A system and process for treating wine

Abstract

A method for aerating a wine product to reduce the time required to mature or age the wine. This is achieved by dosing a flowing body of wine with a gas mixture comprising an inert sparging gas and 0-

Description

Background Aerating wine during production is a deliberate process aimed at enhancing its flavour profile and overall quality. Aeration involves exposing the wine to oxygen, which can help soften harsh tannins, release volatile compounds responsible for aroma, and promote chemical reactions that improve the wine's complexity. Winemakers may choose to aerate wine during production in one of several ways, including splash racking, pumping over, barrel aging and microoxygenation. The splash racking approach involves transferring wine from one container to another in a way that exposes it to air, often causing it to splash and mix with oxygen. In pumping over, during fermentation, winemakers pump the fermenting juice or wine from the bottom of the tank and spray it over the top. This action not only helps with mixing but also introduces oxygen to the wine. Wine stored in barrels naturally undergoes slow oxygenation through the tiny pores of the wood. This process contributes to the wine's development and maturation. Micro-oxygenation is a controlled process where small, precise amounts of oxygen are introduced into the wine through a permeable membrane. It allows winemakers to carefully regulate the level of oxygen exposure and its impact on the wine. Overall, aerating wine during production can help improve its sensory characteristics and overall drinking experience. However, it is a delicate balance, as excessive aeration can lead to oxidation and undesirable flavours. Winemakers must carefully monitor the process to achieve the desired results. Summary of the invention According to a first aspect of the present invention, a method for producing wine comprises dosing a flowing body of a wine product with a stream of bubbles of a gas mixture to promote aeration of the wine product during one or more stages of wine production, wherein the gas mixture comprises an inert sparging gas and no more than 10% by volume of oxygen (02). Preferably, the inert carrier sparging gas comprises nitrogen (N2) and / or argon (Ar). In preferred embodiments, the gas mixture comprises vitiated air. In this application, the term 'vitiated air' means air in which the oxygen content has been reduced. The vitiated air comprises substantially no more than 10% by volume of oxygen, preferably no more than 5%, more preferably in the range of 0.5% to 3%, even more preferably around 1.5%. In some embodiments, the gas mixture is air which has been pressurised using an inert sparging gas such as N2 or Ar, or obtained by mixing oxygen with an inert gas, which may either be pre-mixed within a single vessel, obtained through gas entrainment of air using an inert carrier gas, or mixed in situ when feeding from multiple sources of gas. Preferably, the method further comprises the step of introducing a flow of the wine product through an aeration device where the flow of wine product is dosed with the gas mixture. Preferably, the flow of wine product is obtained from a wine vessel, more preferably a wine tank or a wine barrel. Preferably, the method further comprises the step of directing a flow of aerated wine product to a vessel for storage, the vessel being selected from a bottle, a wine barrel and a wine tank. In preferred embodiments, the wine product is taken at a stage of production selected from one or more of juice settling, fermentation, maturation, barrel or other storage stage, blending, dosage and bottling. According to a second aspect of the present invention, a system for aerating a wine product in the production of wine, comprises: a housing for receiving a flow of the wine product, the housing having an aeration treatment zone, a wine input port coupled to a proximal end of the aeration treatment zone, and a wine output port coupled to a distal end of the aeration treatment zone; a source of aeration gas; and, a gas introducer positioned within the aeration treatment zone and coupled to the source of aeration gas for introducing a stream of gas bubbles in the wine product as it flows through the aeration treatment zone to the wine output port, thereby to aerate the wine product. Preferably, the aeration gas comprises an inert sparging gas mixed with no more than 10% by volume of oxygen. In some embodiments, the aeration gas is vitiated air. Preferably, the system comprises a gas diffuser. Preferably, the gas diffuser is formed from a porous material. Examples of suitable porous materials include a stone air diffuser and a porous sinter diffuser, preferably formed from sintered metal. In some embodiments, a plurality of gas diffusers can be used. Preferably, the housing comprises a gas port for venting excess aeration gas. Preferably, the method comprises the step of adjusting one or more of the following controllable settings to control an aeration dosage selected from: • wine temperature; • wine flow rate; • aeration gas flow rate; • aeration gas composition; and, • exposure (dwell) time. Preferably, the dosing of the wine is effective to modify one or more