System and method for preparing a beverage

0001The invention relates to a system according to the pre-characterising portion of claim 1. The invention also relates to a system according to the pre-characterising portion of claim 20.

0002Such systems are known per se, see for example <patcit id="pcit0001" dnum="EP1295554A"><text>EP 1 295 554</text></patcit>. A special class of these known systems is used for preparing the beverage using a hermetically sealed capsule comprising the extractable product. During beverage preparation the entrance area of such hermetically sealed capsule is pierced, hence providing at least one entrance opening for supplying the fluid under pressure to the exchangeable product in the inner space of the capsule through the entrance opening. Providing the fluid under pressure to the inner space causes the pressure in the inner space of the capsule to rise. This, in turn, causes the exit area of the capsule to be pressed against lid piercing means present in the receptacle. When the exit area is pressed against the lid piercing means with sufficient force, the exit area tears against the lid piercing means creating at least one exit opening through which the beverage can drain from the capsule.

0003It has been found, however, that in the above known systems preferential paths of fluid flow may occur in the extractable product within the capsule, e.g. from the at least one entrance opening to the at least one exit opening, which may lead to undesired strength of the prepared beverage and/or variations in strength of the prepared beverage, from one capsule to another.

0004Further relevant prior art is disclosed in <patcit id="pcit0002" dnum="EP1555219A"><text>EP 1 555 219</text></patcit>.

0005It is an object of the invention to improve the above system, and more specifically to at least diminish the above problem.

0006Thereto, according to a first aspect of the invention, the system is characterised by the characterising portion of claim 1.

0007Thus it is possible to supply the fluid to the extractable product within the capsule without piercing the capsule. Thus, the entrance filter forms an, optionally uniform, entrance area through which the fluid can be supplied to the capsule. This provides the advantage that it is possible for the beverage to enter the capsule over a larger area than when entrance openings are pierced in the known systems, thus diminishing the risk of preferential fluid paths occurring in the extractable product in the capsule and enhancing the reproducibility of the beverage strength.

0008Further, it has been found that providing the entrance filter reduces the risk of extractable product remains spilling from the capsule when removing the capsule from the apparatus.

0009The exchangeable capsule comprises an amount of extractable product, and thus is suitable and intended, for preparing a single portion of the beverage, preferably a single cup of the beverage, e.g. from 30-200ml of the prepared beverage. The exchangeable capsule, thus, is a single-portion-pack. In an embodiment, the capsule comprises 4-8 grams, preferably approximately 7 grams of extractable product, e.g. roasted and ground coffee.

0010Preferably, the exchangeable capsule is disposable after single use.

0011According to a second aspect of the invention, a system is provided according to claim 20.

0012Thus, the exit filter forms a, optionally uniform, exit area through which the beverage can leave the capsule. This provides the advantage that it is possible for the beverage to leave the capsule over a larger area than when exit openings are formed by piercing the lid, thus diminishing the risk of preferential fluid paths occurring in the extractable product in the capsule and enhancing the reproducibility of the beverage strength. Further, the capsule not being pierced by the lid piercing means, and staying intact, provides the advantage that a predetermined pore and/or exit hole size and distribution of the exit filter, defining exit openings of the exit filter, remains intact, so that the size and distribution of exit openings does not depend on chance, as when the exit openings are formed by piercing.

0013Moreover, it has been found that providing the exit filter reduces the risk of extractable product remains spilling from the capsule when removing the capsule from the apparatus.

0014Further, if the extractable product is roasted and ground coffee, providing the exit filter provides the advantage that the exit filter may filter oils from the beverage, i.e. from the coffee, before supplying the coffee to the container, such as the cup. This may be advantageous to remove oils from the coffee which adversely affect the taste and/or quality of the coffee. It is especially advantageous to filter cafestol from the coffee, since cafestol is understood to raise the blood cholesterol content. Thus, providing the exit filter may improve the quality of the coffee with respect to consumer health.

0015Preferably the exit filter has a sufficiently high tear strength and/or forming a sufficiently low flow resistance that the exchangeable capsule of the system, in use, is not pierced by the lid piercing means and the lid stays intact. It has been found that the exit filter having the sufficiently high tear strength and/or forming the sufficiently low flow resistance does not tear against the lid piercing means.

0016According to a further feature of the invention, the capsule may be provided with both the entrance filter and the exit filter as described above. Hence, in use, the capsule is not pierced by the bottom piercing means, nor the lid piercing means, so that the capsule remains fully intact. This provides the advantage that the risk of preferential fluid paths occurring in the extractable product in the capsule and the reproducibility of the beverage strength is enhanced even more.

0017In the first aspect preferably, the entrance filter is formed by a porous sheet, such as of filtering paper, a foil, such as a polymeric film, provided with a plurality of entrance openings, or a plurality of entrance openings provided in the bottom of the exchangeable capsule of the system. Hence, the entrance filter can be provided in a simple manner.

0018In an embodiment in the second aspect, the plurality of entrance openings is distributed over substantially the entire surface of the foil or the bottom, respectively. This provides the advantage that the fluid can be supplied to substantially the entire cross section of the inner space. Hence, the extractable product is wetted very homogeneously.

