AU2008101169A4 - Maturation of Liquid Beverage - Google Patents

Description

01/12 2008 16:58 +61 3 9543 8822 Morcom Pernat #0416 P.007/026 1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION INNOVATION PATENT "Maturation of Liquid Beverage" The following statement is a full description of this invention, including the best method of performing it known to me: COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 16:58 +61 3 9543 8822 NroiPra 01 .0/2 Norcom Pernat #0416 P-008/026 00 2 MATURATION OF LIQUID BEVERAGE Field of the Invention This invention relates particularly but not exclusively to methods for the maturation o of table wine by control of oxygenation and maturation of other liquid beverages 00 having similar oxygenation requirements for maturation.

01 Background of the Invention Many red and some white table wine varieties are matured in bulk quantifies in oak barrels, according to the wine variety, quality and desired character. Many other liquid beverages such as whiskey also benefit from similar maturation in oak by oxygenation.

The general aim of wine aging in Oak barrels, is to develop a desired aged wine bouquet and character, by: Controlled and slow oxidation of various wine substances especially the phenolic compounds. This slow oxidation, followed by polymerization, results from limited and gradual exposure to air oxygen diffusing through the walls of the barrel over months.

Extraction of Oak flavour components, including Oak phenolics to enhance and expand the wine's complexity.

However Oak barrels are expensive to fashion, cumbersome to store and handle, Often inconsistent in wood properties, subject to leakage and limited in usefuil life.

COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 16:59 +61 3 9543 8822 Morcom Pernat #0416 P.009/026 00 3 0 0 Oak barrels also require a voluminous storage facility with a controlled temperature aand humidity environment to minimize evaporative loss due to transpiration through 0their porous walls.

0 Accordingly there have been many attempts to replicate the effects of barrel aging on table wine in bulk quantities, without the actual use of oak barrels. For example: Va oThe addition of Oak sawdust, chips or staves into metal bulk storage 0tanks, to expose the wine to Oak characters. However this only achieves i0 the Oak flavour extraction function of barrel aging, not the oxidative one.

C This can be mitigated to some extent by regularly "pumping over" the wine in the tank, in order to re-aerate it. However this often introduces too much dissolved oxygen all at once, allowing aerobic bacteria such as Acetobacter to become established and begin oxidizing the ethanol in the wine into acetaldehyde, ethyl acetate and ultimately acetic acid, with consequent loss of wine quality. These oxidation products are termed "volatile acidity" in the wine industry.

The development of composite bulk containers made of metal (stainless steel) and fitted with flat Oak panels or ends which can be more easily fashioned and which may be reversed to expose fresh Oak to the wine contents. Such containers usually don't have the optimum ratio of surface area of Oak to volume of wine contained and are usually inadequate both in the extractive and oxidative functions.

More recent developments include the use of "micro-oxygenation" wherein air or pure oxygen is introduced directly into bulk-tanked table wine with added Oak chips or planks, by generating very fine bubbles through the wine by means of a microporous (ie. sintered) dispersion element on the end of a submerged gas line or lines.

This is a difficult process to adequately control and can possibly lead to excess levels of dissolved oxygen at the bubble interfaces, again promoting ethanol oxidation and other degradative side-effects through fast oxidation of table wine. The equipment COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 16:59 +61 3 9543 8822 Morcom Pernat #0416 P.010/026 00 4 0 C required to contain and feed fixed volumes of oxygen or to accurately meter a U continuous flow over set time periods at very low flow rates, is normally expensive 0 and difficult to operate. That cost also means the resource has to be shared over a number of tanks, which militates against long, slow maturation times in individual

O

tanks.

