1. Premature ageing of wine aromas
Denis Dubourdieu and Valérie Lavigne,

2. When Premox phenomenon shake the web
That is the question
Premox or not Premox
When Premox phenomenon shake the web
Estimation
Sources : google, private blog and web site (R.Parker, J.Robinson)

4. Manifestations of defective aromatic ageing
in dry white wines
loss of fruity aromas
appearance of heavier aromatic nuances
reminiscent of wax polish or wax
colour with shades of yellow associated with bitterness on the aftertaste

5. Olfactometric detection
(C-P-G)

6. Comparison of aromagrams obtained from honey extracts and ones from white wine containing honey

7. Aromagrams of honey extracts and of white wine containing honey
Sensory descriptors
Retention time
Organic extract
Organic extract
(min.)
from
honey
from
wine
10.34
strawberry
13.25
overripe pineapple
14.5
hydrocarbons
15.53
herbaceous
herbaceous, forest floor
18.18
burnt meat
19.15
tobacco, cigar
19.53
cep
22.22
mushroom
22.36
vinegar
grapefruit, lemon
22.55
26.37
orange
32.43
bitter almond
bitter almond
32.53
candied fruit
38.17
peaches in syrup
44.02
apricot
47.44
rose
rose
ZO1
ZO2
50.17
honey
honey
53.5
resin
resin
54.22
mothballs
mothballs
60.2
beeswax
beeswax
62.3
vanilla
vanilla

8. Main molecules involved in the "defective" ageing of white wines.

9. Aromatic markers for defective ageing of dry white wines
Methional
Boiled potatoes
0.5 µg/L S
Methionine
(Ferreira et al., 2002)
Carbonyl compounds O2 O
Phenylacetaldehyde
Wilted roses, honey
25 µg/L
Phenylalanine
(Ferreira et al., 2002) N H 2 C 3 O
o-aminoacetophenone
Moth balls, wax polish
0.7 µg/L
Indolacetic acid
Oxidation

10. These molecules cannot alone explain
aromatic defects during ageing because certain prematurely
aged wines do not contain them.

11. Contribution of sotolon to the oxidised aroma of wine3 *
3-hydroxy-4.5-dimethyl-2(5H)-furanone
(Curry, walnuts)
vins jaunes from the Jura and Sherry (Guichard et al., 1993)
fig and rancio aromas of vins doux naturels (Cutzach, 1999)
walnut aromas of old Port (Ferreira, 2003)
aromas of defective ageing in dry white wines (Lavigne, 2002)
Perception threshold of the racemic mixture 7 µg/L

12. Organoleptic characteristics of sotolon

13. Sotolon: a chiral molecule3 O H 3 C R S
The existence of one or several asymmetrical carbons can be responsible for attributing different olfactory characteristics to each enantiomer.

14. Perception threshold of each enantiomer of sotolon
Perception thresholds (µg/L)
Descriptors R 89 W
alnuts
, rancio S
0.8
(Curry, walnuts)
Racemate 2
Model solution
The S form that gives sotolon its smell and taste characteristics. .
The (S)-sotolon is solely responsible for premature ageing of the aromas in dry white wines.

15. Distribution of various enantiomers of sotolon in dry white wines in bottle
50/50
30/70
70/30
Racemic mixutre
100 80
Excess (S)-sotolon 60 %
Excess (S)-sotolon 40 20
PL 81
PL 73
EDM 00
EDM 00
Bx 99
Bx 99
PL 87
PL 75
Graves 80
Graves 81
EDM 01
The olfactory detection threshold determined from a commercial sotolon racemic mixture is insufficient to appreciate the olfactory impact of this compound on wine.

16. How sotolon is formed in dry white wines.
aldocondensation C O O H H O O O
α-ketobutyric acid
Ethanal
Sotolon

17. What are the constituents of white wines likely to prevent the formation of these compounds?

18. in red wines: phenolic compounds,
especially anthocyanins, protect young wine
from oxidative phenomena that can detract from its aroma.
as for white wines, not much is known
about the compounds likely to play a role.
we have showed that certain sulphur peptides,
in particular glutathion, can play a role

19. Glutathion (Glu Cys Gly) Glycine Acide glutamique Cystéine COO -
H+3N CH
CH COO -
CH CO NH CH2
CO NH CH
CH2 SH
Glycine
Acide glutamique
Cystéine

20. Glutathion in must and wine

21. Glutathion, a natural component of grapes
It has been shown to be present in large quantity
in grapes: Cheynier et al, 1989; Liyanage et al., 1993
The accumulation mechanisms are not well-known.
The nitrogenous intake of vines plays en essential role.

22. The relation between the levels of available nitrogen and glutathion in white wine must
Must 1 Must 2 Must 3 Must 4 Must 5 Must 6 Must 7 Must 8
Available nitrogen
(mg/L)
Glutathion

23. Reactivity of glutathion
with oxygen: formation of disulphur
with quinones in the must: formation of GRP
Most of the glutathion in grapes
disappears when the juice is extracted.

