Note: Descriptions are shown in the official language in which they were submitted.
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METIiOD OF IMPROVING FROTi-I ON BEVERAGE DISPENSED FROM A CONTAINER
The present invention relates to a liquid product
in cans ~or bottles or any other suitable containers.
The present invention relates particularly to a
liquid product, such as beer, Which contains nitrogen for
the purpose of causing the liquid product to have a smooth,
non-bitter, taste and excellent foaming characteristics.
The present invention also relates to a method of
producing a liquid product packed in cans or bottles or any
other suitable containers.
In this context, the present invention relates
particularly, although by no means exclusively, to a method
of producing a carbonated beverage product, such as bear,
packed in cans or bottles or any other suitable containers,
which method is characterised by injecting nitrous oxide
and, optionally, one or more than one of nitrogen and
carbon dioxide into the containers.
One particular, although by no means exclusive,
application of the present invention is beer and the
following discussion of the prior art is in this context.
Australian patent application 55602/86 entitled
"Carbonating in Botales and Cans" in the name of gatehouse
Technical Ventures Limited describes that foam is an
important element in the consumer appeal of most beers and
of some other carbonated beverages. More particularly, the
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Gatehouse patent application describes that:
"The most important means by which foam is
produced by any of these liquids is the release
of carbon dioxide from super-saturated solution.
Super-saturation arises when a previously-closed,
pressurised container is opened to atmosphere or
when the ;liquid contents are discharged from
within it through a tap or similar device.
Bubbles of carbon dioxide gas are then released
by turbulent flow, by nucleation on solid
surfaces or particles, or by diffusion into
existing gas bubbles.
=n the case of beers and other carbonated
beverages, bubbles aggregate to produce foam
which rests on top of the beverage in the
drinking-glass (or other drinking container).
More bubbles are released, and foam consequently
produced, as the beverage is drawn into and flows
within the mouth, producing a variety of sensory
impressions including viscosity. As the beverage
is tipped from the glass, foam clings to its
walls, giving an attractive pattern known as
'lacing'."
It is known that carbonation causes beer to have
carbon dioxide bite and, whilst this taste is regarded
favourably by some sections of the consumer market, there
are other sections of the market that regard the taste as
undesirable.
It is known to add nitrogen to beer as an
alternative means of producing foam in beer.
It is also known that nitrogen causes beer to
have a smoother, less bitter, taste.
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It is also knows to add nitrogen to cans to
generate super-atmospheric pressure in the head-spaces of
the cans to prevent deformation of the sealed cans during
normal handling of the cans.
There are a number of known options for
introducing nitrogen into beer.
One option is to dissolve nitrogen in beer prior
to filling into cans or bottles. This option is described
in a number of patent applications and patents including,
by way of example, Australian patents 642219 and 642714 in
the name of The BOC~ Group plc and International application
PCT/SE95/01449 (WO 96/17529) in the name of Tetra Laval
Holdings & Finance S A. In each of these patents and
patent application, the main stated reason for adding
nitrogen to cans is to generate super-atmospheric pressure
in the head-spaces of the cans to prevent deformation of
the sealed cans.
The addition of nitrogen to non-carbonated liquid
products prior to filling into cans or bottles is also
described in a number of patents and patent applications
including, by way of example, Australian patent 642789 in
the name of The BOC'. Group plc, UR patent application
2134496 in the name of Asahi Breweries Ltd, and US patent
4347695 in the names of General Foods Corporation.
The Gatehouse patent application describes the
option of dissolving nitrogen in beer prior to filling into
cans or bottles in the following negative terms:
~~if nitrogen is dissolved in the beverage in a
reservoir before a filling operation carried out
in currently used equipment for filling small
containers with carbonated beverages, most of the
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nitrogen is removed by 'gas washing' because, due
to the much lower solubility of nitrogen than
carbon dioxide in the liquid, any bubbles
liberated by liquid movement entrain nitrogea.~~
Another option for introducing nitrogen into beer
is to add nitrogen to beer at a filling station.
The Gatehouse pateat application describes as an
invention a method of producing cans and bottles containing
beer in accordance with this option which comprises the
steps of
(i) partially filling a can or bottle with a
predetermined quantity of beer;
(ii) adding a predetermined quantity of liquid
nitrogen to the container or bottle; and
(iii)sealing the can or bottle.
The Gatehouse patent application describes that
the addition of nitrogen to beer in amounts of up to 1.14
grams of liquid nitrogen per litre of beer Was found to
progressively improve foaming properties of beer.
