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

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

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…

SensiTIVITY OF thiols TO oxygEn

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

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)

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

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

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

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

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)

Conversion of thiol PRECURSORS TO FRUITY aromA

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

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

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

Conversion of thiol precursors : part of nutrition Subileau & Salmon, FEMS Yeast Res 8 (2008) 771-780 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.

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.

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

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

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

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 : 80-180 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.