24. Reaction of adding a thiol (R-SH) to the catechin quinoneOH O OH
Oxidation H O O H O O O O O H O H
Oxidised catechin (quinone)
Reduced catechin
R-SH
Thiol
(aroma, glutathion,etc.) O H O H H O O S O H R O H
adduct

25. Examples of glutathion content in various Sauvignon Blanc and Sémillon musts
Must 1 Must 2 Must 3 Must 4 Must 5 Must 6 Must 7 Must 8
Glutathion
(mg/L)

26. Changes in glutathion content during alcoholic fermentation

27. Changes in glutathion content in must during alcoholic fermentation
concentration of glutathion (mg/L) 2 4 6 8 10 12
must T1 T3 T6 T9
sulphiting
T20
T30

28. Relation between levels of glutathion in must and in young wine
Glutathion in must
(mg/L)
Glutathion in the corresponding wine

29. Relationship between the initial glutathion content of a model medium and the level at the end of alcoholic fermentation. 5 10 15 20 25 30
Concentration of glutathion (mg/L)
Level of glutathion in the medium before AF
Level of glutathion in the medium after AF

30. Relationship between the level of available nitrogen and the level of glutathion at the end of alcoholic fermentation.
Concentration of glutathion (mg/L) 25 20 15 T0 10
End of AF 5 48 96
190
Level of available nitrogen in the model medium
(mg/L)

31. Signs of premature ageing of aromas in white wines

32. During ageing

33. Traditional ageing on the lees
Protection of the young wine's fruity aromas
Maintaining wine in a state of oxidation-reduction
to encourage the appearance of a bouquet showing signs
of reduction: truffle, burnt and mineral nuances .
Avoids or delays manifestations of aromatic ageing

34. Influence of ageing techniques on the defective ageing of wine
Ageing with or without the lees
New or used barrels
Evolution - of the fruity aroma
- of defective ageing markers
- of glutathion

35. Concentration of 3-M (ng/L)
Changes in the level of 3-MH in a Sauvignon Blanc wine aged different ways in barrel
Concentration of 3-M (ng/L)
200
400
600
800
1000
1200
1400
1600
End of AF
November
April
Used
Barrel
Used barrel
Used
barrel
New barrel
racked
racked

36. Amount of sotolon in the wines at the end of barrel ageing
Concentration of sotolon (µg/L) 1 2 3 4 5 6 7 8 9
Detection threshold
(white wine)
Barrel
Used barrel
Barrel
New barrel
used
on the lees
without lees
new
on the lees
without lees

37. Effect of barrel ageing techniques on changes in the glutathion level of wines
concentration of glutathion (mg/L) 2 4 6 8 10 12 14 16 18
new barrel on the lees
new barrel without lees
used barrel on the lees
used barrel without the lees
Samples
End of AF
December
January
February
May

38. Glutathion, sotolon and 3-mercapto-hexanol at the end of barrel ageing
Glutathion, a natural component of grapes
makes it possible to prevent the defective ageing of white wines.
Used barrel on the lees
New barrel without the lees
Glutathion Sotolon MH
5.8
0.5
1.3
9.7
1400
420
(mg/L)
(µg/L)
(ng/L)
The same ageing conditions most conducive to preserving
the aromatic characteristics of dry white wines also
limit a decrease in the level of glutathion.

39. Interpretation of the protective role of lees
with regard to defective aromatic ageing
Release of reductive compounds
Oxygen fixation by the lees

40. Oxygen consumption (µg/L/h) of a white wine aged for 6 months entirely its lees
Wine aged on its lees
611
Filtered wine
0.01
Lees alone
542
Heat-treated lees 19
(Fornairon et al., 1999)

41. Manifestation of premature ageing once the wine is bottled

42. Identification of the random nature of premature ageing in two dry white wines (tasting in 2005 of 12 bottles of each wine) 70 60
Graves 2001 50 % 40 30 20 10
Little or no signs of age
Showing average signs of age
Looking very aged 70
1997 Pessac Léognan 60 50 40 % 30 20 10
Little or no signs of age
Showing average signs of age
Looking very aged

43. Importance of oxidative-type reactions throughout bottle ageing
Correlation between the oxygen dissolved in bottled wines and prematurely-aged aromas
Analyses of 20 samples of a Graves white wine (1997 vintage) after 7 years in bottle.
Average
6.00 R 2
0.7084
5.00
4.00
3.00
2.00
1.00
0.00 20 40 60 80
100
120
140
Dissolved oxygen (µg/l)
Importance of oxidative-type reactions throughout bottle ageing

44. Effect of dissolved oxygen content on colour2 R =
0.4
0.3
DO420 nm
0.2
0.1 10 20 30 40 50 60 70 80 90
Level of dissolved oxygen (µg/l)

45. Correlation between free SO2 and dissolved oxygen25 20 15
Free SO2 (mg/l) 2 R = 10 5 20 40 60 80
100
120
140
Level of dissolved O2 (µg/l)

46. Choice of closure… R 2 = 0.7191 Dissolved oxygen in bottle (µg/l)
0.5 1
1.5
2.5 3
3.5 20 40 60 80
100
120
140
Dissolved oxygen in bottle (µg/l)
Concentration of sotolon (µg/L)

47. Dissolved oxygen measured in white wine six months
after bottling Effect of closure…
120
100 80
Level of oxygen (µg/l) 60 40 20 1 2 4 5 3
Types of closure used

48. Changes in the level of free SO2 in bottle
Effect of closure… 30 25
Free SO2 (mg/l) 20 15 1 2 3 4 5
Types of closure used

49. To prevent the defective ageing of white wines, IT IS NECESSARY TO
have vines with sufficient vigour
limit the extraction of phenolic compounds during pressing
protect both the must and the wine from oxidation
make sure that alcoholic fermentation is completely finished
reduce the lag period for malolactic fermentation
age the wines in reductive conditions
limit the dissolution of oxygen when preparing the wine for bottling
choose a closure that is suited to the wine