0019In a further embodiment, the plurality of entrance openings comprises side-entrance openings arranged in the circumferential wall. This provides the advantage that the extractable product is, at least partially, also wetted from the side. This provides that advantage that the fluid can be supplied to the extractable product in a very homogeneous and controlled manner.

0020Preferably, the exit filter is formed by a porous sheet, such as of filtering paper, or a foil, such as a polymeric film, provided with a plurality of exit openings, or a plurality of exit openings provided in the lid. Hence, the exit filter can be provided in a simple manner. Also, parameters of the exit filter can be easily chosen to provide the exit filter having the sufficiently high tear strength and/or forming the sufficiently low flow resistance.

0021For instance, in an embodiment, the exit filter may be formed by a sheet of filtering paper. The filtering paper provides the low-cost exit filter. Moreover, parameters of the filtering paper, such as density, thickness and/or PE-content, can easily be chosen to provide the exit filter having the sufficiently high tear strength and/or forming the sufficiently low flow resistance. In an alternative preferred embodiment, the exit filter may be formed by a polymeric film provided with a plurality of exit openings. Parameters of the polymeric foil, such as density, thickness, number of exit openings, size and/or shape of exit openings, can easily be chosen to provide the exit filter having the sufficiently high tear strength and/or forming the sufficiently low flow resistance.

0022In an embodiment, the lid piercing means may have a blunt piercing surface. In such embodiment, the alternative capsule may, nevertheless, be pierced by the blunt piercing means, while the capsule of the system according to the invention has the exit filter having the sufficiently high tear strength and/or forming the sufficiently low flow resistance not to be pierced or torn.

0023It is possible in the first aspect that the lid piercing means comprises at least one ridge against which the lid, in use, abuts. The at least one ridge may form at least 10%, possibly at least 25% of the portion of the surface of the receptacle which, in use, coincides with the portion of the surface area of the lid overlying the second, open, end. In use, the lid may supported by the at least one ridge over at least 10%, preferably at least 25% of the portion the surface area of the lid overlying the second, open, end. The lid of the alternative capsule may be pierced by such piercing means, whereas parameters of the exit filter of the exchangeable capsule of the system may easily be chosen such that the exit filter has the sufficiently high tear strength and/or forming the sufficiently low flow resistance not to be pierced or torn.

0024It is possible that the lid piercing means and/or the at least one ridge comprises edges, wherein the edges are not sharp. Possibly, the edges have a radius of curvature of at least 50 µm, preferably at least 100 µm. The lid of the alternative capsule may be pierced by such piercing means, whereas parameters of the exit filter of the exchangeable capsule of the system may easily be chosen such that the exit filter has the sufficiently high tear strength and/or forming the sufficiently low flow resistance not to be pierced or torn.

0025In an embodiment, the plurality of exit openings is distributed over substantially the entire surface of the lid. This provides the advantage that the beverage can be drained from the capsule over substantially the entire cross section of the inner space. Hence, the beverage can flow out of the inner space very homogeneously.

0026According to a further aspect of the invention, the entire inner space is occupied by the extractable product. This provides the advantage that the extractable product cannot be displaced inside the inner space when the fluid flows through the capsule, so that no preferential paths can be formed. In the second aspect preferably, the bottom is integral with the circumferential wall. This provides the advantage that the capsule can simply be formed from a generally cup-shaped structure forming the circumferential wall and the bottom and a, e.g. sheet-shaped, lid. The lid may be connected to the circumferential wall, e.g. by means of gluing, welding, folding or the like.

0027In an embodiment in the second aspect the capsule comprises an inwardly extending rim at the first end, wherein the bottom is attached to the inwardly extending rim. Hence it is possible to connect the, e.g. sheet-shaped, bottom comprising the entrance filter to the rim. Thus, a simple construction of the capsule may be obtained. It is also possible that the capsule comprises an inwardly extending rim at the second end, wherein the lid is attached to the inwardly extending rim.

0028In an embodiment the capsule comprises an outwardly extending rim at the second end, wherein the lid is attached to the outwardly extending rim. Hence it is possible to connect the, e.g. sheet-shaped, lid comprising the exit filter to the rim. Thus, a simple construction of the capsule may be obtained. It is also possible in the second aspect that the capsule comprises an outwardly extending rim at the first end, wherein the bottom is attached to the outwardly extending rim.

0029In a special embodiment, the capsule further comprises a bottom seal at least partially removable connected to the bottom for sealing the entrance filter prior to use. Hence entering of air into the inner space via the entrance filter prior to use of the capsule may be prevented, improving shelf life of the product inside the capsule.

0030In a special embodiment, the capsule further comprises a lid seal at least partially removable connected to the lid for sealing the exit filter prior to use. Hence entering of air into the inner space via the exit filter prior to use of the capsule may be prevented, improving shelf life of the product inside the capsule.

0031According to a further feature of the invention, the lid seal is arranged to be partially released from the lid under the effect of fluid pressure in the inner space, while remaining attached to the lid at at least one position. Hence, the lid seal need not be removed from the capsule by a user of the capsule. When the fluid enters the inner space pressure will build up until the seal partially releases from the lid and the beverage can flow out through the exit filter. The releasable connection may e.g. be formed as a so-called peel-seal. Since the lid seal is permanently attached to the lid at at least one position, the lid seal will not fully detach from the capsule. This has the advantage, that the lid seal will automatically be discarded from the apparatus when discarding the used capsule.

