DE2233812A1 - METHOD OF TARTAR STABILIZATION USING ELECTRODIALYSIS - Google Patents

Description

Holstein & Kappert E - 107

Maschinenfabrik Phönix GmbH

4000 Dortmund

Juchowstrasse 20 2233812

Process for tartar stabilization by means of electrodialysis

This invention relates to a method for stabilizing tartaric acid of wine, grape must and juice with the help of electrodialysis.

Potassium bitartrate, also known as tartar, precipitates in crystalline form in wine during or after fermentation of grape must. The vulgar name "Weinstein ^11" was already known in antiquity.

Potassium and tartaric acid are already contained in the juice of the ripe grapes. The separation of potassium bit art rat in wine is mainly caused by the formation of ethanol during fermentation, because tartar is much less soluble in ethanol than in water. The decrease of temperature during storage of the wine in the cellar and the malolactic decline '_ contribute to the deposition of tartar. The latter causes a pH increase that is in the range below pH 3 (at this pH value is the minimum solubility of the tartar), and leads to a reduction in the solubility of the tartar. Conversely, the pH value of the wine is lowered when tartar precipitates, provided that it was previously below pH 3 »5. A change in the pH value can also be the reason why tartar separates out when two wines that are each individually stable to tartar are mixed.

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Potassium bitartrate and calcium tartrate form slightly oversaturated Solutions. The excretion of these salts from the wine therefore decreases several months to complete. The elimination of tartar from the oversaturated solutions is particularly unpleasant noticeable when the wine, as the consumer base it with Consumer wines are expected and should be bottled early on. Consumers reject wines with such excretions in wine, although they are harmless to health, generally from ignorance of the processes.

In the case of sparkling wine, in which the increase in the ethanol content during the second fermentation reduces the instability (tendency to separate) of the can increase dissolved tartar again, this has the unpleasant consequence that the carbon dioxide adheres to the separated crystals can easily deliver the tartar and then suddenly become free when the bottle is opened.

The same problems as with wine and sparkling wine also occur with grape juice on. The grape juice usually contains so much tartaric acid and potassium that tartar is eliminated, albeit with Grape juice mostly over a longer period of time.

Since consumers demand wines, sparkling wines and grape juices without crystalline excretions, they are used in the cellar economy Tartar-unstable beverages chilled to accelerate the elimination of fine tartar. Generally the wine is included Chilled in an insulated cooling tank to near freezing point and stirred for several days at this temperature.

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If the costs of setting up cooling systems are avoided, the wine can also be aerated by means of the so-called tartar cold fining can be cooled. The cooling "remains an expensive measure.

Besides the content of potassium, calcium and tartaric acid are the The alcohol content and the pH value are decisive for the crystallization of tartar. In scientific work there are curves for the solution equilibria have been established ^ from which it can be seen whether the wine is tartar-stable, when it is and when not yet. If on the basis of the factors mentioned If the wine is found to be unstable, it must be refrigerated. However, it is often found during cooling that he Despite long-term cooling, no more tartar separates. This leads to the conclusion that besides those mentioned other factors affect the excretion of tartar.

It was recommended that if no tartar was deposited by cooling, the wine should be agitated by stirring or pumping or inoculate it by adding tartar crystals. Despite such measures, it happens that the wine after Bottling still leaves tartar, so it is not tartar stable.

Through research it was found. that the delay the excretion of tartar is mainly caused by polymeric and colloidal substances, and that condensed polyphenols have a particularly inhibiting effect on crystallization.

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The cooling of the wine for the purpose of tartar stabilization does not always lead to the desired success; she is insecure and expensive.

Based on the knowledge that polymeric substances delay the excretion of tartar or prevent it entirely, attempts have been made to stabilize wines by adding polymeric substances to prevent tartar from crystallizing out. In 1956 it was proposed to add polymeric esters of tartaric acid, obtainable by heating tartaric acid to 170 ^° C., in small amounts to the wine for this purpose. After adding to wines, sparkling wines and grape juices, tartar excretion is usually prevented for about 9 months.

Other substances that delay the deposition of tartar have been proposed are rubber rubble and polymeric phosphates.

Another way to get rid of tartar from To prevent crying-unstable beverages consists in; ,, remove the tartaric acid, potassium, or both from them. There is one way to change the concentration of tartaric acid therein, the tartaric acid s "Β. by adding calcium compounds, e.g. to precipitate potassium carbonate j, as in the case of the Kellerteciiiiik commonly known deacidification happens. Further one can add CaO, Ca (OHJp or calcium salts of organic acids.

The use of anion exchangers to remove tartaric acid is also known. They have been in various since 1949

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Countries, as well as CaCO ,, for general deacidification of Used to cry. But since they prefer to exchange polybasic acids, This treatment removes mainly phosphoric acid, sulfuric acid and tartaric acid from the wine.

The concentration of potassium can currently only be in practice can be reduced by cation exchangers. Through the treatment a wine with cation exchangers will have more potassium or less selectively removed from the wine. For the reduction of the potassium concentration it does not matter whether the potassium ion by a hydrogen ion or by another cation, e.g. Sodium, is exchanged. Numerous works and patents have been published on the prevention of the excretion of tartar by removing the potassium with the aid of cation exchangers registered and granted.

