The invention relates to a beverage capsule for an espresso machine, in particular for making espresso under high pressure.

Powered espresso machines are well known. The conventional espresso machine comprises a water chamber, a heating element adapted to heat the water to around 95-98 C, which is then pumped under high pressure of 15 to 19 bar to a filter holder or portafilter. Lower pressure systems also exist. The filter holder typically comprises a handle portion and a holder portion provided with two or three lugs that are adapted to engage in the installed position with the machine brewhead to where the water is pumped. The holder portion is adapted to receive a filter, which is usually a metal bowl with a number of perforations through its bottom. In use, the filter is filled with finely ground coffee and the water is forced through the coffee at the high pressure generated by the pump to produce the espresso coffee which is collected in a cup placed under the filter holder.

The classic coffee machine suffers from two potential drawbacks. The first drawback is that ground coffee starts to lose its freshness and flavour after a few days and so for the optimum espresso, the user will also need to have a coffee grinder. The other drawback is that the used espresso coffee has to be removed from the filter, which can lead to mess as the grinds are fine.

This lead to the development of ESE coffee pods, which can be used in many espresso machines. Coffee pods are generally individually wrapped to maintain freshness and consist of a small pod made of a perforated filter paper which contains the coffee. The pod is placed in the filter holder and then disposed of after use. Coffee pods are convenient but have to fit the filter holder and be placed correctly otherwise water can leak around the edge.

This in turn lead to the development of capsule machines. The coffee capsules for these machines are completely sealed. The capsule machines do not use the conventional filter holder. A capsule machine typically has a two part mechanism. The first part receives the capsule and is provided with an extraction surface upon which the capsule rests. The second part is provided with a locking lever which is used to make the first and second parts integral. In use, the second part cuts the upper surface of the capsule to allow water to enter the capsule and percolate down through the capsule, where it exits through the lower surface of the capsule at multiple locations determined by the geometry of the extraction surface. An example of such a machine is disclosed in EP 0870457 or W02005/004683. Capsules in the known capsule coffee machines are, in use, inserted into a capsule cage of the machine which holds the capsule in position so that it may be cut by a cutting member.

Capsule machines have proved to be commercially very successful as they are very convenient to use and produce a consistent product. However, each manufacturers coffee machines and capsules are designed to work with the manufacturers own brand. The most popular brand of capsule is Nespresso ®, which uses a sealed capsule made of aluminium. In use, the capsule is clamped into position in the machine with a capsule cage part holding the capsule so that it can be cut by typically three prongs to enable water under pressure to enter the coffee capsule.

Aluminium has the considerable advantage that it is oxygen and water impermeable, which means that the coffee in the capsules has a long shelf life. Aluminium however also suffers from several major drawbacks in that the aluminium is easily deformed during the filling and packing stage and it is difficult and expensive to produce a reliable seal on the capsule rim. The only known seal that works is a silicone elastomer disclosed in EP1654966 despite significant research effort. In these capsules the edge of the aluminium rim is rolled over when attached the front foil seal. The known solutions to these problems further require an extremely high capital investment beyond most companies.

Most manufacturers have therefore adopted plastic capsules. Plastic capsules solve the problems of the ease of handling the capsule during the packing process but require other compromises. The plastic capsule needs to be able to be pierced by the blades in the capsule coffee machine without shattering the capsule or damaging the machine. The capsule also needs to be sealed at its open end with an aluminium foil which adheres to the plastic capsule in a reliable manner and at low enough temperatures that the quality of the coffee is not impaired. An exemplary capsule is shown in GB2458013.

The present invention therefore seeks to provide an improved coffee capsule. According to a first aspect of the invention there is provided a capsule for use in a coffee machine having a generally frusto-conical form with a main body and an upper end, an annular flange being provided at the end of the main body remote from the upper end, characterised in that the capsule is provided with a plurality of flutes extending from the vicinity of the boundary between the upper end and main body to a point beyond the mid point between the upper end the flange.

According to a second aspect of the invention there is provided a coffee bag holder having a generally frustoconical or tubular form with side walls and a bottom having one or more openings, wherein the side walls are provided with a plurality of flutes extending substantially along the length of the side wall.

Preferably the holder has a stepped profile, each of the side walls being provided with a plurality of flutes.

