1

Cellulose gum (carboxymethyl cellulose or CMC) was authorised by the European community in 2009 as an alternative to traditional electrodialysis or cold treatments for tartaric stabilisation in wine.

This derivative of cellulose is extracted exclusively from sustainable woods grown specifically for wine making purposes to avoid possible GMO contamination has been used for several decades in a large number of food applications (E468). It has the advantage of being organoleptically neutral, is highly effective for wine stabilisation with regard to potassium bitartrate. Its action is recognised to be effective for at least 4 years.

Institut Œnologique de Champagne www.institut-oenologique.com ZI de Mardeuil- BP25- 51201 Epernay Tél 03 26 51 96 00 – Fax 0326510220 1

The ISSUE of TARTARIC STABILITY

The need for quality is increasingly present. While consumers consider the presence of crystals in mature red wines as a guarantee of quality, the same does not apply to white wines... The presence of colourless crystals is unacceptable to the consumer. The problem is all the more serious when it comes to traditional methods, where the crystals can be a source of ‘gerbage’ (gushing). As an example in Champagne, over 90% of Champagne manufacturers stabilise their wine in respect to tartaric salts.

Natural tartaric acid found in wine (TH 2) has the capacity to combine with potassium (K) in grapes. The corresponding salt - (THK) is soluble in grape juice, but to a lesser extent in the TH 2 TH (THK) s THK presence of alcohol, after fermentation. Naturally, the THK will deposit. If it is not stirred while the wine is still in the tank, THK crystals will deposit in the bottles.

Tartaric stabilisation has been developed for over 40 years now. It has the advantage of being a subtractive technique (the problem (supersaturation in tartaric salts) is removed), easily manageable and requiring little technicality. However, it is widely recognised as a costly technique and any alternative to reduce the cost would be welcomed. Consequently, different researchers have shown that cellulose gum proves to be an excellent alternative; far superior to metatartaric acid, which hydrolyses over time.

Ex ample of calcium tartrate crystals seen using scanning electron microscopy. This type of crystal can be found in numerous bottles of mature white wines or in certain regions that are particularly sensitive to the crystallisation of this salt.

OPERATING MECHANISM of CELLULOSE GUM

?

Cellulose gum inhibits crystallisation. Its intimate action mechanism is still the subject of hypothesis. It is thought that as soon as the crystals are created, CMC deposits on certain surfaces and the potassium or bitartrate ions can no longer increase the size of the crystals.

2

SOME EXAMPLES of CMC EFFECTIVENESS

Using a mini -contact test, the product’s effectiveness can be estimated in just a few Relative Minicontact minutes. The principle is to measure the 15 wine’s difference in conductivity before and very st able after inoculation by potassium bitartrate. 0 Control Here, the example is a particularly unstable -15 +50 mg / L -30 C M C rosé wine (shown clearly by the drop in the +10 0 mg / L st ab le Control curve). Neither 50mg/L nor -45 100mg/L can render this wine stable in -60 warning regard to THK. -75 not st able -90 In very specific cases such as this, it is -105 sometimes recommended to partially -120 stabilise (using cold or electrodialysis -135 treatment) before finalising stabilisation 0 180 360 540 720 900 1080 1260 1440 1620 1800 using cellulose gum. sec

Relative Minicontact Here, the exampl e is a Languedoc white 15 Contr ol wine that has not been stabilised by cold 3,5 very st able

+50mg/ L CM C treatment. Its saturation temperature is -8 20°C. Consequently there is a high risk of -19,5 +1 00 mg/ L st ab le crystallisation. The addition of 50mg/L of -31 CMC (the pink curve) considerably reduces -42,5 war ning this instability. At 100mg/L, this instability -54 is further reduced; the wine is considered to -65,5 not stable be stable. -77 -88,5 A complementary cold test (-4°C for 1 week) -100 will show that the risk of crystallisation 0 180 360 540 720 900 1080 1260 1440 1620 1800 within the bottle is extremely low. sec

A NEW ALTERNATIVE for TARTARIC STABILISATION in WINES

Different methods for stabilising wines in relation to potassium bitartrate (THK) exist throughout the world. The 4 most common and the benefits of replacing them by CMC are listed below:

Subtractive methods

► Cold stabilisation : This offers the advantage of being highly effective (despite the existence of problems concerning rosé wines for example) but is also energy intensive. For either continuous or intermittent techniques, its cost is estimated at between 10 and 20 times higher than that of cellulose gum for identical effectiveness. INOSTAB is a genuine economic alternative to cold stabilisation.

► Electrodialysis : this technique is more recent than cold techniques and is known for its effectiveness and precision. This technology does however require a certain degree of technicality and is costly, both in terms of investment and operation. INOSTAB requires no particular technicality.

3

Additive methods

► Mannoproteins : Adding mannoproteins to an unstable wine helps reduce instability, but it is clear that the price of such a treatment is at least 20 times more expensive than that of adding cellulose gum, not forgetting that the risk of failure is quite common. INOSTAB is highly effective for tartaric stabilisation.

