Оглавление
Keith Grainger. Wine Faults and Flaws
Table of Contents
Guide
Pages
Wine Faults and Flaws: A Practical Guide
Acknowledgements
Preface
Introduction
References
1 Faults, Flaws, Off‐Flavours, Taints, and Undesirable Compounds
1.1 Introduction
1.2 Advances in Wine Technology in Recent Decades
1.3 Changes in Markets and the Pattern of Wine Consumption in Recent Decades
1.4 The Possible Impact of Some Fault Compounds Upon Human Health
1.5 Sulfur Dioxide and Other Possible Allergens
1.6 Faults and Taints
1.7 Distinguishing Between Faults and Flaws
1.8 Sensory Detection (Perception) Thresholds and Sensory Recognition Thresholds. 1.8.1 Sensory Detection Thresholds
1.8.2 Sensory Identification (Recognition) Thresholds
1.8.3 Odour Activity Values
1.9 Consumer Rejection Thresholds (CRTs)
1.10 Basic Categories of Wine Faults. 1.10.1 The Origin of Wine Faults
1.10.2 Microbiological Faults. 1.10.2.1 Types of Microorganisms Involved
Yeasts
Moulds
Bacteria
1.10.2.2 Examples of Microbiological Faults
1.10.2.3 Minimising the Occurrence Microbiological Faults
1.10.3 Chemical Nature Faults. 1.10.3.1 Examples of Chemical Faults
1.10.3.2 Minimising the Occurrence Chemical Faults
1.10.4 Physical Faults, Contamination, and Packaging Damage
1.11 Flaws. 1.11.1 Poor Wines, as a Consequence of Adverse Weather, Sub‐standard Viticulture, Careless Winemaking, or Inappropriate Additives