0032In general, in the second aspect the circumferential wall may be formed by a flexible, optionally porous, sheet or foil, such as filtering paper, preferably integral with the bottom. Hence, a very simple and optionally environmentally friendly capsule may be provided.

0033Alternatively, in the second aspect the circumferential wall may substantially rigid. This provides that advantage that the capsule is not prone to be deformed prior to use, so that the capsule can fit into the receptacle without problems. Preferably, the capsule comprises stiffening ribs integral with the circumferential wall and/or bottom to increase the rigidity of the capsule.

0034In general, the circumferential wall may have any shape such as cylindrical, hemispherical, frustoconical or polygonal, such as hexagonal or octagonal.

0035Preferably, the extractable product comprises roasted and ground coffee. Thus, the capsule is suited for preparing a predetermined amount of coffee by supplying a predetermined amount of hot water under pressure to the capsule.

0036According to a further feature of the invention, the extractable product is compacted into a tablet. This provides the advantage that the risk of preferential flow paths occurring in the compacted extractable product tablet is reduced.

0037Preferably, the tablet comprises at least one bore extending from the side of the tablet facing the entrance area in the direction of the lid. The bore thus provides an infusion means for wetting the tablet in a homogeneous manner.

0038It is also possible that the extractable product is compacted into a plurality of tablets, preferably of mutually different packing density. It is for instance possible that the extractable product is provided as a single stack of tablets having mutually different degrees of compacting. It is for instance possible that the degree of compacting increases per tablet in the direction from the bottom to the lid. In this way the effort to completely wet a tablet will also increase in the direction from the bottom to the lid, insuring that each upstream tablet has been properly wetted when wetting a more downstream tablet, thus providing very homogeneous wetting of the total volume of extractable product.

0039The invention also relates to a method for preparing a beverage.

0040The invention will now be further elucidated by means of, non-limiting, examples referring to the drawing, in which <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001 f0002 f0003">Figs. 1a-1c</figref> shows a system for preparing a beverage holding an alternative/prior art capsule;</li><li><figref idref="f0004">Fig. 2</figref> shows a system holding an exchangeable capsule;</li><li><figref idref="f0005 f0006">Figs. 3a-3d</figref> show embodiments of capsules 2;</li><li><figref idref="f0007">Figs. 4a, 4b and 4c</figref> show examples of further embodiments of a capsule 2; and</li><li><figref idref="f0008">Figs. 5a and 5b</figref> show examples of even further embodiments of a capsule 2.</li></ul><figref idref="f0001 f0002 f0003">Figs. 1a-1c</figref> show a system 101 for preparing a predetermined quantity of beverage suitable for consumption using an extractable product. The system 101 comprises an alternative/prior art capsule 102, and an apparatus 104. The apparatus 104 comprises a receptacle 106 for holding the exchangeable capsule 102. In <figref idref="f0001 f0002 f0003">Figs. 1a-1c</figref> a gap is drawn between the capsule 102 and the receptacle 106 for clarity. It will be appreciated that, in use, the capsule 102 may lie in contact with the receptacle 106. Commonly, the receptacle 106 has a shape complementary to the shape of the capsule 102. The apparatus 104 further comprises a fluid dispensing device 108 for supplying an amount of a fluid, such as water, under a pressure, of e.g. 9 bars, to the exchangeable capsule 102.

0041In the system 101 shown in <figref idref="f0001 f0002 f0003">Figs. 1a-1c</figref>, the capsule 102 comprises a circumferential wall 110, a bottom 112 closing the circumferential wall 110 at a first end 114, and a lid 116 closing the circumferential wall 110 at a second end 118 opposite the bottom 112. The circumferential wall 110, the bottom 112 and the lid 116 enclose an inner space 120 comprising the extractable product.

0042The system 101 of <figref idref="f0001 f0002 f0003">Figs. 1a-1c</figref> comprises bottom piercing means 122 intended for piercing the capsule 102. <figref idref="f0001">Fig. 1a</figref> shows the bottom piercing means 122 in a retracted position. <figref idref="f0002">Fig. 1b</figref> shows the bottom piercing means 122 in an extended position for creating an entrance opening 124 in the bottom 112 for supplying the fluid to the extractable product through the entrance opening 124. In <figref idref="f0001 f0002 f0003">Figs. 1a-1c</figref> the piercing means 122 comprise a bore 126 through which the fluid can be supplied to the extractable product contained in the inner space 120. The system 101 of <figref idref="f0001 f0002 f0003">Figs. 1a-1c</figref> further comprises lid piercing means 128, here embodied as protrusions, intended for piercing the lid 116 of the capsule 102.

0043The system 101 shown in <figref idref="f0001 f0002 f0003">Figs. 1a-1c</figref> is operated as follows for preparing a cup of coffee, wherein the extractable product is roasted and ground coffee.

