Patent Application
20090104308
This description refers to an apparatus and methods for testing and controlling the concentration of substances in wine such as solute gases, alcohol and acetic acid. In particular, the proposed methods and the proposed apparatus make it possible that the concentration of volatile substances of the wine, such as alcohol and acetic acid, can be reduced and the concentration of solute gases can be increased or degraded.
In wine production, the gas CO2 in particular is widely used for preservation of wine quality.
For example, CO2 is used for prevention of an oxidation of wine. Tanks are pressurized with CO2 in order to minimise contact of wine with oxygen (O2). This is especially relevant for white wine after an alcoholic fermentation in order to improve the storage and ripening characteristics.
Furthermore, CO2 is used for removing residuals from filter devices and apparatuses. It is also utilised for artificial carbonation (so-called “Imprägnierverfahren”) for a production of (semi-) sparkling wine. For an application with high quality semi-sparkling wine made from selected grapes (a so called “Qualitätsperlwein b. A.”) it is only allowable to use endogenous CO2 which furthermore must be obtained from a process of alcoholic fermentation.
CO2 is further used in order to remove disconcerting or unbalanced notes or aromas in wine. The wine is flushed at intervals by using CO2 which is dispensed by sintered means of a frit. Components which cause the unbalanced notes or aromas will be attached to small CO2 bubbles and will be removed together with the bubbles from the wine.
CO2 is also used for a pre-evacuation of wine bottles in order to reduce oxidation of wine which occurs during the process of bottling wine, particularly white wine. However, popular apparatuses for bottling use a sub-pressure bottling method which causes the wine to come in contact with atmospheric oxygen of the surrounding air. The bottling of white wine, avoiding the contact between wine and atmospheric oxygen is a further attempt to optimise the quality of the wine.
Furthermore, during the procedure of corking wine bottles, the empty spaces within the bottles can be provided with CO2 in order to reduce the pressure inside of the bottles.
As described above, CO2 is widely used in the field of wine production. However, the concentration of CO2 in wine significantly influences its taste. The relevance of the fact as to whether the CO2 concentration of the wine exists naturally or CO2 is applied during processing the wine is not of importance. Influencing the taste depends on the structure of the wine as well as on the concentration of acid in the wine. This effect is achieved in different ways depending on the kind of wine. For illustration,
Generally, advantageous CO2 concentrations of white wines are arranged within a range of 0.6 to 0.8 g/l. By way of exception, a concentration up to 1.0 g/l can also provide a lively and fresh sensory perception. However, the sensory perception itself is influenced by e.g. regional influences of consumers which effect the respective sensory perceptions. Consumer research concludes that, sensory perceptions and respective assessments are dependent on the consumer market. Research of the German market indicates that the respective consumers prefer a fresh and lively sensory perception. In contrast thereto, the consumers in England have a pronounced sensibility for CO2 within white wine which results in their assessment of the wine being negative.
In contrast to white wine, the CO2 concentration of red whine should be lower than 0.5 g/l to provide a full-bodied and soft sensory perception. The natural CO2 concentrations in red wines vary significantly depending on the way of production and consequent treatment.
Red wine which is produced using the classical process of mash fermentation (the so called “Maischegärung”) is generally provided with low natural CO2 concentrations, as the paring of the berries and pulp parts widely extract CO2 during fermentation. If the wine is further stored within oak-wooden barrels, the CO2 concentrations are further reduced.
If the red wine is produced using a thermal process of heating the wine for a short period, the obtained red must (so-called “roter Most”) will be fermented and stored within stainless steel tanks.
Many different kinds of red wines provide increased CO2 concentrations in the range of 0.6 to 0.8 g/l at the time of bottling. This can be a problem for two reasons: Firstly the CO2 becomes visible while opening the bottle and filling a glass. This causes the appearance of bubbles which build foam. Secondly, the sensory perception tends towards the attributes fresh and tart which are not intended for red wines.