1.11.2 The Presence of ‘Fault’ Compounds at Low Concentrations
1.12 The Incidence of Wine Faults
1.13 ‘Faulty’ Wines that Exude Excellence
1.14 Final Reflections
References
2 Wine Tasting
2.1 Introduction
2.2 Anosimics, Fatigue Effect, and Supertasters. 2.2.1 Anosmics and Fatigue Effect
2.2.2 Supertasters
2.3 Tasting Conditions, Equipment, and Glassware. 2.3.1 The Tasting Room
2.3.2 Appropriate Equipment
2.3.2.1 Tasting Glasses
2.3.2.2 Glass Washing and Storage
2.3.2.3 Water
2.3.2.4 Spittoons
2.3.3 When to Taste
2.4 The Use of a Structured Tasting Technique and Detection of Faults
2.5 Appearance. 2.5.1 The Appearance Assessment
2.5.2 Clarity and Brightness
2.5.3 Intensity
2.5.4 Colour
2.5.4.1 White Wines
2.5.4.2 Rosé Wines
2.5.4.3 Red Wines
2.5.4.4 The Rim and Core
2.5.5 Other Observations
2.5.5.1 Bubbles or Petillance
Still Wines
Sparkling Wines
2.5.5.2 Legs
2.5.5.3 Deposits
2.6 Nose
2.6.1 Condition
2.6.2 Intensity
2.6.3 Aroma Types, Development, and Characteristics
2.6.3.1 Primary Aromas
2.6.3.2 Secondary Aromas
2.6.3.3 Tertiary Aromas
2.6.3.4 Aroma Characteristics
2.7 Palate. 2.7.1 Palate Sensations
2.7.2 Sweetness/Bitterness/Acidity/Saltiness/Umami/Trigeminal Sensations
2.7.3 Dryness/Sweetness
2.7.4 Acidity
2.7.5 Tannins
2.7.6 Alcohol
2.7.7 Body
2.7.8 Flavour Intensity
2.7.9 Flavour Characteristics
2.7.10 Other Observations. 2.7.10.1 Texture
2.7.10.2 Balance
2.7.11 Finish – Length
2.8 Assessment of Quality. 2.8.1 Quality Level
2.8.2 Reasons for Assessment of Quality
2.9 Assessment of Readiness for Drinking/Potential for Ageing. 2.9.1 The Life‐Cycle of a Wine
2.9.2 Level of Readiness for Drinking/Potential for Ageing
2.10 Grading Wine – The Award of Points. 2.10.1 Is the Awarding of Points Appropriate for Wines?
2.10.2 The Systems in Use
2.10.3 Nothing but a Snapshot Reflecting a Moment in Time
2.11 Blind Tasting. 2.11.1 Why Taste Blind?
2.11.2 Blind or Sighted?
2.11.3 Tasting for Quality
2.12 Final Reflections
References
3 Chloroanisoles, Bromoanisoles, and Halophenols
3.1 Introduction
3.2 Haloanisole Contaminations in the Food, Drinks, Water, and Pharmaceutical Industries
3.2.1 Haloanisole Contamination of Pharmaceutical Products
3.2.2 Haloanisole Contamination of Food and Non‐Alcoholic Drinks
3.2.3 Haloanisoles in Tap Water and Bottled Water
3.3 Haloanisole Contamination of Wines
3.4 The Economic and Reputational Costs to Wine Producers and the Wine Industry
3.4.1 The Economic Cost to the Industry at Large
3.4.2 The Economic and Reputational Cost to Individual Wine Producers
3.4.3 The Nightmare of Haloanisole Contaminated Wineries and Cellars
3.4.3.1 California Pays a High Price
3.4.3.2 Affluence and Crisis in Bordeaux
3.4.3.3 Cellar Contaminations in South America
3.5 Sensory Characteristics and Detection of Haloanisoles in Wine
3.5.1 The Odours and Tastes of Haloanisoles in Wine
3.5.2 Variance in Sensory Detection Thresholds and Consumer Rejection Thresholds
3.6 The Haloanisoles Responsible and Their Detection Thresholds
3.6.1 The Main Haloanisoles Responsible
3.6.2 2,4,6‐Trichloroanisole (TCA)
3.6.3 2,3,4,6‐Tetrachloroanisole (TeCA)
3.6.4 Pentachloroanisole (PCA)
3.6.5 2,4,6‐Tribromoanisole (2,4,6‐TBA)
3.7 The Formation Pathways of Haloanisoles from Halophenols. 3.7.1 Origins
3.7.1.1 Chlorophenols
3.7.1.2 Bromophenols
3.7.2 The Biological Transformation of Halophenols into Haloanisoles
3.7.3 The Role of the Pesticides, Herbicides, and Fungicides. 3.7.3.1 Chlorophenol‐Based Products
3.7.3.2 Bromophenol‐Based Products
3.7.3.3 Restrictions on Usage of Chlorophenols and Bromophenols
3.7.3.4 The Advent of Chloroanisole and Bromoanisole Wine Contamination
3.7.3.5 Other Halophenol Formation Pathways
3.7.4 The Fungi that Convert Halophenols into Haloanisoles
3.8 Contamination of Cork with TCA and Other Chloroanisoles
3.8.1 Cork Production and How Cork Becomes Contaminated
3.8.2 The Transmission of TCA from Corks to Wine
3.8.3 The Historic Incidences of So‐Called ‘Cork Taint’ and the Role of the Cork Industry
3.8.4 The Rise in Incidences of So‐Called ‘Cork Taint’
3.9 The Cork Industry in the Dock. 3.9.1 The Industry in Denial
3.9.2 Hostile Coverage in the Wine Press
3.9.3 Alternative Closures to the Fore
3.10 The Cork Industry Begins to Address the Issues. 3.10.1 Cork Producers Fight Back
3.10.2 Many Wine Professionals Remain Hostile to Cork
3.11 The Cork Industry's Recent Initiatives for Haloanisole Prevention and Extraction. 3.11.1 Investment and Initiatives by the Stakeholders
3.11.2 Symbios
3.11.3 Methods to Extract TCA During Cork Production
3.11.3.1 Analysis and Rejection of Bark Affected by Chloroanisoles
3.11.3.2 Changes in Boiling Systems
3.11.3.3 Chloroanisole Removal by Steam Vaporisation
3.11.3.4 Extraction with Supercritical Carbon Dioxide
3.11.3.5 NDtech
3.11.3.6 Other Companies' Non‐Detectable TCA' Guarantees
3.12 Winery and Cooperage Sources of Haloanisole Contamination in Wines
3.12.1 Winery Environment, Structure, Sundry Items, and Routine Processes as Sources of Contamination
3.12.2 Oak Barrels as a Source of Haloanisole Contamination of Wine
3.12.3 Processing Aids and Additives as Sources of Contamination
3.13 Laboratory Analysis for TCA and Other Haloanisoles in Corks and Wine. 3.13.1 Haloanisoles in Wine and Releasable and Total TCA in Corks
3.13.2 Laboratory Methods of Analysis
3.13.2.1 Sample Preparation
3.13.2.2 Separation and Quantification
3.13.2.3 Bioanalytical Methods
3.13.3 Inexpensive Alternatives
3.14 Prevention of Haloanisole Contamination of Wineries and Wines. 3.14.1 Implementation of an HACCP System
3.14.2 In the Vineyard
3.14.3 In the Winery
3.14.3.1 Cleaning and Sanitising
3.14.3.2 Avoidance of Chlorine and Bromine
3.14.3.3 Monitoring of Tap Water
3.14.3.4 Air Renewal and Humidity Control
3.14.3.5 Prohibition of PCP and 2,4,6‐TBP
3.14.3.6 Diligence with Regard to Oenological Products and Processing Aids
3.14.3.7 Periodic Inspections and Testing of Production and Storage Areas
3.14.3.8 Attention to the Barrel Room, Cellar, and Storage
3.14.3.9 Regular Sensory Analysis of Wine Stock
3.14.3.10 Training Cellar Staff for Haloanisole Detection
3.14.4 Cork Screening and Group Cork Soaks
3.15 Treatment of Wines Contaminated with Haloanisoles
3.15.1 Fining with Half and Half
3.15.2 Filtration Using Zeolites Y‐Faujasites
3.15.3 Absorption/Adsorption/Filtration Using Polymeric Media. 3.15.3.1 Use of Polythene Resin Beads and Polymer ‘Fining’
3.15.3.2 Filtration Using Adsorbing Polymers
3.15.3.3 Adsorption by Polyvinylidene Chloride (PVdC)
3.15.4 Adsorbing by Yeast Hulls
3.15.5 Filtration Through Cork Dust
3.15.6 Deodorising with Mustard Seeds
3.16 Chlorophenols and Bromophenols as Taints
3.16.1 The Odours of Chlorophenols and Bromophenols
3.16.2 2,4‐Dichlorophenol
3.16.3 2,6‐Dichlorophenol
3.16.4 2,4,6‐Trichlorophenol
3.16.5 6‐Chloro‐o‐cresol
3.16.6 2‐Bromophenol
3.16.7 2,6‐Dibromophenol
3.16.8 2,4,6‐Tribromophenol
3.17 ‘Musty’ Taints Unrelated to Halophenols and Haloanisoles. 3.17.1 Other Musty Taints in Wine
3.17.2 2‐Methoxy‐3,5‐dimethylpyrazine (MDMP) or ‘Fungal Must Taint’
3.17.3 2‐Isopropyl‐3‐methoxypyrazine
3.17.4 2‐Methoxy‐3‐isopropylpyrazine
3.17.5 2‐Methylisoborneol (MIB)
