BACKGROUND OF THE INVENTION

Recently there has been considerable interest in systems for dispensing beverage such as beer from cans, and other small containers, which gives a similar appearance to dispensing the beverage from draught.

Two ways which have been commercially successful are described in patent specifications GB-B-2,183,592 and WO-A- 91/07326. In both of these the can, or other container, includes a hollow insert located in the container. In the filled container the insert contains gas under pressure and, upon opening the container ejects a stream of gas, or in the case of GB-B-2,183,592 a jet of beer and gas into the beer held in the container. This jetting effect causes shear in the beer which, since it is a super-saturated liquid, leads to the evolution of small bubbles of gas. These small bubbles act to seed the generation of further bubbles so that as the beer is dispensed from the container it is dispensed as a creamy liquid with small bubbles dispersed throughout. After being dispensed into a glass the small bubbles gradually rise and the beer separates to provide a liquid phase and a thick creamy head on the surface.

Both of these methods are subject to various problems which limit their use. In particular, both are very susceptible to excessive over foaming and beer overflow if the containers are opened at too high a temperature, typically at temperatures above about 10°C to 15°C. In both cases, the jet of gas or of beer and gas has a high velocity which means that only low carbonation ales and stouts having less than 1.2 v/v C0 ₂ may be packed. Neither of these systems are suitable for high carbonation ales and lagers as in both the high velocity jet causes massive foam outbreak.

The inserts are typically fitted to the base and/or the side of the containers by an interference fit. If the inserts become dislodged from the base of the container, they float to the top of the liquid and then do not operate correctly when the container is opened. The inclusion of either of the conventional inserts in a container requires a much larger head space. This larger head space requires both an increase in the size of the container and also makes the removal of oxygen from the head space more difficult. Both of these factors increase their cost of manufacture.

The system disclosed in WO-A-91/07326 requires the insert to be pressurised before the container is filled. The inserts may lose pressure before the container is filled, which may result in a failure to operate correctly if the pressure is too low. Accordingly, it is necessary for the container to be filled within a few days of the insert being pressurised. In the system disclosed in GB-B- 2,183,592 a complex evacuation-pressurisation cycle is required to remove the oxygen from within the container and hollow insert during the filling cycle of the container. This complex cycle significantly slows the speed of filling and increases the cost of manufacture.

It is known that gas bubbles can be liberated from a super-saturated solution of the gas by bringing the super¬ saturated solution of the gas into contact with an active surface including a nucleation centre such as a sharp point. An active surface formed by material such as sintered glass, roughened glass, sugar, sand or other crystalline substances or materials with rough surfaces or containing micro-pores may be used to provide nucleation centres and all cause heterogeneous generation of bubbles from a super saturated solution.

It has been found that filling a container which includes an active surface, or adding an active surface to a beverage during filling of the container is unsatis¬ factory as the generation of bubbles causes fobbing and

massive gas break out during the filling process which results in the container being incompletely filled.

SUMMARY OF THE INVENTION

According to the present invention, an apparatus for dispensing a beverage comprises a container containing the beverage, an active surface separated from the beverage, and a means for allowing the active surface to be exposed to the beverage after opening the container to generate foam in the beverage as it is dispensed.

The present invention allows a carbonated beverage contained in a container to be dispensed and to have an appearance similar to that when dispensed from draught. The invention allows the container to be properly filled without excessive gas break out, and prevents excessive over foaming if the container is opened at too high a temperature. The invention also keeps the active surface apart from the beverage and preferably dry during storage of the filled containers and it has been found that this considerably enhances the efficiency of the bubble generation by the active surface when it is subsequently exposed to the beverage. The invention may also be used for higher carbonation beverages such as high carbonation ales and lagers.

The ideal active surface is one having a pore size in the range of 5 to 250 μm with a hydrophobic cavity and hydrophillic outer as this encourages gas nucleation and release of small micro bubbles of typical bubble size 100 to 400 μm rather than large bubble growth which will not provide good beer foam quality.