Under normal pressure about 1.8 g CO2 can be solubilised in 1 litre of wine at 20° C. For a still wine (so-called “Stillwein”) a limit of 2.0 g/l of CO2 is given by law. If pressure is increased, more CO2 can be solubilised in the fluid. In semi-sparkling wines about 3.7 to 5.2 g/l CO2 can be solubilised at an overpressure of about 1.5 to 2.5 bar. In contrast thereto, sparkling-wine is provided with a CO2 concentration of about 6.5 to 9.8 g/l at an overpressure higher than 3.5 bar.
The characteristics of solubilising CO2 within wine are different to those within water. As wine contains a plurality of substances, in particular water and alcohol, especially the alcohol has great influence on the characteristics and a smaller amount of CO2 can be solubilised in wine than in water. Thus, CO2 in wine is outgasing easier than CO2 which is dissolved in water. As a result, it is harder to keep CO2 in wine, especially while bottling sparkling or semi-sparkling wine, when foaming occurs. The effect of foaming can be reduced for sparkling wine which is produced by means of a second barm fermentation. Up until now, it has been assumed that CO2 is better and more effectively solubilised because of a slower release of the barms in the wine and therefore, the CO2 is outgassed more slowly.
However, it has not been possible yet to insert CO2 to wine while providing the same characteristics without using the second barm fermentation.
As can be concluded from the above, the aim is to test and to control the concentrations of substances in wine, such as the CO2 concentration, in order to influence the taste and the quality of wine. Furthermore, there is a need for a method to reduce the outgassing of CO2 and to keep CO2 in wine without the need for a second barm fermentation.
It is an object to provide methods and an apparatus for testing and controlling the concentration of volatile substances within wine such as solute gases, alcohol and acetic acid. Furthermore, it is desired to produce wine where foaming during bottling is avoided and a slow outgassing with small bubbles takes place without the need for a second barm fermentation. As a result of the fact that no distillation is needed, a loss of aromas can thus be avoided.
Therefore, a method is provided for exchanging substances which are in a gaseous state between at least two fluids, namely a first fluid and a second fluid. The method comprises the steps of:
As described below in further detail, the method can be performed for example by means of an apparatus for controlling concentrations of substances within the at least two fluids and for exchanging substances between the at least two fluids. The apparatus can comprise semi-permeable membranes which seperate the at least two fluids and which are designed in such a way that only substances can pass through pores of the membranes which are in a gaseous state of aggregation. The at least one CO2-measuring sensor can be arranged, for example, at at least one appropriate position within the apparatus.
According to another aspect, the method can comprise the further step of automatically adjusting the amount of CO2 by a controlling system by comparing the values measured by the CO2-measuring sensor with corresponding predefined specifications.
The method can also comprise the step of adjusting a lower pressure to the second fluid than to the first fluid to cause solute CO2 in the first fluid to pass through the membranes into the second fluid.
According to another aspect the method can comprise the step of adjusting a higher pressure to the second fluid than to the first fluid to cause CO2 to pass through the membranes from the second fluid into the at least one first flow channel of the first fluid.
