Note: Descriptions are shown in the official language in which they were submitted.
c~ ~~
1
TITLE
"A beverage package"
TECxrtIC~L ~°I~Ln ~ ~a~cxc~oUrrn ~xT
The present invention relates to a beverage package
and a method of forming such a package. More particularly
it concerns beverages containing gas, such as carbon
dioxide and/or nitrogen, in solution and packaged in a
sealed container which, when opened for dispensing or
consumption, causes gas to be evolved or liberated from the
.beverage to form, or assist in the formation of, a head of
froth on the beverage. The beverages to which the
invention relates may be alcoholic or non-alcoholic;
primarily the invention was developed for fermented
beverages such as ale, lager, stout or other beer' and cider
but may be applied with advantage to so--called soft drinks
and beverages, or alcoholic drinks such as spirits,
liquers, wine and the like.
Beverage packages are known which comprise a sealed
container having a primary chamber containing the beverage
having gas in solution and forming a primary headspace
comprising gas at a pressure greater than atmospheric and
in which a secondary chamber containing gas at a pressure
greater than atmospheric has a restricted orifice which
communicates with the beverage in the primary chamber.
Upon opening the package to dispense the beverage, the
primary headspace is opened to atmospheric pressure and
this creates a pressure differential within the container
which causes gas in the secondary chamber to be ejected by
way of the restricted orifice into the beverage in the
primary chamber. The ejection of the gas from the
secondary chamber and through 'the restricted orifice causes
gas in solution in the beverage to be evolved for froth
formation. An eacample of a beverage package having the
2
latter characteristics is disclosed in our British Patent
No. 1,266,351 (where the gas ejection from the secondary
chamber may be through a non-return valve).
In the known beverage packages of the kind discussed
above the restricted orifice is located at or towards the
bottom of the beverage in 'the primary chamber. when the
package is opened and gas is ejected through the restricted
orifice, gas in solution is initially evolved in the region
of the beverage which is local to the restricted orifice
and this evolution of gas develops or grows rapidly to rise
or surge throughout the volume of beverage in the primary
chamber to develop a head of froth which is retained when
the beverage is dispensed from the container. Fox some
beverages, particularly those containing carbon dioxide in
solution (with or without nitrogen gas in solution) it is
possible for a major part, if not all, of the gas in
solution to be evolved from the beverage shortly after the
gas has been ejected from the secondary chamber on opening
the package. As a consequence, when the beverage is
dispensed from the container into a drinking glass for
consumption, it is possible that the absence, or low level,
of gas in solution in the beverage will impart undesirable
characteristics to the beverage (albeit that such beverage
may have a good quality head of froth)> This is
particularly the case for so-called light beers or lagers
where it is preferred that a reasonable volume of gas,
usually carbon dioxide, is retained in solution in the
beverage as dispensed in a drinking glass so that such gas
can evolve naturally to rise as minute bubbles within the
. beverage and the latter retains a ''sparkle" which is
considered desirable aesthetically and can add to the
consumer's enjoyment and °'orouth feel" of the beverage. It
is an object of 'the present invention to provide a beverage
CA 02102037 2002-12-17
3
package of the kind generally discussed which alleviates
the aforementioned disadvantage of excessive liberation of
gas in solution so that the beverage when dispensed will
retain a desirable "sparkle" without detracting from the
desirable characteristics required far froth deve:Lopment in
forming a head on the beverage.
