Abstract:
The invention relates to a method for the preparation of a drink by injection of a liquid thorugh a capsule, containing a food substance which is soluble and/or for extraction, whereby the liquid is injected from at least one injection point, such as to generate a turbulent movement of injected liquid within said capsule, thus causing a brewing of the liquid with said substance.

Description:
BACKGROUND  
       [0001]     This invention relates to a method for preparing a beverage from a substance that is contained in a receptacle and mixed with a liquid under pressure. More specifically, the invention relates to a method whereby the substance is a soluble powder contained in an enclosure such as a capsule.  
         [0002]     This invention also relates to a device as well as a capsule comprising an integrated injection nozzle for implementing the method according to the invention.  
         [0003]     The use of capsules containing a substance for preparing a beverage by dispensing or mixing it under pressure is a well-established practice especially in making espresso coffee, tea or chocolate drinks and is desirable especially for reasons of hygiene, freshness, preservation and ease of use.  
         [0004]     There are various types of machines for preparing beverages from closed or permeable capsules containing an extractable i.e. percolatable substance such as ground coffee or tea or a soluble or dispersible substance such as instant coffee, chocolate, milk or a mixture or simple combination of these substances.  
         [0005]     The Swiss patent CH 605 293 describes a closed capsule. According to that patent, the capsule has the shape of an essentially truncated conical scoop provided with a circular flange with a welded-on metallic membrane. The membrane is equipped with a filter and the capsule holds a certain amount of the substance for brewing a beverage, typically ground coffee. When in use, the capsule is placed in an apparatus through whose centrally perforated container bottom extends an element for the pressure injection of a liquid. The liquid that is injected through the substance breaks the membrane under the effect of the pressure in such fashion that the beverage can flow through an exit opening provided in the apparatus for that purpose.  
         [0006]     One important aspect of that process is that the liquid must flow through the entire volume of the substance contained in the capsule to obtain optimal and reproducible extraction. This is accomplished in that the injection element is in the form of a pin that is hollow in the middle and is provided near its distal end with multiple outlet holes through which water exits laterally so that the pressurized liquid can generate a fluid piston to soak to the extent possible all of the substance contained in the capsule, in this case roasted and ground coffee.  
         [0007]     To that effect, the European patent EP 0 468 080 provides for the water exit holes to extend at an angle relative to the horizontal plane, whereby the injected water is reflected off the bottom surface before impinging on the bulk of the coffee, thus augmenting the dispersion of the water.  
         [0008]     It is a well-known fact that the injection, mixing and steeping conditions make a considerable difference in the quality of the resulting beverage. Accordingly, for a substance that is ground and compacted in a capsule or indeed a substance that is dissolved or dispersed in a liquid, such as soluble coffee or a milk-based substance such as cappuccino, chocolate milk or the like, the manner in which the water circulates through the capsule is considered to have an effect on the extraction and mixing conditions and thus on the ultimate quality of the beverage. A product such as coffee or chocolate should thus be dissolved or dispersed quickly and completely, preferably producing a paste, whereas soluble tea should dissolve without producing any paste. The dissolution or dispersion should be total, homogeneous, quick and without forming lumps or flakes. For products that are to be extracted i.e. percolated, such as ground coffee, the optimal steeping conditions are different. The product should be completely soaked by optimizing the water/coffee contact area and without the water seeking a preferred path through the bulk of the coffee. In fact, establishing a preferred path through the bulk of the coffee can lead to an excessively strong build-up of pressure and thus to too rapid a release of the extract with not enough percolation time, while part of the coffee is still not properly saturated.  
         [0009]     Prior-art methods and equipment are well adapted to the extraction of substances contained in a capsule, for instance roasted and ground coffee, but they are poorly adapted to capsules containing soluble substances such as powdered coffee or chocolate powder.  
