Table Of Content

Handbook of Enology Volume 1 The Microbiology of Wine and Vinifications nd 2 Edition Pascal Ribe´reau-Gayon Denis Dubourdieu Bernard Done`che Aline Lonvaud Faculty of Enology Victor Segalen University of Bordeaux II, Talence, France Original translation by Jeffrey M. Branco, Jr. Winemaker M.S., Faculty of Enology, University of Bordeaux II Revision translated by Christine Rychlewski Aquitaine Traduction, Bordeaux, France Copyright2006 JohnWiley&SonsLtd,TheAtrium,SouthernGate,Chichester, WestSussexPO198SQ,England Telephone(+44)1243779777 Email(forordersandcustomerserviceenquiries):[email protected] VisitourHomePageonwww.wiley.com AllRightsReserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystemortransmittedinanyformorbyanymeans, electronic,mechanical,photocopying,recording,scanningorotherwise,exceptunderthetermsoftheCopyright,DesignsandPatentsAct1988or underthetermsofalicenceissuedbytheCopyrightLicensingAgencyLtd,90TottenhamCourtRoad,LondonW1T4LP,UK,withoutthe permissioninwritingofthePublisher.RequeststothePublishershouldbeaddressedtothePermissionsDepartment,JohnWiley&SonsLtd,The Atrium,SouthernGate,Chichester,WestSussexPO198SQ,England,[email protected],orfaxedto(+44)1243770620. 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Contents:v.1.Themicrobiologyofwineandvinifications ISBN-13:978-0-470-01034-1(v.1:acid-freepaper) ISBN-10:0-470-01034-7(v.1:acid-freepaper) 1. Wineandwinemaking—Handbooks,manuals,etc.2. Wineandwine making—Microbiology—Handbooks,manuals,etc.3. Wineandwine making—Chemistry—Handbooks,manuals,etc.I.Dubourdieu,Denis.II. Done`che,Bernard.III.Traite´d’oenologie.English.IV.Title. TP548.T76132005 663(cid:1).2—dc22 2005013973 BritishLibraryCataloguinginPublicationData AcataloguerecordforthisbookisavailablefromtheBritishLibrary ISBN-13:978-0-470-01034-1(HB) ISBN-10:0-470-01034-7(HB) Typesetin10/12ptTimesbyLaserwordsPrivateLimited,Chennai,India PrintedandboundinGreatBritainbyAntonyRoweLtd,Chippenham,Wiltshire Thisbookisprintedonacid-freepaperresponsiblymanufacturedfromsustainableforestry inwhichatleasttwotreesareplantedforeachoneusedforpaperproduction. Contents Remarks Concerning the Expression of Certain Parameters of Must and Wine Composition vii Preface to the First Edition ix Preface to the Second Edition xiii 1 Cytology, Taxonomy and Ecology of Grape and Wine Yeasts 1 2 Biochemistry of Alcoholic Fermentation and Metabolic Pathways of Wine Yeasts 53 3 Conditions of Yeast Development 79 4 Lactic Acid Bacteria 115 5 Metabolism of Lactic Acid Bacteria 139 6 Lactic Acid Bacteria Development in Wine 161 7 Acetic Acid Bacteria 183 8 The Use of Sulfur Dioxide in Must and Wine Treatment 193 9 Products and Methods Complementing the Effect of Sulfur Dioxide 223 10 The Grape and its Maturation 241 11 Harvest and Pre-Fermentation Treatments 299 12 Red Winemaking 327 13 White Winemaking 397 14 Other Winemaking Methods 445 Index 481 Remarks Concerning the Expression of Certain Parameters of Must and Wine Composition UNITS more correct expression in milliequivalents per literhasnotbeenembracedinFrance.Theexpres- Metric system units of length (m), volume (l) and sion of total and volatile acidity in the equivalent weight(g)areexclusivelyused.Theconversionof weight of sulfuric acid has been used predomi- metric units into Imperial units (inches, feet, gal- nantlythroughouttheseworks.Incertaincases,the lons, pounds, etc.) can be found in the following correspondingweightintartaricacid,oftenusedin enological work: Principlesandpracticesofwine- other countries, has been given. making,R.B. Boulton,V.L. Singleton,L.F. Bisson Using the weight of the milliequivalent of the and R.E. Kunkee, 1995, The Chapman & Hall various acids, the below table permits the conver- Enology Library, New York. sion from one expression to another. More particularly, to convert from total acidity EXPRESSION OF TOTAL ACIDITY expressed in H2SO4 to its expression in tartaric acid, add half of the value to the original value AND VOLATILE ACIDITY (4 g/l H SO →6 g/l tartaric acid). In the other 2 4 Although EC regulations recommend the expres- direction a third of the value must be subtracted. sionoftotalacidityintheequivalentweightoftar- The French also continue to express volatile