System and method for maturing spirits

Abstract

A system for spirit maturation comprising at least one barrel filled with alcoholic spirit, the barrel having a side wall and first and second ends; and a fil applied to cover an upper portion of the

Description

Technical Field

[001] The present disclosure relates to a system and associated method for maturing spirits, e.g. while stored in casks / barrels in a warehouse, prior to bottling and distribution. A maturation container, embodying the system, is also disclosed. Background

[002] The most common form of maturation vessel in the spirit industry is a barrel made from wood. Barrels are typically constructed from a number of staves bound together tightly as a means of forming a sealed container. In general, it is known that barrels lose liquid in three ways, e.g. 1. gross leaks at the seams (e.g., between staves) and imperfections in the wood (knots); 2. leaks of liquid through the pores / tubules / capillaries of the wood; and 3. vapour leaks of water and alcohol through the seams and wood itself. The volume of liquid, including the alcohol, lost through wooden barrel walls over time is a direct commercial loss. This lost quantity of liquid from leakage or evaporation is known as ullage or the "Angels' share."

[003] Wooden barrels are the preferred form of maturation container for many spirits and, in fact, may be prescribed / regulated as necessary in some cases depending on the class of spirit. The chemistry (e.g., vanillin, syringaldehyde) and properties of the wood (e.g. oxygen transfer rate (OTR), ethanol transfer rate (ETR), and moisture vapour transmission rate (MVTR)) vary which leads to uncertainty about performance and is particularly notable when barrels are stored for a long period of time, e.g. four years or more.

[004] Storage methods designed to reduce the angels' share have been proposed where a barrel is wrapped in a film as part of the maturation method. Such a film medium may have a degree of oxygen / ethanol permeability to allow for both oxygen and ethanol transmission through the walls. For example, WO2015 / 010015 describes a process for reducing ethanol loss by substantively covering the barrel in a film having certain OTR and ETR properties. However, while a plausible solution may be presented, it is not optimised for modern warehousing methods. Particularly, due to a focus on "stretchy" polyolefin films, leaked beverage can accumulate (e.g. create a balloon of liquid) under the film and, over time, compromise structural integrity of the barrel by causing the barrel to become "water-logged" and rotting the wood and / or rusting metal binders. A barrel that has been water-logged in this way may fail during storage, potentially causing total loss of the maturing spirit contained therein, and / or preventing the barrel from being refilled for a future re-use. Summary

[005] The present disclosure reveals a different methodology and, in turn, seeks to address issues observed in the prior art. The disclosure herein provides an optimised mode for implementing a spirit maturation system and method.

[006] According to a first aspect, a spirit maturation system is outlined according to claim 1. The system can comprise: at least one barrel filled with alcoholic spirit, a film applied to an upper portion of the barrel, relative to the barrel orientation, leaving a lower portion of the barrel exposed. For example, when oriented in an upright position, an upper portion proximate the top end may be covered, leaving the bottom end-proximate portion of the barrel exposed. In the case of a side-racked barrel, a portion of the underside of the bulging barrel side wall is left exposed.

[007] In this way, the film provides a barrier to evaporation of vapour from a headspace of the alcoholic spirit, while leaving the base / underside proximate portion of the barrel exposed, where liquid may seep through but is then able to drain away, enabling the barrel to dry naturally during storage. Furthermore, while some liquid may seep through and drain away, liquid in the wood will also cause a self-annealing effect, and the barrel becomes more watertight when filled, due to expansion of the wood when exposed to moisture. During development of the present inventive concept, it was surprisingly found that oxygen demand in barrel maturation is relatively low, such that there is no need for a film to have any special / specific oxygen transmission properties, contrary to the known prior art film-wrapped barrel examples where the 2 choice of film was based in part on the assumption that the films needed to exhibit at least a certain level of oxygen transmission.

[008] In embodiments, the system further comprises a pallet having a solid / gapless deck for locating in contact with a top end of the barrel oriented in an upright position. In this way the solid deck of the pallet remains in contact with the top end of the upright barrel to mitigate vapour loss. The solid deck reinforces or replaces the film barrier that may be covering the top end.