3.17.6 1‐Octen‐3‐ol
3.17.7 1‐Octen‐3‐one
3.17.8 1‐Octen‐2‐one
3.17.9 cis‐1,5‐Octadien‐3‐one
3.17.10 cis‐1,5‐Octadien‐3‐ol
3.17.11 Geosmin
3.17.12 ‘Musty’ Monoterpenes and Sesquiterpenes
3.17.13 Guaiacol
3.17.14 Treatment of Musty Taints Unrelated to Halophenols and Haloanisoles
3.18 Final Reflections
References
4 Brettanomyces(Dekkera) and Ethyl Phenols
4.1 Introduction
4.2 Background and History
4.3 The Brett Controversy. 4.3.1 Brettanomyces Paranoia?
4.3.2 The Role of Brettanomyces in Craft and Lambic Beer Production
4.3.3 Brettanomyces: An Extension of Terroir?
4.3.4 Artisans Choosing Brettanomyces for Wine Fermentations
4.3.5 Some Wines with a Notable Brett Influence
4.3.6 An Old World/New World Divide?
4.3.7 Good Brett/Bad Brett?
4.4 Sensory Characteristics and Detection of Brettanomyces‐Related Compounds in Wine
4.4.1 The Odours Associated with Brettanomyces‐Related Compounds
4.4.2 Sensory Detection Thresholds
4.4.3 4‐Ethylphenol (4‐EP)
4.4.4 4‐Ethylguaiacol (4‐EG)
4.4.5 Isovaleric Acid and Isobutyric Acid
4.4.6 4‐Ethylcatechol
4.4.7 Tetrahydropyridines Particularly 2‐Acetyltetrahydropyridine (ATHP) and 2‐Ethyltetrahydropyridine (ETHP)
4.4.8 Guaiacol
4.4.9 The Impact of the Wine Matrix
4.5 The Origins of Brettanomyces and Formation of Related Compounds in Wines. 4.5.1 Microflora on Grapes and Present in Wineries
4.5.2 The Formation Pathways of Brettanomyces‐Related Compounds. 4.5.2.1 Hydroxycinnamic Acids Precursors
4.5.2.2 The Formation of Vinyl Phenols
4.5.2.3 The Formation of Ethyl Phenols
4.6 The Danger Periods and Favourable Conditions for the Growth of Brettanomyces. 4.6.1 The Danger During Winemaking and Cellar Maturation