The active surface may be separate from the container prior to opening, for example by being provided as a lining on the inside of a spout which is inserted into the opening of the container after the container is opened. On pouring the beverage from the container, it passes over the active surface and bubbles are spontaneously released.

Alternatively, the active surface may be located within the container, but held physically separated from the beverage prior to opening of the container. The active surface may be included in a part of the container distant from the beverage, for example in the neck of a bottle, and in this case is preferably covered by a stopper to prevent the exposure of the active surface to the beverage prior to dispensing. Then the active surface is exposed to the beverage as it is poured from the container. Preferably, the active surface is contained within a capsule in the container. On opening the container, the capsule opens or ruptures to expose the active surface to the beverage in the container. The capsule may be formed with a rupturable weakened zone. The capsule may be connected to an easy open feature of the container, for example, a ring pull or stay-on tab on a can so that, as the easy open feature is opened, the capsule is also opened or ruptured to expose the active surface contained within the capsule to the beverage. Preferably however the capsule is charged to a super- atmospheric pressure with a non-oxidizing gas and, in this way, when the pressure inside the container is reduced upon opening, the super atmospheric pressure inside the capsule causes it to open or rupture to expose the active surface to the beverage. Preferably the capsule is formed in two parts in a clam shell arrangement with the two parts snap fitting together or being glued together. The capsule may include a deliberately thinned wall portion through which gas can permeate and, in this case, the capsule is preferably substantially evacuated before being placed in the container and then, some or all of the gas which is super saturated in the beverage, typically a mixture of nitrogen and carbon dioxide, permeates through the thin wall portion of the capsule to build up a super atmospheric pressure inside the capsule corresponding to that inside the unopened container.

In this case it is preferred that the material from which the capsule is made has high gas transmission properties and so is formed of, polyethylene or polypropylene and at least part of the wall thickness is thinned to such an extent that after about two weeks storage at 20°C the pressure inside the capsule is substantially in equilibrium with the pressure of the carbonated beverage which is, typically between 2 and 4 bar. Alternatively the capsule may include means to enable only gas from within the container to enter the capsule to charge it to a super-atmospheric pressure.

The active surface may be loose within the capsule particularly when the active surface is a material compatible with the beverage, such as sugar, but preferably the active surface is physically attached to the inside of the capsule so that it is held captive inside the container and cannot escape and contaminate the beverage.

The capsule is preferably held towards the top of the container and, when the container is a can, the capsule preferably includes a tab which is sandwiched into the seam formed between the walls and the lid of the container, or may be stuck or heat sealed onto the inside of the side wall or the base or the lid of the container, or may have an interference fit with the side walls of the container and so be held in place by friction. Alternatively the capsule may be allowed to float on top of the beverage.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred examples of the present invention will be described with respect to the accompanying drawings, in which:-

Figure 1A shows a view of a capsule enclosing an active surface material;

Figure IB shows a cross section of the capsule of Figure 1A;

Figure 2A shows a view of the capsule of Figure 1A after the seal has broken;

Figure 2B shows a cross sectional view of the capsule of Figure 2A; Figure 3 shows the capsule of Figures 1 and 2 disposed in a can containing beverage;

Figure 4 shows a cross section through a bottle including a capsule floating on a beverage;

Figure 5 shows a plan view of a capsule located in the end of a can containing beverage;

Figure 6 shows a second example of a capsule located in one end of a can containing beverage;

Figure 7 shows a cross sectional view of the can of Figure 6 after the can has been opened; Figure 8 shows a cross section of the neck of a bottle having an active surface liner and a seal;

Figure 9 shows the bottle of Figure 8 after the seal has been removed;

Figure 10 shows a spout including an active surface; Figure 11 shows the spout of Figure 10 in a can; and

Figure 12 shows the spout of Figure 10 in a bottle.