International application PCT/AU98/00540 of the
applicant proposes the addition of nitrous oxide and
optionally nitrogen as an alternative means of producing
beer that has good foaming characteristics and has a
smoother, less bitter taste than beer that contains carbon
dioxide only. The preferred method disclosed in the
International application includes the step of pressurising
beer after injecting nitrous oxide, carbon dioxide and
nitrogen into the beer in order to improve the solubility
of the injected nitrous oxide, carbon dioxide, and nitrogen
in the beer. The disclosed preferred method also includes
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the subsequent step of depressurising the bear to a
suitable filling pressure before filling the beer into
cans, bottles or other suitable containers.
Notwithst~~nding the disclosure in the Gatehouse
patent application and in other patent applications and
patents, as far as 'the applicant is aware, there is no
commercially available canned or bottled, ie packaged, beer
that contain nitrogen in accordance with the above options
that has satisfactory foaming characteristics. In
particular, the applicant is not aware of any commercially
available canned or bottled beer that contain nitrogen in
accordance with the above options that generates foam that
"surges" after the .beer is poured into a glass - which is a
characteristic feature of nitrogenated beers that are
available on tap.
As a consequence of the inadequate foaming
characteristics of canned or bottled beer that contain
nitrogen in accordance With the above options, the brewing
industry has developed a further option for introducing
nitrogen into beer 'which is based on the use of inserts,
commonly referred to as "widgets", positioned in cans or
bottles. The widgets store nitrogen gas when the cans are
sealed and release the gas as small bubbles when the cans
or bottles are subsequently opened.
There has been considerable research and
development work into widgets. As a general proposition it
can be said that widgets improve the foaming
characteristics of nitrogeaated bear. This is reflected in
that, as far as the applicant is aware, commercially
available canned nitrogenated beer is only available in
cans or bottles having widgets. The extent of research and
development work and the importance of widgets is also
reflected by the number of patent families for widgets in
Australia and elsewhere.
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Notwithstanding the improved foaming
characteristics that are attributable to widgets, there is
a cost penalty associated with the use of widgets, and in
the circumstances there is a need for a non-widget solution
to the problem of generating foam in nitrogenated beer (and
other liquid products).
One objective of the present invention is to
provide a method of improving the foaming characteristics
of canned or bottled, ie packaged, nitrogenated beer.
Another objective of the present invention is to
provide an imy~roved method of producing cans or bottles or
other suitable containers containing bear. A particular
objective is to provide a method which is an improvement
over that: described in International application
PCT/AU98,~00540 .
According to a first aspect of the present
invention there is ;provided a method of improving the
foaming characteristics of a nitrogenated liquid product
that is packaged in cans or bottles or other suitable
containers which includes the steps of shaking a sealed can
or bottle or other suitable container to disperse bubbles
of nitrogen throughout the liquid product and immediately
thereafter opening the container and pouring the liquid
product :From the container.
The applicant has now found surprisingly that
shaking a sealed can or bottle or other container
containing nitrogenated beer and thereafter opening the
container and pouring the beer from the container
significantly improves the foaming characteristics and,
more particularly, the surge quality of the beer.
The applicant has found that this surprising
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beneficial result caused by shaking the container applies
to nitrogenised beer in containers:
(i) with or without widgets; and
(ii) with or without other foaming additives,
such as nitrous oxide and carbon dioxide.
The result is surprising because it is usually
the case that deliberate shaking of cans or bottles of beer
should be avoided because, usually, canned/bottled beer is
highly carbonated and shaking has the adverse effect of
producing uncontro7.led spray when the cans or bottles are
opened. The applicant believes that the effect of shaking
is to create small bubbles of nitrogen and to disperse
these throughout the beer, whereby after cans or bottles of
such beer are opened and poured immediately into a glass,
the small bubbles generate a surge effect.
The term "immediately thereafter" is understood
to mean that the beer is poured within 2 minutes of opening
the container.
The extent of shaking may vary considerably
depending on facto~:s such as the amount of nitrogen in the
beer and the amount: of other foaming agents, such as carbon
dioxide and nitrous oxide, in the bear.
Typically., cans or bottles or other suitable
containers are held and are given one or more short, sharp
to and fro movements in the axial direction of the
containers which shake the contents of the containers.
The nitrogenated beer may be produced by any
suitable method.
The nitrogenated beer may include any suitable
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_ g
amount of nitrogen.
The nitrogenated beer may also include one or
more than one other foaming additive, such as nitrous oxide
or carbon dioxide.