0044The capsule 102 is placed in the receptacle 106 (see <figref idref="f0001">Fig. 1a</figref>). The bottom piercing means are activated to pierce the bottom 112 of the capsule 102 (see <figref idref="f0002">Fig. 1b</figref>) for creating the entrance opening 124. The fluid, here hot water under pressure, is supplied to the extractable product in the inner space 120 through the entrance opening 124. The water will wet the coffee grounds and extract the desired substances to form the coffee beverage.

0045During supplying the water under pressure to the inner space 120, the pressure inside the capsule 102 will rise. The rise in pressure will cause the lid 116 to deform and be pressed against the lid piercing means 128. Once the pressure reaches a certain level, the tear strength of the lid 116 will be surpassed and the lid will rupture against the lid piercing means 128, creating exit openings 130 (see <figref idref="f0003">Fig. 1c</figref>). The prepared coffee will drain from the capsule 102 through the exit openings 130 and outlets 132 of the receptacle 106, and may be supplied to a container such as a cup (not shown).

0046During preparation of the beverage in the system 101 shown in <figref idref="f0001 f0002 f0003">Figs. 1a-1c</figref> preferential flow paths may exist in the extractable product inside the inner space 120 of the capsule 102. These preferential paths may extend from the entrance opening 124 to the exit openings 130. One such possible preferential path is indicated with line PP in <figref idref="f0003">Fig. 1c</figref>.

0047<figref idref="f0004">Fig. 2</figref> shows an example of a system 1 for preparing a predetermined quantity of beverage suitable for consumption using an extractable product. The system 1 comprises an exchangeable capsule 2, and an apparatus 104. The apparatus 104 comprises a receptacle 106 for holding the exchangeable capsule 2. In this example, the receptacle 106 has a shape complementary to the shape of the capsule 2. In <figref idref="f0004">Fig. 2</figref> a gap is drawn between the capsule 2 and the receptacle 106 for clarity. It will be appreciated that, in use, the capsule 2 may lie in contact with the receptacle 106. The apparatus 104 further comprises a fluid dispensing device 108 for supplying an amount of a fluid, such as water, under pressure to the exchangeable capsule 2.

0048In the system 1 shown in <figref idref="f0004">Fig. 2</figref>, the exchangeable capsule 2 comprises a circumferential wall 10, a bottom 12 closing the circumferential wall 10 at a first end 14, and a lid 16 closing the circumferential wall 10 at a second end 18 opposite the bottom 12. The circumferential wall 10, the bottom 12 and the lid 16 enclose an inner space 20 comprising the extractable product. In this example, the exchangeable capsule 2 comprises an amount of extractable product suitable for preparing a single portion of the beverage, preferably a single cup of the beverage, e.g. from 30-200ml of the prepared beverage. The exchangeable capsule, thus, is a single-portion-pack.

0049According to a first aspect of the invention, the system 1 of <figref idref="f0004">Fig. 2</figref> comprises bottom piercing means 122 intended for piercing the alternative/prior art capsule 102 as shown in <figref idref="f0001 f0002 f0003">Figs. 1a-1c</figref>. <figref idref="f0004">Fig. 2</figref> shows the bottom piercing means in an extended position, intended for creating the entrance opening 124 in the bottom 112 of the alternative/prior art capsule 102. According to the invention, the capsule 2 comprises an entrance filter 34 which is positioned at a distance from the bottom piercing means 12, such that the capsule 2 is not pierced by the bottom piercing means 122 and the bottom 12 stays intact when the bottom piercing means is brought in the extended position.

0050In <figref idref="f0004">Fig. 2</figref> the piercing means 122 comprise a bore 126 through which the fluid is supplied to an inner space of the receptacle 106. The fluid, here hot water under a pressure of e.g. more than 6 bars, will flow through the entrance filter 34 into the inner space 20 of the capsule 2 for extracting desired substances from the extractable product, in this example approximately 7 grams of roasted and ground coffee, for preparing, in this example the single cup of the beverage, here coffee.

0051Thus, more in general, in the example of <figref idref="f0004">Fig. 2</figref>, the bottom 12 comprises an entrance area, formed by the entrance filter 34, and the system 1 is arranged for bringing the fluid dispensing device 108 in fluid connection with the entrance area for supplying the fluid to the extractable product for preparing the beverage.

0052In the example of <figref idref="f0004">Fig. 2</figref>, the circumferential wall 10 is substantially rigid. The circumferential wall may e.g. comprise a plastics material and may be formed by e.g. injection moulding, vacuum-forming, thermoforming or the like. In the example of <figref idref="f0004">Fig. 2</figref> the bottom 12 is integral with the circumferential wall. In this example the entrance filter 34 is formed by a plurality of entrance openings 24 in the bottom 12. In this example the plurality of entrance openings 24 is distributed over substantially the entire bottom 12. Thus, the fluid is supplied to the extractable product via the plurality of entrance openings 24, which causes the extractable product to be wetted over substantially the entire cross section of the capsule 2. Hence, a very homogeneous supply of fluid to the extractable product is obtained. Thus, the risk of occurrence of preferential paths via which the fluid flows through the extractable product is greatly reduced.

