Cork Industry Perspective

An Industry Perspective for Natural Cork WineFlavor 101 - Dec. 6, 2012

Prepared by the Cork Quality Council www.corkqc.com

CorkIndustryPerspective

CorkIndustryPerspective

Peter WeberCork Quality Council



Unintended Consequences

• Unforeseen variables increase with the length of time the control package has been used

• Magnitude increases with length of evaluation

Mag

nitu

de →

Number of Variables→

Calculating Unintended Consequences



Unintended ConsequencesElapsed Time - As Related to Closures

• Cork, as a sealing material, extends beyond ancient Greece.• It has been used in its current form with wine for over 300 years.• It has been the default closure component in the development of

traditional wine making practices.

Dom Perignon Agoston Haraszathy



Unintended ConsequencesVariables Evaluated - As Related to Closures

1. Off Aromas - TCA

2. Oxygen Permeability

3. Flavor Effects

4. Efficiency and Cost

5. Consumer Perceptions



Sources of TCA in Natural Corks

• Bioconversion of 2,4,6 Trichlorophenol (TCP) • Primarily by fungi

• Bioconversion through the production cycle has been virtually eliminated.

• Studies of forest samples show TCA present at levels between 1% and 3%

• Wood Near the Ground• Yellow Stain (Armillaria Mellea)

• Harvesting Protocols require the avoidance of wood with these characteristics

1 - Cork Closures and Off Aromas



TCA Reductions in Corks ReceivedCQC Members’ TCA Screening Results show an 82% Reduction in TCA over the Last Ten Years.

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

Q3-02 Q3-03 Q3-04 Q3-05 Q3-06 Q3-07 Q3-08 Q3-09 Q3-10 Q3-11 Q3-12

Aver

age

TCA

(ppt

)

Sample Period

CQC Incoming TCA Analysis Average TCA(ppt) from Group Soaks of Natural Corks

TCA Reduction = 82%

• Currently test 30K Samples/year

• Graph includes over 200,000 data points.

• Last Quarter 90% of Samples were less than our MDL of 1ppt.

• Statistics record less than 1ppt as 0.5ppt.




Cork Closures and Off Aromas

Screening for TCA with Group Cork Soaks

AVF/ETS Independent Study Demonstrates Effectiveness

Test# 1 2 3 4 5 6 7 8 9 10 AvgBale A <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 0.5Bale B 1.1 <1 <1 <1 <1 2.8 <1 <1 <1 <1 0.8Bale C <1 <1 4.2 <1 <1 <1 <1 <1 <1 2.0 1.0Bale D 1.4 1.3 1.8 1.7 1.9 1.2 5.2 1.3 2.1 1.7 2.0Bale E 1.9 2.0 2.4 2.8 2.9 2.0 2.2 2.7 2.8 4.1 2.6

Compare to what happened in 60 bottles after 20 months in wines bottled with corks from each of these bales

Replicates of 50-Cork Soak SPME Scores

1-2 ng/L 2-4 ng/L 4-8 ng/L > 8 ng/L % >2pptBottles from Bale A 0 0 0 0 0.0%Bottles from Bale B 0 0 0 0 0.0%Bottles from Bale C 1 0 0 0 0.0%Bottles from Bale D 3 0 1 0 1.7%Bottles from Bale E 3 2 1 0 5.0%



Cork Closures and Off Aromas

Screening for TCA with Group Cork Soaks

Same Results Evaluated by CQC Screening

Compare to what happened in 60 bottles after 20 months in wines bottled with corks from each of these bales

Replicates of 50-Cork Soak SPME Scores

Test# 1 2 3 4 5 6 7 8 9 10 AvgBale A <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 0.5 0 PassBale B 1.1 <1 <1 <1 <1 2.8 <1 <1 <1 <1 0.8 1 PassBale C <1 <1 4.2 <1 <1 <1 <1 <1 <1 2.0 1.0 2 ReTestBale D 1.4 1.3 1.8 1.7 1.9 1.2 5.2 1.3 2.1 1.7 2.0 6 FailBale E 1.9 2.0 2.4 2.8 2.9 2.0 2.2 2.7 2.8 4.1 2.6 10 Fail

CQC Flags

1-2 ng/L 2-4 ng/L 4-8 ng/L > 8 ng/L % >2pptBottles from Bale A 0 0 0 0 0.0%Bottles from Bale B 0 0 0 0 0.0%Bottles from Bale C 1 0 0 0 0.0%Bottles from Bale D 3 0 1 0 1.7%Bottles from Bale E 3 2 1 0 5.0%



So What is the Rate of TCA in Natural Corks?