         [0010]     In fact, the design of the conventional systems for the pressure injection of liquids and the spray patterns obtained by those systems do not allow especially for the mixing effect necessary for efficaciously dissolving the soluble substance in the liquid, so that a not so negligible part of that substance fails to make contact with the liquid and is therefore not dissolved. The result is unsatisfactory reproducibility of the mixing conditions to the point where the amount of dissolved substance cannot be controlled. That in turn leads to beverages of inconsistent strength and in general to a loss of control over the quality of the beverage.  
         [0011]     It follows from the above that there is a need for a method and a device for preparing a beverage in particular from a soluble substance contained in an enclosure.  
       SUMMARY  
       [0012]     An objective of this invention is therefore to satisfy that need by proposing a method for preparing a beverage from a soluble substance contained in an enclosure, whereby that substance is completely dissolved.  
         [0013]     Another objective of this invention is to provide a method that is equally suitable for capsules containing a percolatable substance and for capsules containing a soluble substance.  
         [0014]     This invention is also aimed at “open” beverage brewing devices, i.e. those whose mixing and/or percolation chamber, strictly speaking, is not a capsule but a chamber that is a part of the device itself.  
         [0015]     Another objective of this invention is to provide a method for preparing a beverage from either a percolatable or a soluble substance contained in an enclosure that is easy and inexpensive to make.  
         [0016]     Yet another objective of the invention is to introduce a device for preparing a beverage by the method per this invention.  
         [0017]     The invention further introduces a capsule by means of which the method per this invention can be implemented.  
         [0018]     To that effect, the invention introduces a method for preparing a beverage whereby a liquid is injected through a receptacle, containing a soluble and/or percolatable alimentary substance, from at least one injection point in such fashion as to generate within the said receptacle a turbulence of the injected liquid, causing the liquid to mix with the said substance.  
         [0019]     In one preferred form of implementation of the invention, the liquid is injected at a distance from the center of the receptacle, whereby the jet spray of liquid is directed past that center, thus generating a turbulent movement around the said center of the receptacle. Additionally, the jet is suitably inclined toward the bottom wall of the receptacle.  
         [0020]     In this fashion a turbulence can be created within the receptacle that ensures homogeneous mixing of the substance in the receptacle with the injected liquid, thus leaving no solid residue of the substance in the receptacle. In fact, the injected liquid can move more freely within the receptacle by multiple reflection of the swirling spray off the receptacle walls, thus reaching all of the substance, quickly penetrating the latter. This method thus promotes the dissolution of “soluble” substances such as instant coffee or “dispersible” substances such as chocolate powder while eliminating pockets of accumulated residual solids that tend to form both on the bottom and along internal ridges and rims of the receptacle.  
         [0021]     This process thus lends itself to the preparation of beverages for instance from identical capsules in which the concentration of the percolated or dissolved substance varies very little from one capsule to the next.  
         [0022]     Another advantage lies in the fact that, as the soluble substance is mixed with the injected liquid, air is trapped in the mixture, whereby a frothy beverage can be produced.  
         [0023]     A further advantage is the simplicity and ease of implementing this process.  
         [0024]     Yet another advantage of this method is that it can be used with a large variety of alimentary products.  
         [0025]     One objective of the invention is a device for preparing a beverage by injecting a liquid through a capsule containing an alimentary substance to be dissolved or extracted, said device comprising means for holding the capsule and at least one liquid-injection assembly designed to inject the liquid in the form of ajet spray from at least one injection point inside the capsule, characterized in that the injection point and the direction of the jet spray are configured in a way as to create in the capsule a swirling turbulence that causes the liquid to mix with the substance.  
         [0026]     Another objective of the invention is a capsule containing a soluble and/or percolatable alimentary substance for preparing a beverage by the injection of a liquid under pressure generated by an external apparatus, said capsule incorporating an upper and a lower wall connected by a lateral wall so as to define a chamber in which the said substance is contained, the capsule being characterized in that the upper wall encompasses an injection assembly designed to inject the liquid in the form of a jet spray into the chamber from at least one injection point, said injection point and the direction of the jet spray being so configured as to create in the capsule a swirling turbulence that causes the liquid to mix with the substance.  