According to a second aspect of the present
invention there is provided a method of producing a liquid
product packed in cans or bottles or other suitable
containers which includes the steps of filling the liquid
product auto cans or bottles or other suitable containers
and sealing the cans or bottles or other suitable
containers, and which method is characterised by injecting
nitrous oxide arid, optionally, one or more than one of
nitrogen and carbon. dioxide into the liquid product prior
to, during, or after filling the liquid product into cans
or bottles or other suitable containers and without
externally pressurising the liquid product after injecting
the nitrous oxide a.nd, optionally, one or more than one of
nitrogen and carbon. dioxide.
The term "externally pressurising" is understood
to mean applying pressure to a liquid product by external
means and not as a result of pressure generated by the
injection of nitrous oxide and, optionally, one or more
than one of nitrogen and carbon dioxide.
With reference to ~nteraational application
PCT/A098/00540, this aspect of the present invention is
based on the unexpected realisation that it is not
necessary to externally pressurise a liquid product after
nitrous oxide and, optionally, one or more thaw nitrogen
and carbon dioxide has bean injected into the liquid
product.
The second aspect of the present invention
extends to situations in which nitrous oxide (with or
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without other additives) is injected at say one of the
stages, :namely prior to, during, and after filling
containers and to situations in which nitrous oxide (with
or without additives) is injected and two or more of these
stages.
The nitrous oxide, nitrogen and carbon dioxide
may be i:n a gaseous or a liquid state.
Preferably the method includes:
(i) injecting nitrous oxide and, optionally, one
or mare than one of nitrogen and carbon
dioxide into the liquid product;
(fi) without externally pressurising the liquid
product after step (i), filling the liquid
product into cans or bottles or other
suitable containers; and
(iii)thereafter sealing the cans or bottles or
other suitable containers.
The cans or bottles or other suitable containers
may be made from any suitable material. By way of example,
suitable materials include, metal, glass and plastics.
Preferably the method further includes injecting
nitrogen into the cans or bottles or other suitable
containers prior tc>, during, or after filling the caws or
bottles or other suitable containers. In this context the
present invention extends to situations in which nitrogen
is iajected in each stage, ie prior to, during, and after
filling the cans oz- bottles or other containers.
fore preferably the method further includes
injecting nitrogen into the cans or bottles or other
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suitable containers after filling the cane or bottles or
other suitable containers with liquid product and before
sealing 'the caws or bottles or other suitable containers.
In one embodiment the method includes chilling
the liquid product to a predetermined teu~perature prior to
injecting nitrous oxide and, optionally, one or more than
one of nitrogen and carbon dioxide into the liquid product.
In another embodiment the method includes
chilling the liquid product to a predetermined temperature
after injecting nitrous oxide and, optionally, one or more
than one of nitrogen and carbon dioxide into the liquid
product.
Preferably the predetermined temperature is fn
the range of -1°C-8"C .
More preferably the temperature range is -1°C-
4°C.
It is preferred particularly that the temperature
range be -1°C-1°C.
Nitrous oxide may be the only additive.
Optionally, the method includes injecting any
suitable combination of nitrous oxide and one or more than
one of nitrogen and carbon dioxide. Specifically: nitrous
oxide and nitrogen; nitrous oxide and carbon dioxide; and
nitrous oxide, nitrogen and carbon dioxide may be injected
into the liquid product.
In a situation where the liquid product is bear,
carbon dioxide injection may not be necessary because the
beer has sufficient: carbonation.
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In a situation where the liquid product is beer,
it is preferred that some nitrogen be injected prior to
filling the cans or bottles or other suitable containers
and that further nitrogen or the balance of nitrogen
required be injected into the containers prior to sealing
the contaiaers.
Preferably, the nitrous oxide and, optionally,
one or more than one of nitrogen and carbon dioxide are
injected as a gas.
The nitrous oxide and, optionally, one or more
than one of nitrogen and carbon dioxide may be injected
into the liquid product as a gas mixture or as separate
gases or as a liquid mixture or as separate liquids or as
mixtures of gases and liquids.
Preferably, the liquid product supplied to the
process a carbonated liquid product. The method may
include stripping excess carbon dioxide from the liquid
product prior to injecting nitrous oxide and, optionally,
one or more than one of nitrogen and carbon dioxide.
In a situation where the liquid product is beer,
the principal purpose of nitrous oxide is to take away the
adverse effect of carbon dioxide bite caused by carbon
dioxide. Nitrous oxide also enhances the head of a beer
poured into a glass..