CO2 which is used as the second fluid can be taken for example from gas bottles and can be provided at one side of the membrane with an absolute value of pressure which is for example 0.1 to 0.2 bar above the pressure within the wine which can be used as the first fluid and which passes by at an opposing second side of the membrane. By adjusting the pressure difference between the at least two fluids the method described above causes CO2 to pass through the pores of the membrane into the wine. The small pressure difference is sufficient to cause CO2 to pass through the membrane and to solubilise CO2 within the wine. By adjusting the mass flow of the second fluid (CO2) the amount of CO2 which passes into the wine can be controlled in such a way that CO2 is solubilised within the wine without forming CO2 bubbles. After reaching saturation of CO2 within the wine, as shown in
However, the amount of CO2 passing through the membranes can not only be controlled by adjusting the mass flow of the second fluid but also by adjusting the mass flow of the wine which is used as the first fluid, as indicated in
If the pressure difference between the first fluid and the second fluid is adjusted in such a way that the wine as the first fluid is provided with an absolute value of pressure which is for example 0.05 bar above the pressure of CO2 as the second fluid, solute CO2 within the wine is passing through the membrane into the second fluid. Such an outgassing of wine can be controlled by adjusting the pressures of the two fluids, the temperature of the wine and the mass flow of the wine. The resulting degree of outgassing can be measured for example via the CO2 measuring sensor, as shown in
Furthermore, a method is provided for exchanging substances being in a gaseous state between at least two fluids, namely a first fluid and a second fluid. The method comprises the steps of:
This means that the concentration of alcohol within the wine as the first fluid can be reduced, if water is used as the second fluid. As only substances can pass through the membranes which are in a gaseous state of aggregation, the alcohol has to be provided in gaseous state for passing through. As there is a concentration gradient for the alcohol between the wine and the water, i.e. between the first and the second fluid, a diffusion pressure occurs which forces alcohol to pass into the water. As the alcohol has to be provided in a gaseous state of aggregation to pass through the membranes, the speed of diffusion can be increased by increasing the temperature of the wine. Also an adjustment of mass flows of the wine and the water influence the diffusion of the alcohol, but not as effective as adjusting the temperature of the wine.
This method can be performed by means of the apparatus for controlling concentrations of substances within the at least two fluids and for exchanging substances between the at least two fluids as mentioned above and as described below in further detail.
According to another aspect the method can comprise the step of performing an aroma analysis via a “Bukanter” aroma sampling system for verifying the concentration of alcohol within the first fluid and for adjusting the temperature and/or the mass flow of the first fluid.
A “Bukanter” aroma sampling system is already known for example from DE 10 2006 008 200 and can be used for aroma sampling. Aroma samples can be extracted for example at an input section and at an output section of the apparatus “in-line” and during operation, respectively. Aroma substances are extracted from the samples to analyse them by means of gas chromatography. The “Bukanter” system can either be used for sampling a limited and defined number of aromas or an entire spectrum of aromas of the wine. The analysis of the aromas can be used for example for verification of the concentration of alcohol and CO2. Thus, the reduction of alcohol as well as the increase or degradation of the CO2 concentration can be tested and the adjustments for controlling the apparatus can be verified. The verification can be used to avoid a loss of aromas, which will occur, if temperatures and pressures are too high. As different grape varieties have different spectrums of aromas, it is not possible to provide a global adjustment which is optimised for each grape variety.
Furthermore, a method is provided for exchanging substances being in a gaseous state between at least two fluids, namely a first fluid and a second fluid. The method comprises the steps of:
This means that a reduction of the concentration of acetic acid can be performed in substantially two ways. As the acetic acid is extremely volatile its concentration can be reduced by either applying a pressure to the second fluid which is lower than a pressure applied to the first fluid or using water as the second fluid. If water is used, there is a concentration gradient of the acetic acid between the wine and the water, i.e. between the first fluid and the second fluid, and a diffusion pressure occurs which forces the acetic acid to pass into the water. As the acetic acid has to be provided in a gaseous state of aggregation to pass through the membranes, the speed of diffusion can be increased by increasing the temperature of the wine. Also an adjustment of mass flows of the wine and the water are influencing the diffusion of the acetic acid, but not as effectively as adjusting the temperature of the wine.
The method described above can be performed by means of the apparatus for controlling concentrations of substances within the at least two fluids and for exchanging substances between the at least two fluids as already mentioned above and as described below in further detail.
If a gaseous fluid or particularly CO2 is used as the second fluid, the pressure difference between the first fluid and the second fluid is adjusted in such a way that the wine is provided with an absolute value of pressure which is for example 0.05 bar above the pressure of CO2 as the second fluid. Thus, solute CO2 within the wine is passing through the membrane into the second fluid as already mentioned above. A concentration of acetic acid within the wine can also be reduced in this way and the vapour pressure of the acetic acid enhances the effect of diffusion or outgassing, respectively. Thus, the method for reducing the CO2 concentration can also be used to reduce the acetic acid concentration. Moreover, the effect can also be used for sulphurous acid, which is applied to the wine to reduce oxidation.