4.6.2 Growth in Bottle
4.7 Why Are Brettanomyces‐Related Compounds Found Mostly in Red Wines?
4.8 Prevention: Formulation and Implementation a Brett Control Strategy. 4.8.1 HACCP
4.8.2 The Vineyard
4.8.3 Harvest
4.8.4 The Winery
4.8.5 Winemaking Practices. 4.8.5.1 Approaches to Brettanomyces Management
4.8.5.2 Pre‐fermentation
4.8.5.3 Cold Soaks and Hot Pre‐fermentation Maceration
4.8.5.4 Yeast Starters, Nutrients, and Enzymes
4.8.5.5 The Alcoholic Fermentation (AF), Post‐Fermentation Period, and Pressing
4.8.5.6 The Pre‐MLF Lag Phase and the MLF
4.8.6 Maturation, Barrel Ageing, and Barrel Care. 4.8.6.1 Barrel Maturation
4.8.6.2 Barrel Cleaning and Sanitising
4.8.6.3 Methods of Barrel Cleaning
4.8.6.4 Topping Up Barrels
4.8.6.5 Temperature of the Barrel Store
4.8.7 Maintaining Appropriate Molecular Sulfur Dioxide Levels. 4.8.7.1 The Sulfur Dioxide Quandary
4.8.7.2 Appropriate Levels of Molecular Sulfur Dioxide
4.8.8 Racking
4.8.9 Fining
4.8.10 Filtration
4.8.11 Bottling
4.8.12 Storage
4.9 Laboratory Analysis for Brettanomyces and Volatile Phenols
4.9.1 When Analysis Should Be Undertaken
4.9.2 Analysis for Viable Yeast Cells
4.9.2.1 Plate Cultures
4.9.2.2 Fluorescence Microscopy
4.9.2.3 Polymerase Chain Reaction (qPCR)
4.9.2.4 Flow Cytometry and Fluorescence In Situ Hybridisation
4.9.2.5 Raman Spectroscopy
4.9.2.6 Experimental Technologies for Detection of Brettanomyces
4.9.3 Analysis for Volatile Phenols Using Gas Chromatography with Detection by Mass Spectroscopy (GC‐MS)
4.10 Treatment of Affected Wines
4.10.1 Reduction or Removal of Brettanomyces Cells. 4.10.1.1 Racking
4.10.1.2 Fining
4.10.1.3 Filtration
4.10.1.4 Heat Treatments
4.10.1.5 Chemical Treatments
4.10.2 Reduction in Volatile Phenols
4.10.3 Future Possibilities for Physical Brett Inactivation
4.11 What the Future Might Hold for Microbiological Methods to Inhibit Brettanomyces?
4.12 Final Reflections
References
5 Oxidation, Premox, and Excessive Acetaldehyde
5.1 Introduction. 5.1.1 Oxygen: The Enemy and the Friend
5.1.2 The Importance of Oxygen in Winemaking
5.1.3 Oxygenation Is Not Oxidation
5.1.4 Good and Bad Oxidation?
5.2 Oxidation in Must and Wine. 5.2.1 Oxidation Defined
5.2.2 Types of Oxidation
5.3 Sensory Characteristics and Detection of Excess Acetaldehyde and Oxidation in Wine. 5.3.1 Excess Acetaldehyde. 5.3.1.1 Background
