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Patent Searching and Data


Title:
WINE STORAGE
Document Type and Number:
WIPO Patent Application WO/2003/016177
Kind Code:
A1
Abstract:
A container (1) having an interior for storing wine comprising:- a flexible pouch (3) disposed in its interior- pressure means (7) arranged to supply pressurised fluid to the pouch so as to compensate for loss of wine from the container and maintain contact of the wine with substantially all the interior surface of the container, wherein the combined oxygen transmission characteristics of the container pouch and any other sources are such that the rate of oxygen transmission to the wine totals less than 40cc/litre of wine/yr.

Inventors:
FLECKNOE-BROWN ANTHONY (AU)
HENRY PETER (AU)
BRKOVIC RISTA (AU)
Application Number:
PCT/AU2001/001242
Publication Date:
February 27, 2003
Filing Date:
October 04, 2001
Export Citation:
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Assignee:
FLEXTANK PTY LTD (AU)
FLECKNOE-BROWN ANTHONY (AU)
HENRY PETER (AU)
BRKOVIC RISTA (AU)
International Classes:
B65D81/24; C12H1/22; (IPC1-7): B65D85/72; B65D77/06; B65D90/28; C12G1/00
Foreign References:
FR2649380A11991-01-11
FR2756466A11998-06-05
Other References:
DATABASE WPI Derwent World Patents Index; Class A92, AN 2000-589538/56
DATABASE WPI Derwent World Patents Index; Class A34, AN 1987-089840/13
Attorney, Agent or Firm:
Pernat, Alfred (Victoria 3149, AU)
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Claims:
Claims
1. A method for storing wine in an air and vapour permeable storage container which comprises: providing a flexible pouch inside the container maintaining a pressure of fluid in the pouch sufficient to increase the pouch volume to compensate for at least a proportion of any of the wine lost by evaporation through the walls of the storage container, and controlling the rate of any oxygen transmission from the pouch fluid to the wine in such a manner as to prevent spoilage of the wine by transmission of unacceptably high amounts of oxygen from the pouch fluid into the wine.
2. A method according to claim 1 wherein the combined oxygen transmission characteristics of the container, pouch and any other air or fluid dissolved oxygen sources are such that the total rate of oxygen transmission into the wine is less than 40 cc/litre of wine/yr.
3. A method according to claim 2 wherein the pouch comprises material with low oxygen permeability.
4. A method according to claim 3 wherein the pouch has walls comprising multiple layers of plastic film.
5. A method according to claim 4 wherein the pouch has been formed by heat sealing the pouch walls together.
6. A method according to claim 2 wherein the pouch walls comprise at least three layers of plastic film with at least one of the layers comprising an oxygen barrier material.
7. A method according to claim 6 wherein the pouch walls comprise: an external reinforcing layer and ethanol barrier layer at least one oxygen barrier layer an internal reinforcing layer and ethanol barrier layer an inner water seal layer.
8. A method according to claim 7 wherein, the external reinforcing layer and ethanol barrier comprises polyamide, at least one oxygen barrier layer comprising one of EVOH, PVDC or metallized PET and the inner water seal layer comprises polyethylene.
9. A method according to claim 2 wherein the pressure of fluid in the pouch is maintained at a level which is sufficient to cause the pouch to expand by all of the amount necessary to compensate for all of the loss of wine volume from the container, whereby to cause the wine to remain in contact with substantially all of the interior surface of the container.
10. A method according to claim 9 wherein the pouch is maintained at a pressure in the range 0.5 psi to 5 psi.
11. A method according to claim 1 wherein the pouch is sufficiently large to allow it to expand to substantially fill all of the interior of the container and the container has an outlet through which wine may be dispensed, due to the application of sufficient pressurised fluid into the pouch.
12. A container for storing wine comprising: an outer container a flexible pouch disposed in the interior of the outer container and pressure means arranged to supply pressurised fluid to the interior of the pouch so as to compensate for loss of wine from the outer container and maintain contact of the wine with substantially all the interior surface of the outer container, wherein the combined oxygen transmission characteristics of the container, pouch and any other sources are such that the rate of oxygen transmission to the wine is less than 40cc/litre of wine/yr.
13. A container according to claim 12 wherein the pouch has walls comprising at least three layers of plastic film of which: the outermost layer is a reinforcing layer and an ethanol barrier an intermediate layer is an oxygen barrier the innermost layer is a water seal layer the pouch is expandable to at least 10% of the internal volume of the container.
14. A container according to claim 12 wherein the pressure means comprise: a pressure regulator for regulating the pressure in the pouch to fall within the range 0.5 psi to 5.0 psi safety overflow means for releasing excess pressure in the event that the pressure regulator fails to maintain pressure less than a predetermined limit.
15. A container according to claim 13 comprising: a flow detector for measuring the rate of flow of fluid from the pressure means into the pouch control means responsive to signals from the flow detector when the flow of fluid exceeds a predetermined limit, the control means actuating at least one of an alarm, visual indicator and means for controlling fluid flow through the pressure means.
16. A wine barrel assembly comprising: a plurality of wooden wine barrels completely filled with wine a flexible pouch provided inside each wine barrel an individual liquid supply line connected to each flexible pouch a common supply line for supplying water connected to each individual liquid supply line a pressure regulator operable to maintain pressure in the common supply line between predetermined limits wherein the oxygen transmission characteristics of the pouch are such that the rate of oxygen transmission from the pouch to the wine is less than double the rate of oxygen transmission through the walls of each barrel into the wine contained therein.
17. A wine barrel assembly according to claim 16 including a flow detector for measuring flow of water through the common supply line and control means responsive to signals from the flow detector, the control means actuating at least one of an alarm, visual indicator and means for controlling fluid flow through the common supply line when the flow of water through the common supply line exceeds a predetermined limit.
18. A wine barrel assembly according to claim 17 including a safety stand pipe connected to the common supply line downstream of the flow meter, the safety stand pipe being arranged to allow overflow of water from the common supply line when the water pressure in the common supply line exceeds a predetermined limit.
Description:
WINE STORAGE Field of the Invention This invention relates to a method of storing wine. In a particular non-limiting aspect the invention relates to a method of storing wine in wooden barrels using a method and apparatus which controls the uptake of oxygen and the evaporation rate of the wine through the semi-permeable barrel walls and which can be controlled with consistency from barrel to barrel.