The method for reducing acetic acid can comprise the step of performing an aroma analysis via a “Bukanter” aroma sampling system for verifying the concentration of acetic acid within the first fluid and for adjusting the pressure and/or the temperature and/or the mass flow of the first fluid.
Furthermore, an apparatus is provided for controlling concentrations of substances within fluids and exchanging substances between at least two fluids, namely a first fluid and a second fluid. The apparatus comprises
For example, membranes can be used which are produced for a filtering of drinking water or for clean rooms. They are offered for example by the company “Membrana” (www.membrana.de). The membranes are hydrophobic and have a low surface energy. They are provided with pores which can have, for example, a diameter of about 0.03 μm. As a result only gases which have small sized molecules can pass through the pores of the membranes. By means of such membranes, wine can be produced where foaming during bottling is avoided and a slow outgassing with small bubbles takes place without the need for second barm fermentation. In contrast thereto, dissolving CO2 within water by means of a membrane does not show such effects and does not differ from other known methods (e.g. artificial carbonisation). CO2 being solubilised in water by means of the membranes is rather outgassing as easily as CO2 being solubilised using the other methods.
According to another aspect, the apparatus substantially can have a cylindrical form and the flow channels can be arranged to substantially guide the at least two fluids along a longitudinal axis of the apparatus.
According to a further aspect, the at least one input unit and the at least one output unit for each of the at least two fluids, respectively, can be arranged at opposing front sides of the cylindrical apparatus.
Furthermore, the number of flow channels for at least one of the at least two fluids can be formed as tubes and walls of the tubes can be formed by the membranes.
For example, the tubes can have an inner diameter of about 0.2 mm. However, any other appropriate inner diameter can be used.
According to another aspect, at least the first fluid of the at least two fluids flows around the tubes.
According to a further aspect, the membranes consist of polypropylene.
According to still another aspect, mass flows of the at least two fluids are independently adjustable.
According to still another aspect, temperatures of the at least two fluids are independently adjustable.
According to a further aspect, the apparatus comprises a CO2 measuring sensor. For example, the CO2 measuring sensor can be arranged at the output unit of the apparatus for the first fluid to measure the CO2 concentration of the first fluid at the output unit.
According to another aspect, the apparatus comprises a “Bukanter” aroma sampling system for automated “in-line”-sampling for an aroma analysis.
According to another aspect, the apparatus comprises a controlling system for controlling the exchange of substances between the at least two fluids and the controlling system is connected to the CO2 measuring sensor and the “Bukanter” aroma sampling system.
According to a further aspect, the first fluid is wine and the second fluid can be chosen from a group comprising CO2, water or vacuum.
Vacuum as used herein means that a gas is used as the second fluid, such as CO2 or any other appropriate gas, and a second pressure is applied to the gas or the second fluid, respectively, which is below a first pressure which is applied to the first fluid. Thus, a pressure difference between the at least two fluids can be provided.
Furthermore, a device is provided for controlling concentrations of substances within fluids and exchanging substances between fluids comprising a plurality of apparatuses as described within the present description, wherein the apparatuses can be connected to each other in a serial and/or parallel arrangement.
Thus, using the plurality of apparatuses the first fluid can be processed within a plurality of steps each being performed in a separate apparatus. For example, in a first step a concentration of oxygen can be reduced and in a following second step CO2 can be added as described above. Such an order of steps might be important, as oxygen lowers the absorption of CO2 within the wine as the first fluid.
Further features and embodiments will become apparent from the description and the accompanying drawings.
It will be understood that the features mentioned above and those described hereinafter can be used not only in the combination specified but also in other combinations or on their own, without departing from the scope of the present disclosure.
Various implementations are schematically illustrated in the drawings by means of an embodiment by way of example and are hereinafter explained in detail with reference to the drawings. It is understood that the description is in no way limiting on the scope of the present disclosure and is merely an illustration of a preferred embodiment.
