Common Defects in Common Defects in WineWine

Presented by Presented by

Jef L. StebbenJef L. Stebben

Stebben Wine ConsultantsStebben Wine Consultants

Stebben Wine Stebben Wine ConsultantsConsultants

Formed in 2002 to provide quality Formed in 2002 to provide quality winemaking to small producerswinemaking to small producers

Consistent focus on quality and Consistent focus on quality and improvement at low cost to improvement at low cost to clientsclients

Now working with wineries from Now working with wineries from 9,000 cases to home winemakers9,000 cases to home winemakers

Jef L. StebbenJef L. Stebben

Phone (707) 287-5337Phone (707) 287-5337 E-mail E-mail jef@stebbenwine.comjef@stebbenwine.com www.stebbenwine.comwww.stebbenwine.com

(Notes from this presentation will (Notes from this presentation will be posted on the website.)be posted on the website.)

OverviewOverview

Reduction in Wine – Sulfides Reduction in Wine – Sulfides Oxidation in Wine – Volatile Oxidation in Wine – Volatile

AcidityAcidity Brettanomyces / DekkeraBrettanomyces / Dekkera

Sulfides In wineSulfides In wine

HH22S – The most common in wineS – The most common in wine– Can form during fermentationCan form during fermentation– Forms in stressed fermentationsForms in stressed fermentations– Low nitrogen mustsLow nitrogen musts– Utilizes vineyard Sulfur (Residue on skins)Utilizes vineyard Sulfur (Residue on skins)– Low levels of Vitamins in mustsLow levels of Vitamins in musts– High levels of CysteineHigh levels of Cysteine– Yeast strainYeast strain

– Too much SOToo much SO22

Mercaptans / DisulfideMercaptans / Disulfide

Mercaptans are stable molecules Mercaptans are stable molecules forming from large amounts of Hforming from large amounts of H22S S and Ethanol and/or reduction of and Ethanol and/or reduction of Amino Acids during storage.Amino Acids during storage.

Dimethyl Disulfide and Diethyl Dimethyl Disulfide and Diethyl Disulfide can form from mercaptans Disulfide can form from mercaptans and need to be reduced before they and need to be reduced before they will can be removed from wine.will can be removed from wine.

Prevention of SulfidesPrevention of Sulfides

Vineyard Practices – No Sulfur post Vineyard Practices – No Sulfur post veraisonveraison

Harvest sound balanced fruitHarvest sound balanced fruit Add VITAMINS to fermentationsAdd VITAMINS to fermentations Add NUTRIENTS to fermentationsAdd NUTRIENTS to fermentations Do not add Cu prior to fermentationDo not add Cu prior to fermentation Rack whites after settlingRack whites after settling Do not ferment in the presence of Do not ferment in the presence of

BentoniteBentonite

Removal of SulfidesRemoval of Sulfides

HH22S can be removed by contact with S can be removed by contact with Copper. (CuSOCopper. (CuSO44 or other method) or other method)

Often the addition of nutrients Often the addition of nutrients during fermentation will remove Hduring fermentation will remove H22SS

Often racking or splashing the Often racking or splashing the fermentation will remove Hfermentation will remove H22SS

Removal of DisulfidesRemoval of Disulfides

Perform a test to determine the Perform a test to determine the presence of Disulfides (Cdpresence of Disulfides (Cd++++, Cu, Cu++

++, and Ascorbic Acid), and Ascorbic Acid) Use SOUse SO22 to reduce Disulfides to to reduce Disulfides to

MercaptansMercaptans Treat with CuSOTreat with CuSO44 to remove H to remove H22S S

and Mercaptansand Mercaptans

SamplesSamples

Hydrogen SulfideHydrogen Sulfide Mercaptan / DisulfideMercaptan / Disulfide

Volatile AcidityVolatile Acidity

Defined as those acids which may Defined as those acids which may be removed from solution by be removed from solution by steam distillationsteam distillation

Generally taken to mean Acetic Generally taken to mean Acetic AcidAcid

May include Carbonic, Sulfurous, May include Carbonic, Sulfurous, Sorbic, Lactic, Formic, Butyric, Sorbic, Lactic, Formic, Butyric, and Propionic Acidsand Propionic Acids

Sources of Volatile Sources of Volatile AcidityAcidity YeastYeast Lactic Acid BacteriaLactic Acid Bacteria Acetic Acid BacteriaAcetic Acid Bacteria

Conditions that Conditions that promote VApromote VA Wines with residual sugarWines with residual sugar Wines made from Botrytis Wines made from Botrytis

infected fruitinfected fruit Wines with BrettanomycesWines with Brettanomyces Stuck FermentationsStuck Fermentations ML fermentation in the presence ML fermentation in the presence

of sugarof sugar High sugar fermentationsHigh sugar fermentations

Conditions that Conditions that promote VApromote VA High temperature fermentationsHigh temperature fermentations Wines stored with headspaceWines stored with headspace ““Cold Soaking” without SOCold Soaking” without SO22