         [0027]     By virtue of these characteristics the capsule permits the implementation of the method per this invention with a device of the conventional type with a simple liquid-dispensing nozzle.  
         [0028]     In one preferred form of implementation of the capsule according to the invention, the upper wall encompasses an outer wall section and an inner wall section, together delimiting a cavity that is sealed against the outside and designed to accommodate a perforation and injection element as well as a channel connecting said cavity with the injection assembly.  
         [0029]     In that design version the injection assembly preferably includes a nozzle that is integrated in the inner wall section. The cavity and the channel are advantageously formed into the inner wall while the outer wall is constituted of a perforatable membrane. The cavity is preferably situated essentially in the center of the capsule.  
         [0030]     Other features and advantages of this invention will be evident from the following description of a non-limiting example of a preferred form of implementation of the method and the device per the invention, with reference to the attached diagrams.  
         [0031]     Additional features and advantages are described herein, and will be apparent from, the following Detailed Description and the figures 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0032]      FIG. 1  is a schematic sectional view of a first form of implementation of a device, shown in its open position, for brewing a beverage by the injection of a liquid through a capsule according to the invention;  
         [0033]      FIG. 2  is a schematic sectional view of the brewing device per  FIG. 1 , shown in its closed position;  
         [0034]      FIG. 3  is a schematic top view of a capsule, illustrating in particular the location of the liquid-injection point in the latter, with the cover left off;  
         [0035]      FIG. 4  is a diagrammatic perspective view of a perforation and injection element mounted on the device per this invention as shown in  FIG. 1 ;  
         [0036]      FIG. 5  is a diagrammatic perspective view of a design variation of the device for brewing a beverage by injecting a liquid through a capsule per this invention, with the capsule holder left off;  
         [0037]      FIG. 6  is a schematic sectional view of a second form of implementation of a device for brewing a beverage by injecting a liquid through a capsule per this invention, with the device shown in its closed state and in a first functional mode;  
         [0038]      FIG. 7  is a schematic view of the brewing device per  FIG. 6 , shown in its closed state and in a second functional mode;  
         [0039]      FIG. 8    a  and  8   b  are schematic perspective and, respectively, perspective-section views of the perforation and injection element for use in combination with the second form of implementation of the brewing device;  
         [0040]      FIG. 9    a  and  9   b  are schematic perspective and, respectively, perspective-section views of a design variation of the perforation and injection element for use in combination with the second form of implementation of the device;  
         [0041]      FIG. 10  is a schematic perspective section and partly cut-away view of a capsule per this invention; and  
         [0042]      FIG. 11  is a schematic perspective detail illustration of the capsule per  FIG. 10 .  
         [0043]     For the purpose of the following description, identical components in the diagrams bear identical reference numbers. 
     
    
     DETAILED DESCRIPTION  
       [0044]      FIG. 1  and  2  show a device  1  for brewing a beverage, open in  FIG. 1  and closed for operation in  FIG. 2 . In the device  1 , the beverage is prepared by pressure-injecting a liquid, typically hot or cold water, through a capsule  2  containing a soluble and/or percolatable alimentary substance  4  (not shown), such as roasted ground coffee, or tea, soluble coffee, a mixture of ground and soluble coffee, a chocolate product or any other dehydrated alimentary substance.  
         [0045]     As can also be seen in  FIG. 1 , the capsule  2  is essentially in the form of a small cup with a lateral wall  6  and a lower wall  8  defining the bottom. In the example illustrated, the diameter of the bottom  8  is smaller than the diameter of the mouth of the cup. The free end of the lateral wall  6  terminates in an essentially annular peripheral rim  10  that extends toward the outside of the cup. The lateral wall  6  and the bottom  8  would typically consist for instance of a single- or multi-layered plastic material selected from among the group that includes EVOH, PVDC, PP, PE, PA .The cup is hermetically sealed off by an upper wall  12  constituted of a cover that is mounted on the rim  10  for instance by thermal bonding. The cover  12  is typically made of a material that can be pierced by perforation and injection elements, described in detail below, of the device  1 . The material of the cover  12  could be selected for instance from the group including aluminum, an aluminum/plastic compound, a cardboard/plastic composition, a cardboard/aluminum/plastic combination, plain or multi-layered plastic. Together, the side wall  6 , the bottom  8  and the cover  12  thus form a chamber  14  that contains the alimentary substance  4 . Of course, the capsule  2  may equally well be an open or partly open capsule. In a more general sense, the term “capsule” broadly refers to any replaceable type of container that encloses a substance without limitation as to its shape or constituent materials.  