O Recent studies such as reported in "Gaseous Exchange in Wine Stored in Barrels", Moutounet, Mazauric et al, J. Sci. Tech. Tonnellerie, 1998 (herein incorporated by reference) have explained the mechanism by which barrels add oxygen to wine and 00 O 10 promote "correct" maturation. The oak walls of wine barrels act as semi-permeable C "membranes", allowing oxygen gas in the atmosphere outside the barrel to permeate through the barrel walls and diffuse into the wine. This osmotic exchange is driven by the partial pressure difference of the atmospheric oxygen outside the barrel (0.18 atm) and the effectively zero partial pressure of oxygen inside. This absence of oxygen in the barrel arises because wine continuously consumes all available oxygen in the slow-oxidation reactions that occur in the reductive environment that exists when the rate of oxygen addition occurs at very low rates over long periods, due to slow diffusion.

Furthermore, it has been shown that it is this slow permeation (diffusion) of atmospheric oxygen that contributes most to "barrel softening or maturation".

Moutounet et. al. (referred to above) showed that a typical new oak barrique allows 02 permeation through its walls, in the range of 20-30mg/l.yr. Kelly and Wollan reported an estimated "highest diffusion" (ie. permeation) rate into a typical barrique as 2.2ml Oz/litre wine/month or 26.4 ml/l/yr (34.6mg/l./gr) in their paper "Microoxygenation of Wine in Barrels", Wine Network Technology, www.winenet.com.au, incorporating International Patent Application PCT/AU02/01250 (both herein incorporated by reference).

It has been found that the oxygen permeability of an oak barrel typically decreases by approximately 20% for each year filled. Thus the permeation rate of a typical barrel after 5 years of use may be as lows as 7 milligrams/l/yr ie. thus the oxygen COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 16:59 -i61 3 9543 8822MocmPna#41 P01/2 Morcom Pernat #0416 P.011/026 00 ci permeation rate for normal barrels during the typical 5 years of barrel life lies between 7 and 35 mg/I/yr.

It is well known that older barrels transmit less oxygen than new barrels, as the wood clogs over time with absorbed wine solids. The useful life of a typical barrel is also well known to be limited to 5 years. After that time they are too impermeable to properly mature wine within the usual maturation time frame and are either discarded 2 or retained for use with wine types that do not require much oxygen exposure, such as soeo0h hievreis 00eo h hievreis o0 01 Any free surface arising from head-space in a table wine storage vessel is undesirable, if it contains oxygen. At that surface the levels of dissolved oxygen increase in concentration, to near saturated (9 ppm at 20 Celsius and I atm). In this oxygen rich surface layer aerobic bacteria will propagate, generating volatile acidity and acetaldehyde at a rate dependent usually on the surface area of the free surface and the oxygen content of the surface gas. The lesser the free surface area, the longer that wine can be safely kept in bulk storage.

This approach compares with the approach required for maturing a sherry style wine which typically requires a partially empty vessel with a head space open, or partially open to the atmosphere, such as occurs in a part-filled barrel, which continuously draws in air to replace the evaporative volume lost, as well as permeating it through the walls. Enough oxygen needs to be made available within the vessel to support the growth of crtain yeasts at the surface, which help oxidize some of the wine ethanol into acetaldehyde, giving sherry its basic character. By contrast, in table wines, formation of acetaldehyde needs to be suppressed as its presence gives an undesirable spoiled taint ie. volatile acidity to the wine. Thus the rate of oxygenation needs to be controlled at levels substantially below that applicable for sherry and any significant free surface avoided or rendered inert.

COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 16:59 +61 3 9543 8822NocmPnt#01 P01/2 Morcom Pernat #0416 P.012/026 00 6 Cl Disclosure of the Invention 0 The invention provides a method of maturing a liquid beverage in bulk by slow o oxygenation comprising, Storing the liquid beverage in a closed container having self-supporting polymeric walls over a period of at least 4 months with the walls being exposed to the atmosphere so as to allow atmospheric oxygen to permneate through the walls to be o taken up by the liquid beverage at a rate less than 55 milligranillitre of liquid per year, 00 wherein the walls comprise polymer of an area and thickness chosen to 0 Cl permeation through the walls over the period.

The liquid beverage may suitably comprise table wine.

Preferably the table wine is stored for a period between 4 months and 36 months.

The polymer may suitably be a wine-safe polymer.