taricacid,theFrenchcustomistogivethisexpres- acidity in equivalent weight of sulfuric acid. More sion in the equivalent weight of sulfuric acid. The generally, in other countries, volatile acidity is DesiredExpression KnownExpression meq/l g/l g/l g/l H SO tartaric acid aceticacid 2 4 meq/l 1.00 0.049 0.075 0.060 g/l H SO 20.40 1.00 1.53 1.22 2 4 g/l tartaric acid 13.33 0.65 1.00 g/l acetic acid 16.67 0.82 1.00 Multiplier topass from one expressionof total orvolatile acidity to another viii Remarks Concerning the Expression of Certain Parameters of Must and Wine Composition expressed in acetic acid. It is rarely expressed and then divided by 17 to obtain a fairly good in milliequivalents per liter. The below table also approximation of the TAP. allows simple conversion from one expression to another. In any case, the determination of the Brix or TAP The expression in acetic acid is approximately of a must is approximate. First of all, it is not 20% higher than in sulfuric acid. always possible to obtain a representative grape or must sample for analysis. Secondly, although physical, densimetric or refractometric measure- EVALUATING THE SUGAR mentsareextremelypreciseandrigorouslyexpress CONCENTRATION OF MUSTS the sugar concentration of a sugar and water mix- ture,thesemeasurementsareaffectedbyothersub- This measurement is important for tracking grape stances released into the sample from the grape maturation, fermentation kinetic and if necessary andothersources.Furthermore,theconcentrations determining the eventual need for chaptalization. of these substances are different for every grape This measurement is always determined by or grape must sample. Finally, the conversion rate physical, densimetric or refractometric analysis. of sugar into alcohol (approximately 17 to 18 g/l) The expression of the results can be given accord- variesanddependsonfermentationconditionsand ing to several scales: some are rarely used, i.e. yeast properties. The widespread use of selected degree Baume´ and degree Oechsle. Presently, two yeaststrainshasloweredthesugarconversion rate. systems exist (Section 10.4.3): Measurements Using Visible 1. The potential alcohol content (titre alcoome´t- raque potential or TAP, in French) of musts and Ultraviolet Spectrometry can be read directly on equipment, which is The measurement of optic density, absorbance, is graduated using a scale corresponding to 17.5 widely used to determine wine color (Volume 2, or 17 g/l of sugar for 1% volume of alcohol. Section 6.4.5) and total phenolic compounds con- Today, the EC recommends using 16.83 g/l as centration (Volume 2, Section 6.4.1). In these the conversion factor. The ‘mustimeter’ is a works, the optic density is noted as OD, OD 420 hydrometer containing two graduated scales: (yellow),OD 520(red),OD 620(blue)orOD 280 one expresses density and the other gives a (absorption in ultraviolet spectrum) to indicate the direct reading of the TAP. Different methods optic density at the indicated wavelengths. varying in precision exist to calculate the TAP Wine color intensity is expressed as: fromadensityreading.Thesemethodstakevar- iouselementsofmustcompositionintoaccount CI=OD 420+OD 520+OD 620, (Boulton etal., 1995). Or is sometimes expressed in a more simplified 2. Degree Brix expresses the percentage of sugar form: CI=OD 420+OD 520. in weight. By multiplying degree Brix by 10, Tint is expressed as: the weight of sugar in 1 kg, or slightly less OD 420 than 1 liter, of must is obtained. A conversion T = table between degree Brix and TAP exists in OD 520 Section 10.4.3 of this book. 17 degrees Brix The total phenolic compound concentration is correspond to an approximate TAP of 10% and expressed by OD 280. 