GB2280415A

GB2280415A - Packaged yeast containing beverages

Info

Publication number: GB2280415A
Application number: GB9315520A
Authority: GB
Inventors: Christopher Alan Boulton
Original assignee: Bass PLC
Current assignee: Bass PLC
Priority date: 1993-07-27
Filing date: 1993-07-27
Publication date: 1995-02-01
Anticipated expiration: 2013-07-27
Also published as: GB9315520D0; GB2280415B

Abstract

A beer can is provided with yeast mat forming means so enabling beer to ferment in the can. The yeast forming means may be an insert 3, eg a disc of PET material, or the inside surface of the can (2) may be treated, for example by giving it a lining (8) of plastics material, such that yeast bonds to the specially introduced surface. The mat of yeast (7) laid down during secondary fermentation is strong enough to survive the stresses of opening the can (2). <IMAGE>

Description

IMPROVEMENTS IN AND RELATING TO PACKAGED BEVERAGES This invention relates to improvements in and relating to packaged beverages, and more particularly to packaging for beverages.

It has long been known to provide glass bottles of beer in which the beer contains yeast. The yeast assists in secondary fermentation of the beverage in the bottle and when the bottle is stored prior to sale the yeast settles out at the bottom of the bottle and forms a mat of yeast sediment on the bottom of the bottle. The yeast cells stick to each other and also in some instances stick to the glass. When the bottle is opened and the beer poured into a glass care must be taken to ensure that it is poured carefully. If it is not poured in one smooth tilting motion bits of the yeast mat can become disturbed and even break off, and small clumps of yeast are carried with the beer into the glass. This leaves the glass of beer cloudy. It is commonly regarded as better to have a bright beer (non-cloudy).If care is taken when pouring such a bottle of beer a glass of bright beer can be achieved.

It is usual to leave the final dregs of beer in the bottle so as to avoid carrying out sediment with the last portion of the beer.

An example of such a known bottled beer is "White Shield" (Trade Mark) brewed by ourselves and sold for at least fifty years or more.

According to a first aspect of the invention we provide a package of beverage comprising a container, beverage containing yeast, and yeast-mat forming means, the yeast-mat forming means being such that the yeast in the beverage forms a better mat on the yeast-mat forming means than it would if the yeast-mat forming means were not provided.

The deliberate provision of yeast-mat forming means enables us to provide cans or bottles of beer which contain yeast, the yeast forming a mat on the yeast-mat forming means.

We have appreciated that it may be possible to can live beer (this has not, so far as we know, ever been contemplated before). Once we had made the revolutionary thought of canning beer with free suspended yeast in it we tried to do that and encountered a problem. The yeast used in our White Shield beer (a strain of saccharomyces cerevisae) did not stick to the can very well at all. When beer was poured from a can the resultant glass of beer was cloudy and contained many floculate clumps of yeast. No mat was present at the base of the can once the beer had been poured out, unlike the case with a bottle of beer. We suspect that a mat is formed, but that it is not very strong and that when the can is broached the sudden mixing effect caused by the sudden drop of pressure, and pouring itself, disrupts the weak mat and it is churned up into the beer.

The strain of yeast which we use normally sticks to the glass very well, but a can is not, of course, made of glass. It was surprising to find that the yeast which is conventionally thought to be sticky did not stick to a conventional can. Conventional cans are made from steel or aluminium and are coated with a lacquer.

We have found, surprisingly, that PET (polyethylene tetrepthalate) forms a good susbstrate for the yeast. The yeast mat is strong enough if it is based on a PET surface. This discovery forms another contribution to the present invention.

Preferably the yeast-mat forming means comprises at least an area of non-glass material. The yeast-mat forming means preferably comprises at least an area of plastics material. The plastics material is preferably PET, or the like.

Alternatively the yeast-mat forming means may comprise at least an area of glass or the like.

The yeast-mat forming means may comprise at least an area of material which is capable of having a positive electrostatic charge. We have surmised that one reason why the yeast forms a better bond with PET than with lacquer of a conventional tin can is because yeast cells carry a negative charge and the bonding may be at least in part electrostatic.