Background of the Invention Fine wines need time to mature. Reduction of astringency, enhancement of colour and development of integrated character occur by means of a time-dependent, sequential series of chemical changes, notably slow-oxidation, condensation and polymerization reactions, in and between many of the flavour and colour elements in wine, most notably the phenolic compounds.

In general these time sequential redox reactions are initiated and sustained by a limited availability to the wine, of air oxygen and other oxidative reaction products from the earlier reactions in the sequence. The primary initial source of such oxidants is both the initial dissolved oxygen within the wine and more importantly, the limited and gradual air oxygen that diffuses through the walls of typical"fresh"Oak barrels over months and/or that which is randomly added during barrel topping-off.

Furthermore, the extraction of Oak characters from the wood of"fresh"barrels also generally enhances the wine's character and complexity.

By"fresh"we generally mean barrels which have not contained wine for more than 3 to 4 years of elapsed time, in total. After that time, barrels lose:

their ability to provide further Oak character, by depletion their permeability to air oxygen, thought to be due to clogging of the stave wood grain by wine precipitates such as tartaric compounds The presence of too much oxygen is also to be avoided. This can cause undesirable "fast-oxidation", leading to oxidative odour and taste, browning or other undesirable change of colour and/or development of other off-characters, such as from undesirable aerobic bacterial infections. All of these effects reduce the quality of the wine or cause total spoilage.

Oak barrels are also porous to moisture and ethanol and this results in evaporative losses for all barrel stored wine, in the order of 2% to 10% of wine volume per year, depending on the air temperature and humidity in the barrel storage area, the character and density of grain of the wood from which the barrels are made, their surface area to volume ratio and the internal pressure within them relative to atmosphere.

