Note: Descriptions are shown in the official language in which they were submitted.
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BREWllVG CARBONATED BEVERAGES
This invention relates to closures, in particular to closures incorporating a
pressure relief valve for use in the brewing of carbonated beverages, and to
an apparatus for brewing, and to a method of brewing facilitated by said
apparatus.
The brewing of carbonated beverages in the domestic context has
traditionally been a two stage process employing a primary fermentation in
which the bulk of fermentable material in a liquor is converted into alcohol
and carbon dioxide by the metabolism of yeast at one atmosphere pressure.
A carbonated beverage is produced by decanting the liquor into a second,
sealed container and allowing the remaining, or additional fermented material
to be metabolised under pressure and thereby force more C02 into solution.
The problem with this method is controlling the secondary fermentation such
that the correct amount of C02 is produced.
Too little and the result is a flat beverage.
Too much and bottles will burst.
Further, different styles of beverage, for example, spritz, beer, and
Champagne, each contain different amounts of C02 , thus adding another
level of complexity for the brewer.
Careful use of a hydrometer and some calculation will often overcome these
problems, but even experienced brewers can be defeated by variations in
materials, or in subsequent ambient storage conditions.
It is an object of this invention to greatly simplify the brewing process,
making
the use of the hydrometer unnecessary and reducing the risk of burst bottles
to insignificant levels.
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It is another object of this invention to produce carbonated beverages of
different levels of dissolved C02 by means of brewing under different, preset
pressure levels.
It is a further object of the invention to provide an integrated package for
fermentable liquors ,for example fruit juice, such that a consumer may
purchase, brew and consume a carbonated beverage all from a single
container, simply and safely.
It is a further object of the invention to modify the brewing process
facilitated
by the invention to allow choice of alcohol content in brewed beverages from
less than 1 % to around 20%
The invention consists of an outer rigid member in the upper face of which is
formed one or more apertures; and an eiastomeric membrane containing a
substantially linear slit such that under ambient pressure when the
membrane is brought sealingly into contact with a container by means of the
rigid member the slit forms a closed valve, which, under elevated pressure,
progressively deforms outwardly through one of said apertures, opening at a
predetermined pressure and allowing excess gas to escape, and closing at
a predetermined pressure, thereby maintaining said container at a specified
pressure, which may take any value from 1 to 4 atmospheres, being
controlled by means of aperture diameter and membrane characteristics.
Closures incorporating pressure relief valves are generally well known in the
trade and literature.
The membrane valve in this case is formed from sheet material, the
punching and slitting operations being performed in one simultaneous
operation. Working within this method of manufacture, it has been found that
determining the operating characteristics of these valves is a matter of
controlling the following variables:
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Elastomeric properties of membrane and membrane thickness.
Diameter of aperture formed in the upper face of the outer rigid member.
Extent of elastic deformation of membrane whilst slit is machined.
Cutting characteristics, including length, of incision tool.
It is noted that many combinations of material and aperture size may be
employed to achieve a desired result across a wide range of operating
pressures. It is therefor possible to apply the closure to a wide range of
existing containers, for example, glass bottles, soda bottles and wide necked
polymer bottles, as illustrated in Figs. 1-5 , each of which is a bisecting
cross
sectional view.
Fig. 1 shows the closure applied to a screwed neck bottle at ambient
pressure. The membrane (1 ) is freely located within the outer rigid member
(2), and is brought sealingly into position on the bottle neck (4) as the
outer
rigid cap is tightened into a closed position. At this stage the membrane is
substantially flat, with the slit forming a closed valve across the aperture
(3)
sealing against both escape of contents, when the bottle is shaken, and
intrusion of extraneous microbes, during the early stages of fermentation, as
pressure within the bottle moves up from ambient to the preset level.
Fig. 2 shows the closure at operating pressure, the membrane (5) being
progressively deformed outwardly through the aperture until the slit opens to
allow the excess gases of fermentation to escape. As fermentation subsides,
or is halted, and the production of gas declines, the valve re-closes,
maintaining the bottle at the pressure appropriate for the chosen level of
carbonation. Typical values for these operating pressures are; spritz style:
1.5 atmospheres, beer style: 2 atmospheres, Champagne style: 3
atmospheres.
The configuration of Figs. 1 & 2, is perhaps the most appropriate where the
closure is to be used for repeated cycles of brewing, in that it can be easily
disassembled for washing and sterilising. Yet it is cheap enough to be used
in one-use or disposable applications.
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In these configurations the membrane containing the slit/valve extends
wholly over the inside upper face of the outer rigid member, and thus both
the sealing and valuing functions are performed by the same membrane.
However, an O ring may be used to perform the sealing function inside the
outer rigid member with the membrane incorporating the valve extending
over the whole of the inside face of the outer rigid member, or merely over a
small portion in excess of the actual aperture, in this case being bonded in
position over the aperture.
It is also understood that the aperture need not be centrally located in the
outer rigid member.
Fig. 2A shows how an additional aperture in the outer rigid member might be
formed to accommodate a pressure dispensing capability (1 ) for the
container, whilst maintaining the relief valve. In such an embodiment, the
membrane will probably be bonded to the outer rigid cap to ensure alignment
of the apertures and their respective slit/perforation in the membrane (the
membrane being punched at (2) with a perforation of smaller diameter than
the dispensing tube (1 ) to effect an elastomeric seal around said tube.)