of the following measurable characteristics of the wine product: • titratable acidity; • PH; • dissolved oxygen • aroma • taste • level of condensed tannins; • level of monomeric tannins; • level of anthocyanins; • colour density; • free SO2; • bound SO2; • total SO2; • total phenolics; • total hydroxycinnamic acids; • total flavonoids; • Somers Chemical Age 1; • Somers Chemical Age 2; and, • pigmentation. In preferred embodiments, the method comprises the step of using feedback control of one or more of the controllable settings to achieve a desired level of one or more of the measurable characteristics of the wine. Feedback control may be at least partially automated. The method may include a test phase for determining a set of controllable characteristics to achieve a set of desired wine characteristics for a sample of the wine product. Once these have been determined, system settings can be set accordingly before applying the treatment to the production batch. Brief description of the drawings Examples of the present invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 shows a typical set of stages in the traditional commercial production of wine; Figure 2 shows an example of a wine treatment system in accordance with the present invention; and, Figures 3 to 5 each show a simplified schematic of an alternative gas injection apparatus for use in the wine treatment system of Figure 2. Detailed description Figure 1 shows several of the typical production stages of wine making. As disclosed herein, a wine treatment system and process in accordance with the present invention can be used by a winemaker at one or more of these production stages. Figure 1 - Once pressing (stage 3) has completed the wine treatment system may be employed. In juice settling (stage 4) it is used here to improve colour stability, phenolic structure. Dissolved 02 may also be altered at this stage. It can also be used here to alter the SO2 composition within the wine including reducing total SO2. It may also be used to prevent the need for SO2 addition at this stage. During maturation (stage 6) the wine treatment system may be employed, either before SO2 addition, or of just after. It may be used here to improve colour stability, phenolic structure, aromatic integration and either increasing the wines reductive strength still further or reduce it, dependent upon the uptake and interaction of the 02. Dissolved 02 may also be adjusted at this stage. It may also be used to alter the titratable acidity. It can be used here to alter the SO2 composition within the wine including reducing bound and total SO2. The wine treatment system may also be employed during storage (stage 7). It is used here to provide additional phenolic structuring, aroma integration and to alter the wines reductive strength. Dissolved 02 may also be altered at this stage. It can also be used here to alter the S02 composition within the wine including reducing bound and total S02. It may be used to alter the titratable acidity. The wine treatment may also be used during blending (stage 8). It could be used on one or more of the components of the wine blend, or the final blend. The wine treatment system can also be employed immediately prior to bottling (stage 11). The wine treatment system described herein may also be used at similar stages in the production of sparkling wine (not shown), particularly in what is known as the dosage stage to further adjust the sensory profile of the wine to the needs of the winemaker. Figure 2 shows an example of a wine treatment system and process in accordance with aspects of the present invention. In Figure 2, untreated wine is held in a storage vessel 1 prior to treatment. Depending on the relevant stage of wine production, the storage vessel 1 may be a wine tank or a wine barrel. Wine enters a Gas Reactor System (GRS) 50 via a pump 2. In preferred embodiments, pump 2 is a peristaltic pump which allows the flow rate of the wine to be accurately set. Wine flows horizontally through an inlet pipe 3 and then into a vertically aligned pipe section 4 of the GRS 50. An aeration gas is introduced to the vertical pipe section 4 below the level of the inlet pipe 3 via a gas diffuser 5. As described below, more than one gas diffuser may be employed, each either carrying the same aeration gas or a different gas which collectively forms the aeration gas. Aeration gas is obtained from a storage vessel 12, whose flow is regulated by a regulator valve 13 and passes through a flow meter 14. It is coupled to the gas diffuser 5 along a gas transport pipe 15. In preferred embodiments, the aeration gas comprises vitiated air. In this application, the term 'vitiated air' means air in which the oxygen content has been reduced. In some embodiments, the gas mixture is air which has been pressurised using nitrogen. It is possible to achieve substantially the same mixture of gases using other set ups, some of which are described below with reference to Figures 3 to 5. The vitiated air comprises substantially no than 10% by volume of oxygen, preferably no more than 5%, more preferably in the range of 0.5% to 3%, even more preferably around 1.5%. The flow of the wine entrains aeration gas bubbles 6 within the flowing body of wine. The aeration