[009] In embodiments, there will be coverage of the barrel by a suitable film, preferably the upper side walls of an upright barrel, to achieve a desirable reduction in spirit loss. The film may cover approximately 50% of the total outer surface, preferably approximately 40%. As mentioned, the film barrier may be implemented in combination with a solid deck pallet fitted against an end of the barrel, e.g. proximate a headspace above the liquid. Accordingly, a barrier inhibiting escape to atmosphere of vapour is especially created at the upper portion of a barrel, while at a lower portion any liquid leak has an opportunity to drain / dry.

[0010] The pallet, as implemented in the system, may comprise decks of wood, plastic or metal. A seal or gasket may be incorporated with the system, e.g. where the barrel contacts the pallet face, to improve the vapour barrier. However, it is expected that the weight of the pallet and / or at least one stacked barrel placed on top of the pallet will inherently create an adequate seal between a rim of the barrel top end and the pallet, preferably at a solid underside deck surface, above it. Modern warehousing methods can involve stacking as many as six pallet-loads of casks on top of one another.

[0011] In embodiments, the film may be heat shrunk, wrapped or stretched about the barrel to achieve a tight seal against a surface thereof. A proportion of the outer surface area of the barrel is therefore contacted with the film.

[0012] In a variation, the system envisages tightly stretch-wrapping a pallet of multiple barrels with a plastic film that is stretched and / or heat shrunk about the barrel cluster. The pallet may have a solid deck / underside in contact with the top ends of the 3 barrels.

[0013] In embodiments, a covering of, say, 50% film may be incorporated with a container to seal its sides and axial end(s). This may be in combination with a pallet having a solid deck in contact with the container's upper end. In this way, any rips in the film at the head of the barrel, caused by stacking, are mitigated by the solid deck underside of the pallet. Furthermore, the practice described herein of leaving a lower portion of the barrel exposed provides an accessible surface for contacting with moving equipment when barrels are to be relocated (e.g. to be restacked) thereby mitigating damage to the covering at the upper portion of the barrel.

[0014] There are a number of benefits to the system of the present disclosure. For example: • It is easily implementable in and applicable to modern warehousing methods, where barrels are stored and stacked in an upright orientation (rather than being racked on their sides in the more traditional style). For example, by use of a pallet design outlined herein; • Barrels are able to breathe, such that liquid leaks drain off and evaporate without accumulating. Particularly, instances of rusting of the metal binding rings and rotting of the bottom / lower portion of barrels are reduced because most liquid loss is due to gravity forcing liquid through the walls. Implementing a system where the bottom / lower portion is exposed enables natural drying and stops further leaking as the tubules in the wood become clogged; • There is a reduction in material use, e.g. less total film use compared to prior art methods with total or majority barrel coverage; • Vapour loss from the headspace is reduced over extended periods due to contact with a film and / or the solid deck of a pallet; • A range of non-specialist, e.g. off-the-shelf, films can be utilised from impermeable to highly permeable. The main consideration is a sufficient vapour barrier that provides (even when stretched) no or very little passage. The OTR is not critical because most flavour compounds are from fermentation and extracted from wood, and the practical demand for oxygen has been discovered 4 to be low; • Candidate material types such as Polylactic acid (PLA) and Polyethylene terephthalate glycol (PETG) are sustainable and can incorporate recycled content. PLA is also made from renewable resources and compostable; and • It is particularly suited for high ABV beverages, such as those with an ABV over 30%.

[0015] According to the foregoing, the present disclosure relates to distilled spirit ullage reduction through the use of novel methods of implementation. A combination of pallet design and films (or sufficient coverage of film alone at the upper part of an upright barrel) is able to reduce the angels' share loss when spirits are stored in new or used wooden barrels. The pallets specified for this use can incorporate a solid deck made of wood, plastic, or metal. The films can be any polymeric material that can be applied onto the barrels, with polyesters being most favourable, especially those that are relatively environmentally friendly (recyclable and / or biodegradable). Optional gaskets can be used with the pallets to form a good seal at the heads of the barrels and can be made from several different appropriate materials. The films can be utilized with racked barrels, but most particularly with barrels stored upright in a modern maturation warehouse. The pallets are only used with barrels stored upright.