20 degrees Brix correspond to a TAP of about TheanalysismethodsaredescribedinChapter 6 12%. Within the alcoholrange most relevantto of HandbookofEnology Volume 2,TheChemistry enology, degree Brix can be multiplied by 10 ofWine. Preface to the First Edition Wine has probably inspired more research and Wine Analysis J. Ribe´reau-Gayon and E. Peynaud publications than any other beverage or food. In (1947and1958);TreatiseonEnology (2 Volumes) fact,throughtheirpassionforwine,greatscientists J. Ribe´reau-Gayon and E. Peynaud (1960 and have not only contributed to the development of 1961); Wine and Winemaking E. Peynaud (1971 practical enology but have also made discoveries and 1981); Wine Science and Technology (4 volu- in the general field of science. mes)J. Ribe´reau-Gayon,E. Peynaud,P. Ribe´reau- A forerunner of modern enology, Louis Pasteur Gayon and P. Sudraud (1975–1982). developed simplified contagious infection mod- For an understanding of current advances in els for humans and animals based on his obser- enology, the authors propose this book Handbook vations of wine spoilage. The following quote of Enology Volume 1: The Microbiology of Wine clearly expresses his theory in his own words: and Vinifications and the second volume of the ‘when profound alterations of beer and wine are Handbook ofEnology Volume 2:TheChemistry of observed because these liquids have given refuge Wine: Stabilization andTreatments. tomicroscopicorganisms,introducedinvisiblyand Although written by researchers, the two vol- accidentally into the medium where they then umes are not specifically addressed to this group. proliferate, how can one not be obsessed by the Youngresearchersmay,however,findthesebooks thought that a similar phenomenon can and must useful to help situate their research within a par- sometimes occur in humans and animals.’ ticular field of enology. Today, the complexity of Since the 19th century, our understanding of modern enology does not permit a sole researcher wine, wine composition and wine transformations to explore the entire field. has greatly evolved in function of advances in rel- These volumes are also of use to students and evant scientific fields i.e. chemistry, biochemistry, professionals. Theoretical interpretations as well microbiology. Each applied development has lead as solutions are presented to resolve the problems to better control of winemaking and aging con- encountered most often at wineries. The authors ditions and of course wine quality. In order to have adapted these solutions to many differentsit- continue this approach, researchers and winemakers must strive to remain up to date with the latest uationsandwinemakingmethods.Inordertomake scientific and technical developments in enology. the best use of the information contained in these Foralongtime,theBordeauxschoolofenology works,enologists shouldhaveabroadunderstand- was largely responsible for the communication of ing of general scientific knowledge. For example, progress in enology through the publication of the understanding and application of molecular numerous works (Be´ranger Publications and later biology and genetic engineering have become Dunod Publications): indispensable in the field of wine microbiology. WineAnalysis U. GayonandJ. Laborde(1912); Similarly, structural and quantitative physiochem- Treatise on Enology J. Ribe´reau-Gayon (1949); ical analysis methods such as chromatography, x Preface to the First Edition NMR and mass spectrometry must now be treatments’ is completed when the wine is bottled. mastered in order to explore wine chemistry. Aging specifically refers to the transformation of The goal of these two works was not to create bottled wine. an exhaustive bibliography of each subject. The This distinction of two phases is certainly the authorsstrovetochooseonlythemostrelevantand result of commercial practices. Traditionally in significant publications to their particular field of France, a vine grower farmed the vineyard and research. A large number of references to French transformed grapes into an unfinished wine. The enological research has been included in these winemerchanttransferredthebulkwinetohiscel- works in order to make this information available lars, finished the wine and marketed the product, to a larger non-French-speaking audience. preferentially before bottling. Even though most In addition, the authors have tried to convey wines are now bottled at the winery, these long- a French and more particularly a Bordeaux per- standing practices have maintained a distinction spective of enology and the art of winemaking. between ‘wine grower enology’ and ‘wine mer- The objective of this perspective is to maximize chant enology’. In countries with a more recent the potential quality of grape crops based on the viticulturalhistory,generallyEnglishspeaking,the