DESCRIPTION OF PREFERRED EXAMPLES

In a first example of the present invention, an active surface material, which may be sintered or roughened glass, sugar, sand or other crystalline substances or materials with rough surfaces containing micro-pores, is contained within a capsule 1. The capsule is made of a plastics material such as polypropylene or polyethylene which allows rapid gas diffusion. The active surface material is placed in the capsule with an inert gas at atmospheric pressure. The inert gas prevents subsequent oxygen diffusion into the beverage. Such oxygen diffusion may impair the taste of the beverage. The capsule has a seal 2 which is glued, heat sealed or interference fitted to the container and which ruptures when the container is

opened to expose the active surface material 3 contained within the capsule 1 to the beverage. When the container is filled with beverage and is closed, the capsule 1 is initially at atmospheric pressure, whereas the container is at a higher pressure due to the gases in the beverage, primarily nitrogen and carbon dioxide. The capsule 1 allows rapid gas diffusion, therefore the pressure inside the capsule l increases until it is in equilibrium with the pressure in the container within about five to ten days at a normal ambient temperature of between 5 and 25°C. The pressure in the container and in the capsule is then about 2 to 3 bar. When the container is opened, the pressure in the container rapidly decreases to atmospheric pressure. Due to the higher pressure in the capsule 1 compared to that in the container, the seal 2 ruptures as shown in

Figure 2 and exposes the active surface 3 to the beverage.

The capsule 1 must be positioned within the container, and arranged in such a way that the exposure of the active surface 3 to the beverage can be controlled. This is necessary to avoid excessive gas break out which leads to gushing and over-spill of the beverage from the container. Ideally, the active surface 3 is only be exposed to the beverage as the beverage is poured from the container so that the resulting gas nucleation creates an ideal foam formation in the glass.

Various examples of the positioning of the capsule 1 within the container are shown in Figures 3 to 7.

Figure 3 shows a capsule 1 included in a can 5. The capsule 1 is not attached to the can 5, but instead is able to float on the beverage 4. On opening the can 5, the seal 2 of the capsule 1 ruptures, exposing the active surf ce 3 to the top of the beverage 4. This ensures that the active surface 3 is only exposed to the beverage 4 as it is poured from the can 5. Figure 4 shows a similar system where the container is a bottle 6.

When the capsule 1 floats on the surface of the beverage it may include means in its upper wall to allow gas from the head space to enter the capsule to ensure more rapid equilibrium between the gas in the head space and that in the capsule than when relying on gas permeation through its walls. The means may include a non-return valve or a small aperture.

An alternative positioning of the capsule 1 is shown in Figure 5 in which the capsule 1 is shaped to fit inside the top of a can 5. The capsule 1 has a recess 8 so that the pouring aperture 7 is not blocked by the capsule 1. In this example, the capsule 1 is fixed to the can by either gluing or riveting, or by holding the capsule 1 within the double seam at the top of a can 5. Figures 6 and 7 show another example of a capsule. In this example, one end of the capsule 1 is attached to the end of the can 5 using a rivet 10. The capsule l extends below the pouring aperture 7. When the ring pull or stay- on tab 11 is pulled to open the can, the end of the capsule 1 which is not fixed to the top of the can 5 is depressed into the beverage 4. This enables the beverage 4 to be poured from the pouring aperture 7 without the capsule 1 disturbing the flow.

In a further example, the capsule 1 may be punctured by the easy open feature of the container. This then exposes the active surface to the beverage.

Figures 8 and 9 show yet another example of the present invention for use in bottles. An active surface liner 20 is included around the neck 21 of the bottle 22 and a crown 23 or stopper is placed in the bottle 22 to cover the active surface. This ensures that the active surface is not exposed to the beverage 24 prior to pouring. When the crown 23 is removed, the active surface liner 20 is exposed, and as the beverage 24 is poured from the bottle 22, it passes over the active surface liner 20 and gas nucleation and foam formation occur.

Figure 10 shows another example of the present invention. In this example, the active surface 31 forms the inner lining of a pouring spout 30.

As shown in Figures 11 and 12, after a can 32 or a bottle 33 is opened, the spout 30 is inserted into the opening of the container. The beverage is poured from the container through the spout 30, where it is exposed to the active surface 31 causing gas nucleation and foam formation. In this example the active surface is not enclosed within the container prior to opening the container. This example has the advantage that the spout 30 can be used in any container having the same shaped opening as the spout 30.