Moutounet, Mazauric, St. Pierre and Hanocq in their study"Gaseous Exchange in Wines Stored in Barrels", Journal des Sciences et Techniques de la Tonnellerie, Vol. 4, 1998 (herein incorporated by reference) report that the difference between the rate of evaporation out of and the permeation of air (and it's oxygen) into Oak wine barrels is usually sufficient to depress the internal pressure in a well-made, sealed (solid bung) barrel, by about 0.12 atm. below external atmospheric pressure.

At this equilibrium partial vacuum value, evaporation losses are minimized but the oxidative effects of head space air are maximized. This is mitigated to some extent by the deflection of the barrel ends under vacuum, which takes up part of the lost volume of the accumulated evaporation by reducing the head-space volume available to the wine.

Whilst this equilibrium pressure depression appears to be more or less constant for well- made barrels over a wide range of atmospheric conditions, the actual rate of gas exchange

into and out of a barrel is dependent on the temperature and humidity of the environment in which the barrels are stored. For example a change of humidity from 65% RH to 85% RH can change the rate of evaporation loss (and the linked rate of air entry into the barrel) by a factor of 2 or more.

Oak barrels, being hand-made from natural materials, exhibit a wide range of properties, in terms of their ability to retain pressure. Approximately one barrel in four will"leak"at least sufficiently to not retain a partial vacuum at all. This means that the actual rate of evaporation loss and the linked rate of air entry is different for almost every barrel.

This, in turn, means that the availability of oxygen to the wine also varies substantially from barrel to barrel, requiring individual monitoring of wine quality, condition and state of maturation.

For the above reasons, storage of Oak barrels in a controlled temperature, high-humidity storage facility has been the only practical way to manage natural barrel to barrel variability and minimize the rate of undesirable gaseous exchange. This is done in conjunction with frequent topping up of barrel head space with new wine and by constant barrel by barrel wine quality sampling and assessment. Both operations are labour- intensive and repeated assessment, to be effective and consistent, requires a high degree of skill by the taster/winemaker.

Regular topping-up of the wine barrels serves to: (i) Minimize the head space in the barrel and thus to reduce the air oxygen from becoming available to the wine.

(ii) Maintain as much surface contact of the wine with the inner barrel surface as is possible, so as to ensure that sufficient Oak character is infused into the wine.

However, the greater the frequency of topping up, the more external air is made available to the wine and the greater the oxidative effect.

Also, the regular"breaking of the vacuum"increases the average evaporation rate by as much as 50%.

Thus, no matter how carefully barreled wine is treated, there remains a significant and undesirable barrel to barrel variability in the quality and consistency of the wine, which could be substantially reduced if it was possible to"break the connection"between rate of evaporation and rate of air oxygen uptake.

The sensitivity of wine to excess oxygen cannot be overstated. After barrel aging, wine is traditionally"portion-packed"into oxygen impermeable packaging, such as glass bottles, to preserve it for an extended period. Further slow change occurs to wine in bottles and many premium red wines are at their best only after being held in this way for a number of years.

However, the cost of such portion-packaging typically doubles the cost of the finished wine and this added cost is also"marked up"at each stage of commercial distribution and sale, meaning that the cost of production of the wine liquid itself (fruit cost plus winemaking cost plus bulk storage cost plus Oak barrel aging cost), is typically less than 20% and sometimes less than 10% of the retail price of a bottle of medium-quality table wine.

Disclosure of the Invention Accordingly, the invention provides a method for storing wine in an air and vapour permeable storage container, such as an Oak wine barrel, wherein head space air can be positively excluded, despite evaporation and or leakage from the barrel. An uncontrolled and variable partial vacuum inside the barrel can be prevented from forming, hence stabilizing the availability and rate of oxygen permeation into the wine.