specificnaturalconditionsthatconstitutetheir‘ter- vine grower is responsible for winemaking and roir’. The role of enology is to express the char- winesales.Forthisreason,theAnglo-Saxontradi- acteristics of the grape specific not only to variety tion speaksof winemaking, whichcoversalloper- and vineyard practices but also maturation condi- ations from harvest reception to bottling. tions, which are dictated by soil and climate. In these works, the distinction between ‘vinifi- It would, however, be an error to think that the cation’ and ‘stabilization and treatments’ has been world’s greatest wines are exclusively a result of maintained,sincethefirstphaseprimarilyconcerns tradition, established by exceptional natural con- microbiology and the second chemistry. In this ditions, and that only the most ordinary wines, manner, the individual operations could be linked produced in giant processing facilities, can ben- totheirparticularsciences.Thereareofcourselim- efit from scientific and technological progress. its to this approach. Chemical phenomena occur Certainly, these facilities do benefit the most from during vinification; the stabilization of wines dur- high performance installations and automation of ing storage includes the prevention of microbial operations. Yet, history has unequivocally shown contamination. that the most important enological developments Consequently, the description of the different in wine quality (for example, malolactic fermenta- steps of enology does not always obey logic as tion)havebeendiscoveredinultrapremiumwines. precise as the titles of these works may lead Thecorrespondingtechniqueswerethenappliedto to believe. For example, microbial contamination less prestigious products. during aging and storage are covered in Vol- High performance technology is indispensable ume 1.TheantisepticpropertiesofSO incitedthe 2 for the production of great wines, since a lack descriptionofitsuseinthesamevolume.Thisline of control of winemaking parameters can easily of reasoning lead to the description of the antioxi- compromise their quality, which would be less of dant related chemical properties of this compound a problem with lower quality wines. in the same chapter as well as an explanation of The word ‘vinification’ has been used in this adjuvants to sulfur dioxide: sorbic acid (antisep- work and is part of the technical language of tic) and ascorbic acid (antioxidant). In addition, the French tradition of winemaking. Vinification the on lees aging of white wines and the result- describes the first phase of winemaking. It com- ing chemical transformations cannot be separated prises all technical aspects from grape maturity from vinification and are therefore also covered and harvest to the end of alcoholic and some- in Volume 1. Finally, our understanding of pheno- times malolactic fermentation. The second phase lic compounds in red wine is based on complex of winemaking ‘winematuration, stabilization and chemistry. All aspects related to the nature of the Preface to the First Edition xi correspondingsubstances,theirpropertiesandtheir cases i.e. phenolic compounds, whose different evolutionduringgrapematuration,vinificationand families are often defined by analytical criteria. aging are therefore covered in Volume 2. The authors thank the following people who These works only discuss the principles of have contributed to the creation of this work: equipment used for various enological operations J.F. Casas Lucas, Chapter 14, Sherry; A. Brugi- and their effect on product quality. For example, rard, Chapter 14, Sweet wines; J.N. de Almeida, temperaturecontrolsystems,destemmers,crushers Chapter 14, Port wines; A. Maujean, Chapter 14, and presses as well as filters, inverse osmosis Champagne; C. Poupot for the preparation of machines and ion exchangers are not described in material in Chapters 1, 2 and 13; Miss F. Luye- detail.Bottlingisnotaddressedatall.Anin-depth Tanet for her help with typing. descriptionof enologicalequipment would merita TheyalsothankMadame B. Masclefin particu- detailed work dedicated to the subject. larforherimportantpartinthetyping,preparation Wine tasting, another essential role of the and revision of the final manuscript. winemaker, is not