         [0046]     In the example illustrated it can be seen that the capsule  2  incorporates in its lower segment a thin film  16  sealed onto an inner rim  18  of the cup and closing off the lower part of the chamber  14 . That thin film  16  sits on top of a disc  20  featuring on its upper surface multiple evenly spaced protrusions that form multiple channels leading to the perimeter of the disc and into a collection chamber  22  which is delimited by the disc  20  and the bottom  8  and itself opens up to the outside via an exit port  24 . The thin film  16  will break on contact with the protrusions under the pressure load inside the chamber  14 . As can be seen, the exit port is integral to the capsule  2 , the advantage of which is that it permits the direct delivery of a product into a drinking cup without direct contact with the device, ensuring the absence of any beverage cross-contamination, better hygiene, less cleaning, and greater design simplicity even of the device itself. For a more detailed description of the capsule  2 , reference is made to the European patent application PCT No. 03/00384 filed on Jan. 13, 2003 in the name of this claimant and whose entire content is made a part hereof by reference.  
         [0047]     The device  1  incorporates a generally cylindrical liquid-injection head  26  situated on a generally cylindrical capsule holder  28 . The injection head  26  and the capsule holder  28  can be vertically moved relative to each other between the open position ( FIG. 1 ) in which the capsule  2  can be placed on the capsule holder  28  and the closed position ( FIG. 2 ) in which the device  1  can be activated.  
         [0048]     More precisely, the capsule  2  is placed in a retainer  30  in the capsule holder, the shape of which typically matches in complementary fashion that of the capsule to be accommodated. In its lower section the retainer  30  is provided with an opening  32  that lines up with the exit port  24  of the capsule  2 . The capsule holder thus constitutes the support for the capsule  2  in the device  1 .  
         [0049]     The injection head  26  includes an essentially bell-shaped support  34  in whose throat  34   a  a core shaft  36  is mounted. The latter comprises a liquid-intake channel  38  that extends between a liquid-input well  40  and a perforation and injection element  42  with an injection port  42   a . The perforation and injection element, described below in detail, serves to pass through the cover  12  so as to connect the injection port  42   a  with the inside of the capsule upon the relative movement of the injection head  26  and the capsule holder  28  that puts the brewing device in the closed position.  
         [0050]     The well  40  is designed to connect to a liquid feeder tube from an apparatus (not shown) capable of supplying hot or cold liquid under pressure. The injection head  26  thus constitutes an injection assembly that can inject a liquid in the form of ajet spray J from at least one injection point defined by the injection port  42   a  of the perforation and injection element  42 .  
         [0051]     In the example shown, the throat  34   a  is essentially cylindrical and its base  34   b  features a central opening  44  that extends axially toward the outside through a sleeve  46  with an internal thread.  
         [0052]     The core shaft  36  includes a first cylindrical, large-diameter segment that extends in the throat  34   a  and a second segment with a smaller diameter that screws into the sleeve  46 . The injection head  26  also comprises an annular gasket  48  interpositioned between the first segment of the core shaft  36  and the inner side wall of the throat  34   a . The gasket  48  is so placed that, in the closed position ( FIG. 2 ) it presses against the rim  10  of the capsule which in turn sits on an upper peripheral support surface  28   a  of the capsule holder  28 . The gasket  48  also projects axially from the throat  34   a , allowing it to be appropriately compressed when it makes contact with the rim  10 , thus ensuring a good seal. In the example shown, it can be seen that the gasket  48  also seals off the intake channel  38  in the area of the perforation and injection element  42 .  