gas bubbles 6 travel in the direction of the flow of the wine for a time until they reverse direction and rise upwardly to the top of the vertical pipe section 4. Millions of aeration gas bubbles 6 are created by the diffuser 5. As soon as the aeration gas bubbles 6 enter the wine, oxygen (02) starts to dissolve into the wine. As the 02 dissolves it then reacts with the compounds and other chemistry in the wine. Dissolved 02 that has not reacted with the wine, unreacted 02, is removed from solution by the nitrogen (or argon) content in the gas, through an action known as sparging. The wine continues to flow down the vertical pipe section 4 where it then travels horizontally into a horizontal pipe section 7. Any residual gas bubbles 8 that remain entrained in the wine rise up vertically and are collected in a gas trap section 9. This residual gas may be vented via a valve 24. Valve 24 is shown as a pressure release valve but could equally be a release valve or a gas permeable membrane, for instance a hydrophobic membrane. The treated wine continues to travel horizontally and exits this section via an outlet pipe 10 to a pump 11, where it then exits the GRS 50. The treated wine may then be sent for bottling or returned to a storage vessel until it is ready to be bottled. Some of the stored wine may be kept for a period of time to mature further or, it may be used in dosage, blending and other stages of wine making. It will be understood that the height of the column of wine within the vertical pipe section 4 can be adjusted through selection of the height or diameter of the vertical pipe section. The vertical pipe section 4 could be telescopically adjustable. Likewise, the position of each gas diffuser 5 within the vertical pipe section 4 may be raised or lowered. The column of the vertical pipe section 4 from the top surface of the wine 16 to the base section 17, where the vast majority of the aeration gas bubbles turn back and travel up the vertical pipe section 4 towards the surface, is known as the reaction zone (RZ). In preferred embodiments, a material 18 such as stainless-steel wire wool or other suitable material(s) is placed into the RZ to help prevent foaming of the wine. The material 18 could also incorporate a quantity of iron or copper to further aid chemical reactions within the wine. In some embodiments, oak chips 19 or other additional ingredients can be placed in the RZ. The aeration gas bubbles 6 and wine pass through the oak chips 19, reacting with and drawing out properties from within the chips, such as tannins. Remnants of the aeration gas 6 that have come out of solution rises to the top of the vertical pipe section 4 and can accumulate at or around point 20. It can then exit the vertical pipe section 4 via a valve 21. Valve 21 is shown as a pressure release valve but could equally be a release valve or a gas permeable membrane, for instance a hydrophobic membrane. Alternatively, the top of the vertical pipe section 4 could simply be open to the surrounding atmosphere to vent remnants of the aeration gas. Gas and wine may also exit the vertical pipe section 4 via an outlet pipe 22 governed by a valve 28, where it can be sent back to the storage vessel 1 to allow for any overfilling of the vertical pipe section 14. Alternatively, the overspill of wine can simply be drained or stored for further use. The pressure within the GRS 50 may be regulated or it could be kept broadly at atmospheric pressure. A higher than atmospheric pressure within the system may help to increase the solubility of the aeration gas into the wine. The temperature of the wine can also be controlled to affect the take-up rate of the 02 and other characteristics of the wine product. A wine sampling port 23 is provided so that a wine maker can take samples of the wine. Such sampling is then used to inform any adjustments needed to the system. Other sampling ports (not shown) may be used to sample wine at various points in the system. An oxygen meter 29 can be used to read the dissolved oxygen levels within the wine product prior to treatment. A further oxygen meter 30 can be used to read the dissolved oxygen levels within the treated wine product. Comparisons can then be made and then used to inform any adjustments needed to the system. The system can be controlled through appropriate adjustments as follows: • the temperature of the wine • the percentage of 02 within the mix • the volume of flow of gas can be adjusted by valve 13 • the volume of flow of the wine can be adjusted via the pump 2 • the height of the column of wine in the vertical pipe section 4 can be adjusted to alter the total volume of wine in contact with the gas bubbles • the diameter of the vertical pipe section 4 can be selected along with its shape • the height of the vertical pipe section 4 can be selected as well as its diameter • the pressure within the GRS 50 An example of the settings for an experimental system for the GRS 50 of Figure 2, is given below in Table 1. Various system parameters can be altered manually, semi automatically or even automatically using feedback control, and a feedback control system 31 may be provided for this purpose. They may be adjusted based upon the measurements taken from one or more locations within