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, and 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 7th French 2017 edition, and is published 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 2: The Chemistry of Wine and Stabilization and Treatments looks at the wine itself in two parts. Part One analyzes the chemical makeup of wine, including organic acids, alcoholic, volatile and phenolic compounds, carbohydrates, and aromas. Part Two describes the procedures necessary to achieve a perfect wine: the clarification processes of fining, filtering and centrifuging, stabilization, and aging.

Coverage includes: Wine chemistry; Organic acids; Alcohols and other volatile products; Carbohydrates; Dry extract and mineral matter; Nitrogen substances; Phenolic compounds; The aroma of grape varieties; The chemical nature, origin and consequences of the main organoleptic defects; Stabilization and treatment of wines; The chemical nature, origin and consequences of the main organoleptic defects; The concept of clarity and colloidal phenomena; Clarification and stabilization treatments; Clarification of wines by filtration and centrifugation; The stabilization of wines by physical processes; The aging of wines in vats and in barrels and aging phenomena.

The target audience includes advanced viticulture and enology students, professors and researchers, and practicing grape growers and vintners.

Authors: Pascal Ribéreau-Gayon, Yves Glories, Alain Maujean and Denis Dubourdieu

Coordinator: Philippe Darriet

With contributions from Patricia Ballestra, Jean-Christophe Barbe, Marguerite Dols-Laffargue, Laurence Geny, Rémy Ghidossi, Aline Lonvaud, Patrick Lucas, Axel Marchal, Isabelle Masneuf-Pomarède, Martine Mietton-Peuchot, Claudia Nioi, Alexandre Pons, Sophie Tempère, Cécile Thibon.

Translator: John Towey

Foreword

Preface to the Second Edition

Preface to the First Edition

Remarks Concerning the Expression of Certain Parameters of Must and Wine Composition

Part I Chemistry of Wine

1 Organic Acids in Wine

1.1 Introduction

1.2 The Main Organic Acids

1.3 Different Types of Acidity

1.4 The Concept of pH and Its Applications

1.5 Tartrate Precipitation Mechanism and Predicting Its Effects

1.6 Tests for Predicting Wine Stability

1.7 Preventing Tartrate Precipitation

References

2 Alcohols and Other Volatile Compounds

2.1 Ethanol

2.2 Other Simple Alcohols

2.3 Polyols

2.4 Aliphatic Fatty Acids

2.5 Esters

2.6 Miscellaneous Compounds

References

3 Carbohydrates

3.1 Introduction

3.2 Glucose and Fructose

3.3 Other Sugars

3.4 Chemical Properties of Sugars

3.5 Sugar Derivatives

3.6 Pectic Substances in Grapes

3.7 Exocellular Polysaccharides from Microorganisms

References

4 Dry Extract and Minerals

4.1 Introduction

4.2 Dry Extract

4.3 Ash

4.4 Inorganic Anions

4.5 Inorganic Cations

4.6 Iron and the Iron Casse Mechanism

4.7 Copper and Copper Casse

4.8 Heavy Metals

References

5 Nitrogen Compounds

5.1 Introduction

5.2 The Various Forms of Nitrogen

5.3 Amino Acids

5.4 Other Forms of Nitrogen

5.5 Proteins and Protein Haze

5.6 Preventing Protein Haze References

References

6 Phenolic Compounds

6.1 Introduction

6.2 Types of Substances

6.3 Chemical Properties of Anthocyanins and Tannins

6.4 Anthocyanin and Tannin AssaysSensory Properties

6.5 Evolution of Anthocyanins and Tannins as Grapes Ripen

6.6 Extracting Tannins and Anthocyanins during Winemaking

6.7 Chemical Reactions Occurring during Barrel and Bottle Aging

6.8 Precipitation of Coloring Matter (Color Stability)

6.9 Origin of the Color of White Wines

References

7 Varietal Aroma

7.1 The General Concept of Varietal Aroma

7.2 Terpene Compounds

7.3 C13-Norisoprenoid Derivatives

7.4 Methoxypyrazines

7.5 Sulfur Compounds with a Thiol Function

7.6 Furanones

7.7 Lactones

7.8 Aromas of American Species

References

Part II Wine Stabilization and Treatments

8 Main Sensory Defects: Chemical Nature, Origins and Consequences

8.1 Introduction

8.2 Oxidative Defects

8.3 Effect of Various Forms of Bacterial Spoilage

8.4 Microbiological Origin and Properties of Volatile Phenols

8.5 Cork Taint

8.6 Sulfur Derivatives and Reduction Odors

8.7 Premature Aging of White Wine Aroma

8.8 Sensory Defects Associated with Grapes Affected by Various Types of Rot

8.9 Miscellaneous Defects

References

9 The Concept of Clarity and Colloidal Phenomena

9.1 Clarity and Stability

9.2 The Colloidal State

9.3 Colloid Reactivity

9.4 Protective Colloids and Gum Arabic Treatment

References

10 Clarification and Stabilization Treatments: Fining Wine

10.1 Treating Wine

10.2 Sedimentation of Particles in Suspension

10.3 Racking: Role and Techniques

10.4 Theory of Protein Fining

10.5 Tannin-Protein Interactions

10.6 Effect of Fining on the Organoleptic Quality of Wine: Concept of Overfining

10.7 Products Used in Fining

10.8 Fining Techniques

10.9 Bentonite Treatment

10.10 Miscellaneous Clarification Treatments

References

11 Clarifying Wine by Filtra...