         [0053]     Referring to  FIG. 3 , which is a top view of the capsule  2  with the cover  12  left off and in which only the perforation and injection element  42  of the injection head  26  is shown, it can be seen that the perforation and injection element  42  and more specifically its injection port  42   a  is situated at a distance from the center C of the capsule  2  and is thus off center relative to its vertical axis A-A. The axis  50  of the injection port  42   a  is oriented at one end in a first direction that passes by the center C ( FIG. 3 ) of the capsule  2  and at the other end in a second direction oriented toward the bottom of the latter ( FIG. 2 ). With this positional configuration of the injection port  42   a  in the capsule and the particular orientation of the axis  50  of that port, the injection of a liquid produces a jet spray J that creates in the capsule a swirling turbulence of the liquid around the center C of the capsule, with concurrent, multiple jet-spray reflections off its inner walls. The general swirling movement of the injected liquid in combination with its multiple reflections leads to a thorough mixing of the liquid with, and complete saturation of, the substance  4 .  
         [0054]     To obtain that mixing result, i.e. to create in the capsule  2  an optimal vortex effect, the claimant has found that part of the axis  50  of the injection port  42   a  has to be at an angle α of between 20° and 60°, and preferably between 35 and 45°, relative to the line  52  that connects the injection point with the center C of the capsule  2 , and that the axis  50  has to be at an angle β of between 50° and 70°, and preferably between 55 and 65°, relative to the vertical axis A-A of the capsule. It was also found that the injection port  42   a  should preferably be located near the side wall  6  of the capsule so as to be able to progressively moisten the substance from the perimeter of the capsule towards its center, ensuring that all of the substance comes in contact with the liquid. As an example, the diameter of the injection port  42   a  is about 0.7 mm, the rate at which the liquid is injected is about 4 ml/s.  
         [0055]      FIG. 4  is a section view of an implementation example of the perforation and injection element  42 , which serves the purpose of piercing and extending through the cover  12  when the brewing device is in its closed position. The perforation and injection element  42  includes a hollow pin with a channel  42   b  that is open at both ends. The first end connects to the intake channel  38  as the second end leads to the outside through the injection port  42   a . The channel  42   b  contains a first rectilinear segment that is extended by a second segment which terminates in the injection port  42   a  and forms an angle with the first segment. The slope of the second segment of the channel is identical to the angle at which the liquid is injected into the capsule, with the first segment extending essentially parallel to the axis A-A when the pin is positioned in the core shaft  36 . It can also be seen in  FIG. 4  that the hollow pin that constitutes the perforation and injection element  42  features a bevel  42   c  at its distal end and that the injection port  42   a  leads to a surface opposite the bevel  42   c . That particular configuration of the distal end of the pin advantageously allows the pierced section of the cover  12   a  to be pushed toward the opposite side away from the injection port when the pin  42  punches through the cover  12 , so that the injection port is always completely free and that section of the cover  12   a  does not interfere with the injection of the liquid into the capsule.  
         [0056]     According to one design variation, not illustrated, a seal may be provided around the perforation and injection element  42  to keep the chamber sealed off from the outside when the brewing device is in the operating state.  
         [0057]     Of course, the location of the injection port  42   a  is such that the injection of the liquid takes place a few millimeters below the cover  12 , typically 4 mm.  
         [0058]      FIG. 5  is a perspective diagram of a design variant of the device  1  for brewing a beverage by injecting a liquid through a capsule per this invention, showing only the injection head. In that design variation the capsule holder is identical to that described above in reference to  FIG. 1  and  2 , while the injection head  26  comprises not only one single perforation and injection element  42  but several, in this case  3 , all identical in design and identical in their orientation to the perforation and injection element  42  described in connection with  FIG. 1  to  4 . As can be seen, the three perforation and injection elements  42  are evenly spaced apart on a lower surface of the injection head  26 , serving to act on the cover  12  of the capsule  2  when the brewing device is in the operating state. Typically, these elements  42  are spaced apart 120° from one another around the center of the injection head  26 . In this case the intake channel  38  is, of course, designed to connect to each of the three perforation and injection elements  42 .  