0053According to a second aspect of the invention, which may be practiced in addition to the above described first aspect or separate thereof, the system 1 of <figref idref="f0004">Fig. 2</figref> comprises lid piercing means 128 intended for piercing the lid 116 of the alternative/prior art capsule 102 when the lid 116 sufficiently presses against the lid piercing means 128 under the influence of the pressure of the fluid and/or beverage in the capsule 102 for creating at least one exit opening 130 through which the beverage can drain from the prior art capsule 102. According to the invention, the capsule 2 comprises an exit filter 36, through which the beverage can drain from the capsule 2. The exit filter 36 is arranged to having a sufficiently high tear strength not to be pierced by the lid piercing means 128 under the influence of the pressure inside the capsule 2. Alternatively, or additionally, the exit filter 36 forms a sufficiently low flow resistance for the beverage exiting the capsule 2, that the exit filter 36 is not pressed against the lid piercing means 128 with sufficient force to be pierced by the lid piercing means 128 and the lid stays intact. Hence, the exit filter 36 is adapted to the lid piercing means 128 such that the capsule 2, in use, is not pierced by the lid piercing means 128 and the lid 16 stays intact. More in general it applies that the exit filter 36 and the lid piercing means 128 are adapted to each other such that the capsule 2, in use, is not pierced by the lid piercing means 128 and the lid 16 stays intact.

0054In the example of <figref idref="f0004">Fig. 2</figref> the exit filter 36, forming an exit area of the capsule 2, through which the beverage, here coffee, can drain from the capsule, is formed by a porous sheet, such as filter paper. In this example the entire lid 16 is formed as the exit filter 36. In the example of <figref idref="f0004">Fig. 2</figref>, the capsule 2 comprises an outwardly extending rim 38 at the second end 18, wherein the lid 16 is attached to the outwardly extending rim 38, e.g. by gluing, welding or the like. Hence, in this example the exit filter 36, i.e. the porous sheet, is attached to the outwardly extending rim 38.

0055In this example the exit filter 36 forms a substantially continuous fluid-permeable sheet spanning substantially the entire second, open end 18 of the capsule 2. Thus, the fluid can drain from the capsule 2 over a large area. Hence, a very homogeneous drain of beverage from the extractable product is obtained. Thus, the risk of occurrence of preferential paths via which the fluid flows through the extractable product is greatly reduced.

0056In general, parameters of the exit filter of the capsule 2 of the system 1 according to the invention can be chosen such that the exit filter does not tear or rupture, e.g. has the sufficiently high tear strength and/or forming the sufficiently low flow resistance not to be pierced or torn. It will be appreciated that the lid and/or the exit filter may deform against the lid piercing means, although it will not rupture or be torn. When the exit filter 36 is e.g. made of filtering paper, parameters of the filtering paper, such as density, thickness and/or PE-content, can easily be chosen to provide the exit filter having the sufficiently high tear strength and/or forming the sufficiently low flow resistance. Alternatively, when the exit filter 36 is e.g. formed by a polymeric film provided with a plurality of exit openings, parameters of the polymeric foil, such as density, thickness, number of exit openings, size and/or shape of exit openings, can easily be chosen to provide the third wall having the sufficiently high tear strength and/or forming the sufficiently low flow resistance.

0057In the example of <figref idref="f0004">Fig. 2</figref>, the lid piercing means 128 are shown having sharp toothed points intended for piercing the lid. It will be appreciated that, alternatively, the lid piercing means 128 may have blunt piercing surfaces, e.g. as indicated with dashed lines in <figref idref="f0004">Fig. 2</figref>. In such embodiment, the alternative/prior art capsule 102 may, nevertheless, be pierced by the blunt piercing means 128, e.g. when the lid 116 consists of a sheet of aluminium foil. Parameters of the exit filter of the capsule 2 of the system according to the invention can be chosen such that the exit filter has the sufficiently high tear strength and/or forms the sufficiently low flow resistance not to be pierced or torn. It will be appreciated that when the lid piercing means are blunt, the parameters of the exit filter may be chosen to suit these blunt piercing means. When the piercing means are blunt, the exit filter may e.g. be thinner than when the lid piercing means are sharp, while guaranteeing that the exit filter has the sufficiently high tear strength and/or forming the sufficiently low flow resistance not to be pierced or torn.

0058It is possible that the lid piercing means comprise ridges against which the lid, in use, abuts. Such ridges may be formed by the blunt piercing means 128 as shown with dashed lines in <figref idref="f0004">Fig. 2</figref>. The ridges may e.g. form at least 10%, possibly at least 25% of the portion of the surface of the receptacle 106 which, in use, coincides with the portion of the surface area of the lid 16 overlying the second, open, end 18. Hence, in use, the lid 16 may be supported by the ridges over, e.g. at least 10%, preferably at least 25%, of the portion the surface area of the lid 16 overlying the second, open, end 18. As already indicated, the lid 116 of the alternative/prior art capsule 102 may be pierced by such ridges, whereas parameters of the exit filter 36 of the capsule 2 of the system 1 according to the invention may easily be chosen such that the exit filter has the sufficiently high tear strength and/or forms the sufficiently low flow resistance not to be pierced or torn. It will be appreciated that when the lid piercing means comprise ridges, the parameters of the exit filter may be chosen to suit such lid piercing means.