Overall, the extensive literature on the treatment of wines with cation exchangers shows that the excretion of Weinstein can be prevented with certainty in this way. Other improvements can also be made.

In the sparkling wine industry in particular, there is a great deal to do with it passed over, the wines intended for the production of sparkling wines by a treatment with ion exchangers tartar-stable close.

Despite the simple and safe feasibility of the procedure it has a major disadvantage insofar as the wine comes into contact with substances whose nutritional and physiological harmlessness respectively Non-toxicity has not yet been established ".

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There is also the possibility that the ion exchangers will release monomeric, oligomeric or polymeric substances into the wine are and remain in it, so that the consumer may or may not be nutritionally harmless. toxic Ingests substances. This has led the legislature to stop the use of ion exchangers for the treatment of food and to prohibit luxury foods as a matter of principle. Wine and sparkling wine producers are embarrassed as a result come and would have to go back to the old, technically and economically unsatisfactory processes described above, if not a usable, safe and economically satisfactory method of tartaric stabilization that works without ion exchangers is being developed.

The present invention was therefore based on the object of creating such a method.

According to the invention, this object was achieved in such a way that Wines, grape musts and grape juices are subjected to electrodialysis.

It is known that electrodialysis can be used to desalinate whey ("Deutsche Milchwirtschaft", Hildesheim 48/1971, Pages 2158 and 2161/2162, and 49/1971, pages 2204/2205). Electrodialysis is also already being used to desalinate seawater and brackish water.

Also in the field of the treatment of radioactively contaminated wastewater in the area of weak specific activities at one mean ion content of the wastewater ClO DH should the electrodia-

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lysis may be applicable while being radioactive for processing Wastewater with higher specific activity due to mechanical {The instability of the membranes is still too uneconomical ("Radioactive Waste ", May 1967, Volume 27 - Preparation, Storage, Disposal -, Author: S.J.B. Krawczynski, Publishing House Earl Thiemig KG, Münehen).

Other known uses of electrodialysis are recovery of catalysts that had gone into solution, processing of dilute acids, cleaning of chemical and pharmaceutical products Products and purification of certain by-products in the sugar industry.

Through this known areas of application of electrodialysis is a technically useful process for the tartar stabilization of wines and grape musts, based on the principle of electrodialysis, not given to the expert. It took extensive thought and experimentation to make electrodialysis to make suitable for the method according to the present invention.

According to the new method for tartaric stabilization according to the invention As with the treatment with ion exchangers, the concentration of potassium and tartrate ions is reduced, but without this Now the wine comes into contact with any nutritionally and physiologically imperfect substances.

The course of the procedure and the devices required for it are shown schematically in Figure 1:

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The wine or grape must or juice is passed through a dialysis chamber D directed, on both sides by one or more nutritionally harmless, for potassium and tartrations permeable semipermeable membrane 1 is limited and so separated from the surrounding rinsing liquid. Left and right of of the dialysis chamber D are anode compartment A with anode 2 and cathode compartment KA with cathode 3 arranged. The electrodes 2 and 3 are bathed in a conductive liquid. Place the digits 4 Pumps and the digits 5 represent gas separators.

If a direct current voltage of up to about 80 V is applied to the electrodes, the potassium ion migrates through the membrane to the cathode 3 and the acid ion through the membrane to the anode 2. 1 amp. Is required for the deposition of 0.406 mg of potassium. The strength of the current is therefore based on the amount of potassium to be deposited. The task of the electrolytic rinsing solution is that in The substances present in the ion form and the gases produced when the ions are discharged at the electrodes are removed. The flow the wine through the dialysis chamber and the rinsing fluid through the anode and cathode compartments can be designed continuously will. Voltage, amperage and flow rate are now regulated in such a way that the concentration of potassium and acid in the wine is lowered to such an extent that the wine can be considered tartar-stabilized. It has been found that it is useful to lower the potassium content of the wine, grape must or juice so much that it still contains about 450 mg of potassium per liter. Experience has shown that wine and juices are stable when the potassium concentration falls below this level, i.e. normal concentrations of tartar, namely 1 to 4g / l.

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It has been found that it is important to bring the rinsing liquids in the anode and cathode compartments to the same or approximately the same osmotic pressure as is present in the liquid to be treated. Wine, must and an aqueous alcohol solution are suitable for this. As a result of this measure, semipermeable membranes can be used which are cheap and easily available on the market. If the osmotic pressure in the anode and cathode compartments is not adjusted, membranes must be used which only allow the migration of anions or cations but prevent the passage of water. Experience has shown that such membranes are difficult to manufacture and are therefore expensive. If the membranes allow even traces of water to pass through as a result of the osmotic pressure gradient, an undesirable dilution of the wine or juice occurs . ■■■ ■

It has also been found that it is particularly useful to rinse the anode and / or cathode compartment with the liquid, to be subjected to electrodialysis (Fig.2).