The yeast-forming means may comprise an insert or member provided in the container. Alternatively, or additionally, the yeast-forming means may comprise a layer or coating in the container preferably provided on the base of the container, on one of the walls of the container, or on both the base and walls of the container. In one preferred example substantially all of the side walls and base of the container are coated with an area of material which constitutes the yeast-forming means.

Preferably the package comprises a can of beverage.

According to a second aspect of the invention we provide a package of beverage comprising a container, beverage in the container, yeast-mat forming means provided in the container such that yeast forms a better mat on the yeast-mat forming means than it does on the container itself, and a mat of yeast formed on the yeast-mat forming means.

Thus we aim to protect the packaged beverage after the mat has formed as well as beforehand.

A third aspect of the invention comprises a package of beverage adapted to ferment into a beverage of higher alcohol content than that originally packaged, the package comprising a beverage-forming liquid, yeast, yeast-mat forming means, and a container; the yeast-mat forming means being such that the yeast forms a better mat on the yeast-mat forming means than it would on the container alone.

The invention will probably be used for secondary fermentation of beverages which ferment in the package, but perhaps not necessarily. The invention could conceivably simply be used to allow suspended yeast to settle out and form a mat, substantially all fermentation perhaps being completed before the package is sealed.

According to a fourth aspect of the invention we provide a method of improving the beverage poured from a package of beverage, the method comprising providing the package with yeast-mat forming means such that yeast held in the beverage settles out over a period of time to form a mat of yeast leaving the beverage bright, and in which the yeast-mat forming means is such that the mat of yeast formed on it is strong enough to remain substantially intact when the container is opened and the beverage poured out, the poured beverage still being bright.

It will be appreciated that the aim is to have substantially no clumps of yeast in the poured beverage.

The method preferably comprises providing a package container holding the beverage and providing yeast-mat forming means having at least a region of different material than that of the container, or than the material which gives the container its strength.

Preferably the method comprises providing a plastics material, most preferably PET, substrate upon which the yeast-mat forms.

An alternative is to have a container which is made from yeast-mat forming means. For example we may provide a PET plastics "can". The choice of material for the can would then avoid the need for a separate yeast-mat forming means of different material, but the yeast-mat forming means would be constituted by the material of the plastics can itself.

Another way of looking at the invention is as a method of preventing or hindering the break-up of a yeast mat in a beverage having a yeast mat, the method comprising providing yeast-mat forming means in a container of the package, and choosing the material and nature of the yeast-mat forming means such that the yeast sticks to it better than it would stick to the container alone.

Thus the yeast-mat forming means is provided in addition to the structural material of the container necessary for confinement of the beverage.

According to a fifth aspect of the invention we provide a component for assembly to form a package of beverage, the component defining a chamber for beverage and having yeast-mat forming means such that the yeast in the beverage to be contained in the container forms a better yeast mat on the component than it would do on the container if no yeast-mat forming means were provided.

It will be appreciated that we wish to claim protection for the unfilled shell-component of a can, and the like.

According to a sixth aspect of the invention we provide apparatus for producing a component for assembly into a package of beverage, the apparatus comprising mat substrate introduction means which introduces yeast-mat forming means into the component, or attaches it to the component, the yeast-mat forming means providing a substrate for a yeast-mat to which the yeast mat will stick better than it would stick to the material of the container.

Thus we wish to protect the assembly line.

According to a further aspect of the invention we provide yeast-mat forming means adapted to be introduced into a container for a yeast-containing beverage, the yeast-mat forming means being capable of providing a substrate upon which a mat of yeast can form.

It will be appreciated that when- the yeast-mat is formed on the yeast-mat forming means it will adhere with sufficient strength that the resultant yeast mat remains substantially intact under the conditions experienced when the container is opened and the beverage poured.