         [0059]      FIG. 6  and  7  depict a second form of implementation of a device for preparing a beverage by injecting a liquid through a capsule according to this invention. The brewing device is shown in its closed position in both figures but in a first functional mode in  FIG. 6  and in a second functional mode in  FIG. 7 . For the purpose of this invention, the term functional mode refers to the desired way in which the substance contained in the capsule  2  is to be wetted, that mode essentially depending on the type of substance used.  
         [0060]      FIG. 6  shows the brewing device in a first wetting mode whereby the liquid is injected into the capsule in a way as to create a swirling movement of the liquid around the center C of the capsule in combination with multiple reflections of the jet spray off its inner walls, as described in reference to  FIG. 1  and  2 . This saturation mode is best suited to capsules containing soluble substances since it permits the complete and rapid dissolution of substances of that nature.  
         [0061]      FIG. 7  shows the brewing device in a second wetting mode whereby the liquid is injected into the capsule in a way that, in addition to the swirling turbulence of the liquid around the center C of the capsule, the upper part of the capsule is soaked with the aid of a jet that diverts some of the liquid in the form of a fine sheet, wetting the substance in the capsule from above. That saturation mode is particularly useful in capsules containing percolatable substances since it permits the complete and rapid dissolution [sic] of that type of substances.  
         [0062]     According to this second form of implementation of the invention, the brewing device comprises a perforation and injection element  60  with a first injection port  62  positioned and oriented in the same way as the injection port  42   a  of the perforation and injection element  42  described in reference to  FIG. 1  to  4 , and a second injection unit  64  whose injection axis extends in essentially horizontal fashion to produce that divergent stream in the form of a fine sheet of liquid. In both  FIGS. 8    a  and  8   b  it can be seen that, in the example illustrated, the perforation and injection element  60  is in the form of a hollow pin with a channel  60   b  that leads outside to a first end by way of the first and second injection units  62  and  64 , respectively. The channel  60   b  also connects to the intake channel  38  in its median section through an opening  66 . The perforation and injection element extends at the end opposite the injection units  62  and  64  into a cam  60   c  that interacts with a lever  68  controlled by switching elements (not shown) connected to the head  26 . The perforation and injection element  62  includes in its middle part a segment with a larger diameter, in which the opening  66  is located and by which it is mounted so as to permit translatory movement in a shoulder-equipped track  70  that extends parallel to the vertical axis of the injection head set in the core shaft  36 , with a pullback spring  72  positioned between the bottom of the track and one shoulder of the perforation and injection element  62 . Two O-ring gaskets are located on either side of the opening  66  on the perforation and injection element  60 , making contact with the inner surface of the track  70 .  
         [0063]     In this form of implementation the perforation element  60  can move between two distinct positions, i.e. one first position ( FIG. 6 ) in which only the first port  62  connects to the inside of the capsule  2  and which corresponds to the first wetting mode, and a second position ( FIG. 7 ) in which the first port  62  and the second injection unit  64  connect to the inside of the capsule  2  and which corresponds to the second wetting mode. The switchover from the first wetting mode to the second wetting mode is accomplished via the switching elements that shift the perforation and injection element  60  under the action of the pullback spring  72  by way of the lever  68 . Of course, the diameter of the intake channel  38  and that of the opening  66  and the path of the perforation and injection element for shifting from the first to the second wetting mode are such that the opening  66  is at all times at least partially connected to the intake channel  38  regardless of the wetting mode selected.  
         [0064]     Preferably, and as is evident from  FIG. 8    a  and  8   b , the second injection unit  64  by means of which a divergent stream in the form of a fine sheet of liquid is produced, contains several ports  64   a , distributed around part of the perimeter of the perforation and injection element  60 . While the perforation and injection element  60  is located off-center inside the capsule, and more specifically near the side wall of the latter, the ports  64   a  are aimed toward the center of the capsule. For reasons that have to do with the fabrication of the element  60 , the ports  64   a  are advantageously staggered in height relative to one another. These ports  64   a  produce several diverging streams that combine to form a fine sheet of liquid that soaks and saturates the substance contained in the upper part of the capsule.  