The method and apparatus of the invention comprises: a flexible pouch inside the container, submerged in the wine a fluid within the pouch with a density equal to or greater than the wine and maintained under sufficient pressure above atmospheric to increase the pouch volume to compensate for a substantial proportion or preferably all of any of the wine lost by evaporation through the walls of the storage container.

-means to control the rate of any oxygen transmission from the pouch fluid through the pouch walls, into the wine in such a manner as to control the rate of such dissolved oxygen transmission.

Most suitably the rate of oxygen transmission from the pouch is to be controlled such that the combined rate of oxygen transmission from all sources including the pouch and the storage container, into the wine is to be less than 40cc/litre of wine/yr. More suitably the combined rate of oxygen transmission should be less than 20cc/litre of wine/yr.

The rate of oxygen transmission through the pouch may be controlled in a number of ways. For example the pouch may be pressurised with a fluid which does not contain oxygen, such as de-oxygenated water, alcohol or mixtures thereof. Oxygen scavengers such as sulphur dioxide may also be used to remove oxygen from the fluid in the pouch.

Another suitable alternative is to construct the pouch from a membrane material which has low oxygen permeability. Such membrane material may be edge-bonded to form a pouch. The bonding may be by any method known in the art such as heat sealing, gluing, welding or stitching.

Where the membrane used for the pouch is comprised of multiple layers of plastics film it is preferred that at least one of such layers be a material which has low permeability to oxygen, a so-called oxygen barrier layer. The oxygen permeability of the resulting composite, multi-layer membrane is to be less than 100 cc of pure oxygen/m2/24 hours at

STP and 100% RH. More suitably its permeability will be less than 20 cc of pure oxygen (4 cc of air oxygen) Im2124 hours at 100% RH. For a pouch with a total membrane surface area of 0. 6m2 filled with air (or air-oxygen saturated water) at STP, this equates to a maximum of about 2.4 cc of 02 per 24 hours or 3.9 cc/litre of wine/year for a 225 litre barrique.

Some oxygen barrier layer materials are moisture sensitive, so it may be desirable to add moisture barrier layers on each side of the oxygen barrier layer. It may also be desirable to comprise into the multi-layer membrane, a layer or layers of material which have low permeability to ethanol and/or volatile wine flavour compounds.

Other layers may provide physical and chemical protection for the wine and it may be desirable to add reinforcing layers to mechanically strengthen the final composite membrane.

To cope with the evaporation of wine through the permeable barrel wall, the pouch should be able to expand to a volume equal to the amount of liquid lost through permeation. This will vary with different barrel sizes given the differing surface area to volume ratios. For a typical 225 litre barrique, which may be used to mature wine for a period of 12 to 18 months, the typical total evaporative loss in a well controlled barrel store will be about 5% per year or 17 litres over 18 months.

Hence, for use in a barrique, a pouch which is initially fully collapsed, should have a fill volume of at least 20 litres so that no significant tension may develop in the walls of the pouch towards the end of the storage period.

Should such tension be allowed to develop, it will be necessary to increase the internally applied fluid pressure to a level sufficient to physically extend the pouch material, if the development of head-space within the barrel is to be prevented. This is not desirable as tension damage to the seams of the pouch may result in a leak, whereby pouch fluid could enter the wine. Furthermore, excess pressure can"drive"the rate of permeation higher and hence, increase the rate of evaporation loss of wine.

It is thus preferred that the fluid in the pouch be maintained only at a slight positive pressure above atmospheric, so that the wine within the barrel is also at that same slightly elevated pressure. This positively prevents air entry through any barrel leak points and enables easy automated detection of barrel leaks, dislodged barrel bungs, disconnected fittings, etc.

It is thus preferred that the pressure of the fluid in the pouch be maintained in the range 0.5 to 10 p. s. i. but more preferably 0.5 to 5 p. s. i.

Such a pressure may be applied simply by providing a head of liquid such as water. The water may be supplied from a tank or it may be from a conventional town water supply.