The nitrogen is added principally to generate
small bubbles which produce foam when sealed cans or
bottles .are opened.
The carbon dioxide and nitrous oxide are more
soluble than nitrogen and therefore are not as effective as
nitrogen in generating foam - although a portion of both
gases will contribute to producing foam when the cans or
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bottles are opened.
The principal purpose of adding carbon dioxide to
beer is to ensure that beer does not go "flat" shortly
after being poured from the can or bottle into a glass or
other container.
In addition to the above, each of nitrogen,
carbon dioxide and nitrous oxide contributes to producing a
super atmospheric pressure in the head spaces of sealed
cans or bottles or other suitable containers to withstand
deformation during normal handling of the sealed cans or
bottles or other suitable containers.
According to the present invention there is also
provided a liquid product contained under pressure in a
sealed can or bottle ar other suitable container, which
liquid product includes nitrous oxides, nitrogen, and
carbon dioxide, which are released as gaseous phases and
cause foaming of the liquid product when the can or bottle
or other suitable container is opened.
Preferably the sealed can or bottle or other
suitable container contains 0.01-4 volumes of nitrous oxide
per unit volume of the liquid product.
More particularly the aesied can or bottle or
other suitable container contains 0.01-1.2 volumes of
nitrous oxide per unit volume of the liquid product.
More preferably the sealed can or bottle or other
suitable container contains 0.01-0.8 volumes of nitrous
oxide per unit volume of the liquid product.
Preferabl~,y the sealed can or bottle or other
suitable container contains 0.1-3.5 volumes of carbon
dioxide per unit volume of the liquid product.
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More preferably the sealed can or bottle or other
suitable container contains 0.5-2.6 volumes of carbon
dioxide per unit volume of the liquid product.
More preferably the sealed can or bottle or other
suitable container contains 0.9-1.7 volumes of carbon
dioxide per unit volume of liquid product.
=t is preferred particularly that the sealed can
or bottle or other suitable container contains 1.2-1.6
volumes of carbon dioxide per unit volume of liquid
product.
Preferably the sealed can or bottle or other
suitable container contains 0.1-2.8 volumes of nitrogen per
unit volume of the liquid product.
More particularly the sealed can or bottle or
other suitable container contains 0.5-1.2 volumes of
nitrogen per unit volume of the liquid product.
More preferably the sealed can or bottle or other
suitable container contains 0,8-1.2 volumes of nitrogen per
unit volume of the liquid product.
=t is preferred particularly that the sealed can
or bottle or other suitable container contains 1-1.2
volumes of nitrogen per unit volume of the liquid product.
Preferably the internal pressure of the sealed
bottle o,r contaiae=' is greater than 3 atmosphere absolute
at ambient tea4perat.ure .
More preferably the internal pressure is 4-5
atmospheres abaolut.e.
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Preferably the sealed can or bottle or other
suitable container does not include a "widget" or other
device for storing .nitrogen, carbon dioxide and nitrous
oxide for release when the can or bottle is opened.
Preferably the liquid product is beer.
The applicant has carried out a series of
experiments/trials ;producing and thereafter tasting liquid
products in sealed cans. The applicant found that canned
products,, such as beer, produced in accordance with the
method of the second aspect of the present invention,
exhibited excellent foaming characteristics and taste.
The applicant also found in the series of
experiments/trials that the foaming characteristics of the
packaged beer were enhanced in accordance with the first
aspect of the present invention by shaking the cans prior
to opening the cans and pouring out the liquid products. As
is indicated above, this is a surprising result in relation
to carbonated liquid products because usually it is the
case that even minor amounts of shaking generate excessive
amounts of foaming .and are undesirable for this reason.
The following discussion highlights the key results of the
experiments/trials for this aspect of the present
invention.
Def init ions
1. Surge - a cascade or ripple affect produced by
effervescence or dispersed gas bubbles in the
beverage (particularly beer) as the bubbles rise
to the top of the beer. This phenomenon can be
observed where beer is dispensed from a tap into
a conical beer glass.
2. Surge time - duration of the surge measured from
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the time t:he beer glass is fully filled to the
time the surge disappears, ie When the boundary
between the head and the beer is distinct or
clear cut..
3. Head size - the height of the foam above the beer
in a glass .
4. Serving temperature - the temperature of beer
measured after it is filled into a beer glass.
5. Head-spacE~ - the empty space above the liquid
content in a container.
6. Gas volume - total volume of a gas dissolved in
the beer or present in the head-space per volume
of beer in the container.
