1. Ways to reveal and preserve them
The fruity thiols
Ways to reveal and preserve them

2. THE THIOLS : MAIN TYPES
3-mercaptohexan-1-ol (3MH): citrus fruits and passion fruit
Acetate of 3-MH (A3MH): flowers, passion fruit
4-mercapto-4-methylpentan-2-one (4MMP): boxwood, broom

3. Characteristics and types of thiols
Highly perfumed (perception threshold of
ng/L or x10 ng/L)
Sensitive to oxidation
Aroma poorly developed from precursor, by yeast during fermentation
Present in numerous varieties: colombard, sauvignon blanc, pinot noir, gamay, shiraz, grenache…

4. SensiTIVITY OF thiols TO oxygEn

5. Oxygen : all about time and quantity.
Sensory Analysis (n=6) on 3 batches of the same wine with various doses of oxygen: differences appear after 3 months
O2 minimal O2 ~2mg/l O2 ~5 mg/l
Plant, citrus fruit, sulfur fruity jam cooked fruits madeira
floral yeast évent roasting butter lactic
As said before, it is a matter of dose. It is obvious, the more oxygen, the more the effect can be disastrous. Also, it is a matter of time as shown in this experiment where differences between the dose of oxygen are detected after 3 months...
Excess of oxygen leads to the formation of new substances, sometimes pleasant and desired (ripe fruits,, honey, …) and to the missing of fruity aroma which are typical of wine. (This sketch is a simplified representation of statistics study with 3 parameters: Champagne without O2, the same with 2 mg/l d’O2 and the third with 5 mg/l.) This last value seems high, but it is frequently encountered in several wine storehouses.
reduction oxidation

6. Why is it detected too late ?
Oxygen combines quickly with wine
19°C
13°C
4°C 10 8
cContent O2 (mg/l) 6 4
« This curve is not a reference » means : in function of the quality of the wine (essential), the content of oxidisable phenols and several heavy metals… This combination can be fast or slow. In Champagne, we measured base wines with 0,1 mg/l of oxygen/day and others with more than 2. 2
Time (day) 2 4 6 8 10 12
And when measuring … nothing visible
(this curve is not a reference)

7. Oxygen : Need to take action quickly!
Phenols
Catechins
Acids
Quinones

8. Oxygen : Need to take action quickly!
QUINONES
strong Reduction weak

9. GLuTaRoM A natural solution : Inactivate yeast rich in glutathion
100% natural Origin
For a preventative and fast action

10. GLuTaRoM Natural solution:
250
270
290
310
330
350
370
390 1 2 3 4 5 6 7 8
[oxygen] (mg/L)
Without LIS enriched in glutathion
With LIS enriched in glutathion
Wine redox potential (mV)
From INRA Montpellier, UMR « Sciences pour l’œnologie »
White sauvignon wine enriched or not in glutathion during alcoholic fermentation and ageing on lees.
Volatile Thiols : impact of inactivated yeast enriched in glutathion
3 MH (ng/L)
3 MHA (ng/L)
Without LIS enriched in GSH
With LIS enriched in GSH
From INRA Montpellier, UMR « Sciences pour l’œnologie »
200
300
400
500
600
700
800
1000
900
100
These results are confirmed on shiraz rosés and grenache

11. How to use
GLuTaRoM
Preventative Action : addition of GLUTAROM in must (yeast culture… or earlier)
End of Alcoholic Fermentation (AF) : step where wine is most vulnerable to oxygen  addition of GLUTAROM possible and strongly recommended if AF failing
Really efficient on white, and rosés, especially for sensitive fruit (poor initial content of glutathion)

12. Conversion of thiol PRECURSORS TO FRUITY aromA

13. Conversion of thiol precursors : the part of yeast
Strong concentration of precursors in several varieties…
… but poorly transform in aroma ! (often less than 1%)
A moderate change in the conversion output can have important consequences in terms of concentrations in the wine
Select the yeast with good output of conversion of precursors to thiols with fruity aromas

14. A new selection of yeast: IOC Revelation Thiols
Results of different tests with IOC Revelation Thiols compared to classical yeasts used to obtain thiols
Over expression of 3MH
Under expression of 4MMP

15. A new selection of yeast: IOC Revelation Thiols
Comparative tests done on colombard vine – wine tested 3 months after alcoholic fermentation by a jury of 24 customers who are not involved in wine business.
Citrus fruits
Nose aromatic intensity
Pleasant
aroma
Complexity
Pleasant
taste
Exotic fruits
Mouth
Aroma
intensity

16. Conversion of thiol precursors : part of nutrition
Subileau & Salmon, FEMS Yeast Res 8 (2008)
Sauvignon blanc Languedoc 2004
Sauvignon blanc Gers 2006
Too much ammonium added at the beginning of the fermentation can limit the entrance of the precursor into the yeast and then limit the thiols conversion. Use of NUTRIBIO® at start of fermentation is recommended to avoid deficiency.

17. Conversion of thiol precursors : Fermentation Temperature
Levels of 4MMP, 3MH and A3MH are higher when fermentation is conducted at 20°C rather than 13°C. (Masneuf-Pomarède, 2006)
SWIEGERS and col. (2006) notice that 18°C should be better than 23°C to promote higher concentration in A3MH.

18. Conversion of thiols precursors : AF temperature
Ltemp.
Htemp.
3MH: no discrepancies between 14°C and 18°C except in case 1
Ltemp.
Htemp.
Grnache/Shyraz
Grnache/Shyraz
Htemp.
A3MH: all cases
Grnache/Shyraz
Grnache/Shyraz

19. Conversion of thiol precurseurs : role of clarification
Experiments show a turbidity of 180 NTU is favorable to synthesise thiols.
To touch up: origin of yeast, use of yeast protector, etc…
Low temperature and low turbidity promote the production of acetate esters : equilibrium and synergy between aromas

20. The fruity thiols: to reinforce
The protection of musts against oxidation is a determining factor
Efficiency of GLUTAROM
New yeast to enhance the fruity fraction of thiols :
IOC Revelation Thiols encourage the use of organic nitrogen rather than ammoniacal nitrogen
 Manage deficiencies with NUTRIBIO
AF temperature and turbidity : manage in conjunction with fermentation to get the aroma ratio you want

21. Process of optimal revelation of fruity thiols
OBJECTIVES:
Protection against oxidation
enhances the main expression of thiols
Protection against oxidation (action on phenols, acids + quinones oxidatives)
Promote conversion of fruity thiol precursors
Avoid masking thiols by amylic notes
Avoid the catabolic repression of thiol synthesis by ammoniacal nitrogen
Inert Pressing
Clarification (optimum : NTU)
Addition of GLUTAROM (20 g/hL) on cleared must + K-antiox (50 g/hL)
Inoculation of IOC REVELATION THIOLS (20 g/hL) rehydration with BIOPROTECT (20 g/hL)
AF: T°=16-18°C
Nitrogen deficiency medium to high (<140 mg/L assimilable nitrogen)
- NUTRIBIO (20 g/hL) at initial density (Di) minus 5 points,
NUTRIBIO (20 g/hL) at Di –30 points (if major deficiency can link this addition with DAP).
If low deficiency:
- NUTRIBIO (20 g/hL) at Di –30 points only.