0059In the example of <figref idref="f0004">Fig. 2</figref>, the ridges comprise edges which are not sharp. In this example a radius of curvature of the edges is approximately 50 µm, although other radii are conceivable, such as 100, 200 or 500 µm. The alternative/prior art capsule 102 may, nevertheless, be pierced by the blunt piercing means 128, e.g. when the lid 116 consists of a sheet of aluminium foil. It will be appreciated that when the lid piercing means comprise non-sharp edges, the parameters of the exit filter may be chosen to suit such lid piercing means. Parameters of the exit filter of the capsule 2 of the system according to the invention can be chosen such that the exit filter has the sufficiently high tear strength and/or forming the sufficiently low flow resistance not to be pierced or torn.

0060It is also possible that the ridges of the lid piercing means 128 have a convex top against which the lid 16 abuts. Hence, when the lid, in use, is pressed against the ridges, the surface area over which the lid is supported by the ridges increases, thus reducing the local pressure exerted on the lid by the ridges. Thus it is possible to provide, in an easy manner, that the lid, in use, does not tear and/or rupture and stays intact.

0061<figref idref="f0005 f0006">Figs. 3a-3d</figref> show embodiments of capsules 2.

0062In <figref idref="f0005">Fig. 3a</figref> the bottom 12 is integral with the circumferential wall 10 like in <figref idref="f0004">Fig. 2</figref>. The entrance filter 34 is formed by the plurality of entrance openings 24 in the bottom 12. The exit filter 36 is formed by a foil 40, e.g. a flexible polymeric foil, provided with a plurality of exit openings 30.

0063In <figref idref="f0005">Fig. 3b</figref> the exit filter 36 is formed by the flexible porous sheet, such as filter paper, like in <figref idref="f0004">Fig. 2</figref>. In <figref idref="f0005">Fig. 3b</figref> the entrance filter 34 is also formed by a flexible porous sheet, such as filter paper. In this example the entrance filter is attached to an inwardly extending rim 42. In this example, the entrance filter 34 is attached to the inner side of the inwardly extending rim 42. This maximizes the internal volume of the capsule 2, as the rim thickness is not present in the inner space 20 of the capsule 2.

0064In <figref idref="f0006">Fig. 3c</figref> the exit filter 36 is formed by the flexible porous sheet, such as filter paper, like in <figref idref="f0004">Fig. 2</figref> and <figref idref="f0005">3b</figref>. In <figref idref="f0006">Fig. 3c</figref> the entrance filter 34 is also formed by a flexible porous sheet, such as filter paper. In this example, the entrance filter 34 is attached to the outer side of the inwardly extending rim 42. Hence, the risk is reduced that the fluid under pressure tears the entrance filter 34 from the inwardly extending rim 42. It is possible that the entrance filter 34 overhangs a circumferential edge of the bottom. Hence, a larger surface area is available for attaching the entrance filter 34 to the bottom 12 and the circumferential wall 10, resulting in a stronger bond.

0065In <figref idref="f0006">Fig. 3d</figref> the exit filter 36 is formed by a foil 40, e.g. a flexible polymeric foil, provided with a plurality of exit openings 30, as in <figref idref="f0005">Fig. 3a</figref>. In <figref idref="f0006">Fig. 3d</figref> the entrance filter 34 is also formed by a foil 44, provided with the plurality of entrance openings 24.

0066In all embodiments of <figref idref="f0005 f0006">Figs. 3a-3d</figref> the exit filter is formed by a flexible sheet-shaped material. More specifically, in all embodiments of <figref idref="f0005 f0006">Figs. 3a-3d</figref> the lid is solely formed by the flexible sheet-shaped material. It has been found that in general no supporting structure, such as a substantially rigid grid, e.g. downstream of the exit foil, is required to support the exit foil to prevent the exit foil from tearing an/or rupturing.

0067In all embodiments of <figref idref="f0005 f0006">Figs. 3b-3d</figref> the entrance filter is formed by a flexible sheet-shaped material. More specifically, in all embodiments of <figref idref="f0005 f0006">Figs. 3b-3d</figref> the entrance area is solely formed by the flexible sheet-shaped material. It has been found that in general no supporting structure, such as a substantially rigid grid, e.g. downstream of the entrance foil, is required to support the entrance foil to prevent the entrance foil from tearing and/or rupturing.

0068In all embodiments of <figref idref="f0005 f0006">Figs. 3a-3d</figref> the exit filter forms the outermost boundary of the capsule in the axial direction thereof.

0069It will be appreciated that the capsule 2 may comprise any entrance filter according to any one of the shown embodiments in combination with any exit filter according to any one of the shown embodiments. Although not shown, it is possible that the lid comprises a substantially rigid wall provided with the exit openings 30.

0070In general, the exit openings 30, or pores of the porous sheet, are dimensioned such that a dimension of the opening 30 or pore is sufficiently small to retain the extractable product, such as ground coffee, inside the capsule 2. Also in general, the entrance openings 24, or pores of the porous sheet, are dimensioned such that a dimension of the opening 24 or pore is sufficiently small to retain the extractable product, such as ground coffee, inside the capsule 2.