7. Shake - a complete to and fro swing of a beer
container. A light shake is one where the
distance traversed by the container is less than
200mm. A heavy shake is one Where the distance
traversed is more than 250mm.
=n the experiments/trials, the applicant found
that, for a given gas mixture and composition, a given
level of foaming agents (eg hop extract and PGA used in the
brewing i.ndustry), and a given serving temperature, the
number of light shakes given to the packaged beer affects
the surge time aad l:he head size. Typical examples are:
1. Type of beer: bitter, draught
Gas composition: 1.2 v/v COa, 0.03 v/v NsO,
0 . 8 v/v Ns
Serving temperature:4°C
Surging times: 20 seconds after 1 light
shake; 30 seconds after 2
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light shakes; 50 seconds
after 3 or more light shakes
Head sizes: l5mm after 1 light shake;
l8mm after 2 light shakes;
25mm after 3 or more light
shakes.
2. Type of beer: stout, draught
Qas composition: 1.2 v/v CO~, 0.03 v/v NaO,
0.9 v/v Na
Serving temperature:4C
Surging times: 35 seconds after 1 light
shake; 55 seconds after 2
light shakes; 90 seconds
after 3 or more light shakes
Head sizes: l8mm after 1 light shake;
20mm after 2 light shakes;
23mm after 3 or more light
shakes.
3. Type of beer: lager, draught
c3as composition: 1.4 v/v COa, 0.03 v/v NsO,
0.8 v/v N2
Serving temperature:4C
Surging times: 20 seconds after 1 light
shake; 30 seconds after 2
light shakes; 45 seconds
after 3 or more light shakes
Head sizes: 20mm after 1 light shake;
22mm after 2 light shakes;
25mm after 3 or more light
shakes.
One heavy shake approximates 2 light shakes; 2
heavy shakes approximate 3 or more light shakes.
Shaking the container before opening imparts two
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things to the beer;
1. Gases in the head-space are dissolved or
dispersed into the beer; and
2. A foamy head is formed in the container.
The foamy head and the extra gases dissolved or
dispersed in the beer help to produce the surge when the
container is subsequently opened and the beer poured into a
conical glass.
Similar patterns in surge time and head size can
be obtained with beer containing COa and Nz, with or
without NsO.
The second aspect of the present invention is
described further by way of exan4ple with reference to the
accompanying drawing which is one preferred embodiment of a
method o:E producing canned beer in accordance with the
present invention.
The preferred embodiment described below relates
to producing beer. It is emphasised that the present
invention is not limited to producing beer and extends to
producing any carbonated and non-carbonated liquid product.
With reference to the figure, carbonated beer
produced by conventional beer-making technology flows along
a line 1;2 and excess carbon dioxide (if any) is stripped
from the beer prior to the beer reaching a holding tank 14.
The beer flows from the holding tank 14 through a
chiller 16 in which. the beer is chilled to a temperature in
a range of -1°C to ~4°C.
Thereafter, the beer flows to a filling station
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26 at which the beer is filled into cans and the filled
cans are sealed.
Nitrous oxide in gaseous form is injected into
the beer upstream of the chiller 16.
The gas may be injected on its own or as a gas
mixture with one or more than one of carbon dioxide and
nitrogen. In a situation where carbon dioxide and nitrogen
are injected into t:he beer, each gas may be injected on its
own or as a gas mixture with the other gases.
The amount of each gas injected iato the beer
should be within the broad ranges described above and
having regard to the levels of injection of the other
gases. ors a general guideline, as the level of injected
carbon dioxide increases, the level of injected nitrous
oxide can decrease.
In addition to the gas injection prior to the
chiller :16, liquid .nitrogen is injected into the head space
of each filled can ;prior to sealing the can. The injection
of liquid nitrogen at this point rather than upstream of
the filling station 26 is preferable in view of the
comparatively low solubility of nitrogen in beer.
Moreover,, injection of liquid nitrogen at this point
obviates the capital and operating costs associated with
pressurising beer to improve the solubility of nitrogen in
the beer and thereafter depressurising the beer to a
suitable filling pressure as is required in the
International application of the applicant that is
discussed above.
Many modifications may be made to the preferred
embodiments described above without departing from the
spirit and scope of the present invention.
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By way of example, whilst the preferred
embodiment described above chills the beer after injecting
nitrous oxide and, optionally, one or more than one of
nitrogen and carbon, dioxide into the beer, the present
invention is not limited to this arrangement and Qas
injection can be made after chilling the beer.