the system. System parameters which can be adjusted to control an aeration dosage include (but are not limited to): • wine temperature; • wine flow rate; • aeration gas flow rate; • GRS 50 pressure • aeration gas composition; and, • exposure (dwell) time. Dosing of the wine may be effective to modify one or more of the following measurable characteristics of the wine product: • titratable acidity • PH • dissolved oxygen • aroma • taste • level of condensed tannins • level of monomeric tannins • level of anthocyanins • colour density • free SO2 • bound SO2 • total SO2 • total phenolics • total hydroxycinnamic acids • total flavonoids • Somers Chemical Age 1 • Somers Chemical Age 2 • pigmentation Wine can be sampled before treatment and tested using industry standard tests such as the Modified Somers Method to determine the ratio of monomeric and polymerised phenolics. The wine can be sampled again after treatment to determine the increase in polymerisation and adjustments made accordingly dependent upon the result the wine maker requires. Other tests that can be performed include such tests as total, free and bound SO2, PH, dissolved oxygen, acetaldehyde and colour. Taste, smell, feel and appearance tests may also be performed. The results of these and other tests or measurements may be used to adjust the system. The following are examples of measurements of the wine can be taken in situ: • dissolved oxygen • temperature • PH • titratable acidity • colour Other measurements can be taken ex vivo including: • phenolic compound composition • SO2 Levels • condensed tannins • monomeric tannins An example of a device that can be used to measure tannins is a High-performance liquid chromatograph (HPLC). Table 1 Wine Temperature °C 20 Wine Flow - LPM 5 Gas Flow - LPM 1.5 Gas Composition Gas Composition - / L Oxygen ML / L 14 1.40% Nitrogen ML / L 986 98.6% Exposure Exposure Chamber L 0.5 Exposure Time in Secs 6 Total 02 Exposure in ML 2.10 Total Gas Exposure per ML / L 1.05 Table 2 below shows the results of these experimental settings when used to treat a sample body of red wine. Table 2 Red wine sample Measurements Pretreatment Posttreatment Titratable Acidity g / l 5.013 4.875 PH 3.688 3.688 Condensed Tannins (mg / l Epicatechin) 30.754 32.054 Anthocyanin Mg / l 107.556 75.157 Colour Density au (Absorbance Units) 6.765 7.168 It can be seen that the red wine's titratable acidity went from 5.013g / l in the untreated wine to 4.875g / l in the treated wine. There was no change in the PH which remained at 3.688. Condensed Tannins (Epicatechin) went from 30.754 mg / l in the untreated wine to 32.054 mg / l in the treated wine. Anthocyanins went from 107.556 mg / l in the untreated wine to 75.157 mg / l in the treated wine. Colour Density went from 6.765 au in the untreated wine to 7.168 au in the treated wine. The treatment positively correlated with higher condensed tannins and higher colour density against the untreated wine. Table 3 below shows results of the same experimental settings when used to treat a body of white wine. Table 3 White wine sample Measurement Pretreatment Posttreatment Titratable Acidity g / l “7 Q C / .JJ 7.05 Free SO2 27.2 24 Bound SO2 68.8 67.2 Total SO2 96 91.2 Total Phenolics 1.892 2.216 Total Hydroxycinnamic acids 2.74 2.998 Total Flavonoids 0.06533 0.21733 Brown Pigments 0.114 0.06 The white wine's titratable acidity went from 7.35g / l in the untreated wine to 7.05g / l in the treated wine. Free SO2 went from 27.2 to 24. Bound SO2 went from 68.8 to 67.2. Total SO2 went from 96 to 91.2. Total Phenolics went from 1.892 to 2.216. Total Hydroxycinnamic acids went from 2.74 to 2.998. Total Flavonoids went from 0.065533 to 0.21733. Brown Pigments went from 0.114 to 0.06. Figure 3 shows a simplified schematic of an alternative gas injection apparatus suitable for use in the GPS 50 in Figure 2 for providing the aeration gas. In this example, pure 02 gas stored in gas cylinder 12 is introduced via a first gas diffuser 5i, whilst a flow of inert sparging gas from a gas cylinder 32, such as N2, is introduced via a separate gas diffuser stone 52 to create a combined volume of micro-bubbles 6 of aeration gas. The respective flow rates of the two gases can be controlled to effect various levels of solubility, reaction and 02 removal or addition. The distance between and relative positioning of the diffusers 5 can be adjusted. Figure 4 shows a simplified schematic an alternative gas injection arrangement for use in the GR.S 50 of Figure 2 for providing the aeration gas. In this example, gas cylinder 12 contains 100% N2 and a separate gas cylinder 33 contains 100% 02. The 02 could be regulated into the flow of the N2 so as to achieve similar or the same result as premixing both gases or using a source of vitiated air. This would allow the percentage of 02 to be altered more easily. Figure 5 shows yet another alternative gas injection arrangement for use in the GRS 50 of Figure 2 for providing the aeration gas, where a gas cylinder 12 contains N2 and atmospheric air is entrained into the flow by means of a venturi 26 Alternatively, a pump (not shown) can be provided to introduce atmospheric air into the flow of N2 as to achieve the desired mix of vitiated air for the purpose of aeration.