More suitably the water supply circuit may include a pressure regulator to maintain pressure in the pouch within the desired range. It may also include safety means to compensate for excess water pressure should the regulator not work correctly. This safety means may simply be an open-topped, vertical stand pipe. Such a stand pipe will provide automatic overflow of excess water pressure and may be constructed to provide a head pressure of say 2 to 4 metres of water (3 to 6 p. s. i.).

The water supply circuit may also include a flow detector. Thus if the water flows at a rate in excess of a predetermined maximum it can be inferred that there is a system leak.

Thus the flow detector may be associated with a malfunction indicator or other alarm means. Any of the following events would then trigger an alarm.

. dislodged barrel bung leaking barrel excess system pressure (flow over stand pipe) 'barrel sampler tube left open 'any dislodged tube in the water supply circuit damaged pouch

Preferred aspects of the invention will now be described with reference to the accompanying drawings.

Brief Description of the Drawings Figure 1 shows an isometric view of an apparatus according to the invention; Figure 2 shows an isometric view of an alternative form of apparatus according to the invention; and Figure 3 shows an isometric view of an assembly of wine barrels according to the invention.

Detailed Description of the Preferred Embodiments Figure 1 shows, in partial sectional view, a typical Oak wine barrel (1), which typically may be a Barrique (225 litres capacity), Hogshead (300 litres) or Puncheon (500 litres).

This barrel is filled with wine. h this embodiment a flexible rubber bung (2) is fitted with two through-tubes. One of these tubes is securely attached to an initially collapsed empty pouch (3) of heat-seamed oxygen-barrier thermoplastic material (generally made up of multiple layers of thermoplastic materials), by means of a screwed or bayonet fastened spout attachment (8) itself heat sealed to the pouch material and opening to the inside of the pouch, now herein termed an"ullage pouch", "ullage"being another term for"head-space"in a liquid-filled container.

This assembly is then entered into the wine via the open bung hole and the rubber bung is firmly pushed into the barrel fill opening. The ullage pouch (3) is then connected to a source of normal tap-water via a pipe (7) fitted with a stop-cock (6). A pressure regulator (not shown) may be used to reduce the pressure of the tap water source (eg. to less than 20 kPa or 3 psi).

In use, stop-cock (6) is left open for the duration of the barrel maturation time, so that the ullage pouch (3) partially inflates internally with water, then becomes pressurized, transferring it's internal pressure to the wine surrounding it and ensuring that no additional head space can develop within the barrel due to evaporation of the wine through the barrel walls. Any head space present when the bung is first fitted to the barrel can be expelled via tube 9, after first pressurizing the system, by opening valve 4 until wine begins to flow.

Because most dry wines, (i. e. where all the available sugars have been converted into ethanol by fermentation), have a specific gravity of approx. one, the water-filled ullage pouch (3) has little or no relative buoyancy and easily becomes fully submerged in the wine, thus ensuring that the wine surrounding the ullage pouch has access to all of the internal wood surface of the barrel. This also means that there is no detectable net pressure across the walls of the pouch, meaning that whatever the internal pressure which is allowed to develop within the barrel, the pouch itself experiences no significant net internal pressure. Thus the ullage pouch (3) can be constructed of a minimal amount of thin, flexible, no-taint wine and food-contact materials, such as Nylon and polyethylene.

By this means it is thus possible to keep the barrel effectively"topped-up"to brim-full for long periods of time, far longer than the approximate two to four weeks that is normally required between manual barrel top-ups, to make up for continuous evaporation losses.

Furthermore, because the wine in the barrel is at a positive pressure to that of the atmosphere surrounding the barrel, any leaks in the barrel staves, ends or bung, can be relatively easily discovered and remedied or the wine transferred over to a sound barrel.

Should any slow leaks be present, such as between the wooden staves of the barrel, a partial vacuum that may draw-in external air oxygen or contaminants cannot develop within the barrel. Hence slightly leaky barrels may be utilized without compromising the integrity of the environment within them.