We are aware with hindsight, after having made the invention, that it has already been proposed to coat the inside of cans with PET to take advantage of its inert nature and corrosion resistance. It has not, however, been proposed to have a can with a significant amount of free yeast in it, let alone to use a PET coated can to promote a good yeast-mat. Suspended yeast, as discussed previously, does not form a good mat in normal lacquer-coated cans. A can with a strong yeast-mat in it has not been proposed, nor has it previously been realised that plastics in general, and PET in particular, is a good substrate upon which a strong yeast-mat can be formed.

Embodiments of the invention will now be described by example only with reference to the accompanying drawings of which: Figure 1 shows a can of beer in accordance with the invention; and Figure 2 shows another can of beer in accordance with the invention.

It will be appreciated that the term "beer" covers beer, ale, stout, lager, cider, porter, and the like.

In the examples descrived the beverage can be taken to be beer.

The drawings show a package 1 comprising a can of beer. The package has a steel or aluminium can 2 comprising a container for beer, and a mat-forming insert 3 held at the bottom of the can. The can 2 comprises a body shell member 4, typically of steel or aluminium, and a can end 5 secured to the top of the body shell member 4 to close the can. The can end 5 has an openable aperture, such as a ring-pull or the like, but that is not shown in the drawings. The beer is referenced as number 6.

The can of beer 2 is ready for sale, and use, and a mat 7 of yeast has formed on the mat-forming insert 3. The beer above the mat 7 is bright: it does not contain particles of suspended yeast.

When the can is opened, or broached, there is a sudden release in pressure and this causes turbulence in the beer 6 in the can. Furthermore, when the beer is poured this also causes disturbance of the beer in the region of the mat. However, the mat is sufficiently strong that it does not break up during opening and pouring of the beer so that the beer that is poured out remains bright and can provide a good, clear, glass of beer without particles or clumps of yeast floating around in the beer.

It will be appreciated that the can 2 is a conventional can of, say, 440ml or 500ml size and is made of steel or aluminium, which is conventionally lacquer coated.

The mat-forming insert is a disc of PET plastics material fixed relative to the can. The disc of PET material may be physically or mechanically attached to the can, glued to the can, or most simply be a friction fit in the can. One possible arrangement is for the mat-forming insert to be oversized so that it is bent slightly in its final position, the compression of the insert holding it in place. The mat-forming insert covers substantially the whole of the area of the base of the can (however, there may be alternatives where it does not).

The package 1 is produced on a filling line which has a clean environment. No pasteurisation step is required, and indeed pasteurisation would kill the yeast and prevent any secondary fermentation that is required. The filling line takes body shell members 4 which have previously had the mat-forming insert 3 introduced into them, fills them with beer having yeast suspended in it, and seals the can end to the top of the body shell member to close the package. The package is then left for several weeks so that the yeast can settle out and floculate, forming a strong mat on the mat-forming insert.

The body shell member and its associated mat-forming insert can be provided to the canning line assembly together or they can be assembled on the canning line. If they are provided already assembled then there will, of course, be a corresponding production line for the assembly of body shell members and their pre-loaded mat-forming can inserts.

The process by which yeast cells stick to a conventional glass bottle is not the same process by which they stick to each other. There are, it is believed, binding sites on the yeast cells which are strain specific to create yeast-yeast bonds. Some strains of yeast stick to glass better than others.

They have a better yeast-glass bond. Thus the choice of the strain of yeast may be of some significance, but there are very many known strains of yeast and the actual selection of a particular strain is not part of the present invention. It is, however, surprising that a yeast which sticks to glass does not stick to a conventional can. We believe that is because conventional cans are coated with lacquer and the yeast has difficulty adhering to the lacquer. We believe that the cell to glass bond is probably an electrostatic bond. Yeast has a negative charge. We suspect that the problem with yeast trying to bond to the lacquer which coats a conventional beer can is that no electrostatic bond (or not a very strong bond) can be formed.This discovery suggests that one way of looking at the invention might be to say that it is the choice of the material for the substrate on which the yeast mat is to be formed to be such that the material is capable of having at least a component of bond of an electrostatic nature with yeast. This implies that it must be able to acquire a positive electrostatic charge, or have one induced in it by the yeast.