The capsule of the invention facilitates the use of an aluminium capsule with a seal that can be recycled in common mixed recyclable kerbside collections.

Exemplary embodiments of the invention will now be described with reference to the drawings, in which:

Fig. 1 shows a perspective view of the capsule

Fig. 2 shows a coffee bag or filter holder.

Figure 1 shows a cross-section of capsule 1 having a generally frustoconical form for the main body 2. The upper end 3 of the capsule has a second frustoconical section 4 with a smaller diameter than the lower end. The upper end 3 is further provided with an additional frustoconical indent 5 at the centre of the upper end 3. The capsule is provided with a flange 7 at the end of main body 2 remote from the upper end 3.

The flange 7 comprises an upstanding wall 8, which thereby forms a gutter 9 between the wall of the capsule and the upstanding wall 8. The upstanding wall 8 then bends back down towards the same side as the opening such that the distal end is substantially in the longitudinal plane of the capsule but below the gutter 9. The shape of the distal end forms an open hook. The open hook receives a seal to close the capsule after filling. The open hook shape provides a plurality of webs at the rim of the flange which provide a degree of reinforcement so that the foil can be easily attached to the capsule made of softer, more ductile materials such as aluminium.

The gutter 9 receives a ring shaped seal that is preferably made of a cullose backed material such as paper, fibre or cork or, alternatively, polystyrene. The seal can be substantially in the range of 0.1 -0.3mm thick. A particularly preferred seal comprises 120 gnr ² , 0.2 mm thick paper. A polypropylene material seal of 0.1 mm also provides a good seal. The seal is retained in position by a plurality of protrusions or pips 10 formed on the side wall of the capsule spaced a short height above the flange. The pips can be formed by pushing out from the inside of the capsule and are substantially equidistantly disposed around the circumference of the capsule wall. An exemplary number of pips is 3, 6 or 8.

The capsule wall is provided with flutes 1 1 which extend over substantially the length of the side wall part 2 of the main body towards the pips 10. The flutes are recessed by between 0.1 and 0.3mm from the maximum outer radius of the side wall 2. The flute may be between 0.5 and 10mm wide. The flutes may be substantially contiguously disposed in the side wall.

It has been surprisingly discovered that the provision of the flutes 1 1 extending over a substantial part of the side wall 2 greatly increase the strength of the capsule, which becomes much less likely to deform. It has been established that a force of around 1 N will deform prior art capsules manufactured by Nespresso or l”Or, whereas the fluted design requires 4N to deform. This greatly improves the ease of handling the capsule both in the manufacture of the capsule and its filling. It is also less likely to be damaged in transit. This will reduce wastage in capsule production and facilitate the wider use of aluminium capsules which are preferable to plastic with respect to their recyclability.

Figure 2 shows an inverted coffee bag or filter holder 20 adapted to hold a coffee bag or filter for making a filter coffee, also called a drip coffee. Coffee bag holders are known in the market and manufactured from plastic such as polystyrene.

The coffee bag holder has a generally frustoconical or almost tubular form having a stepped profile in which the part 23 closest to the bottom 22 has a reduced diameter compared to the part 24 closest to the opening. The opening is provided with a flange 25 which may rest on the cup or mug rim. In use, the coffee bag is substantially housed in the part 23 and water will be poured on top of the bag and held in the part 24 until it percolates through the coffee bag.

The bottom 22 is provided with a number of perforations to allow the coffee to egress the holder and drip into a cup.

Each of the holder wall parts is provided with flutes 26 which extend over substantially the length of the side wall part 2 The flutes are recessed by between 0.1 and 0.3mm from the maximum outer radius of the side wall. The flute may be between 0.5 and 10mm wide. The flutes may be substantially contiguously disposed in the side wall.

It has been surprisingly discovered that the provision of the flutes 26 extending over a substantial part of the side wall greatly increase the strength of the capsule, which becomes much less likely to deform. This greatly improves the ease of handling the capsule both in the manufacture of the capsule and its storage as the holders tend to be stacked when stored.

In both the embodiment of Figure 1 and Figure 2, the aluminium is approximately 0.1 mm thick.

Although the capsule has been specifically described as being used to make espresso coffee, it would be possible to use the capsule to make other beverage capsules such as tea or chocolate.