““Cold Soaking” without gassing Cold Soaking” without gassing tanktank

And many more…And many more…

YeastYeast

Kloeckara apiculata / Hanseniaspora Kloeckara apiculata / Hanseniaspora uvarum will produce large amounts uvarum will produce large amounts of Ethyl Acetateof Ethyl Acetate

Brettanomyces will produce acetic Brettanomyces will produce acetic acidacid

Sacharomyces will produce VA in a Sacharomyces will produce VA in a normal fermentation (about 0.4 g/L)normal fermentation (about 0.4 g/L)

VA production is higher in the VA production is higher in the presence of Botrytis cineriapresence of Botrytis cineria

BacteriaBacteria

Lactic Acid Bacteria will utilize Lactic Acid Bacteria will utilize sugars during fermentation to sugars during fermentation to make VA. They can out-compete make VA. They can out-compete yeast and stop a fermentation.yeast and stop a fermentation.

Acetic Acid Bacteria can utilize Acetic Acid Bacteria can utilize sugars and oxidize ethanol to sugars and oxidize ethanol to make VA. They are more make VA. They are more common after fermentation.common after fermentation.

Prevention of VAPrevention of VA

Cleanliness and good cellar Cleanliness and good cellar techniquetechnique

Good, clean, and sound fruitGood, clean, and sound fruit Keep up with topping in barrelsKeep up with topping in barrels Overflow barrels when topping, Overflow barrels when topping,

combined with direct addition of SOcombined with direct addition of SO22

Minimize headspace in tanksMinimize headspace in tanks Keep up with monthly SOKeep up with monthly SO22 additions additions

Removal of VARemoval of VA

Mechanical separation of VA from wineMechanical separation of VA from wine– Reverse osmosis, followed by ion Reverse osmosis, followed by ion

exchangeexchange BlendingBlending Re-fermentation of contaminated wine Re-fermentation of contaminated wine

is not very effective and may spread is not very effective and may spread the contaminationthe contamination

Tannin and/or Yeast lees may reduce Tannin and/or Yeast lees may reduce perception of oxidation in wineperception of oxidation in wine

SamplesSamples

Elevated VA in wineElevated VA in wine Oxidation in wineOxidation in wine

Brettanomyces/Brettanomyces/DekkeraDekkera One of the most common spoilage One of the most common spoilage

yeastsyeasts Present in every wine regionPresent in every wine region It has never been isolated in the It has never been isolated in the

vineyardvineyard Contributes unwanted phenols in Contributes unwanted phenols in

winewine– 4-ethylguaiacol (4EG) 4-ethylguaiacol (4EG) – 4-ethylphenol (4EP)4-ethylphenol (4EP)

Brettanomyces/Brettanomyces/DekkeraDekkera It can survive on minute amounts It can survive on minute amounts

of sugarsof sugars It can metabolize cellobiose (from It can metabolize cellobiose (from

cooperage)cooperage) Thrives in wines with RS and low Thrives in wines with RS and low

SOSO22

Prevention of BrettPrevention of Brett

CleanlinessCleanliness Maintain SOMaintain SO22 and Topping and Topping Fermentation ManagementFermentation Management Control VectorsControl Vectors

– Used cooperageUsed cooperage– Purchased winePurchased wine– Pumice and winery wastePumice and winery waste

Brettanomyces NotesBrettanomyces Notes

SOSO22 levels over 25 ppm will inhibit levels over 25 ppm will inhibit enzymes which allow production enzymes which allow production of 4EP and 4EGof 4EP and 4EG

SOSO22 will degrade thiamine will degrade thiamine required for Brettanomyces required for Brettanomyces growthgrowth

Removal of Brett TaintRemoval of Brett Taint

Blending of wine is not effective Blending of wine is not effective (sensory threshold for taint is 1.6 (sensory threshold for taint is 1.6 ppb)ppb)

Mechanical removalMechanical removal– Reverse Osmosis combined with Ion Reverse Osmosis combined with Ion

ExchangeExchange

SamplesSamples

2005 Cabernet Sauvignon2005 Cabernet Sauvignon 2006 Petite Syrah2006 Petite Syrah

ReferencesReferences

Concepts in Wine TechnologyConcepts in Wine Technology, Yair , Yair Margalit, PhD., The Wine Appreciation Margalit, PhD., The Wine Appreciation Guild,Guild, 20042004

Production Wine AnalysisProduction Wine Analysis, Bruce Zoecklein, , Bruce Zoecklein, Kenneth C. Fugelsang, Barry H. Gump, & Kenneth C. Fugelsang, Barry H. Gump, & Fred S. Nury, Van Nostrand Reinhold, 1990Fred S. Nury, Van Nostrand Reinhold, 1990

Wine Analysis and Production, Wine Analysis and Production, Bruce Bruce Zoecklein, Kenneth C. Fugelsang, Barry H. Zoecklein, Kenneth C. Fugelsang, Barry H. Gump, & Fred S. Nury, Aspen Publishers, Gump, & Fred S. Nury, Aspen Publishers, 19991999

Wine MicrobiologyWine Microbiology, Kenneth C. Fugelsang, , Kenneth C. Fugelsang, Chapman and Hall, 1997Chapman and Hall, 1997