing Metabolic Pathways 82
2.4 . Metabolism of Nitrogen Compounds 93
References 101
3 Conditions of Yeast Development 103
3.1. Introduction 103
3.2. Monitoring and Controlling Fermentations 104
3.3. Yeast Growth Cycle and Fermentation Kinetics 108
3.4. Nutrition Requirements 110
3.5. Fermentation Activators 115
3.6. Inhibition of Fermentation 122
3.7. Physicochemical Factors Affecting Yeast Growth and Fermentation Kinetics 126
3.8. Stuck Fermentations 135
References 142
4 Lactic Acid Bacteria 145
4.1. The Different Components of the Bacteria Cell 145
4.2. Taxonomy of Lactic Acid Bacteria 154
4.3. Identification of Lactic Acid Bacteria 156
4.4. The Oenococcus oeni Species 170
References 171
5 Metabolism of Lactic Acid Bacteria 175
5.1. Generalities: A Review 175
5.2. Metabolism of Sugars: Lactic Acid Fermentation 177
5.3. Metabolism of the Principal Organic Acids of Wine 182
5.4. Other Transformations Likely to Occur in Winemaking 189
5.5. Effect of the Metabolism of Lactic Acid Bacteria on Wine Composition and Quality 195
References 197
6 Lactic Acid Bacteria Development in Wine 201
6.1. Lactic Acid Bacteria Nutrition in Wine 201
6.2. Physicochemical Factors of Bacterial Growth 204
6.3. Evolution of Lactic Acid Bacteria Microflora: Influence on Wine Composition 210
6.4. Microbial Interactions During Winemaking 218
6.5. The Importance of Bacteriophages 224
References 226
7 Acetic Acid Bacteria 229
7.1. Principal Characteristics and Cytology 229
7.2. Classification and Identification 230
7.3. Principal Physiological Characteristics 232
7.4. Metabolism of Acetic Acid Bacteria 233
7.5. Acetic Acid Bacteria Development in Grape Musts 237
7.6. Evolution of Acetic Acid Bacteria During Winemaking and Wine Aging and the Impact on Wine Quality 238
References 240
8 The Use of Sulfur Dioxide in Must and Wine Treatment 243
8.1. Introduction 243
8.2. Physiological Effects 246
8.3. Chemistry of Sulfur Dioxide 248
8.4. Molecules Binding Sulfur Dioxide 252
8.5. Practical Consequences: The State of Sulfur Dioxide in Wines 261
8.6. Antimicrobial Properties of Sulfur Dioxide 262
8.7. The Role of Sulfur Dioxide in Winemaking 265
8.8. The Use of Sulfur Dioxide in the Winery 270
References 277
9 Products and Methods Complementing the Effect of Sulfur Dioxide 279
9.1. Introduction 279
9.2. Sorbic Acid 280
9.3. Octanoic and Decanoic Acids (Saturated Short-Chain Fatty Acids) 283
9.4. Dimethyl Dicarbonate (DMDC) 285
9.5. Lysozyme 286
9.6. Destruction of Yeasts by Heat (Pasteurization) 289
9.7. Ascorbic Acid 293
9.8. The Use of Inert Gases 297
References 301
Part II Vinification 303
Reflections on Global Taste and Typicity of Wines 305
10 The Grape and Its Maturation 309
10.1. Introduction 309
10.2. Description and Composition of the Mature Grape 310
10.3. Changes in the Grape During Maturation 322
10.4. Definition of Ripeness - Concept of Vintage 343
10.5. Impact of Various Other Factors on Maturation and Grape Composition at Ripeness 366
10.6. Botrytis cinerea 375
References 391
11 Harvest and Pre-fermentation Treatments 399
11.1. Introduction 399
11.2. Improving Grape Quality by Overripening 400
11.3. Harvest Date and Operations 401
11.4. Acidity Adjustments of the Harvested Grapes 408
11.5. Increasing Sugar Concentrations 412
11.6. Enzymatic Transformations of the Grape After Harvest 418
11.7. Use of Commercial Enzymes in Winemaking 427
References 429
12 Red Winemaking 431
12.1. Generalities 431
12.2. Mechanical Processing of the Harvested Grapes 433
12.3. Tank Filling 440
12.4. Controlling Alcoholic Fermentation 446
12.5. Maceration 452
12.6. Draining Off the Skins and Pressing 469
12.7. Malolactic Fermentation 480
12.8. Automated Red Winemaking Methods 494
12.9. Carbonic Maceration 499
References 511
13 White Winemaking 513
13.1. Distinctive Characteristics of White Winemaking 513
13.2. White Grape Quality and Picking Criteria 517
13.3. Juice Extraction 526
13.4. Protecting Juice from Oxidation 538
13.5. Clarification 543
13.6. Juice Treatments and the Advisability of Bentonite Treatments 552
13.7. Fermentation Operations 552
13.8. Making Dry White Wines in Barrels 557
13.9. Controlling Reduction Off-Aromas During White Wine Aging 564
References 568
14 Other Winemaking Methods 571
14.1. Rosé Wines 571
14.2. Botrytized Sweet Wines (Sauternes and Tokaji) 577
14.3. Champagne and Sparkling Wines 588
14.4. Fortified Wines 602
14.5. Flor Wines 608
References 612
Index 615