Current CQC screening statistics • 94% below the minimum reporting level of 1ppt. • 5% are between 1-2%• 3% are rejected

Interpolating the AVF study of bottled wine at 20 months• translates to well under 1% taint

Observations - Christian Butzke • “TCA No Longer a Major Problem for the U.S. Wine

Industry” (Christian Butzke – 2011 - less than 1%)• Higher estimates often have broader definitions




Methods Used to Measure Oxygen Ingress

• Mocon • Optical Density at 420 nm• Free SO2 / Total SO2

• Fluorescence Quenching• Colormetric

Indigo Carmine +Sodium Dithionite

Reduced…………..……………………….Oxidized

2 - Oxygen Permeability




Colormetric Method (Bordeaux 2006)

Screwcap Natural Cork SyntheticsReduced Oxidized




Variation between Corks

• Air volume in 44mm cork estimated at 3.4 to 3.6 mL• Compression during bottling is estimated to create

internal air pressure of 6-9 atm. • Sets up an environment for diffusion from high

pressure air in cork cells connected by Plasmodema (60 nm)

• Pressure is subject to variation in cork structure and bottling action

• Variances seen to expand over the first six months with gradual flattening after 12 months

• Indicates moderate ingress by diffusion, and does not show the steady ingress seen with permeability

Diffusion of Oxygen Due to Bottling ?




Routes of Oxygen Ingress – for Two Closures

Lopes, P.; Saucier, C.; Teissedre, P.L., Glories, Y. Main routes of oxygen ingress through different closures into wine bottles. J. Agric. Food Chem. 2007,55, 5167-5170.

In this 24 month study - closures were tested with two levels of impermeable coverage…

1. Results for cork were similar under all scenarios indicating oxygen originating inside the cork with slight diffusion

2. Results are consistent with estimates of air displaced by cork compression during bottling

3. The uncovered Synthetic appeared to be permeable through the center of the closure body

Natural Cork Extruded Synthetic




Wine is a Four Dimensional ProductIn a survey of 100 wineries we asked respondents to estimate the average bottle age of their wine production before consumption• 17% >24 Months• 23% 12 -24 Months• 36% 3-12 Months• 24% 0-3 Months

0%

20%

40%

60%

80%

100%

1 3 6 9 12 18 24 36Estimated Months in Bottle Until Purchase

Estimated Bottle Ageby Winery Survey

17% + 24 Mos

23% 12-24 Mos.

36% 3-12 Mos.

24% 0-3 Mos.




Summary of Findings• Tested Synthetics showed steady permeability• Natural Corks showed initial diffusion slowing at six

months and flattening after twelve months• Variation of OTR for Natural Corks range between

that seen for tested Synthetics and Screwcaps• Technical Corks had similar OTR performance to

that seen with Screwcaps• Screwcap with saran tin had the lowest level of

oxygen ingress• Both Synthetics and Screwcaps have developed

alternatives to improve performance.



3 - Flavor Effects

Comparisons need better consistency• Studies favoring cork include parameters of

“developed”, “buttery”, “balanced”, and “complex”• Studies favoring alternatives include parameters of

“fruit”, “fresh”, “lively”• Better integration with traditional evaluations

Attribute PtsAppearance 3Aroma/Bouquet 6Taste/Texture 6Aftertaste 3Overall Impression 2

20

American Wine SocietyAttribute PtsOxidised 1Glue-Like 1TCA 1Reduced 1Citrus 1Lime 1Pineapple 1Overall Fruit 1

AWRI Closure Study



3 - Flavor Effects

Reduction - Dimethyl SulfideIn a market study of Sauvignon Blancs, cork closures had significantly lower DMS levels than wines finished with screwcaps – by a ratio of 2.2 to 1



3 - Flavor Effects

Continued Flavor Research• DMS Example – mixed reviews at different

concentrations• REDOX properties effect more flavor components

than can be listed here• This is a great opportunity to study wine chemistry• But these flavor components are interconnected

and express themselves in a living wine over time• Can we control compounds that were developed in

the vineyard and fermentation tanks with targeted post bottling Oxygen permeation ?



4 - Efficiency and Cost

Opportunities and Challenges

• Higher Consistency = Less Adaptability• Glass Tolerances

• +/- 2.5mm for corks• Less for synthetics• +/- 0.25mm for threads

• Cost Difference• Alternatives and Technical Corks are

significantly less costly



4 - Efficiency and Cost

Technical Corks

1+1 Corks•Agglomerate very low in TCA•Disk Quality controls TCA transfer•Excellent Physical Consistency•Low Oxygen Ingress

Micro Agglo•Very low levels of TCA •Excellent Physical Consistency•Low Oxygen Ingress•Low Cost

Limited Suppliers



5 - Consumer Perceptions

Quality Considerations for the Consumer

11%

31%

93%

50%

16%

0%

0% 50% 100%

ScrewCaps

Synthetics

Natural Cork

Very High/High Moderate Somewhat Low/Very Low

Perception of Quality by Closure Type

• US Consumers have traditionally viewed cork closures to be associated with quality

• 2011 Updated Survey shows 93% of consumers perceiving High or Very High Quality



5 - Consumer Perceptions

Sustainable Attributes are a Consumer Plus

• Promoted by International Environmental Groups

• Supported by regional recycling programs

• Viewed a a model for sustainable industries

• Appeals to the natural attributes of the grape and vineyard



Thank You

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Cork Industry Perspective