5.3.1.2 Detection
5.3.1.3 Appearance
5.3.1.4 Nose
5.3.1.5 Palate
5.3.1.6 Sensory Detection Threshold
5.3.2 Oxidation
5.3.2.1 Appearance
5.3.2.2 Nose
5.3.2.3 Palate
5.4 Deliberately Oxidised and Highly Oxygenated Wines. 5.4.1 Fortified and Speciality Wines
5.4.1.1 Speciality Unfortified Wines
5.4.1.2 Fortified Wines
5.4.2 Deliberate Oxidation in High‐Quality ‘Table’ Wines
5.4.3 The Strange Case of Orange Wines
5.4.4 Grape Varieties Susceptible to Oxidation
5.5 Metal Ions and Substrates for Oxidation. 5.5.1 The Role of Metal Ions
5.5.2 Substrates for Oxidation
5.5.3 Classes of Phenolics
5.5.3.1 Flavonoids
5.5.3.2 Non‐flavonoids
5.6 Enzymatic Oxidation. 5.6.1 Substrates
5.6.2 Polyphenol Oxidases, Tyrosinase, and Laccase
5.6.3 Glutathione and Grape Reaction Product (GRP)
5.6.4 Prevention of Tyrosinase‐Catalysed Enzymatic Oxidation
5.6.5 Laccase
5.6.6 Hyperoxygenation
5.7 Chemical Oxidation
5.7.1 Substrates
5.7.2 Chemical Oxidation Pathways
5.8 Microbial Oxidation
5.9 Acetaldehyde
5.9.1 Biological Production
5.9.2 Chemical Production
5.9.3 Acceptable and Unacceptable Levels of Acetaldehyde
5.9.4 Binding of Sulfur Dioxide
5.10 Sotolon
5.11 Oxygen Management in Winemaking
5.11.1 The Role of Oxygen During Fermentation
5.11.2 Post‐fermentation Oxygenation
5.11.3 Barrel Maturation
5.11.4 Lees Ageing
5.12 Oxygen Uptake During Cellar Operations
5.13 Containers and Closures
5.14 Pinking
5.15 Premature Oxidation (Premox) 5.15.1 Premature Oxidation Rears Its Head
5.15.2 Reversible Oxidation?
5.15.3 Causes of Premature Oxidation. 5.15.3.1 Possible Causes
5.15.3.2 Clonal Selection
5.15.3.3 The Phenolic Ripeness and High pH of Fruit
5.15.3.4 Low Levels of Glutathione in Grapes
5.15.3.5 The Use of Pneumatic Presses
5.15.3.6 The Increased Use of New Oak Barrels
5.15.3.7 Bâtonnage
5.15.3.8 Insufficient Free Sulfur Dioxide Levels
5.15.3.9 Interventionist Operations Undertaken to Speed the Wine to Market
5.15.3.10 Ingress of Oxygen When Bottling
5.15.3.11 Low‐Quality Cork Closures and Corks Washed with Peroxide
5.15.4 Prune Aroma
5.16 Prevention of Excess Acetaldehyde and Oxidation. 5.16.1 Basic Principles
5.16.2 Picking at Appropriate Ripeness
5.16.3 Harvesting and Transporting Fruit
5.16.4 Sorting
5.16.5 Crushing
5.16.6 Pressing (for White Wines)
5.16.7 Juice Clarification (White Must)
5.16.8 Inoculate with Commercial Strains of Saccharomyces
5.16.9 Fermentation
5.16.10 Post‐fermentation Maceration
5.16.11 Malolactic Fermentation (MLF)
5.16.12 Avoiding Ullage in Tanks and Barrels
5.16.13 Reducing Oxygen Uptake in Cellar Operations Including Rackings and Transfers
5.16.14 Maintaining Appropriate Levels of Free SO2
5.16.15 Reducing Heavy Metals
5.16.16 Controlling Cellar Temperature and Humidity
5.16.17 Barrel Ageing and/or the Addition of Ellagitannins
5.16.18 Lees Ageing
5.16.19 Cold Stabilisation
5.16.20 Ultrafiltration Before Bottling
5.16.21 Bottling. 5.16.21.1 A Major Source of Oxygen Uptake
5.16.21.2 Total Package Oxygen (TPO)
5.16.21.3 Dissolved Oxygen in the Wine
5.16.21.4 Oxygen in the Empty Bottle Pre‐filling
5.16.21.5 Headspace Oxygen
5.16.21.6 Oxygen Content of the Closure
5.16.21.7 Addition of Glutathione Prior to Bottling
5.16.22 Storage. 5.16.22.1 Oxygenation During Storage
5.16.22.2 Oxidation Due to Poor Storage
5.17 Additions of Ascorbic Acid: Antioxidant or Oxidising Agent?
5.18 Laboratory Analysis. 5.18.1 Acetaldehyde
5.18.2 Dissolved Oxygen
5.18.3 Oxidation
5.19 Treatments. 5.19.1 Acetaldehyde
5.19.2 Oxidation
5.20 Final Reflections
References
6 Excessive Sulfur Dioxide, Volatile Sulfur Compounds, and Reduced Aromas
6.1 Introduction. 6.1.1 Volatile Sulfur Compounds
6.1.2 Thiols
6.2 The Presence and Role of Sulfur, Sulfur Dioxide, Sulfite, and Sulfate in Wine Production
6.2.1 Sulfur Contained in Grapes
6.2.2 Sulfur‐Containing Fungicides
6.2.3 Sulfur Dioxide Generated by Yeast During Fermentation
6.2.3.1 Sulfur‐Containing Amino Acid
6.2.4 Additions of Sulfur Dioxide During the Winemaking Process. 6.2.4.1 The Use of Sulfur Dioxide in Winemaking
6.2.4.2 Total, Bound, Free, and Molecular Sulfur Dioxide
6.2.4.3 Additions of Sulfur Dioxide to Prevent Enzymatic Oxidation
6.2.4.4 The Use of Sulfur Dioxide to Prevent Chemical and Microbial Oxidation
6.3 Excessive Sulfur Dioxide. 6.3.1 High Levels of SO2: Flaw or Fault?
6.3.2 Sensory Detection of Excess Sulfur Dioxide
6.3.3 Possible Reasons for High SO2 Levels
6.3.4 Removal of Excessive Sulfur Dioxide from Wine
6.4 Oxygen Management in Winemaking
6.4.1 The Role and Management of Oxygen During Fermentation
6.4.2 Oxygenating During Fermentation
6.4.3 Micro‐oxygenation During Fermentation
6.4.4 Micro‐oxygenation Post‐fermentation
6.4.5 Barrel Maturation
6.4.6 Lees Ageing
6.5 Reduction in Wine: Positive and Negative. 6.5.1 Reducing Agents
6.5.2 Positive Reduction. 6.5.2.1 Reduced Notes as a Hallmark?
6.5.2.2 Desirable Aromas of Some VSCs
6.5.2.3 Minerality
6.5.3 Negative Reduction
6.6 Hydrogen Sulfide. 6.6.1 Hydrogen Sulfide: A Serious Fault When Present Above Sensory Threshold
6.6.2 Sensory Characteristics and Detection of Hydrogen Sulfide in Wine
6.6.3 The Formation of Hydrogen Sulfide in Wine
6.6.3.1 Formation by the Actions of Yeasts During the Alcoholic Fermentation
6.6.3.2 Production by Reduction of Elemental Sulfur or Inorganic Sulfur
6.7 Prevention of Hydrogen Sulfide Formation
6.8 Treatment for Hydrogen Sulfide in Wine
6.8.1 Physical Treatments. 6.8.1.1 Splash Racking
6.8.1.2 Aeration or Inert Gas Bubbling
6.8.2 Chemical Additions as Treatments