0071In general, the entrance openings 24 are preferably distributed over substantially the entire surface of the bottom or the foil 44, at least substantially the entire surface of the opening defined by the inwardly extending rim 42. Optionally, entrance openings 24 are also present in the circumferential wall 10, e.g. in the portion of the circumferential wall 10 near the first end 14. This allows homogeneous supply of the fluid to the extractable product inside the capsule 2. In general, the exit openings 30 are preferably distributed over substantially the entire surface of the lid or the foil 40, at least substantially the entire surface of the opening defined by the outwardly extending rim 38. This allows homogeneous draining of the beverage from the extractable product inside the capsule 2.

0072In the examples of <figref idref="f0004">Figs 2</figref>, <figref idref="f0005 f0006">3a-3d</figref> the entrance openings 24 and exit openings 30 have a circular cross section. The openings 24, 30 with circular cross section are easily manufactured. Optionally the cross section of the entrance openings 24 tapers (narrows) towards the inner space 20. This provides the advantage that the entrance openings act as nozzles that cause a jet of fluid to enter the inner space 20.

0073It will be appreciated that the entrance openings 24 and/or exit openings 30 may also have alternative shapes. The openings 24,30 may for instance have the shape of elongate slits. Preferably, the small dimension of the slits is sufficiently small to retain the extractable product inside the capsule 2.

0074In a special embodiment, the slits may have a shape that defines a tongue in the plane of the bottom. The slits may then be substantially U-shaped, such as semi-circular, horse-shoe shaped, rectangular or V-shaped. This has the advantage that the tongue may be bent out of the plane of the bottom under the effect of the flow of fluid through the opening defined by the tongue. Thus, a larger volume flow of fluid may be attained. If the bottom is made of a resilient material, the tongue will bend back into the plane of the bottom once the flow of fluid stops, thus preventing the spilling of extractable product (prior to and) after preparation of the beverage. It will be appreciated that slits defining a tongue may be applied in the lid mutatis mutandis.

0075<figref idref="f0007">Fig. 4a</figref> shows an example of a further embodiment of a capsule 2. <figref idref="f0007">Fig. 4a</figref> shows a modification of the capsule shown in <figref idref="f0005">Fig. 3a</figref> . It will be appreciated that this modification may be applied to any capsule 2 referred to hereinabove. In the example of <figref idref="f0007">Fig. 4a</figref> the capsule 2 further comprises a bottom seal 46. The bottom seal 46 closes off the entrance openings 24 (or the porous sheet) prior to use. The bottom seal 46 is at least partially removable connected to the bottom 12. In this example the bottom seal 46 comprises a lip 48 to allow easy removal of the bottom seal 46 by a user of the capsule 2. In <figref idref="f0007">Fig. 4a</figref> the capsule 2 further comprises a lid seal 50. The lid seal 50 closes off the exit openings 30 (or the porous sheet) prior to use. The lid seal 50 is at least partially removable connected to the lid 16. In this example the lid seal 50 comprises a lip 52 to allow easy removal of the lid seal 50 by a user of the capsule 2. The bottom seal 46 and lid seal 50 improve shelf life of the product inside the capsule by preventing air to enter the capsule via the openings 24,30 or porous sheet.

0076In a special embodiment (not shown) the lip 46 of the bottom seal 46 is connected to the lip 52 of the lid seal 50. Thus, the bottom seal 46 and the lid seal 50 can be made unitary. Hence, it may be prevented that a user accidentally forgets to remove one of the bottom seal and the lid seal.

0077<figref idref="f0007">Figs. 4b and 4c</figref> shows an example of a plan view of a further embodiment of the capsule 2 when viewed from the side of the lid 16. In <figref idref="f0007">Figs. 4b and 4c</figref> the capsule comprises the lid seal 50. The lid seal 50 is attached to the lid 16 with a releasable seal 54. In this example the releasable seal forms a circumferential seal adjacent a circumferential edge of the lid 16. The releasable seal 54 is arranged to be released from the lid 16 under the effect of fluid pressure in the inner space 20. The releasable seal may e.g. be a peel-seal of predetermined release-strength. Hence, it is not required that the user removes the lid seal 50 from the capsule 2, as the seal is opened automatically while preparing the beverage.

0078In <figref idref="f0007">Figs. 4b and 4c</figref> the lid seal 50 is further attached to the lid 16 with a permanent connection 56. The permanent connection may e.g. be a glued or welded connection. In <figref idref="f0007">Fig. 4b</figref> the permanent connection is positioned adjacent the centre of the lid. In <figref idref="f0007">Fig. 4c</figref> the permanent connection 56 is positioned adjacent the circumferential edge of the lid. This provides the advantage that the releasable seal may be released under the effect of pressure for allowing the draining of the beverage from the capsule, while the lid seal 50 remains attached to the lid 16 at at least one position. Hence, the lid seal 50 need not be discarded separately, improving ease of use, and cannot be lost.

0079It will be appreciated that instead of, or in addition to, being attached to the lid, the lid seal 50 may also be attached to the rim positioned near the second end 18, and/or to the circumferential wall 14.