Claims

28 01 251. A method for producing wine comprising dosing a flowing body of a wine product within an aeration treatment zone with a counterflowing stream of bubbles of a gas 5 mixture to promote aeration of the wine product during production, wherein the gas mixture comprises an inert sparging gas and between 0.5% and 3% by volume of oxygen.

2. A method according to claim 1, wherein the inert sparging gas comprises 10 nitrogen.

3. A method according to claim 1 or 2, wherein the gas mixture comprises vitiated air.15 4. A method according to claim 1 or 2, wherein the gas mixture is air which hasbeen pressurised using an inert sparging gas, or obtained by mixing oxygen with an inert gas, which may either be pre-mixed within a single vessel, obtained through gas entrainment of air using an inert carrier gas, or mixed in situ when feeding from multiple sources of gas.

205. A method according to any preceding claim, comprising the step of introducing a flow of the wine product through an aeration device where the flow of wine product is dosed with the gas mixture.25 6. A method according to claim 5, wherein the flow of wine product is obtainedfrom a wine vessel, preferably a wine tank or a wine barrel.

7. A method according to any preceding claim, comprising the step of directing aflow of aerated wine product to a vessel for storage, the vessel being selected from a 30 wine bottle, a wine barrel and a wine tank.

8. A method according to any preceding claim, wherein the wine product is taken at a stage of production selected from one or more offermentation, maturation, barrel dosage or other storage stage, blending and bottling.

359. A method according to any preceding claim, comprising the step of adjusting one or more of the following controllable settings to control an aeration dosage:i. wine temperature;ii. wine flow rate;40 iii. aeration gas flow rate;iv. aeration gas composition; and, v. exposure (dwell) time.101528 01 252010. A method according to any preceding claim, wherein the dosing of the wine is effective to modify one or more of the following measurable characteristics of the wine product:I. titratable acidity;ii. PH;iii. level of condensed tannins;iv. level of monomeric tannins;v. level of anthocyanin;vi. colour density;vii. aroma;viii. taste;ix. free SO2;x. bound SO2;xi. total SO2;xii. total phenolics;xiii. total hydroxycinnamic acids;xiv. total flavonoids;xv. Somers Chemical Age 1;xvi. Somers Chemical Age 2; and,xvii.pigmentation.25 11. A method according to claim 10 when dependent on claim 9, comprising thestep of using feedback control of one or more of the controllable settings to achieve a desired level of one or more of the measurable characteristics of the wine.

12. A method according to claim 11, wherein the feedback control is at least 30 partially automated.

13. A method according to claim 11 or 12, comprising running an initial test phase on a sample of the wine product for determining a set of controllable characteristics to achieve a set of desired wine characteristics for the wine product, to be applied during 35 a subsequent production phase.

14. A system for aerating a wine product during the production of wine, comprising: a housing for receiving a flow of the wine product, the housing having an aeration treatment zone, a wine input port coupled to a proximal end of the aeration28 01 25treatment zone, and a wine output port coupled to a distal end of the aeration treatment zone;a source of aeration gas containing an inert sparging gas and between 0.5% and 3% by volume of oxygen; and,5 a gas introducer apparatus positioned within the aeration treatment zone andcoupled to the source of aeration gas for introducing a counterflowing stream of aeration gas bubbles in the wine product as it flows through the aeration treatment zone to the wine output port, thereby to aerate the wine product.10 15. A system according to claim 14, wherein the aeration gas comprises an inertcarrier gas mixed with around 1.5% by volume of oxygen.

16. A system according to claim 14 or 15, wherein the aeration gas is vitiated air.15 17. A system according to claim 16, wherein the aeration gas is air which has beenpressurised using an inert sparging gas, or a gas mixture obtained by mixing oxygen with an inert gas, which may either be pre-mixed within a single vessel, obtained through gas entrainment of air using an inert carrier gas, or mixed in situ when feeding from multiple sources of gas.2018. A system according to any of claims 14 to 17, wherein the housing comprises a gas port for venting excess aeration gas.

19. A system according to any of claims 14 to 18, further comprising a pump for 25 creating a flow of wine.

20. A system according to any of claims 14 to 19, further comprising a feedback control system for feedback control of one or more controllable settings to achieve a desired level of one or more measurable characteristics of the wine product.3021. A system according to claim 20, wherein the controllable settings include one or more of:i. wine temperature;ii. wine flow rate;35 iii. aeration gas flow rate;iv. aeration gas composition; and, v. exposure (dwell) time.

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