[0016] The films described herein are preferably wrapped or heat shrunk onto the barrels and do not "give" when there are severe liquid leaks, i.e. mitigating the formation of pockets or balloons. This allows the film barrier to reduce the loss of liquid through the sides of the barrel, while enabling any liquid that is lost to drain away. In a particularly advantageous form, use of films and pallets together in a modern warehousing method allows the spirit maker to control where and how the barrel ullage is reduced. It becomes an entirely more controllable process which trades off ullage with long term barrel preservation.

[0017] In other words, the problem the invention addresses is this: wooden barrels are known to leak vapour / liquid and have considerable variability, barrel to barrel, with respect to how much liquid and vapour leakage occurs. Liquid and vapour loss from wooden barrels amounts to a substantial cost to the distilled spirits industry every year. For example, new barrels lose about 5% in the first year and used barrels lose 2-3% per year. The spirit may be stored for many years and has greater value the older it is. Losses may be even greater (e.g. up to 10% per year) in warmer climates.

[0018] The presence of a properly applied material according to the above slows down liquid and vapor losses, regardless of the specific properties, by creating a tortuous path for vapor and or liquid on its journey between the interior and exterior of the barrel. Furthermore, by omitting to apply a covering at the bottom of a barrel, the liquid is able to self-anneal in the gaps between the staves.

[0019] It is noteworthy that known prior art such as WO2015 / 010015 teaches away from a solution as proposed herein. Previously, the skilled person sought to form a perfect seal around the barrel, but this is now found to be inadvisable. When the barrels leak, as they are prone to do especially when racked on their sides, balloons of liquid are created beneath the barrel which is messy and can destroy the barrels if severe and long enough, because the leaked liquid is captured and cannot escape. This problem can be overcome by annealed polymers (e.g., polyesters) that do not stretch and by intentionally not completely covering the barrel, e.g. not trying to form a perfect seal around the barrel.

[0020] Experimentally collected weight loss data, ABV data, and sensory data all support a proposition that properties of the films and the coverage methods in the embodiments described herein have little impact on ullage loss. Any film can be used, from impermeable to highly permeable, as long as it has a reasonable ethanol / vapor barrier and applied to achieve some kind of tortuous path for liquid and vapor based on the barrel storage method. Liquid leaks cannot be stopped outright but, when barrels do leak, the liquids needs to be able to drain out / dry up over time. According to the method herein, a self-annealing effect prevents liquid loss. Brief Description of Drawings

[0021] Illustrative embodiments will now be described with reference to the accompanying drawings in which: Figure 1 illustrates an overview of a spirit maturation container, e.g. a barrel or cask, as known in the art; Figure 2 illustrates a schematic view of a barrel, to be wrapped in a film prior to long term storage for maturation; Figure 3 illustrates an overview of a solid deck pallet for use with the maturation system described herein; and Figure 4 illustrates a schematic view of stacked barrels in a maturation system described herein. Detailed Description

[0022] The following description presents exemplary embodiments and, together with the drawings, serves to explain principles of the invention. However, the scope of the invention is not intended to be limited to the precise details of the embodiments or exact adherence with all system features and / or method steps, since variations will be apparent to a skilled person and are deemed also to be covered by the description. Terms for components used herein should be given a broad interpretation that also encompasses equivalent functions and features.

[0023] In some cases, several alternative terms (synonyms) for structural, system features have been provided but such terms are not intended to be exhaustive. For the avoidance of doubt, any terms separated by the "I" symbol generally refer to alternative "or" expressions where the terms can be used interchangeably. Descriptive terms should also be given the broadest possible interpretation; e.g. the term "comprising" as used in this specification means "consisting at least in part of" such that interpreting each statement in this specification that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner. Any directional terms such as "vertical", "horizontal", "up", "down", "sideways", "upper" and "lower" are used for convenience of explanation usually with reference to the form shown in illustrations and are not intended to be ultimately limiting if an equivalent function can be achieved with an alternative dimension and / or direction. All directional terms are relative to each other.

[0024] The description herein refers to embodiments with particular combinations of steps or features, however, it is envisaged that further combinations and crosscombinations of compatible steps or features between embodiments will be possible. Indeed, isolated features may function independently as an invention from other features and not necessarily require implementation as a complete combination.

[0025] It will be understood that the illustrated embodiments show uses only for the purposes of explanation. In practice, the invention may be applied to many different configurations (e.g. of barrel design), where the embodiment is straightforward for those skilled in the art to implement.