Thus, not only may the frequency of manual topping-up of barrels be reduced, but also the improved in-barrel integrity that this invention provides may reduce the frequency needed for periodic monitoring of the per-barrel wine quality and substantially improve the barrel to barrel consistency of the contained wine.

Nevertheless, it will generally be important to the winemaker to be able to conveniently sample the wine within the barrel at extended intervals, to generally determine it's state of maturation. Accordingly the method of our invention can also provide for a convenient wine outlet means, wherein a wine sample can be tapped from the barrel by means of a further stop-cock (4) fitted to the second through-tube (9), which is open to the wine held within the barrel.

Because the wine within the barrel is maintained by the water-pressurized, part-filled ullage pouch within it, at a slightly elevated pressure above atmospheric, it is only required that this stop-cock (4) be opened momentarily to allow some wine to be forced up into a glass or flask, held under the outlet spout (5). This is of significant additional convenience to the winemaker, because the current method involves removing the barrel bung (allowing air oxygen to enter) entering a glass or stainless steel pipette into the wine, (a potential contamination source), collecting the sample, emptying the pipette contents into a glass or flask, laying down the pipette, replacing the barrel bung securely, washing or wiping off the pipette.

The capacity of the water-containing ullage pouch (3) of the embodiment of Fig. 1. does not need to be greater than the total wine evaporation loss normally experienced during the maturation period, typically about 5% per year in a well-controlled barrel store.

Use of readily available drinking-grade potable water is recommended. In that case, should an ullage pouch develop a leak for any reason, the water then accidentally introduced into the barrel wine will not generally contaminate the wine with harmful bacteria. Should such an event happen, the wine will also not generally be diluted beyond recovery, as the volume of water introduced will not exceed the volume of liquid, mostly water, that is anyway normally lost by evaporation.

In Figure 2, a second embodiment of the invention shows the flexible rubber bung (2) or other barrel access and closure means, fitted with a single water-tube only. This through- tube is again securely attached to an initially fully-collapsed empty pouch (3) made up of flexible, oxygen barrier thermoplastic material, by means of a screwed or bayonet fastened spout attachment (8) itself heat sealed to the pouch material and opening to the inside of the pouch.

However, the internal, fully-inflated capacity of the pouch of this embodiment is to be 90% to 120% of the volume capacity of the barrel and is to be shaped, via end-gussets, so that it can generally conform to the internal surface geometry of the barrel.

We term the pouch of this embodiment to be a"dispenser pouch", as substantially all of the wine within the barrel can be dispensed via the end tap (6) whilst the dispenser pouch takes up the lost volume by progressively being inflated with external water. The water within the dispenser pouch thus displaces all of the dispensed wine and prevents an air- space from forming within the barrel.

Furthermore, if the water source for the dispensing pouch is maintained at a slightly elevated pressure above atmospheric pressure, the wine will be forced from the barrel when the tap (6) is opened and there will be no opportunity for air to be sucked back into the wine, either via the open tap, or via any minor leaks or porosity in the barrel staves.

The initially fully collapsed, empty dispenser pouch (3), pre-connected to the through tube and bung (2), is usually entered into a partially-filled wine barrel via the open bung hole. The water hose (7) is then connected to a low-pressure source of normal tap-water via a stop-cock (4). The bung is not pushed into the barrel fill opening. The water is turned on and allowed to fill the dispenser pouch (3) until the wine initially filled into the barrel begins to run out of the bung hole. At this point, the stop-cock (4) is closed and the bung is driven home, to seal the barrel.

The barrel is now able to be stored or transported, as necessary, until the wine within it has matured and/or is ready to be dispensed to the end-consumer, at a restaurant or public bar. Any dissolved oxygen (typically from 2 to 9 ppm) within the water of the dispenser pouch is prevented from permeating into the wine at an unacceptable rate, by means of the oxygen barrier material incorporated into the walls of the flexible dispenser pouch.

