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Synthetic closures: practical solutions. Maurizio Ugliano November 2012. Wine bottle aging. Sensory quality. Time in bottle. Wine improves with a period of aging in bottle. Clearly accepted for very high end wines Still true for most red wines but consumption is very rapid nowadays

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Synthetic closures practical solutions

Synthetic closures: practical solutions

Maurizio Ugliano

November 2012


Wine bottle aging
Wine bottle aging

Sensory quality

Time in bottle

Wine improves with a period of aging in bottle

  • Clearly accepted for very high end wines

  • Still true for most red wines but consumption is very rapid nowadays

  • Observed often for white wines too, but gerenally less prone to long aging


Wine styles and market trends
Wine styles and market trends

Less oxygen

More oxygen


Synthetic closures practical solutions

What is actually happening?

O2

Roasted, smoky

Complex black fruits, dry fruit, chocolate, tobacco,

Simple fruity aromas

Ageing time

Bottling

Aging with low O2

Aging with high O2

Wine style

2

Wine faults


Synthetic closures practical solutions

Reduction and wine fruitiness: importance of sulfur compounds

Reduction

  • ‘Good’ sulfur compounds

  • 3-mercapto

  • hexanol

  • 3-mercaptohexyl acetate

Fruity aromas

Dry fruit, dry flowers, honey

Sauvignon blanc, Verdejo, Manseng, Verdicchio, some Rieslings…

Little oxygen will preserve the ‘good’ sulfur compounds....

  • ‘Bad’ sulfur compounds (Reduction)

  • Hydrogen sulfide

  • Methyl mercaptan

… but too little oxygen could bring in the ‘bad’ sulfur compounds!!


Synthetic closures practical solutions

Good guys and bad guys: 3MH and H compounds2S/MeSH in Sauvignon blanc

Outliers

Wines bottled with high levels of glutathione and kept under no oxygen

H2S+MeSH (mg/L)

3MH (ng/L)

  • A correlation exists

  • Some wines have a tendency to over-produce H2S and MeSH. In this case this was linked to the presence of a strong quinone scavenger such as glutathione. Lack of oxygen in the bottle will exacerbate this tendency


Synthetic closures practical solutions

Winemaking compounds and closureslection

Partnership with AWRI

5

Reductive winemaking

(inerted press, aging on lees, addition of glutathione)

Non reductive winemaking

4

3MH (ng/L)

3

mg/L

3MH (ng/L)

2

This wine can lose varietal aromas rapidly…

This wine retains high varietal fruity aromas, but….

5

1

800

800

4

0

H2S

600

600

H2S

3

Methyl mercaptan

Methyl mercaptan

mg/L

400

400

2

200

200

… it also has a tendency to develop reduction

…. but is less likely to develop reduction

1

More O2 to prevent reduction (Select 300)

Less O2 to avoid loss of varietal aromas (Select 100)

0

0

0


Synthetic closures practical solutions

Bad guys: Formation of methyl mercaptan (MeSH) in bottle compounds

Closure with low oxygen ingress (e.g. screw cap)

MeSH (mg/L)

Closure with medium oxygen ingress (e.g. synthetic or natural)

Profiles of oxygen evolution in the bottle

  • Oxygen in the bottle stays at very low levels regardless of closure permeability

  • But we can see the outcomes of different levels of closure oxygen permeability


Synthetic closures practical solutions

Origins of MeSH and link with oxygen exposure compounds

DMDS unlikely to be involved: its concentration does not change with oxygen exposure

Higher MeSH with lower oxygen exposure

mg/L

Days

mg/L

Which precursors

?

Lower MeSH with higher oxygen exposure

Days

Lower MeSH due to reaction with quinones

Mercaptan trapping

Catecol

Quinone


Reduction
Reduction compounds

Intensity

6

18

12

months

  • If a wine has a ‘reductive tendency’ , it will show typically between 6 and 18 months

  • Before 6 months it is not evident, but wine can be ‘closed’ with little aroma expression and aggressive palate

  • After 18 months it disappears in some wines, while some others keep unplesant aromas


Managing wine complexity
Managing wine complexity compounds

Less oxygen

More oxygen

Methyl 2-methyl-3-furyldisulfide

Benzyl mercaptan

ng/L

GC-O MF (%)

Aldehydes

MND

Closure O2 permeability

Shiraz

Carmenere


Oxidative aroma compounds methional in carmenere wines
Oxidative aroma compounds: Methional in Carmenere wines compounds

  • Background

  • Storage at higher temperature increases the risk of oxidative damage

  • Methional has been identified as one key off-odor compounds in oxidized wines

Partnership with PUC

7

6

5

Natural cork 15°C

Select 300 15°C

4

ppb

Select 500 15°C

3

Natural cork 30°C

2

Select 300 30°C

Select 500 30°C

1

0

Methional concentration after 6 months

  • Conclusion

  • At low temperature methional concentration not different across closure types

  • At high temperature closure has an influence, and thighter closure allows lowering methional levels


Premature oxydation in red wines influence of closure o 2 permeabilty
Premature oxydation in red wines compoundsInfluence of closure O2 permeabilty

Partnership with AWRI and University of Zaragoza

  • Background

  • Premature oxidation in red wine is becoming a cause of concern in some winemaking regions (e.g. Bordeaux), with high intensity of dry plum off-odor

  • MDN (3-methyl-2,4-nonanedione) is responsible for these dry plums off-odors

5

4

3

Intensity of ‘developed’ character

Aroma impact of MDN (GC-O)

2

1

0

1

1,8

3,6

O2 consumed after 18 months in bottle for a Shiraz wine in mg/L

  • Conclusion

  • Choice of right permeability allows controlling the risk of premature oxidation due to MDN (lower MDN at lower oxygen consumption)


How much oxygen a matter of style two sauvignon blanc cases
How much oxygen? A matter of style compoundsTwo Sauvignon blanc cases

0.6 mg/L of oxygen in 6 months

1.5 mg/L of oxygen in 6 months

Yeasty/Cheesy

Bitter

Struck flint

0.6 mg/L oxygen consumed in 12 months

Fresh green

Yellow

Overall fresh fruit

Honey

O/all fruit fl.

Bruised apple

Tropical

1.2 mg/L oxygen consumed in 12 months

2008 Sauvignon bl.

Trained panel at AWRI

2011 Sauvignon blanc. Preference rating

Wine journalists at 2012 EWBC

  • Relatively small differences in oxygen consumption seem to make a big difference in Sauvignon blanc

  • But not always the one receiving less oxygen is the preferred one


Synthetic closures practical solutions

How compoundsmuchoxygen? A matter of styleChianti Classico Riserva

2.9 mg/L of oxygen in 18 months

3.8 mg/L of oxygen in 18 months

In this case we have a rather clear preference for higher oxygen permeability

Preference rating

Wine journalists at 2012 EWBC


A series of closures with defined and consistent oxygen ingress
A series of closures with defined and consistent oxygen ingress

Defined values of oxygen ingress

Batch-to batch and cork-to-cork consistency

mg of O2