6.8.2.1 Sulfiting
6.8.2.2 Use of an Oxidising Agent
Copper Sulfate Pentahydrate
Copper Citrate
Legal Restrictions on the Use of Copper
Silver Chloride
Silicon Dioxide
6.9 Mercaptans, Sulfides, Disulfides, Trisulfides, and Thioesters. 6.9.1 Low‐ and High‐Boiling‐Point VSCs
6.9.2 Mercaptans
6.9.2.1 Methanethiol, Also Known as Methyl Mercaptan (MeSH)
6.9.2.2 Ethanethiol, Also Known as Ethyl Mercaptans (EtSH)
6.9.3 Sulfides Other than H2S. 6.9.3.1 Dimethyl Sulfide (DMS)
6.9.3.2 Ethyl Sulfide
6.9.3.3 Diethyl Sulfide
6.9.4 Disulfides
6.9.4.1 Carbon Disulfide
6.9.4.2 Diethyl Disulfide
6.9.4.3 Dimethyl Disulfide (DMDS)
6.9.5 Trisulfides: Dimethyl Trisulfide (DMTS)
6.9.6 Thioesters
6.9.6.1 Methyl Thioacetate
6.9.6.2 Ethyl Thioacetate
6.10 Post‐bottling Reduction. 6.10.1 A New Wine Fault
6.10.2 The Causes of Post‐bottling Reduction
6.10.3 The Oxygen Transmission Rates (OTRs) of Closures
6.11 Lightstrike
6.11.1 Wines Likely to Be Affected by Lightstrike
6.11.2 Sensory Detection
6.11.3 Causes and Incidences of the Fault. 6.11.3.1 The Transmission of UV Light Through Clear Glass Bottles
6.11.3.2 The Role of Riboflavin, Sulfur‐Containing Amino Acids, and Iron Tartrate
6.11.4 Prevention of Lightstrike
6.11.4.1 Vinification Measures
6.11.4.2 Packaging Measures
6.11.4.3 Storage Measures
6.11.5 Treatment
6.12 Laboratory Analysis for Sulfur Dioxide, Hydrogen Sulfide, and Volatile Sulfur Compounds. 6.12.1 Sulfur Dioxide
6.12.2 Hydrogen Sulfide and Volatile Sulfur Compounds. 6.12.2.1 A Quick and Easy Test for H2S Using Copper Sulfate
6.12.2.2 The Copper/Cadmium Test for H2S, Mercaptans (–SH Group), Disulfides, and Dimethyl Sulfide
Solutions:
Procedure:
6.12.2.3 Gas Chromatography
6.13 Final Reflections
References
7 Excessive Volatile Acidity and Ethyl Acetate
7.1 Introduction
7.2 Volatile Acidity and Ethyl Acetate
7.3 The Controversy of High Levels of Volatile Acidity. 7.3.1 Are Elevated Levels of Volatile Acidity Sometimes Acceptable?
7.3.2 1947 Château Cheval Blanc – The Greatest Faulty Wine Ever Made
7.4 Fixed Acids and Volatile Acids. 7.4.1 Total Acidity
7.4.2 Fixed Acids
7.4.2.1 Tartaric Acid
7.4.2.2 Citric Acid
7.4.2.3 Malic Acid
7.4.2.4 Lactic Acid
7.4.2.5 Succinic Acid
7.4.3 Volatile Acids
7.4.3.1 Acetic Acid
7.4.3.2 Butyric Acid
7.4.3.3 Isobutyric Acid
7.4.3.4 Propionic Acid
7.4.3.5 Hexanoic Acid
7.4.3.6 Sorbic Acid
7.4.3.7 Sulfurous Acid
7.5 Sensory Characteristics and Detection of Volatile Acidity
7.6 Legal Limits
7.7 Acetic Acid Bacteria
7.8 Production of Acetic Acid in Wine
7.8.1 Microbiological Production. 7.8.1.1 Production by Yeasts
7.8.1.2 Production by Bacteria, Including Acetic Acid Bacteria
7.8.2 Physiochemical Production
7.9 Ethyl Acetate
7.9.1 Production of Ethyl Acetate in Wine
7.9.2 Microbiological Production. 7.9.2.1 Production by Yeasts
7.9.2.2 Production by Acetic Acid Bacteria
7.9.3 Chemical Production
7.9.4 New Barrels Do Not Contain Ethyl Acetate
7.9.5 Sensory Characteristics and Detection of Ethyl Acetate
7.10 Prevention of Excessive Volatile Acidity and Ethyl Acetate
7.10.1 Fruit Selection and Processing
7.10.2 Exclusion of Vectors
7.10.3 Cleaning
7.10.4 Avoiding Cross‐Contamination
7.10.5 Must Adjustment Including Nutrient Additions
7.10.6 Addition of Lysozyme
7.10.7 Cold Soaking (Red Wines)
7.10.8 Inoculation with Desired Strains of Saccharomyces cerevisiae
7.10.9 Alcoholic Fermentation
7.10.10 Malolactic Fermentation
7.10.11 Addition of Sulfur Dioxide and Maintaining Appropriate Molecular SO2
7.10.12 Avoiding Ullage in Vats and Barrels
7.10.13 Micro‐oxygenation
7.10.14 Cleaning and Sanitising Barrels that Show Signs of Acetic Acid
7.10.15 Cautious Use of Citric Acid
7.10.16 Avoiding the Growth of Brettanomyces
7.10.17 Minimising Oxygen Uptake During Cellar Operations
7.10.18 Barrel Ageing
7.10.19 Monitoring and Analysis
7.10.20 Bottling
7.11 Laboratory Analysis. 7.11.1 Volatile Acidity and Acetic Acid Bacteria
7.11.2 Laboratory Analysis – Ethyl Acetate
7.12 Treatments. 7.12.1 Excessive Volatile Acidity
7.12.1.1 Dealing with Rising Levels of VA
7.12.1.2 Blending
7.12.1.3 Fining
7.12.1.4 Nanofiltration Coupled with Ion Exchange
7.12.1.5 Reverse Osmosis
7.12.1.6 Future Possibilities of Bio‐reduction of VA Levels
7.12.2 Ethyl Acetate
7.13 Final Reflections
References
8 Atypical Ageing (ATA) – Sometimes Called Untypical Ageing (UTA)
8.1 Introduction
8.2 The Atypical Ageing Controversy
8.3 The Causes of Atypical Ageing and Formation Pathways. 8.3.1 The Role of 2‐Aminoacetophenone (2‐AAP)
8.3.2 The Formation of 2‐AAP
8.3.3 The Role of Other Chemical Compounds
The Involvement of Sotolon, Phenylacetaldehyde
8.3.4 Distinguishing ATA from Premature Oxidation (Premox), and Reduction
8.4 Sensory Detection. 8.4.1 Sensory Characteristics
8.4.2 Sensory Perception Threshold of 2‐AAP
8.5 Laboratory Detection
8.6 The Main Viticultural Causes of ATA
8.7 Prevention. 8.7.1 In the Vineyard
8.7.2 In the Winery
8.7.3 Ascorbic Acid Addition
8.8 Treatments
8.9 Final Reflections
References
9 Fermentation in Bottle
9.1 Introduction. 9.1.1 Bottle–Fermented Sparkling Wines
9.1.2 Pétillant–Naturels
9.1.3 Unwanted Bottle Fermentation
9.2 Sensory Detection
9.3 Alcoholic Fermentation in Bottle
9.4 Malolactic Fermentation (MLF) in Bottle
9.5 Prevention: Preparing Wine for Bottling and the Bottling Process
9.5.1 Preparing Wine for Bottling. 9.5.1.1 Fining and Other Clarification
9.5.1.2 Adjustment of Free and Molecular SO2
9.5.1.3 Addition of a Fermentation Inhibitor
Lysozyme
Dimethyl Dicarbonate (DMDC) (Velcorin)