STATEMENT OF INVENTION & ADVANTAGES
According to the present invention there is provided a
beverage package comprising a sealed container having a
primary chamber containing beverage having gas is solution
therewith and forming a headspace comprising gas at a
pressure greater than atmospheric; a secondary chamber
formed by a hollow insert located the primary chamber at or
towards the bottom of the primary chamoer and containing
gas at a pressure greater than atmospheric fo:r communica-
tion with beverage in the primary chamber by way of an
aperture and an upwardly extending tubular extension
carried by the inert, the package being openable to open
the primary chamber to atmospheric pressure and said
opening creating a pressure differential causing gas under
pressure from the secondary chamber to be introduced by way
of the aperture into the beverage in tine primary chamber
for said introduction to liberate gas from soi~ation in the
beverage to form froth in the primary headspace and wherein
said liberation of gas is restricted to a minor proportion
of the volume of beverage in the primary chamber, wherein
the insert comprises a base part located at or towards the
bottom of the primary chamber and the tL_bular extension is
carried by the base part, said base part tubular extension
together forming the secondary chamber and wherein the
aperture is located cn the tubular extension in the
CA 02102037 2002-12-17
3a
beverage at a position nearer to the surface of the
beverage than to the bottom of the bever~~.ge in the primary
chamber for said liberation of gas to be restricted to
beverage in the primary chamber disposed within a miner
depth of the beverage from: she surface Thereof.
Beverage packages are well known, for example as
disclosed in our British Patent No. 1,266,:351, in. which in
response to a pressure differential developed on opening of
the package, gas under pressure from a secondary chamber is
injected into beverage in the primary chamber for the
purpose of liberating gas from solution in beverage in the
primary chamber. This ejection is effected from the
secondary chamber through an aperture and in the prior
proposals such aperture is located at or towards the bottom
of the beverage in the primary chamber. As a consequence
high energy from the gas injection liberates gas from
solution in the beverage initially in the region of the
aperture and this seeds the further liberation of gas from
the beverage so that a surge of gas bubbles develops and
grows rapidly to rise, predominantly, throughout the volume
of beverage in the primary chamber. By the present
invention the aperture is located in the beverage in the
primary chamber nearer to the surface of that beverage than
to the bottom of the beverage and as a consequence the
aforementioned liberation of gas from solution in the
beverage by the rising surge of gas bubbles from the
aperture restricts the gas liberation to a minor proportion
of the volume of beverage in the container. Typically
the minor proportion of beverage from which gas is
liberated will be less than 30~ of the total volume of
beverage within the container. The result of such
restricted gas liberation is that a major proportion of the
volume of beverage in the container will retain gas in
solution - this is particularly so for carbon dioxide.
Therefore when the beverage is dispensed from the containex-
into a drinking glass for consumption, gas may continue to
evolve from solution to maintain "sparkle" and other
characteristics considered desirable for the beverage
~ product.
The secondary chamber may be integral with the
container but is preferably formed by a hollow insert
located in the. primary chamber. The insert will usually
5
be located at or towards the bottom of the primary chamber
and in such case it may be provided with an extension that
projects upwardly in the beverage to locate the aperture at
its submerged position nearer to the surface of the
beverage than to the bottom of the beverage in the primary
chamber. Usually the insert will be formed of plastics
having a base part which carries a tubular extension
projecting upwardly within the beverage so that the base
part and tubular extension together form the secondary
chamber and the aperture can be located at or towards the
top of the tubular extension. Conveniently the base part
of the insert is located within the container through an
open top thereof during formation of 'the beverage package
and subsequently the extension part can be fitted and
sealed to the base part within the primary chamber. The
aperture of the insert is likely to be restricted
sufficiently to alleviate flow of beverage from the primary
chamber into the secondary chamber when the contents of the
sealed package are in equilibrium. However, in a
preferred insert structure the aperture has a non-return
valve associated therewith which restrains entry of
beverage into the secondary chamber and which is responsive
to the pressure differential (developed when the package is
opened to open the primary headspace to atmospheric
pressure) to permit the injection of gas under pressure
from the secondary chamber into the upper region of
beverage in the primary chamber for froth development.
The latter form of insert may be received within an open
topped container during formation of the package with the
aperture closed so that the secondary chamber is sealed and
contains gas at a pressure greater. than atmosphericg
following charging of the container with its beverage and
subsequent sealing of the container, the sealed package may
e~ p1
6
be processed (for example as a result of the package being
heated for pasteurising the beverage, so that the structure
of the insert is modified, for example by thermal
distortion of plastics material. from which the insert is
formed) to ensure that when the sealed package is opened
and the pressure differential applied, communication is
effected, possibly by way of a known non-return valve in
the insert, between the secondary chamber and the beverage
in the primary chamber.