► Metatartaric acid: This additive demonstrates a genuine action, but only on a short term basis. It is known that metatartaric acid is hydrolysed within 1 month at wine pH and at room temperature. CIVC studies have shown that CMC remains active for at least 4 years. INOSTAB is a stable product over time.

USING CELLULOSE GUM

INOSTAB comes in 2 forms: granular form (INOSTAB G) which rapidly dissolves the CMC and liquid form (INOSTAB MES) which is a 50g/L preparation of INOSTAB G.

IMPLEMENTING CELLULOSE GUM

When using I NO STAB in powder form, it should be dissolved in hot water (around (50°C), mix ed vigorously and the powder carefully incorporated while stirring. It is always preferable to prepare the CMC the day before it is to be used to make sure all residual lumps have been completely dissolved and to allow the bubbles to surface. On the day it is used, and to avoid any heterogeneity in the treatment, the volume of cellulose gum is firstly diluted by 1/3 or 1/4 by the wine to be treated (perfect homogeneity is essential) then the mixture is added to the final volume by way of a fining link or all in one go into the total volume by way of a complete pump over that corresponds to the volume of the tank to be treated.

FAQs

How to check that the INOSTAB dosage is correct?

Preliminary tests are required before finalising the dosage. The laboratory dedicated to these tests receives the wine in the state that is as close as possible to that of the wine at the moment of treatment (for example, in the case of CMC addition during racking using the traditional method, alcohol qsp is added to bring the wine up to 13% vol.). At least 2 concentrations of CMC are tested, using 2 methods:

► Cold treatment: the appearance of crystals is observed following storage at -4,5°C for 6 days. This procedure is lengthy but is similar to what can occur in real conditions.

► Minicontact treatment: this technique permits the wine’s state of instability to be assessed. CMC effectiveness can be quantified by comparing it to the untreated control. It does not imitate what occurs in real conditions but experiments between this technique and cold treatment show a strong correlation between the two methods.

4

Can I filter my wine after adding CMC?

Where possible, lNOSTAB should be introduced after filtration as, depending on the case, a significant amount of CMC can be retained on the filter. In fact it is strongly recommended not to use tangential filtration as this clogs up rapidly. As an example, the diagrams below show that waiting a few days at tank temperature is sufficient to eliminate this problem, whatever the concentration of CMC used (CMC1: 50mg/L and CMC2: 100mg/L)

Can INOSTAB be used on any wine colour?

It is recommended to use cellulose gum particularly on white or rosé wines. On red wines, there is the risk of losing colloidal matter and specific tests must be implemented to avoid any problems after bottling. It can be said that the more polyphenols there are in the wine, the greater the risk of haze formation.

… and on whites… ?

If certain precautions are taken the success rate is 100%. There are recommendations to follow: CMC can react with the proteins by forming colloidal instability. Hence it is always recommended to carry out a heat test to ensure there are no subsequent problems. Likewise, it is advisable to carry out a cold test to ensure that no haze is visible at consumption temperature.

Is CMC active on calcium tartrate?

As with all additive techniques, CMC is active up to a certain point on this tartaric acid salt. In comparison with potassium bitartrate, it is less active but its activity is not nil. It is important to understand that if the wine is unstable with regard to the 2 tartaric salts THK and TCa, and if there is extremely high instability with regard to THK, the CMC introduced into the wine will be mobilised to counteract the formation of these crystals and will thus be less available to inhibit TCa crystallisation.

Bibliography: Utilisation de CMC pour la stabilisation tartrique de vins blancs. Partie 1/2 : La CMC en œnologie – Détermination expérimentale de la température de stabilité d’un vin. R. Marchal, M. Laigre, P. Jeandet, B. Robillard, V. Legras. Rev. des Œnologues, N°133, 2009. Utilisation de CMC pour la stabilisation tartrique de vins blancs. Partie 2/2 : Résultats expérimentaux. R. Marchal, M. Laigre, P. Jeandet, B. Robllard, V. Legras. Rev. des Œnologues, N°133, 2009. Cellulose gum: a new alternative for wine tartaric stability: Tentative of structures determination involved in the haze formation after CMC addition in wine. C. Bliard, P-Y. Bournérias, M. Luigi, B. Robillard. Technical Wine Symposium , Adelaïde, août 2010. Courte mise au point sur les gommes de cellulose (CMC) après une année d’utilisation. C. Bliard, R. Marchal, B. Robillard, Rev. des Œnologues, n°139, avril 2011.

5

OBTAINING CELLULOSE GUM

Harvesting forests in a sustainable manner .

Isol ation of the purified cellulose

1/ alk alinisation, 2/ addition of monochloroacetic acid, 3/ neutralisation, 4/ purification, 5/ drying … granulation

DP is the molecule’s degree of polymerisation . This parameter, which expresses the molecule’s size, has an influence on the product’s viscosity and effectiveness. DS is the degree of substitution and concerns the number of carboxylate groups (in red) present on the molecule. DS has a direct influence on the molecule’s charge and acts on other parameters including interactions between the cellulose gum and proteins.

These 2 parameters, DP and DS condition the Cellulose gum majority of CMC’s properties.

6