         [0065]     Of course, that fine sheet of liquid could just as conceivably be produced by a single port  64   b  in the form of a slit extending transversely in the longitudinal direction of the element  60  as shown in  FIG. 9    a  and  9   b . In that case the diverging stream is spread over a circular area large enough to soak essentially all of the substance in the upper part of the capsule.  
         [0066]     As will be evident, the ports  64   a  and the port  64   b  are respectively positioned in a way as to produce an essentially continuous fine sheet of liquid over an angular sector of between 90° and 180° and preferably about 160°. Moreover, these ports  64   a  and  64   b  are designed to produce a sheet of liquid having a thickness of less than or equal to 0.5 mm and preferably less than 0.3 mm. To that effect, the diameter selected for the ports  64   a  is preferably about 0.5 mm while the diameter selected for the port  64   b  is about 0.7 mm.  
         [0067]     In an advantageous variation of the second form of implementation, the axis of the second injection units  64 , i.e. the axis of the ports  64   a  and  64   b , respectively, that defines the direction of the liquid spray, forms an angle of between 0° and 25° and preferably an angle of about 15° with the horizontal plane. The liquid that is injected by these ports is thus directed upward and is first reflected off the lower surface of the cover  12 , then sent back in a second step toward the bulk of the substance in substantially more dispersed form, further improving homogeneous saturation of the substance.  
         [0068]      FIG. 10  shows a capsule  100  that contains a soluble and/or percolatable alimentary substance  4  for brewing a beverage by injecting a pressurized liquid and which is suitable for implementing the method per this invention with a conventional device equipped with a single liquid distribution nozzle. To that effect the capsule  100  differs from the capsule  2  described in reference to  FIG. 1  and  2  in that the upper wall  110  comprises an injection assembly  112  so configured as to inject liquid into the chamber  14  from one jet-type injection point J, with the injection point and the direction of the said jet spray J being so chosen as to create in the said capsule a swirling turbulence, causing the liquid to mix with the said substance.  
         [0069]     More specifically, the upper wall  110  encompasses an outer wall element  114  and an inner wall element  116 , which together define a cavity  118  that is sealed off against the outside, as well as a channel  120  that connects the cavity  118  with the injection assembly  112 .  
         [0070]     The outer wall element  114  is in the form of a cover comprising at least one region of a material that can be pierced by a perforation and injection element (not shown) such as the injection nozzle of a conventional beverage-brewing device. In the example illustrated, the outer wall element  114  is a cover thermobonded onto the rim of the capsule, with the structure of this cover being identical to that of the cover  12  described in connection with  FIG. 1  and  2 .  
         [0071]     In this form of implementation the cavity  118  and the channel  120  are directly recessed at specific depth levels into the inner wall element  116 , with the cavity  118  produced essentially in the center of the capsule. Since the cavity  118  is designed to receive the perforation and injection element of a conventional brewing device, its location and depth could of course vary as a function of the device with which it is to be used.  
         [0072]     The inner wall element  116  also encompasses the injection assembly  112  constituted of an injection nozzle  112   a . Preferably, and as illustrated, the injection nozzle  112   a  is an integral part of the inner wall element  116 . The injection nozzle  112   a  includes an injection port  112   b  that is positioned and oriented in the same way as the injection port  42   a  of the perforation and injection element  42  described in reference to  FIG. 1  to  4 .  
         [0073]     In a design variation, not shown, of the capsule according to this invention, the injection nozzle may also comprise second injection elements whose injection axis extends in an essentially horizontal direction, producing a second diverging stream in the form of a fine sheet of liquid. These second injection elements could typically be constituted of multiple ports or of a slit as described above in reference to  FIG. 8    a  and  9   a.    
