Wine

The chemical analyses presented in this report are the results of 10 years of experimentation with tartrate stabilization of wines using membranes  (TSM), a system based on electrodialysis. These experimentation were conducted on many types of wines, in France and elsewhere.

treatment rate and evaluation
of the main analytic parameters

Treatment rate

The conductivity test developed by INRA (the French National Agronomic Research Institute) determines a specific reduction of conductivity for each wine to be stabilized. The treatment is done by extraction of the ions until the conductivity is reduced to the desired level. Experience, gained from many years of testing and dozens of units currently in operation worldwide, shows that the conductivity reduction required for tartaric stability  typically between 6 and 30%.  

The analyses presented in the following tables are from 10 years of experiments on tartaric stabilization of wine by electrodialysis.

Deionisation kinetic: impact on mineral content

The following table demonstrates the effect of varying the degree of reduction to the wine’s conductivity on the concentrate of other constituents.

Table 1: changes the mineral content during deionisation varying from 0% to 30%.

Evolution of the main analytic parameters

The following table demonstrates the effect of varying the degree of conductivity reduction on a wine’s general characteristics. These are the results from a test run in Languedoc Roussillon on 12000 hl of wine.

Table 2: Evolution of the analytic parameters after TSM for white wines (20% of treated wines)

Table 3: Evolution of the analytic parameters after TSM  for rosé wines ( 22% of treated wines)

Table 4: Evolution of the analytic parameters after TSM for red wines (IPT <50: 48% of treated wines)

Table 5: Evolution of the analytic parameters after TSM for red wines (IPT >50: 10% of treated wines)

These analyses show that three main characteristics: pH, volatile acidity, and alcohol percent remain within the variation limits allowed legally. These are:

• A reduction of the pH less than 0.3: it is generally limited to 0.1 and always lower than 0.15.

• A reduction of the volatile acidity way below 0.12 g/l: it is generally equal to the analytical precision.

• A reduction of the alcohol percent lower than 0.1%vol

Tables 2, 3, 4, and 5 are taken from the bibliographic reference 2

Stability for coloring substances and polyphenolic structure

Table 6 shows analyses done by INRA of Pech Rouge (for AOC Corbières Rouges).

Table 6 :Comparison of color and structure parameters

Tartrate stabilization by membrane systems does not impact the color and structure of the wine. The cooling stabilization process leads to losses of tannins and anthocyanises.

stability for aminated compounds

Tables 7, 8, and 9 present the results of  trials conducted on wines from various regions in Europe.

Table 7: Results of trials on red wines in the Bordeaux and Beaujolais regions in 1996

Table 8: Results of trials on white wines in Germany in1998

Table 9 :Results of trials on AOC Champagne wines in 1998

These results on high-quality wines from various regions, and different treatment rates, illustrate a perfect conservation of the amino acid content after stabilization by membranes.  This criteria not affected by TSM.

Preservation of sensory qualities

Each trial included, a sensory evaluation. The sensory evaluation were performed by professional organizations, with panels composed of trained tasters familiar with the regional characteristics of the treated wines.

These sensory evaluations showed no noticeable differences between the reference wines and the wines stabilized by membranes. The panel members did not observe significant differences between wine samples collected before and after membrane stabilization.

In some cases, differences may be discerned between samples of wine stabilized by the cooling method and those stabilized by membranes: electrodialysis. This suggests that preserves the polyphenol structure of wines.

CONCLUSION

Tartrate stabilization of wines by membranes is a gentle removal technique that preserves the main characteristics of the wine. The industry, including the winemakers, management, and the regulator are familiar with the small degrees of variation in the wine’s characteristics, and consider them acceptable.

Changes to important parameters such as alcohol content, pH, total acidity, and volatile acidity are generally less than those caused by the cold stabilization method.

Other parameters such as amino acids, structure, and color are preserved: the overall quality of the wine is therefore preserved.

This method is compatible with the traditional production of wines. The implementation of mobile units makes this system available even to the small wineries. It is clearly a method that meets the requirements of quality insurance and tractability for food production, while continuing its traditions.

Bibliographic references :

Moutounet M. , Escudier J.L, Saint-Pierre B., 1994, in Les acquisitions récentes dans les traitements physiques du vin, B. Donèche éd., Tec et Doc, Lavoisier, Paris

(2) Biau G., Siodlack A, Conception, réalisation et utilisation d’une unité industrielle de stabilisation tartrique, Revue française d’œnologie, 162, pp 18-20, (1997)

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For more information about the technology / references / analysis of the qualities of the treated wine

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