By wine-safe polymer, we mean a polymer which is suitable for contact with wine, does not impart an undesirable taste to the wine and does not leach dangerous levels of chemicals toxic to humans into the wine. Polyethylene is a particular example of a suitable polymer.

By self-supporting polymeric walls we mean that the thickness and configuration of the walls and the strength and rigidity of the polymer are such that the container Can maintain its own shape without support when it is empty. The walls may include the base, sides and top of the container. It may be moulded in one piece from polymer by a conventional process, such as rotational moulding.

The relationship between the various factors governing oxygen transmission into wine is described by the following equations where: COMS ID No: ARCS-215436 Received by IP Australia: Time (I-tm) 16:03 Date 2008-12-01 01/12 2008 17:00 ±61 3 9543 8822 MroiPra 01 .1/2 Morcom Pernat #0416 P.013/026 00 7 c1 OTR (mg/I/day) P(matl. permeability, mgO2/sqnilday for 1nmn) divided by t(nm thickness) all multiplied by A (area sqm) divided by V (volume litres) oLe.0OTR =P/t x(ANV) or OTR x Pit or V/A P/(t x 0Th) IND or t= (P x A) (OTR x V) 0 range versus surface area versus thickness can be used to define the characteristics of Cl a suitable plastic container provided a plastic with a particular range of physical properties and thickness range can be used.

The thickness of the container walls (eg. Polyethylene) may then be adjusted having regards to the desired volume and surface area of the container to ensure that the rate of oxygen transmission is maintained at levels suitable for the maturation of table wines, ie. at rates similar to conventional oak barrels.

From the foregoing equations it can be seen the permeation of oxygen through the walls of a polyethylene container reduces in inverse proportion to the increase in wall thickness. The oxygen permeability of polyethylene depends on its solid density and varies (increases) with temperature. Oxygen from the atmosphere (ie. at 0.18 atm partial pressure) typically permeates through polyethylene at rates from 13mg to of oxygen per square metre per day at room temperature, ie. at about 20-25 degrees C. the applicants have found that a container volume ranging from 5 to hectolitres per square metre of container surface area for a wall thickness of 1mm will allow oxygen permeation to proceed at rates similar to barrels of various ages.

To illustrate the application of this three-way ratio, a typical example of a polyethylene container of 1,000 litres (10 hectolitres) and a nominal 6 square metre wall surface area is considered.

The broad thickness range is: COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 17:00 +61 3 9543 8822 Morcom Pernat #0416 P.014/026 00 8 0 0

C-)

U9 At 5 hl.mm/sqm t 5 x 6/10 3mm At 30 hl.mm/sqm t 30 x 6/10 18mm Depending on the polyethylene permeability chosen, the oxygen transmission rate (OTR) ranges are: At 3mm: Min. OTR :13/3 x 6 x 365/1000 9.5 mg/l./yr Max. OTR: 65/3 x 6 x 365/1000 47.5 mg/l/yr 00 0 ci At 18mm: Min. OTR: 13/18 x 6 x 365/1000 1.6 mg/i./yr Max. OTR: 65/18 x 6 x 365/1000 7.9 mg/1./yr For a container of this layout, the atmospheric oxygen permeation range thus lies between 1.6 mg/I/yr and 47.5 mg/I/yr.

Of course, because the broad transmission range quoted above exceeds that for normal table wine, the parameters of the container can be adjusted so that the OTR is less than 80mg/l/yr and preferably lies within the typical range for wine barrels, namely 7 to The properties of polyethylene are fortunately such that it is sufficiently rigid within a 3mm to 18mm thickness range as to provide a self supporting bulk container according to the invention. The container may even be up to 10 hectolitres or more.

Furthermore, the oxygen transmission characteristics of polyethylene are such that it is suitable for constructing bulk containers capable of performing maturation of wine or other liquid beverages similar to that achievable with oak barrels.

In order to limit the transfer of oxygen into the surface of the wine, a barrier member may be floated on the wine surface. Suitably, the barrier member has a peripheral portion which is in sliding contact with the container walls to separate the wine surface from the head space in the container.

COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 17:00 +61 3 9543 8822MocmPnt#01 P.1/2 Morcom Pernat #0416 P-015/026 00 9 Cl Oak staves may optionally be suspended in the wine during the storage period.

0 In another aspect, the invention provides a container for controlling rate of oxygen o transfer from the atmosphere into a table wine stored in the container comprising, a bulk polymeric container having self supporting walls, the walls having a thickness chosen to permit oxygen to permeate the walls from the atmosphere into the table wine at a rate sufficient to promote controlled maturation of the table wine over o a prolonged period.

00 The rate of permeation is suitably less than 55mg/L/yr. The rate of permeation is Cl suitably comparable with permeation rates typically associated with maturation of bulk table wines in oak barrels.

The container may comprise a barrier member for providing a barrier to limit oxygen access from head space in the container to a surface of the wine the barrier member having a construction which causes it to float on the wine surface.

A peripheral flange may surround the barrier member so that it makes slidable contact with the walls of the container.

In another aspect the invention provides a barrier member as described herein.

The method and apparatus of the invention can be used to achieve the simultaneous extractive and slow-oxidative effects of Oak barrel aging without the need to use such barrels or to add extra oxygen gas or air into the wine.

Furthennore the method of our invention can allow the independent adjustment of both the degree of Oak extraction and the degree of slow-oxidation. In this way it is possible to replicate the different extractive and oxidative effects of Oak casks of different ages (the oxygen permeability of a barrel decreases by about 20% for each year it is used) and of different surface area to volume ratios. Commion Oak cask sizes are Barriques (225 litres), Hogsheads (300 litres) and Puncheons (500 litres).

COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 17:00 +61 3 9543 8822 Morcom Pernat #0416 P.016/026 00 0 0, Preferred aspects of the invention will now be described with reference with to the c 9 accompanying drawings.

0 Brief Description of the Drawings SFigure 1 shows a cut away isometric view of a container constructed in NO accordance with the invention; Figure 2 shows an enlarged view of the circled area at the top of Figure 1; Figure 3 shows an enlarged view of the circled area shown at the bottom of 00 S 10 Figure 1; C Figure 4 shows an alternative tank construction; Figure 5 shows an enlarged cross sectional view of part of the circled region of Figure 4; and Figure 6 shows an isometric view of a barrier member for use with the invention.

Detailed Description of the Preferred Embodiments The various elements identified by numerals in the drawings are listed in the following integer list.

Integer List 1 Cover 2 Water trap 3 Level 4 Plastic tank Staves 6 Hole 7 Rod 8 Base valve 9 Cylinder Outer cylinder COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 17:00 ±61 3 9543 8822 MroiPra 01 .1/2 Morcom Pernat #0416 P.017/026 0 c-I11 Disc 12 Lip 014 Top panel Skirt 20 Plastic tank 21 Neck 22 Closure 23 Skirt 24 Water trap 00 25 Circumferential wall 026 Tap 28 Wine Barrier member 31 Foamed plastic core 32 Polyuretha-ne film overwrap 34 Peripheral flange Wall 36 Tag 37 Hole/loop Whilst the following aspects of the invention are particularly described with reference to table wine it is to be appreciated that they may also be applicable to other liquid beverages.

Referring to Figures 1 to 3, there is shown an optionally thermally insulated plastic tank with an opening in the top defined by a neck formed as a cylinder 9 forming part of the tank, to which any closure can be fitted.

In this embodiment an optional circumferential wall in the form of an outer cylinder 10 is welded to or molded as part of the tank 4 and an optional base valve 8 is fitted through the side wall, above the base of the tank so as to enable bottom filling or discharge of the tank contents without disturbing sediment that may have settled to the bottom of the tank.