Given the economical nature of the method of manufacture of these
closures, and , as one highly preferred application of the closure is the
brewing of commercially available fruit juice, it will be seen from the
closure
so described that an advantageous embodiment would include a dose of
yeast within the cap, thus allowing the consumer to brew directly in the
bottle
of purchase. The package of purchase then also becomes the brewing
apparatus.
Fig. 4 shows the closure where the outer rigid cap is formed with an aperture
and membrane valve brought sealingly into position over a container as
before. In this embodiment the outer rigid cap consists of two parts; a main
body, which is substantially similar to the simple forms of the closure,
together with a rigid sleeve section (13) which is screwed or pressed into a
closed position as in Fig. 4a . In this position the closure holds a dose of
yeast, (12) (which may be granulated, tabletted or encapsulated), in a fixed,
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sealed position between the membrane and a cavity (11 ) formed as an
integral part of the outer rigid member. So fixed and sealed the yeast is kept
dry and immobilised during transit and storage. The whole closure being
encased in a thin film sleeve (14) to ensure tamper-proofing and the
exclusion of foreign matter. In such a configuration, the yeast and liquid
contents of the container are kept apart until the consumer peels off the
outer sleeve and unscrews the upper sleeve and shakes the bottle. Fig. 5
shows the bottle just prior to shaking, which will bring yeast and liquid into
mutual contact, ( the upper and lower sections of the outer rigid member
being connected by communicating passages), which is at this stage
prevented from escaping the bottle by the membrane valve (10) being
substantially flat and in a closed position.
Having set the fermentation in progress, it continues at ambient temperature
in the sealed bottle until such point as the pressure in container opens the
valve and allows excess gas to escape to the atmosphere.
Whilst the arrangement in Fig. 5 illustrates an upward opening outer rigid
sleeve, it could equally be employed to house a capsule of liquid yeast which
would be intentionally ruptured by a downward repositioning of the rigid outer
sleeve.
It will be apparent that the closures and containers so disclosed form part of
a method of producing carbonated alcoholic beverages across a wide range
of carbonation values and also make possible the safe brewing of beverages
across a wide range of alcohol content.
The method comprises six elements, disclosed as follows;
1 ) A vessel capable of safely operating at the appropriate pressure for the
desired level of carbonation.
2) A sealing and venting method for said vessel.
3) Fermentable material placed in said vessel.
4) A dose of yeast brought into contact with fermentable material.
5) Means of establishing the alcohol content of fermenting or fermented
material.
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6) Means of halting the fermentation at any stage in the fermentation
process.
Dealing with each of these elements in turn:
1 ) Suitable vessels are to be found in many forms, for example, the soft
drink
or soda bottle, glass beer or champagne bottles, wide necked fruit juice
bottles , and others.
2) The sealing and venting of such a vessel may take many forms; the two
operations may be achieved by one elastomeric membrane, or by any of a
vast variety of pressure relief mechanisms. The vessel must be sealed so as
to maintain the chosen operating pressure and also vented to allow excess
gases of fermentation to escape.
3) Fermentable material may take many forms and may embody an
abundance of fermentable material such that the limiting factor in the
production of alcohol is the alcohol tolerance of the yeast, such material
being susceptible to the halting step (6), or they may be self limiting by
being
formulated so that fermentation exhausts the available fermentable material
at some point below the alcohol tolerance of the yeast. Fermentable
materials may be liquids, syrups, concentrates or powders.
4) Yeast is brought into contact with the fermentable material in the
appropriate proportion to establish fermentation.
5) Means of estimating the alcohol content will take two general forms:
A) use of prior data to establish the likely alcohol content of the liquor.
Each fermentable liquor and each variety of brewing yeast will, in concert,
exhibit a particular fermentation profile. That is, the rate at which
fermentable
material is converted into alcohol and C02 will be to some degree peculiar to
each liquor/yeast combination (and also a function of temperature and
pressure). In practice, a generalised profile as shown in Fig. 6 will usually
be
adequate for estimating the alcohol content at any point in the fermentation
profile.
Based on this relationship, a suitable graphical representation can be
consulted without recourse to opening the container and making physical
measurement.
B) Measurement directly by means of hydrometer or other means requiring
contact with fermenting material.
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6) Means of halting fermentation. Fermentation typically exhausts itself when
all the fermentable material in a liquor is converted into alcohol and C02, or
the yeast reaches its alcohol tolerance level. Such self limiting processes
are
one route to a halted fermentation but refrigeration to a temperature below
that where the yeast is active is a convenient and effective option.
One preferred embodiment of this process would consist of;
1) The standard soda bottle, carbonated soft drink bottle or wide mouth juice
bottle.
2) Closure for said bottle incorporating a pressure relief mechanism.
3) Fruit based fermentable material.
4) Granulated yeast.
5) Printed fermentation profrie attached to bottle.
6) Use of domestic refrigeration at 5 degrees Celsius or less, combined with
a yeast active at 10 degrees Celsius or greater.
A carbonated alcoholic beverage is thus brewed in a vented container at
ambient temperature, set at an operating pressure commensurate with the
chosen level of carbonation. Fermentation continues for a time period which
corresponds with the chosen level of alcohol {as read off fermentation
profile). Fermentation is arrested by refrigerating the container to a
temperature at which the yeast is inactive, at which point the alcohol content
remains substantially fixed. The beverage is now ready for consumption at
the consumer's leisure. This method has the added advantage of being able
to re-carbonate the contents of containers where consumption is spread over
two or more sittings. By the simple expedient of allowing the container to
remain unrefrigerated for a few hours the yeast reactivates, and, as long as
the pressure relieved closure is in place, safely re-carbonates the beverage.
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