DRAWING
One ernbodiment of a beverage package constructed in
accordance with: the present invention will now be
described, by way of example only, with reference to the
accompanying illustrative drawing, which shows a section
through the package.
DETAINED DESCRIPTION OF DRAWING
The beverage package illustrated comprises a
conventional form of container such as a light metal can 1
having an externally concave circular base 2 on which the
package will normally stand, a cylindrical side wall 3 and
a circular top 4 which will usually be seamed to the side
wall 3 to seal the container. The top 4 will be openable,
typically by a ring pull, displaceable tab or other
conventional means for the purpose of dispensing beverage
contents of the container.
In the present example, the beverage for the package
may be considered as a light beer or lager having in
solution a mixture of carbon dioxide and nitrogen gases,
typically the carbon dioxide content will be 1.25 to 6.0
~ gramme per litre and the nitrogen gas content will be 3% to
5o vols./vol. The term "vols./vol>" is well known in the
art but a definition of it may be found in our British
Patent No. 1,588,624. The container 1 forms a primary
Y
7
chamber 5 and prior to fitting and sealing the top 4 and
with the container in an upstanding condition, an insert 6
is inserted into the primary chamber through the open top
of the container and located on the base 2 at the bottom of
the primary chamber 5.
The insert 6 is conveniently assembled from plastics
mouldings to have a hollow generally cylindrical drum part
7 from which extend diametrically opposed flanges 8 and a
tubular extension part 9 which projects upwardly from the
drum part 7 towards the open top of the container. The
insert 6 is fitted within the container so that the flanges
8 frictionally engage with the cylindrical side walls 3 to
retain the insert at the bottom of the primary chamber.
It will be appreciated however that alternative means of
retaining the insert 6 at the bottom of the container may
be provided, for example by suction or magnetically. The
hollow drum part 7 and extension part 9 of the insert form
a secondary chamber 10 which is to communicate with the
primary chamber 5 by way of an aperture or port 11 at the
upper end of the extension part 9.
The secondary chamber 10 contains gas, usually
nitrogen, at a pressure greater than atmospheric.
Pressurisation of the secondary chamber 10 may be effected
in either of two ways as will be discussed hereinafter.
After the insert 6 has been fitted within the open
topped container, the primary chamber 5 is charged with the
beverage 20 containing gas in solution and thereafter the
container is closed and sealed by the top 4~ so that a
primary headspace 21 in the primary chamber of the
~ container is at a pressure greater than atmospheric.
Pressurisation of the headspace 21 may be achieved 3.n
conventional manner, for example by dosing the primary
chamber with liquid nitrogen immediately prior to the top
t'! r1
4 being fitted and sealed. In the sealed package and as
will be seen from the drawing, the aperture 11 is submerged
in the beverage 5 and is located much nearer to the surface
22 of the beverage than it is to 'the bottom of the primary
chamber 5; in practice the aperture 11 is likely to be
submerged to a depth at which approximately 10% to 200 of
the volume of beverage 20 in the primary chamber is located
above that aperture.
When the sealed package is opened, for example by a
ring pull (not shown) in the 'top 4 to dispense the beer 20,
the primary headspace 21 is opened to atmospheric pressure
and rapidly depressurises. As a consequence, a pressure
differential is developed whereby the pressure of gas in
the secondary chamber 22 exceeds the pressure in the
headspace 21. This causes the gas in the secondary
chamber 10 to be injected through the aperture 11 into the
beer 20. As a consequence of this injection, and in a
manner well known in the art, gas is liberated from
solution in the beverage 20 to provide a surge of gas
bubbles which develops, predominantly, throughout the
beverage 20 above the aperture 11 and rises to develop
froth in the headspace 21. By locating the aperture 11
at a relatively shallow depth beneath the surface 22 of the
beverage 20, gas from solution, particularly carbon
dioxide, is liberated to form froth in the headspace 21
from a minor proportion, say less than 20%, of the total
volume of beer 20 in the container. Therefore when the
" , beer 20 is,poured from the container into a drinking glass
shortly after opening the can, the froth developed by the
. evolutian of gas from part only of the beverage may provide
a desirable head on the beer in the glass. ~3owever,
adequate gas is maintained in solution in the beer in the
glass for such gas to evolve gradually and naturally and
~~0'~ ~"l
9
present a slight effervescent ef:Eect or °°sparkle'° to
the
body of the beer - this is considered most desirable far
aesthetic quality in lager or light beer and may also
enhance the flavour characteristics and mouth feel of the
beer.