[0026] Figure 1 shows an overview of a maturation container for alcoholic beverages / spirits, in the recognisable form of a barrel 10 comprised of staves 11, a top end 12, a bottom end 13 and rings 14 which keep the structure tightly bound together. Staves 11 and ends 12 / 13 are typically made from wood and so have a natural permeability. Rings 14 are made from metal belts wrapped and secured in place about the staves. In most designs, the staves overshoot the ends in order to form a rim 15, 16 which is bound by a ring 14. In other words, when resting against a flat surface, a rim will cause a gap between the end and the ground (or a pallet above if stacked).

[0027] A sealing compound is typically applied to the internal join between staves and each round end, but usually not between the abutting edges of respective staves. As such the initially constructed barrel is often somewhat leaky, but becomes more watertight when filled, due to expansion of the wood when exposed to moisture.

[0028] As explained in the background section above, ullage is the term given to a shortfall in liquid within a container over time due to evaporation or leakage, sometimes also called the "angels' share". To mitigate such loss, Figure 2 schematically illustrates the application of a film F to be wrapped around the barrel. The film typically covers from the sides / staves 11 of the barrel from a top edge (rim 15) down to a midpoint of the barrel. Two film coverage options are indicated 17 and 18, depending on how far down the barrel the film is to extend. The film may also be wrapped over the top end across rim 15.

[0029] It will be apparent that covering the upper portion of barrel 10, when oriented upright, on-end, leaves a lower portion E of the barrel exposed. In this way, leakage and evaporation from the upper portion covered by film F will be inhibited, while leakage of liquid under gravity is not inhibited at the lower portion E. Therefore, while some ullage is still expected, it is much less (e.g. approximately half) and the barrel integrity is maintained by allowing natural drying in the lower half.

[0030] By way of example, in a 200 litre capacity barrel, a typical head / end diameter may be 54cm, the largest diameter at the mid-point is 65cm, with an overall height of 89 cm. The ends account for about 20-25% of the total surface area of the barrel, such that covering the upper half of the side walls (to line 18), without covering the end 12, results in a total film coverage of less than 40%. Covering both the upper half of the side walls and one end of a barrel requires a total film coverage of 50%.

[0031] To create a further barrier to vapour loss, the system herein may utilise a solid flat surface to be brought into contact with a rim of a barrel, e.g. the upper rim 15. Such a surface can be provided as a deck of a pallet 19, as shown by Figure 3.

[0032] In the illustrated view of pallet 19 from Figure 3, deck 20 appears as a single piece of sheet material, such as wood, plastic or metal. Deck 21, obscured from full view, may be comprised of multiple planks and, as such, provides gaps therebetween. The decks 20 and 21 are separated by spacer blocks or lengths 22 in the known way.

[0033] Referring to Figure 4, in practice it is preferable that a pallet 19 be used to assist stacking of multiple barrels 10, where the solid (no gaps) deck 20, schematically represented by solid lines, is oriented to face and be in contact with the top rim 15 of a barrel. In this way, the sheer weight of the pallet and / or a stacked barrel above will form a seal to egress of vapour through an upper end of barrel 10, proximate rim 15. Meanwhile the open deck 21, schematically represented by dashed lines in Figure 4, becomes the upper deck, in contact with a base / rim 16 of the barrel.

[0034] Barrels 10 may be stacked, for example, six high in a modern warehouse. Accordingly, at least for all but the top row, the selection of pallet structure (i.e. a solid deck) reduces ullage in combination with selective covering by a film of a portion of the side walls and / or the barrel end, while leaving a portion of the side walls exposed for drying, oxygen permeation and enabling a tortuous path thereto.

[0035] Film F may be applied manually or by machine in a manner suitable for the required use. Multiple layers or selected thickness may be applied as needed, subject to optimisation calculations. The film itself is intended to be a commercially available polyester film or the like to provide a reasonable ethanol vapour barrier. PLA or PETG is preferred. However, alternatives materials may become available which provide an equivalent function.