addressed in these works. Many related publications are, however, readily Pascal Ribe´reau-Gayon available.Finally,wineanalysisisanessentialtool Bordeaux thatawinemakershouldmaster.Itis,however,not covered in these works except in a few particular Preface to the Second Edition The two-volume Enology Handbook was pub- individual terroirs. Scientific winemaking has not lishedsimultaneouslyinSpanish,French,andItal- resulted in standardization or leveling of quality. ian in 1999 and has been reprinted several times. On the contrary, by making it possible to correct The Handbook has apparently been popular with defects and eliminate technical imperfections, it students as an educational reference book, as well has revealed the specific qualities of the grapes as with winemakers, as a source of practical solu- harvestedin differentvineyards, directlyrelatedto tions to their specific technical problems and sci- the variety and terroir, more than ever before. entific explanations of the phenomena involved. Interest in wine in recent decades has gone It was felt appropriate at this stage to prepare beyond considerations of mere quality and taken an updated, reviewed, correctedversion, including on a truly cultural dimension. This has led some thelatestenologicalknowledge,toreflectthemany people to promote the use of a variety of tech- newresearchfindingsinthisveryactivefield.The niques that do not necessarily represent significant outline and design of both volumes remain the progress in winemaking. Some of these are sim- same.Somechaptershavechangedrelativelylittle ply modified forms of processes that have been as the authors decided there had not been any sig- known for many years. Others do not have a suf- ficiently reliable scientific interpretation, nor are nificantnewdevelopments,whileothershavebeen their applications clearly defined. In this Hand- modified much more extensively, either to clarify book, we have only included rigorously tested and improve the text, or, more usually, to include techniques, clearly specifying the optimum con- new research findings and their practical applica- ditions for their utilization. tions. Entirely new sections have been inserted in As in the previous edition, we deliberately some chapters. omitted three significant aspects of enology: wine Wehavemadeeveryefforttomaintainthesame analysis, tasting, and winery engineering. In view approach as we did in the first edition, reflecting of their importance, these topics will each be theethosofenologyresearchinBordeaux.Weuse covered in separate publications. indisputable scientific evidence in microbiology, The authors would like to take the opportunity biochemistry, and chemistry to explain the details of the publication of this new edition of Volume 1 ofmechanismsinvolvedingraperipening,fermen- tothankallthosewhohavecontributedtoupdating tations and other winemaking operations, aging, this work: and stabilization. The aim is to help winemakers achieve greater control over the various stages in — Marina Bely for her work on fermentation winemaking and choose the solution best suited kinetics (Section 3.4) and the production of to each situation. Quite remarkably, this scientific volatile acidity (Sections 2.3.4 and 14.2.5) approach, most intensively applied in making the finest wines, has resulted in an enhanced capac- — Isabelle Masneuf for her investigation of the ity to bring out the full quality and character of yeasts’ nitrogen supply (Section 3.4.2) xiv Preface to the Second Edition — Gilles de Revel for elucidating the chemistry — Paulo Barros and Joa Nicolau de Almeida for of SO , particularly, details of combination their work on Port (Section 14.4.3) 2 reactions (Section 8.4) — Justo. F. Casas Lucas for the paragraph on — Gilles Masson for the section on rose´ wines Sherry (Section 14.5.2) (Section 14.1) — Alain Maujean for his in-depth revision of the — Cornelis Van Leeuwen for data on the impact section on Champagne (Section 14.3). of vineyard water supply on grape ripening (Section 10.4.6) March 17, 2005 — Andre´ Brugirard for the section on French Professor Pascal RIBEREAU-GAYON fortified wines—vins doux naturels (Section Corresponding Member of the Institute 14.4.2) Member of the French Academy of Agriculture