Gas under pressure may be provided in the secondary
chamber 10 where that secondary chamber is in constant
communication by way of the aperture 11 with the primary
chamber 5 by locating and maintaining the insert 6 in the
open topped container in a gas environment where the
pressure is greater than atmospheric and this environment
is maintained to pressurise the secondary chamber during
charging of the primary chamber with, beverage and sealing
the open top of the container. With this technique the
aperture 11 should form a restriction which ensures that
any beer which may flow from the primary chamber through
the restricted aperture 11 into the secondary chamber 10
(during charging of the container with beverage, during
the period in which the contents of the sealed package come
into equilibrium, and during general handling and storage
of the sealed package) is negligible. With such a
proposal in which the secondary chamber 1o is pressurised
within the open topped container and prior to charging the
container with beer 20, the insert 6 may, for ease of
mechanical handling, be assembled within the open topped
container by first fitting the base part 7 of the insert
within the container and subsequently fitting and sealing
the extension part 9 to the base part 7 within the
container. As an alternative possibility 'the insert 6 as
~ received by the primary chamber 5 may have its secondary
chamber 10 sealed and containing gas, typically nitrogen
gas, at a pressure greater than atmospheric. With this
latter proposa:~ the port 11 will initially be closed but
~~~a~~~"~
arranged to open, following charging of the primary chamber
5 with beer 20 and subsequent pressurisation of the
headspace 21 and sealing of the container with the top 4,
by appropriate processing of the sealed package. For
5 example, the sealed package may be subjected to heat during
pasteurisation of the beverage 20 and such heat may cause
a change in the characteristics of the plastics material of
the extension part 9 which results in automatic opening of
the port 11. A further possibility for this latter
10 technique where the insert 6 as received by the open topped
container has its secondary chamber 10 sealed and
containing gas,under pressure, is for the port 11 to be
closed by the upper end of a projection indicated at 30
extending upwardly within the extension part 9,
conveniently projecting from a bottom wall of the drum part
7. The projection 30 closes the port 11 to seal the
secondary chamber 10 throughout the period during which the
container is charged with beverage and sealed. However,
during subsequent processing of the sealed package, for
example by subjecting the package to heat as
aforementioned, the characteristics of the plastics insert
6 change to the extent that the free end of the projection
co-operates with the port 11 to form a non-return valve
which is responsive to the pressure differential developed
25 between the pressure of gas in the secondary chamber 10 and
that in the headspace 21 (when the top 4 is opened to open
the headspace to atmospheric pressure). The non-return
valve presented by the projection 3o and port 11 normally
restrains beer from entering the secondary chamber 10
30 ~ through the port 11. On opening of the container the
plastics material of the extension part 9 (or insert
generally) may flex in response to the pressure
differential that is developed and relative to the
11
projection 30 so that gas under pressure is injected from
the secondary chamber 10 through the port 11 into the upper
region of the beer 20 in the primary chamber 5 for froth
development.
Although in the drawing the aperture 11 is shown as
being directed towards the surface 22 of the beer 20 it
will be appreciated that this aperture may be arranged to
provide the gas injecta.on into the beer in any direction as
preferred and probably depending upon 'the depth at which
l0 the port 11 is submerged within the beer 5, for example
where the aperture 11 is located immediately below the
surface 22 of the beer 20 it is likely that the port 11
will be arranged to inject gas towards the cylindrical side
wall of the container or even downwardly into the beverage
to alleviate loss of energy from the gas injection into the
headspace 21.