Potassium Sorbate
9.5.1.4 Heat Treatments
9.5.1.5 Membrane Filtration
9.5.2 The Bottling Process. 9.5.2.1 The Final Production Source of Contamination
9.5.2.2 The Bottling Line and Operation
9.6 Treatment
9.7 Final Reflections
References
10 Hazes
10.1 Introduction
10.2 Protein Haze. 10.2.1 The Formation and Impact of Protein Hazes
10.2.2 Prevention of Protein Haze Formation. 10.2.2.1 Pre‐fermentation Reduction in Haze‐Forming Proteins
10.2.2.2 Post‐fermentation Reduction in Haze‐Forming Proteins
10.2.2.3 Testing for Protein Stability
Heat (Stability) Tests
Reagent‐Based Tests
10.2.2.4 Fining with Bentonite
Fining Trials
Bentonite Additions
10.2.2.5 Alternatives to Bentonite. Ultrafiltration
The Use of Chitosan and Chitin–Glucan
10.2.2.6 Possible Future Alternatives to Bentonite
10.3 Microbial Hazes
10.4 Metal Hazes
10.4.1 Copper Haze. 10.4.1.1 Formation of Copper Haze
10.4.1.2 Prevention/Removal of Copper Haze
10.4.2 Iron Haze. 10.4.2.1 Formation of Iron Haze
10.4.2.2 Prevention/Removal of Iron Haze
10.5 Final Reflections
References
11 Lactic Acid Bacteria‐Related Faults
11.1 Introduction to Lactic Acid Bacteria
11.2 Lactic Acid Bacteria and Their Natural Sources
11.3 Malolactic Fermentation (MLF) 11.3.1 History of the Understanding MLF
11.3.2 The MLF Process
11.3.2.1 Temperature
11.3.2.2 Sulfur Dioxide (SO2)
11.3.2.3 pH
11.3.2.4 Alcohol
11.3.2.5 Nutrients
11.4 Undesirable Aromas, Off‐Flavours, and Wine Spoilage Caused by Lactic Acid Bacteria. 11.4.1 Off‐Odours Associated with Lactic Acid Bacteria
11.4.2 Acrolein
11.4.3 Excess Diacetyl
11.4.4 Mannitol
11.4.5 Ropiness
11.4.6 Mousiness
11.4.7 Tourne
11.4.8 Indole
11.4.9 Geranium Taste
11.5 Prevention of Lactic Acid Bacteria‐Related Faults
11.6 Analysis
11.7 Final Reflections
References
12 Smoke Taint and Other Airborne Contaminations
12.1 Introduction
12.2 Smoke Taint Compounds in the Atmosphere
12.3 Critical Times in the Growing Season and Duration of Exposure for Smoke Taint to Impact
12.4 The Volatile Phenols Responsible for Smoke Taint; Their Odours and Flavours and Sensory Detection Thresholds
12.5 Smoke Taint in Wines
12.6 Other Sources of Guaiacol and 4‐Methyl‐guaiacol in Wines
12.7 Laboratory Testing
12.8 Prevention of Development of Smoke‐Related Volatile Phenols from Affected Grapes
12.9 Treatments
12.9.1 Activated Carbon
12.9.2 Other Fining Treatments
12.9.3 Reverse Osmosis (RO) and Solid Phase Adsorption
12.9.4 The Addition of Oak Products to Affected Wines
12.9.5 Blending
12.9.6 Limiting Time in Bottle Pre‐sale
12.10 Other Airborne Contaminations. 12.10.1 Spray Drift
12.10.2 Eucalyptol – 1,8‐Cineole
12.10.2.1 Prevention
12.11 Final Reflections
References
13 Ladybeetle and Brown Marmorated Stink Bug Taints
13.1 Introduction
13.2 Methoxypyrazines
13.3 Ladybeetles (Also Known as Ladybirds and Ladybugs) 13.3.1 Background
13.3.2 Infested Grapes
13.3.3 Sensory Characteristics, Detection, and Consumer Rejection Thresholds. 13.3.3.1 Sensory Characteristics
13.3.3.2 Sensory Detection Thresholds and Consumer Rejection Thresholds
13.3.4 Prevention
13.3.5 Treatments
13.4 Brown Marmorated Stink Bug (Halyomorpha halys) Taint. 13.4.1 Background
13.4.2 Infested Grapes
13.4.3 Sensory Characteristics, Detection, and Consumer Rejection Thresholds. 13.4.3.1 Sensory Characteristics
13.4.3.2 Sensory Detection Thresholds and Consumer Rejection Thresholds (CRT)
13.4.4 Prevention
13.4.5 Treatments
13.5 Final Reflections
References
14 Sundry Faults, Contaminants, Including Undesirable Compounds from a Health Perspective and Flaws Due to Poor Balance
14.1 Mycotoxins, Particularly Ochratoxin A
14.1.1 The Presence of Ochratoxin A
14.1.2 The Origins of Ochratoxin A in Wines
14.1.3 Prevention of, or Minimising, Contamination with OTA
14.1.4 Analysis
14.1.5 Treatment of Affected Wines
14.2 Dibutyl Phthalate and Other Phthalates
14.3 Ethyl Carbamate
14.3.1 Production of Ethyl Carbamate in Wines
14.3.2 Prevention of Ethyl Carbamate in Wines
14.3.3 Analysis
14.4 Biogenic Amines
14.5 Ethyl Sorbate and Sorbyl Alcohol (Geraniol) Off‐Odours. 14.5.1 The Use of Potassium Sorbate and Conversion to Compounds Giving Off‐Odours
14.5.2 Prevention
14.6 Paper‐Taste
14.7 Plastic Taints – Styrene
14.8 Indole. 14.8.1 The Presence of Indole in Wine
14.8.2 Sensory Perception
14.9 Geosmin. 14.9.1 Sources of Geosmin in Wine
14.9.2 Organoleptic Detection and Sensory Perception Thresholds
14.9.3 Treatment
14.10 2‐Bromo‐4‐methylphenol – Iodine, Oyster Taste
14.11 Heat Damage. 14.11.1 Transport and Storage
14.11.2 Sensory Detection
14.11.3 Pathways to Heat Damage
14.12 Matters of Balance. 14.12.1 Unbalanced Wines May Be Regarded as Flawed
14.12.2 Alcohol
14.12.3 Acidity
14.12.4 Body and Structure
14.12.5 Tannins
14.12.6 Fruit and Flavour Concentration
14.12.7 Residual Sugar (If Any)
14.13 Final Reflections
References
15 TDN and Tartrate Crystals: Faults or Not?
15.1 TDN. 15.1.1 What Is TDN?
15.1.2 The Formation of TDN
15.1.3 Sensory Characteristics and Sensory Detection Thresholds. 15.1.3.1 Sensory Characteristics
15.1.3.2 Sensory Detection Thresholds
15.1.3.3 Prevalence of TDN in Riesling Wines
15.1.4 Minimising TDN in Wine Production
15.1.5 TDN in Bottled Wine
15.1.6 The TDN Controversy
15.2 Tartrate Deposits
15.2.1 The Formation of Tartrate Deposits
15.2.2 Sources of Calcium in Wines
15.2.3 Calcium Tartrate Instability
15.2.4 Sources of Potassium in Wines
15.2.5 Potassium Bitartrate Instability
15.2.6 Prevention of Tartrate Formation