         [0074]     The following describes the method per this invention for brewing a beverage by injecting a liquid through a capsule containing a soluble alimentary substance, employing the first form of implementation of the device per the invention as illustrated in  FIG. 1  and  2 . First, the capsule  2  is placed in the capsule holder  28  while the device is in its open position ( FIG. 1 ). Next, the device is closed with a relative vertical movement of the capsule holder  28  and of the injection head  26  ( FIG. 2 ). That clamps the rim  10  of the capsule between the lower annular surface of the gasket  48  and the upper perimeter of the support  28   a  of the capsule holder. At the same time the cover  12  is pierced by the perforation and injection element  42 . In that configuration the injection port  42  is situated inside the capsule  2 , preferably several millimeters below the cover. The liquid used for brewing the beverage, for instance hot water, is then pressure-injected in the capsule through the port  42   a  so oriented as to lead in a first step to the progressive dissolution of the substance to be dissolved, in a direction past the center as well as at an angle toward one wall of the capsule, digging a tunnel up to that wall of the capsule  2 . Having reached that wall, and given the orientation of the jet spray and its kinetic energy, the spray is deviated and continues to dissolve the substance in another direction until it is again shifted toward another wall, thus creating a swirling movement of the injected liquid around the center of the capsule. That swirling turbulence thus mixes the liquid with the substance, permitting thorough dissolution of the latter. At the same time, the pressure inside the capsule rises slowly, progressively dilating the membrane around the protrusions on the disc  20  illustrated in the examples per  FIG. 1  and  2 . As soon as the breaking tension of the membrane  16  is reached as a result of the pressure, the membrane bursts and the dissolved liquid can run out through the exit port  24  of the capsule  2 . The swirling jet continues its multiple reflections so as to reach the remaining amounts of the substance until these are completely dissolved.  
         [0075]     In preparing a beverage by injecting a liquid through a capsule that contains an extraction-type i.e. percolatable alimentary substance by employing the second form of implementation of the device per the invention as illustrated in  FIG. 6  and  7 , the method according to the invention differs from that described above in that the device is first switched into the wetting mode that corresponds to the substance contained in the capsule, in this case the second wetting mode illustrated in  FIG. 7 . That wetting mode additionally triggers an injection of liquid in the upper part of the capsule in the form of one or several fine sheets of liquid for wetting the substance from above via the injection units  64 . The claimant has found that wetting the substance with a combination of the jet spray J and the fine sheet of liquid is particularly effective especially in brewing beverages from percolatable substances.  
         [0076]     It can be seen that with a capsule  100  as shown in  FIG. 10 , a device equipped with a conventional perforation and injection element can be used to employ the brewing method according to the invention. Indeed, all that is needed is for the position of the cavity  118  to be aligned with the perforation and injection element of the device when the capsule  100  is situated in the device so that at the moment that the cover  110  is pierced the perforation and injection element can penetrate into the cavity  118 . At that point the injected liquid fills the cavity and is then channeled via the channel  120  to the injection port  112   a  where it is injected under pressure into the capsule, leading to the events described above.  
         [0077]     course, this invention is not limited to the forms of implementation described above, and it will be understood that various modifications and/or enhancements that are obvious to those skilled in the art can be made without departing from the essence of the invention as defined in the attached claims. In particular, as far as variants are concerned, one could envision a design in which the perforation takes place not through the cover  12  but through other walls of the capsule, so long as the perforation element is so located and oriented as to cause the injected liquid spray to generate a swirling movement around the center C of the capsule, permitting the liquid to mix with the substance contained in the capsule. For example, the perforation and injection element could pass through the side wall or even through the bottom of the capsule.  
         [0078]     Abbreviations  
         [0079]     EVOH: copolymer of ethylene and vinyl alcohol  
         [0080]     PVDC: Vinylidene polychloride  
         [0081]     PP: Polypropylene  
         [0082]     PE: Polyethylene  
         [0083]     PA: Polyamide  
         [0084]     It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.