By using different types of rinsing liquids in the anode and cathode compartments, measures can be taken which are particularly surprising:

For example, if you subject musts or wines made from grapes from southern countries with low acidity to electrodialysis and so on processes that the wines, grape musts or juices emerging from the dialysis chamber are used as rinsing liquid through the anode compartment, possibly even several times, an increase in the content of filterable total acid is achieved (Fig.3).

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If one proceeds the other way around in such a way that one enters the dialysis chamber Wines, grape musts or grape juices with a low potassium content conducts and acts as a rinsing liquid through the cathode compartment sends liquid escaping from the dialysis chamber, the content of titratable acid is reduced (Fig. 4).

The new process is also suitable for acidifying wines and musts that are low in tartaric acid, if they are used as rinsing liquid in the cathode compartment a liquid of the same osmotic pressure, e.g. wine or must ^ is used and as a rinsing liquid through the anode space wine or must with less acidity (Fig.5).

A lowering of the acidity in wine or must with a low potassium content is possible in such a way that as a rinsing liquid In the anode compartment a liquid with the same osmotic pressure, e.g. wine or must, is used and that as a rinsing liquid the lower-potassium wine is passed through the cathode compartment (Fig. 6)

In the schematic figures 1 to 6, K stands for potassium ion, HT for tartrate ion, H ₂ for hydrogen and O ₂ for oxygen. The results of using electrodialysis to stabilize tartaric acid in wines and musts are surprising and varied. One can first achieve the effect that, as with the natural deposition of tartar, the concentration of. Potassium and tartaric acid are reduced to such an extent that no more tartar is excreted. The process corresponds to the accelerated elimination of tartar, as it is achieved by the expensive and lengthy cooling process, but it is much cheaper and quicker to carry out. Against-

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above-the method for treating wines and musts with In addition to the results already described above, the new process has the particular advantage of ion exchangers, that the wines retain their natural taste. If at treatment with ion exchangers potassium versus hydrogen ions is exchanged, you get wines with such a sour taste that they are no longer palatable. When potassium against Sodium is exchanged, you get wines with an unnatural high content of sodium. The result is a wine that is completely different from its natural composition is. Wines treated with ion exchangers can be identified analytically without difficulty, especially when potassium versus sodium is exchanged. This is not the case with the wines treated with the new process, since their composition is the same corresponds to how it is present after the tartaric stabilization by cooling. But it was not to be foreseen that by electro-dialytic treatment, that is, by removal of potassium and tartaric acid ions, a tartar sta- bilisierjung-ierreich would be achieved. It is particularly surprising that the process can be made so variable that it is possible is to control the content of titratable acidity through appropriate management of the wines and musts to be treated with various potassium and acid levels through dialysis chamber and anode and cathode rinsing rooms to raise or lower.

The new process for tartar stabilization can be continuous and carried out discontinuously.

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Figure 7 shows the scheme of a device for carrying out the electrodialysis according to the method according to the invention. It Numbers 1 each represent a pressure plate, numbers 2 each a plastic plate, number 3 the anode and number 4 the cathode, the numbers 5 seals, number 6 a frame, numbers 7 semipermeable membranes, numbers 8 support inserts in the form of wavy Plastic bodies, numbers 9 pumps for the flushing liquids and numbers 10 gas separators.

As semipermeable membranes for the present process, membranes made from polymers such as polyolefins are chlorinated Polyolefins, polyamides and polysaccharides, such as cellulose acetate or cellulose ethyl ether, are used.

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Claims (8)

Claims 1. A method for tartar stabilization of wine, grape must and juice, characterized in that they are subjected to electrodialysis. ■ 2. The method according to claim 1, characterized in that the wine, grape must or juice through a MaIysierkammer (D) is directed on both sides by a nutritional harmless semipermeable membrane (l) permeable to potassium and tartarotipnene and limited so of the surrounding flushing liquids in the anode compartment (A) separated with anode (2) and im.Kathodenraum (KA) with cathode (3) is, and further characterized in that rinsing liquids with any in the anode and cathode compartment osmotic pressure can be used (Fig.l). 3 · The method according to claim 2, characterized in that im Anode and cathode compartment rinsing fluids are used that have the same or approximately the same Osraotic - Have pressure like the wine, grape must or juice to be stabilized (Fig.2). 4. The method according to claim 3, characterized in that as Rinsing liquids in the anode and cathode compartment wine, grape must or juice can be used (Fig.2). 3 0 98 * 86/0 520 5. The method according to claims 2 to 4, characterized in that . that as a rinsing liquid through the anode alysierkammer from the Di alysierkammer escaping wine or must is directed (Fig.3). 6. The method according to claims 2 to 4, characterized in that the rinsing liquid through the cathode chamber from the
Wine escaping from the dialysis chamber is directed (Fig.4). 7. The method according to claims 2 to 4, characterized in that a low-acid rinsing liquid through the anode space
Wine or must is passed (Fig.5). 8. The method according to claims 2 to 4, characterized in that a wine is used as the rinsing liquid through the cathode space
low potassium content (Fig.6). 3098-86 / QS20