We have found that plastics materials in general work well as a substrate to form a yeast mat. PET (polyethylene tetrepthalate) is the best plastics material we have found for forming a substrate for a yeast mat, and in particular Mylar (Trade Mark).

We have also found that perspex (Trade Mark) works well, and some forms of paper may work adequately. We have found that glass fibre, DEAE cellulose papers, and various grades of glass paper, can work effectively.

The idea that by an appropriate choice of substrate it is possible to improve the mat-forming properties of a container of beer has enabled us to consider the possibility of using yeast strains which are not necessarily very good at adhering to glass, or even yeast strains which are not very good at yeast something else adherence in general. If we specifically introduced a mat-forming means to which a strain of yeast which does not generally form a mat very well can actually stick to we can produce beers in cans which are made from different yeasts, widening the choice of canned beer available.

Figure 2 shows another embodiment of the invention. In this example similar components are given the same reference numbers as for the example of Figure 1. However, instead of having an insert as a mat-forming member the interior surface of the shell member 4 has been coated with a thin layer 8 of PET plastics material. For example, the interior of the shell could be sprayed with PET.

The yeast in the beer still settles out, flocculates, and forms a mat which has yeast-yeast bonds and yeast-PET adherence and forms a strong mat on the base of the can.

Of course, if the can was stored on its side the yeast mat would be formed along the side of the can.

It would be possible to coat only the bottom of the can, or perhaps the bottom of the can and a part of the side walls of the can, but we expect that it will be cheaper simply to coat the entire shell member.

Other plastics material which may be useful to form a substrate for a yeast mat include nylon, pvc and unexpanded polystyrene.

We have also found that the smoothness of the surface of the substrate upon which the yeast mat is formed may contribute to the degree of adherence of the yeast to the substrate. We found that roughening the interior surface of a conventional can did improve the formation of the yeast mat, but not enough for commercial use. However, another aspect of the invention may consist in treating the interior surface of a can, or other container, so as to improve its yeast-mat forming characteristics.

This treatment may comprise coating with another material, as shown in Figure 2, or may comprise working the surface of the container, for example by making it rougher or smoother.

There may be occasions when we want to have little or no yeast growth during conditioning of the beer in the can (or other container). It may be necessary to use a relatively high innoculation (or pitching) rate such that there is sufficient yeast to form a continuous mat.

The production line for the production of containers of beverage will be operated under sterile, or at least clean, conditions. The can shell is preferably empty of any other contents when it is filled with beverage (apart from the insert or coating of mat-forming means). We would usually wish to produce a base beer using one yeast strain, filter the base beer to ensure that all or substantially all of the primary strain is removed (or otherwise ensure that this is done), and then secondary ferment the base beer in the can (container) using a second strain of yeast.

It is possible to use a mixed yeast culture of different strains which co-floculate together.

There is a possibility that we may wish to use an insert or layer with yeast already attached to it as the yeast-mat forming means. However, this is not at present preferred because of the difficulties in ensuring a sterile (or clean) fill of the can. On the other hand there may be occasions when such difficulties are worth overcoming.

Claims

1. A package of beverage comprising a container, beverage in the container, yeast-mat forming means provided in the container such that yeast forms a better mat on the yeast-mat forming means than it does on the container itself, and a mat of yeast formed on the yeast-mat forming means.

2. A package of beverage comprising a container, beverage containing yeast, and yeast-mat forming means, the yeast-mat forming means being such that the yeast in the beverage forms a better mat on the yeast-mat forming means than it would if the yeast-mat forming means were not provided.

3. A package according to claim 1 or claim 2 in which the yeast-mat forming means comprises at least an area of plastics material.

4. A package according to claim 3 in which the plastics material is PET, or the like.

5. A package according to any preceding claim in which the yeast-mat forming means comprises at least an area of material which is capable of having a positive electrostatic charge.

6. A package according to any preceding claim in which the yeast forming means is provided at or towards the bottom of the package.