In use, stop-cock (4) is left open. As wine 50 is dispensed via the tap 60, the dispenser pouch thus can remain filled and internally pressurized with water, transferring it's internal pressure to the barrel-wine surrounding it and aiding in dispensing the wine directly via a tap inlet (90) or conveying the wine to a remote tap (not shown) by means of the typical pressurized beverage tubes and taps utilized in public bars. The continuous maintenance of a positive internal pressure within the barrel also ensures that no external air can be sucked back into the barrel.

By this means wine can be stored for long periods within a barrel and dispensed at-will, whilst remaining fully protected from the degradative effects of air oxygen or other contaminants, even when the barrel wine is nearly exhausted.

Furthermore the apparatus of this embodiment easily allows for additional wine to be added to the barrel at any time, without the need to remove the bung, which can introduce degradative air oxygen. In this case, the water-hose (7) is re-directed to a drain line held at or near atmospheric pressure, the end spout of the tap (60) or it's access port (90) is connected to a wine fill line that is at a slightly elevated pressure (i. e. by means of a height difference) and the taps (60) and (4) are opened at the same time. Then, the incoming wine exerts external pressure on the flexible dispenser pouch, forcing some of the water within it to the drain and displaces the volume of this discharged water with wine.

It will also be possible to monitor the rate and total amount of wine added or dispensed from the barrel, by metering and totalising the incoming or outgoing water that displaces or is displaced by it. Flow metering of wine is much more difficult than flow metering of water, due in part to the acidic and thus more chemically aggressive nature of wine, the

particulates and sugars it may contain and because it is anyway undesirable to trap enclosed small volumes of wine in an environment where spoilage may occur, hence introducing contamination.

Materials of Construction The walls of both the Ullage (Fig. 1) and Dispenser (Fig. 2) pouches (3) will generally be constructed from one or more plastic membranes, each comprising a number of layers of different polymers of chosen thicknesses, which together give a certain level of Oxygen permeability and permeability to ethanol.

Generally the various co-extruded layers of such a membrane will have a combined thickness in the range 50 to 300 micron. Adhesive layers will generally be used to bond the other materials into a composite structure. The typical layer structure through such a membrane will be: External Adhesive °2 Control Adhesive Reinforcing Adhesive Inner Seal Reinforcing Layer Layer Layer & Ethanol Layer Layer &Ethanol Barrier Barrier Layer Polyamide-Admer EVOH, Admer Polyamide-Admer Poly- PA (Nylon) (extruded Saran PA (Nylon) ethylene adhesive (PVDC), polymer) Metallised PET

Ethylene Vinyl Alcohol (EVOH), is a typical extrudable polymer oxygen control (i. e. high oxygen barrier) material. For example, a 20 micron thick layer of this material has an oxygen permeability (in air) of only about 0. 4cc/sqrm/24 hours at 45% relative humidity. A similar thickness layer of Polyethylene on the other hand, has an oxygen permeability some 8,000 times greater.

Polyethylene (LDPE, LLDPE or HDPE) has a very low permeability to water or water vapour and forms high-integrity, liquid-tight heat-seals.

Polyamide (Nylon or PA), typically PA-6, is a commonly used food and medical (i. e. human blood) packaging material, known for toughness, flexibility, high barrier to flavour, solvents (i. e. ethanol) and other volatiles and low to no taint. It is a preferred material for the outer surface of the multi-layer film, where it will be in contact with the wine.

PA has a substantially higher melting point, (PA-6 = 220 degr. C), than Polyethylene (LLDPE = 120 degr. C). This facilitates the making of leak-free heat-seal seams because the PA layer does not melt when the heat seals are made. PE-only structures often thin excessively near the seam due to the pressure of contact with the heat-sealer.

PA also provides a good intermediate-level barrier to the permeation of oxygen, being some 40 times more permeable than an equivalent thickness EVOH layer (which has a very high barrier to oxygen permeation), but some 200 times less permeable to oxygen than polyethylene.

PA is also creep resistant and has a higher tensile strength than LLDPE and is therefore generally also a suitable material to reinforce the pouch wall The multi-layer structure may optionally incorporate materials known to react with and scavenge oxygen during permeation through the bladder wall.