15.2.7 Prevention of Precipitation of Potassium Bitartrate Crystals in Packaged Wine. 15.2.7.1 Methods Used for KHT Stabilisation
15.2.7.2 Cold Stabilisation
15.2.7.3 Ion Exchange
15.2.7.4 Electrodialysis
15.2.7.5 Metatartaric Acid Addition
15.2.7.6 Carboxymethylcellulose (CMC)
15.2.7.7 Mannoproteins
15.2.7.8 Potassium Polyaspartate (KPA)
15.2.7.9 Considerations as to the Choice of Methods of Prevention of KHT Crystallisation
15.2.7.10 Gum Arabic and Co‐blends of Additives
15.2.8 Prevention of Precipitation of Calcium Tartrate Crystals in Packaged Wine. 15.2.8.1 Methods Permitted by the OIV
15.2.8.2 The Addition of Calcium Tartrate
15.2.8.3 The Addition of Racemic (DL) Tartaric Acid
15.2.9 Predictive Tests. 15.2.9.1 Potassium Bitartrate
15.2.9.2 Calcium Tartrate
15.3 Final Reflections
References
16 Must Correction, Wine Correction, and Alcohol Reduction Using Membrane Technologies
16.1 Introduction. 16.1.1 The Use of Membranes in Stabilising Wines for Export Markets
16.1.2 Wine as a ‘Natural’ Product
16.2 Membrane Processes Used in the Wine Industry
16.3 Clarification. 16.3.1 ‘Traditional’ Clarification and Filtration Methods in Common Use
16.3.2 Membrane Filtration of Must and Wine. 16.3.2.1 Clarification of Must
16.3.2.2 Clarification of Wine
16.3.3 Cross‐Flow Micro Filtration
16.4 Membrane Fouling
16.5 Must Correction, Wine Correction, and Alcohol Reduction. 16.5.1 Reverse Osmosis
16.5.1.1 Must Correction by RO – Increasing Sugar Concentration
16.5.1.2 Must Correction by RO, Ultrafiltration/Nanofiltration – Reducing Sugar Concentration
16.5.2 Ultrafiltration
16.5.3 Wine Correction – Reducing Alcohol Content
16.6 Fault Correction. 16.6.1 Removing Acetic Acid
16.6.2 Removal of Brettanomyces Yeasts, and the Treatment of Volatile Phenols
16.6.3 Removal of Smoke Taint
16.7 Wine Stabilisation and pH Adjustment by Electrodialysis
16.7.1 Tartrate Stabilisation
16.7.2 pH and Acidity Adjustment
16.8 Final Reflections
References
17 The Impact of Container and Closure Upon Wine Faults
17.1 Introduction
17.2 Glass Bottles. 17.2.1 Overview
17.2.2 A Brief History of Glass Bottles for Wine
17.2.3 The Impact of Bottle Size Upon Wine Development and Quality
17.2.4 The Impacts of Bottle Colour and Glass Thickness/Weight
17.3 Bottle Closures
17.3.1 Types of Closure
17.3.2 Dissolved Oxygen in Wine. 17.3.2.1 Sources of Dissolved Oxygen and Total Package Oxygen in Wine
17.3.2.2 Consequences of Oxygen Uptake During the Bottling Operation
17.3.2.3 Oxygen Transmission Rates (OTRs), Permeation, Migration, and Scalping. Permeation
Migration
Scalping
17.4 The Maintenance of Adequate Fee and Molecular SO2 in Bottled Wine. 17.4.1 The Adjustment of Free and Molecular SO2 at Bottling
17.4.2 Retention of Adequate Free Sulfur Dioxide in Bottle
17.4.3 The Influence of Closure Type Upon Reductive Characters
17.4.4 The Market for the Various Types of Closures
17.5 Cork Closures
17.5.1 A Brief History of Cork Closures
17.5.2 The Origin of Cork and Production of Cork Stoppers
17.5.3 The Cork Production Process
17.5.4 Natural Corks and Colmated Corks. 17.5.4.1 Grades of Natural Cork
17.5.4.2 Colmated Corks
17.6 Technical Corks and Agglomerated Corks
17.6.1 Micro‐agglomerated Corks
17.6.2 Twin Top, 1 + 1 and Sparkling Wine Other Technical Corks
17.6.3 Helix
17.6.4 ProCork
17.7 Diam Cork Closure. 17.7.1 History: From the Altec Disaster to Diam Success
17.7.2 The Technology of the Diam Closure
17.7.3 The Range of Diam Closures and OTRs
17.8 Synthetic Closures
17.8.1 Co‐extruded Closures
17.8.1.1 Nomacorc
17.8.2 Injection‐Moulded Closures
17.8.3 Flavour Scalping
17.9 Screw Caps
17.9.1 History
17.9.2 Screw Cap Liners
17.9.3 Post‐Bottling Reduction
17.9.4 Damage to Screw Caps
17.10 Vinolok
17.11 Some Advantages and Disadvantages of Various Closure Types
17.12 The Bottling Operation
17.13 PET Bottles
17.14 Cans
17.15 Bag‐in‐Box
17.15.1 History of Bag‐in‐Box
17.15.2 The Manufacture of the Bag
17.15.3 Filling Bag‐in‐Box Wines
17.16 Final Reflections
References
18 Best Practice for Fault and Flaw Prevention
18.1 The Wine Industry
18.2 HACCP
18.3 Standard Operating Procedures (SOPs)
18.4 Traceability
18.5 Winery Design
18.6 Cleaning and Sanitation
18.6.1 Winery Water
18.6.2 Cleaning Agents
18.6.3 Cleaning of Equipment
18.6.4 Suggested Sequence for Cleaning Equipment
18.6.5 Barrel Cleaning
18.7 Good Practice Winemaking Procedures to Avoid Spoilage, Faults, and Flaws
18.7.1 Harvesting
18.7.2 Transportation of Harvested Fruit
18.7.3 Sorting
18.7.4 De‐stemming, Crushing
18.7.5 Pressing (for White or Rosé Wines)
18.7.6 Yeast Nutrients
18.7.7 Oxygenating During Fermentation
18.7.8 Use of Inert Gasses and Topping of Containers
18.7.9 Bottling
18.8 The Use of Oenological Additions and Processing Aids. 18.8.1 Sulfur Dioxide. 18.8.1.1 Properties of Sulfur Dioxide
18.8.1.2 Total, Bound, Free, and Molecular Sulfur Dioxide
Free Sulfur Dioxide
18.8.1.3 Health and Legal Considerations
18.8.1.4 The Use of Sulfur Dioxide in Winemaking
Potassium Metabisulfite (PMBS)
Aqueous SO2
18.8.2 Dimethyl Dicarbonate (Velcorin)
18.8.3 Lysozyme
18.8.4 Chitosan
18.9 Routine Wine Analysis
18.10 Final, Final Reflections
References
Appendix A Levels of Free SO2 Required to Give 0.5, 0.625, and 0.8 mg/l of Molecular SO2 for Differing Wine pH Values
Further Reading. Easily Readable Books
Books with a More Scientific Approach
Glossary
Useful Websites
Index. a
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c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
y
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