[0036] In some forms, a gasket may be included at the interface between an upper end of a barrel and pallet (e.g. a solid deck pallet). Particularly, for the top row of barrels in a stack, a gasket / cap structure may be fitted over the barrel since a free weight / compression force of solid deck against barrel end is not available. Alternatively, an uppermost pallet layer, with solid deck facing downwards and no barrels above it on the open deck, may be weighted or strapped down under tension to the stack below in order to seal the upper end of the barrels in the top row in a stack.

[0037] An analogous method may be developed for barrels racked on their sides where film is wrapped around an upper portion of a sideways oriented barrel.

[0038] By way of summary, the disclosure herein outlines a system and method for spirit maturation, e.g. in a barrel within a warehouse. The system and method firstly comprises applying a film layer to cover an upper portion of the barrel's side wall (and, potentially, its top end), while leaving a lower portion of the side wall (and the bottom 10 end) exposed. Such a configuration allows drainage of liquid leaks at the bottom of the barrel while inhibiting evaporation from the upper portion. Secondarily, a pallet having a solid / gapless deck may be contacted with a top end of an upright barrel. Weight from the pallet and / or a further barrel stacked thereon creates a seal and further inhibition of vapour loss from the headspace while the spirit is matured over an extended time period.

[0039] The system facilitates the use of off-the-shelf films, such as polyesters, that provide adequate ullage reduction performance when films are applied with far less than full coverage of the barrel sides. The methods herein may work with barrels stored in the more traditional racked style, and barrels stored upright in modern warehouses while taking advantage of modern warehousing techniques.

Claims

1. A system for spirit maturation, comprising:at least one barrel filled with alcoholic spirit, the barrel having a side wall, a first end and a second end; anda film applied to cover an upper portion of the side wall, relative to an orientation of the barrel, while leaving a lower portion of the side wall exposed.

2. The system of any preceding claim, wherein up to half of the side wall is covered by the film at the upper portion.

3. The system of any preceding claim, wherein the film is a polyester.

4. The system of any preceding claim, wherein the film is heat shrinkable and / orelastically deformable.

5. The system of any preceding claim, wherein the film comprises PLA.

6. The system of any preceding claim 1 to 4, wherein the film comprises PETG.

7. The system of any preceding claim, wherein the barrel orientation is upright, such that the first end is a top end and the second end is a bottom end.

8. The system of claim 7, wherein the top end is also covered by the film.

9. The system of claim 7 or 8, comprising at least one pallet for enabling uprightstorage and stacking of a plurality of barrels.

10. The system of claim 9, wherein the at least one pallet includes at least one solid deck, having a flat surface area with no gaps thereacross.

11. The system of claim 10, wherein the solid deck is configured for contacting with the top end of the at least one barrel, to form a seal therewith by virtue of the weight of the pallet, a downward force applied thereto and / or a stacked barrel supported upon the pallet.

12. The system of any preceding claim 10 or 11, wherein the solid deck is comprised of wood, plastic, metal or a combination thereof.

13. The system of any preceding claim 9 to 12, comprising a gasket at the top and / or bottom end of the at least one barrel to facilitate a seal between the pallet and barrel.

14. A method of warehousing barrels for maturing a spirit, comprising the steps of: filling at least one barrel with alcoholic beverage; and applying a film to cover an upper portion of the barrel, while leaving a lower portion of the side wall exposed.

15. The method of claim 14, including the step of locating the at least one barrel on a pallet.

16. The method of claim 15, including the step of locating a second pallet above the at least one barrel, the second pallet comprising a solid deck in contact with a top end of the at least one barrel.

17. The method of claim 16, including the step of locating a further barrel upon the second pallet, with the weight of the pallet and / or the further barrel compressing the solid deck against the top end of the at least one barrel.

18. The method of any preceding claim 14 to 17, including the step of heat shrinking the film to the at least one barrel.

19. The method of any preceding claim 14 to 18, including the step of stretching the film around and / or over the at least one barrel.

20. A container for maturation of alcoholic beverages, comprising:a barrel shaped wooden side wall;a first end;a second end;a vapour barrier film layer wrapping to cover at least a first portion of the barrel shaped side wall, proximate the first end, while leaving a second portion of the side wall proximate the second end uncovered, wherein the first portion is covered by up to half of a surface area of the side wall.

21. The container of claim 20, wherein the barrier layer is polyester, such as PLA or PETG.

22. The container of claim 20 or 21, wherein the first end is also covered by the barrier layer.

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