By varying the relative thickness and type of the various above layers, it will clearly be possible to construct a pouch with the necessary oxygen impermeability (of water dissolved oxygen) that is desired to properly protect the wine within the barrel. In most applications this maximum oxygen permeation rate is preferably no more than the oxygen permeation rate (per litre of wine), that is encountered in a typical new oak barrel of the most common size (usually 225 litre Barriques for table wines).

However there may be some instances where higher permeation rates may be acceptable eg. where the barrel is old and is"blocked"to oxygen transmission or where a significant proportion of the walls of the barrel or another other container comprise a relatively non- permeable material such as stainless steel.

The materials chosen for bungs will be those commonly used in the wine industry, i. e. silicone rubber and for connectors and tubes in wine-contact the materials of choice shall be either Nylon, polyolefine (polypropylene or polyethylene), PVC or 316 stainless steel, all materials that are familiar to winemakers.

In Figure 3 there is shown an assembly of wine barrels generally designated 20 set up in such a way that the method of the invention may be applied for the storage of wine in the barrels.

The barrels 1 which are stacked in the racks (21) each include a rubber bung (2), pouch (3) (not shown), spout (5) acting as a wine sampler tube and water supply pipe (7), arranged in generally the same manner as has been described with reference to Figure 1.

In place of the stop cock (6) shown in Figure 1 the spout (5) of Figure 3 is a flexible tube which is sealed by folding it over on itself and holding it in place with the clip (22). This can be used to sample wine whenever desired by removing the spout from the clip and unfolding it to unseal it.

Water pressure is supplied to inflate the pouches in each of the barrels though the pipes (7) which are supplied by the supply line (23). The supply line connects to a pressurised supply of potable tap water (24).

Pressure to the pipes (7) is regulated by the pressure regulator (26). A safety stand pipe (25), flow switch and alarm (27) and drain line (28) are also connected to the supply line for purposes to become apparent.

After installing each pouch into a near-full barrel and firmly pressing-in the bung, water is connected and the system is pressurized. A slightly elevated pressure is generated in the barrel by the water pressure applied to the pouch (1 to 4m head or about 1 to 5 psi).

Any head-space air remaining is then discharged, barrel by barrel, through the wine sampler tube until wine flows. Then that tube is bend-sealed.

Assuming dry wine in the barrels, (SG=1+ 0.01), the barrel ullage pouches will remain fully submerged in wine at a minimum depth of about 150mm. The wine will also be in full contact with the inside barrel surface and the underside of the bung.

Wine can be sampled at any time, by opening the bent-over sampler tube and letting the slightly higher internal barrel pressure drive wine out.

The bags, being mainly Nylon (as in blood bags and other medical products) can be washed-off and boiled, or sterilised with common winery sterilants.

The number of re-use times will depend on the individual user. In many bigger wineries, it will not be worthwhile trying to clean bags. They can be exchanged for new ones, each cycle.

For high-stacked barrels, a single pressure regulator valve can be installed for each of two tier levels as shown in Figure 3 ie. 4 high tiers would have two regulator valves, one for the top two rows, one for the bottom two.

This approach can be used to limit the applied pressure to no more than 2 m head, to remove the risk of popping the bungs.

A 3 to 5 m high vertical stand-pipe with an open connection drain is also installed in the system in case any regulator valve fails.

The flow switch activated alarm system is turned on after all the barrels in the circuit are air bled.

This sets off an audible alarm when there is any flow in the water circuit, other than barrel evaporation loss (usually less than 10 litres per year max. per barrique/hogshead).

It is to be understood that the word"comprising"as used throughout the specification is to be interpreted in its inclusive form ie. use of the word"comprising"does not exclude the addition of other elements.

It is to be understood that various modifications of and/or additions to the invention can be made by those skilled in the art, without departing from the basic nature of the invention. These modifications and/or additions are therefore considered to fall within the scope of the invention.