COMS ID No: ARCS-21 5436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 17:01 +61 3 9543 8822 Morcom Pernat #0416 P.018/026 00 12 0 0 SThe tank 4 is sealed by means of a closure comprising an inverted dome-shaped cover 1 having a top panel 14 and depending skirt 15, The skirt is partially submerged in a water trap 2 formed by adding water to the space between the two concentric cylinders 9 and 10. Whilst the specific embodiment shown uses a water trap it is to Sbe appreciated that a simple closure such as a wide mouth screw cap can be used. It ID is preferable that the closure and container neck be wide enough to allow a person to have hand access to all internal surfaces for cleaning.

00 S 10 The tank 4 and top cylinders 9 and 10 are made from polyethylene with an oxygen Ci permeability in the range between 13mg to 65mg of atmospheric oxygen per sqm of tank surface per 24hr for each 1mm of tank wall thickness at typical storage temperatures of 20-25 degr C.

The ratio of contained volume to surface area of the container falls within the range to 30 hectolitres per square metre of surface for a 1mm thick container wall exposed to atmospheric oxygen, to ensure that an adequate rate of permeation of oxygen is maintained. Thus for example, for a 4mm thick wall the contained volume range becomes 1.25 to 7.5 hectolitres per square metre of surface.

Suspended within the wine-filled tank are an optional number of oak-wood staves of the desired variety and degree of toast (ie. charring). At the lower end of each stave a hole 6 is drilled to enable that stave to be threaded onto or otherwise attached to a solid rod 7 usually made of stainless steel, which is sufficiently heavy to keep all of the wooden staves attached to it from floating to the surface. The total surface area of oak-wood presented to the wine will depend on the variety of wine, the degree to which the winemaker wants to impart oak character to it and the number of times the oak staves have already been used in wine.

In this embodiment, the stainless steel rod 7 is bent into a shape, so that the ends hang downwards and the staves float upwards. By this simple means the staves are prevented from floating off the ends of the rod 7.

COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 17:01 +61 3 9543 8822 MroiPra 01 .1/2 Morcom Pernat #0416 P.019/026 00 13 0 Alternatively, the oak planks may be pro-assembled into a pack, not requiring a hole or rod to fit them onto. The pack may be inserted preassembled through the mouth of 0 the tank and removed for replacement, cleaning or sterilization as and when required.

The level of wine 3 in the tank will normally lie within the top cylindrical chamber formed by the cylinder 9. Resting or floating on the wine surface is a barrier member comprising a buoyant disc 11 made of wine-safe polymer such as polyethylene. It 2 may comprise an upside down dish shape. Alternatively it may be a composite structure comprising a disc of plastic foam overwrapped and scaled within a wine- 00 safe film of predetermined oxygen barrier properties. The outer perimeter of the 0 buoyant disc may optionally be furnished with a flexible lip 12 which forms a "wiper seal" with the inner face of the chamber cylinder 9. The purpose of the buoyant disc is to lie in and block the free wine surface from access to the head space air or gas in the chamber 9. The disc minimizes the rate at which particular gases in the head space, such as oxygen, can dissolve into the wine via the free surface.

The buoyant disc acts as a barrier member which can also have tailored gas permeability suitably at the levels already described to enable controlled oxygen permeation into a tank made from impermeable material, such as Stainless Steel.

Thus, the barrier member and poly tanks can be used together or separately, to passively "meter" the addition of atmospheric oxygen into wine, without allowing conditions to develop where a significant free surface area of wine is directly exposed to the atmosphere.

The upper rate limit of mass transfer of oxygen into wine by permeation is typically about 80mg/I/year. At rates higher than that wine is not capable of using up all the available oxygen in typical maturation reactions and a measurable concentration of dissolved oxygen results. In those conditions, aerobic bacteria Such as acetobactor, and gluconobacter, which are always present in low populations in all wine that hasn't been sterile-filtered will propagate and damage the wine.

COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01 01/12 2008 17:01 ±61 3 9543 8822MocmPra#01 P00/2 Morcom Pernat #0416 P.020/026 00 14 when used in the main body of a tank as is shown in Figure 4 C0 2 or another inert gas can be added into the head space to protect the small area of exposed wine around 0 the perimeter of the added baffler member. As gas dissolves into liquid at a rate o directly proportional to the exposed surface area re-charging the head space with

CO

2 only needs to be done very infrequently when a barrier member is used, ie. once per month rather than every couple of days, due to the 50 to 100 fold typical reduction in exposed surface area. The exposed annulus is typically about 5mm. wide.

o If the tank body has a diameter of in meters, the exposed surface without baffler a x D 2 4 and with a barrier it is 0.005 x n x D. For a tank of Im diameter, the 00 oio exposed surface with a baffler is proportionally 0.005 x 413 or just 2% of that without (N a barrier member.

The edge flap helps to centralize the disc, keep out contamination and contain S02 gas that is coming out of solution from the wine so that 'mould cannot grow there.

Referring to Figures 4 to 6, there is shown a plastic tank 20 for wine with a neck construction generally designated 21. The illustrated tank uses any typical closure that seals the opening.

A closure 22 having a depending circumferential skirt 23 closes off the neck.

As in the case of the previously described container, a circumferential wall surrounds the neck and provides a water trap 24 between the neck and circumferential wall and the skirt 23 of the closure fits into this water trap to seal off the neck.

A tap 26 is provided at the bottom of the container to drain off the wine 28 as and when needed.

A baffler member 30 having a foamed plastic core 31 floats on top of the wine in the body of the container. The foamed plastic core 31 of the baffler member is overwrapped with a polyurethane film overwrap 32 which comprises two separate layers covering the top and bottom of the foamed plastic core. These two separate layers are laminated together at their edges to form the peripheral flange 34. The COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2005-12-01 01/12 2008 17:01 +61 3 9543 8822MocmPnt#01 P02/6 Morcom Pernat #0416 P.021/026 00 peripheral flange provides a slidable seal with the wall 35 of the container so as to substantially reduce the rate of oxygen transfer from the head space of the container 0 through the surface of the wine and hence limits the growth of undesirable aerobic bacteria.

The barrier member is provided with three tags 36 distributed around its upper surface, each of the tags being formed with a hole or loop 37. The tags assist with 2 allowing the baffler member to be correctly located in the container in contact with the wine initially and to be removed after the container has been emptied. In this 00 O 1 regard, it is noted that the barrier member comprising the foamed plastic core and c-I polyurethane film overlap may suitably be formed of flexible materials in order to allow it to be folded so that it may be inserted through the neck of the container during initial setup and to be removed through the neck when the container is emptied.

Whiilst the above description includes the preferred embodiments of the invention, it is to be understood that many variations, alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the essential features or the spirit or ambit of the invention.

It will be also understood that where the word "comprise", and variations such as "comprises" and "comprising", are used in this specification, unless the context requires otherwise such use is intended to imply the inclusion of a stated feature or features but is not to be taken as excluding the presence of other feature or features.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the conumon general knowledge in Australia.

COMS ID No: ARCS-215436 Received by IP Australia: Time 16:03 Date 2008-12-01

Claims (4)

1. 01. A method of maturing a liquid beverage in bulk by slow oxygenation o comprising, storing the liquid beverage in a closed container having self-supporting polymeric walls over a period of at least 4 months with the walls being exposed to the atmosphere so as to allow atmospheric oxygen to permeate through the walls to be o taken up by the liquid beverage at a rate less than 55 milligranilitre of liquid per year, wherein the walls comprise a polymer of an area and thickness chosen to 00 promote controlled maturation of the liquid beverage by controlling oxygen Cl permeation through the walls over the period.
2. 2. The method according to claim 1 wherein the period is between 4 and 36 months.
3. 3. The method according to claim 1 or claim 2 wherein the oxygen permeation rate falls within a range typical for table wine maturation in oak barrels.
4. 4. The method according to any one of the preceding claims wherein the polymer is polyethylene. The method according to any one of the preceding claims wherein the liquid beverage is table wine and the capacity of the container is at least 225 litres. Dated this I1st day of December 2008 Flextank International Ltd by their patent attorneys Morcom Pernat COMS ID No: ARCS-215436 Received by IP3 Australia: Time 16:03 Date 2008-12-01