7. A package according to any preceding claim in which the yeast forming means comprises an insert or member provided in the container.

8. A package according to any preceding claim in which the yeast forming means comprises a layer or coating provided in the container.

9. A package according to claim 8 in which the layer or coating is provided on a wall of the container.

10. A package according to claim 9 in which the layer or coating is provided on the bottom wall of the container.

11. A package according to claim 9 or claim 10 in which the layer or coating is provided on a side wall of the container.

12. A package according to claims 10 and 11 in which the layer or coating is provided on at least a part of the bottom wall of the container and on at least a part of a side wall of the container.

13. A package according to any preceding claim which is a can of beverage.

14. A package of beverage substantially as described herein with reference to Figure 1 of the accompanying drawings; or substantially as described herein with reference to Figure 2 of the accompanying drawings.

15. A package of beverage adapted to ferment into a beverage of higher alcohol content than that originally packaged, the package comprising a beverage forming liquid, yeast, yeast-mat forming means, and a container, the yeast-mat forming means being such that the yeast forms a better mat on the yeast-mat forming means than it would on the container alone.

16. A package according to claim 15 in which the yeast-mat forming means is an insert or member.

17. A package according to claim 15 or 16 in which the yeast-mat forming means comprises a coating or layer.

18. A package according to any one of claims 15 to 17 in which the yeast-mat forming means is made at least in part of plastics material.

19. A method of improving the beverage poured from a package of beverage, the method comprising providing the package with yeast-mat forming means such that yeast held in the beverage settles out over a period of time to form a mat of yeast, leaving the beverage bright, and in which the yeast-mat forming means is such that the mat of yeast formed on it is strong enough to remain substantially intact when the container is opened and the beverage poured out, the poured beverage still being bright.

20. A method according to claim 19 which further comprises providing a package container holding the beverage and providing yeast-mat. forming means having at least a region of different material than that of the container.

21. A method according to claim 19 or claim 20 in which the yeast-mat forming means is not made of glass.

22. A method according to claim 19 in which the yeast-mat forming means is of plastics material.

23. A method according to any one of claims 19 to 22 in which the yeast-mat forming means is of PET.

24. A method of improving the quality of beverage poured from a package of beverage substantially as described herein with reference to Figure 1 of the accompanying drawings, or with reference to Figure 2 of the accompanying drawings.

25. A method of preventing or hindering the break-up of a yeast mat in a packaged beverage having a yeast mat comprising providing yeast-mat forming means in the container of the package and choosing the material and nature of the yeast-mat forming means such that the yeast sticks to it better than it would stick to the structural material of the container alone.

26. A method of preventing or hindering break-up of a yeast mat in a packaged beverage having a yeast mat substantially as described herein.

27. A component for assembly to form a package of beverage, the component defining a chamber for beverage and having yeast-mat forming means such that the yeast in the beverage to be contained in the container forms a better yeast mat on the component than it would do on the container if no yeast-mat forming means were provided.

28. Apparatus for providing a component for assembly into a package of beverage comprising mat substrate introduction means which introduces yeast-mat forming means into the component, or attaches it to the component, the yeast-mat forming means providing a substrate for a yeast mat to which the yeast mat will stick better than it would stick to the material of the container.

29. Apparatus according to claim 28 in which the mat substrate introduction means introduces an insert or member to the container.

30. Apparatus according to claim 28 or claim 29 in which the mat substrate introduction means coats at least a part of the interior of the container with a layer of yeast-mat forming material.

31. Apparatus according to any one of claims 28 to 30 in which beverage with yeast is introduced into the component.

32. Yeast-mat forming means adapted to be introduced into a container for yeast containing beverage, the yeast-mat forming means being capable of providing a substrate upon which a mat of yeast can form and adhere with sufficient strength that the resultant yeast mat remains substantially intact under the conditions experienced when the container is opened and the beverage poured.

33. A method of improving the quality of a yeast-containg beverage poured from a package comprising treating the interior surface of the package so as to improve its yeast-mat forming, or retaining, characteristics.