0080It will be appreciated that the capsule 2 may in a similar way alternatively, or additionally be provided with the bottom seal 46, e.g. positioned on the inner side of the bottom 12, arranged to be released from the bottom 12 under the effect of pressure of fluid supplied to the capsule 2, and optionally provided with at least one permanent connection between the bottom and the bottom seal 46. It will be appreciated that instead of, or in addition to, being attached to the bottom 12, the bottom seal 46 may also be attached to the rim positioned near the first end 14, and/or to the circumferential wall 14.

0081It will also be appreciated that the lid seal 50 and/or the bottom seal 46 may also be used in conjunction with alternative capsules, wherein the lid does not form an outermost boundary of the capsule in the axial direction thereof, e.g. a capsule having an axially extending rim extending beyond the lid.

0082Preferably, the circumferential wall is substantially rigid. Hence, the capsule will not be prone to deform by shipping and/or handling, so that the capsule 2 will always fit in the receptacle 106. In addition, the circumferential wall is preferably resilient, so that any possible deformation of the circumferential first wall will be reversed once the force causing the deformation is removed. In order to improve rigidity of the capsule 2, the capsule 2 may comprise stiffening ribs integral with the circumferential wall 10. The stiffening ribs may extend from the first end 14 towards the second end 18. Alternatively, or additionally, the stiffening ribs may extend in a circumferential direction. When the bottom 12 is integral with the circumferential wall 10, the stiffening ribs may also be integral with the bottom 12.

0083Nevertheless, it is possible that the circumferential wall is formed by a flexible, e.g. porous, sheet or foil, preferably integral with the bottom. Hence, substantially the entire capsule may be manufactured of the flexible sheet, reducing the amount of material required for providing the capsule. Optionally, the outwardly extending rim may be substantially rigid to enhance ease of handling of the capsule.

0084In the examples the circumferential wall is substantially frustoconical. It will be appreciated that the exchangeable capsule is not limited to this shape. The circumferential wall may e.g. be cylindrical, hemispherical, or polygonal, such as hexagonal, octagonal, etc.

0085According to a further aspect of the invention, the extractable product in the inner space 20 is compacted. <figref idref="f0008">Fig. 5a</figref> shows an example wherein the extractable product is compacted into a plurality of, in this example four, tablets 58,60,62,64. In <figref idref="f0008">Fig. 5a</figref> the tablets are stacked inside the inner space 20. In <figref idref="f0008">Fig. 5a</figref>, each tablet 58,60,62,64 spans substantially the entire cross section of the capsule 2. In this example a density, i.e. a degree of compaction, of the tablets is different for each of the tablets. The density of the tablets 58,60,62,64 increases in the direction from the bottom 12 to the lid 16. This provides the advantage that the fluid will more easily wet a tablet of lower density than a tablet of higher density, so that each upstream tablet is properly wetted while the water wets a subsequent downstream tablet. Thus, highly homogeneous wetting of the extractable product is achieved. Although the example shows four stacked tablets, it will be appreciated that any number of tablets may be used.

0086<figref idref="f0008">Fig. 5b</figref> shows an example of a capsule 2 comprising a single tablet 66 of compacted extractable product. In the example of <figref idref="f0008">Fig. 5b</figref> the tablet 66 comprises bores 68 extending into the tablet 66 from the side of the tablet 66 facing the bottom 12 in the direction of the lid 16. The length of the bores 68 is shorter than the thickness of the tablet 66 in the direction along the bore 68. Thus, the bores 68 do not form shortcut passages for the fluid through the tablet 66, but provide the fluid a passage into the core of the tablet 66. These bores allow a predetermined penetration of the fluid into the tablet. Thus, a preferred wetting of the compacted extractable product may be obtained.

0087In the examples of <figref idref="f0008">Figs. 5a and 5b</figref> the entrance filter 34 and exit filter 36 of the capsule are substantially as shown in <figref idref="f0006">Fig. 3c</figref>. It will be appreciated that the tablet 66 or plurality of tablets 58,60,62,64 may be used in conjunction with any capsule 2 referred to hereinabove. It will also be appreciated that if the extractable product is compacted into the tablet(s) the bottom 12 of the capsule is not strictly required, since the extractable product is not likely to spill from the capsule prior to use.

0088It will be appreciated that the capsules 2 referred to hereinabove may also be used in alternative apparatus for preparing the beverage, for instance in apparatus not provided with the bottom piercing means and/or not provided with the lid piercing means.

0089In the foregoing specification, the invention has been described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein without departing from the scope of the invention as set forth in the appended claims.

0090It is for instance possible that the capsule 2 is contained in an air-tight wrapping prior to use to improve shelf-life.

0091It is also possible that the bottom comprises a recessed area for receiving the bottom piercing means without the bottom being pierced; for increasing the capsule volume.

0092In above examples, the exit filter forms the lid. It is also possible that the exit filter forms part of the lid. The lid may for instance be partially porous and/or partially perforate.

0093In above examples, the entrance filter forms the bottom. It is also possible that the entrance filter forms part of the bottom. The bottom may for instance be partially porous and/or partially perforate.

0094However, other modifications, variations and alternatives are also possible. The specifications, drawings and examples are, accordingly, to be regarded in an illustrative rather than in a restrictive sense.

0095In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of other features or steps then those listed in a claim. Furthermore, the words 'a' and 'an' shall not be construed as limited to 'only one', but instead are used to mean 'at least one', and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.