Abstract:
The invention relates to a method for preparing a beverage through a capsule inserted in a beverage machine; the capsule comprising an enclosure containing one or more beverage ingredients, wherein a brewing fluid is introduced in the enclosure to brew the one or more beverage ingredients, characterized in that: a discharge wall is placed in association with the enclosure, wherein the discharge wall comprises a discharge member that restrains the brewed liquid from being discharged from the capsule or limits the liquid flow in case the pressure inside the enclosure is below a predetermined value, and the discharge member enables the delivery of the brewed liquid in case the pressure exceeds the predetermined value.

Description:
PRIORITY CLAIM 
       [0001]    The present application is a divisional application of U.S. patent application Ser. No. 13/823,793, filed on Mar. 15, 2013, which is a National Stage of International Application No. PCT/EP2011/065850, filed on Sep. 13, 2011, which claims priority to European Patent Application No. 10176834.9, filed Sep. 15, 2010, the entire contents of each of which are being incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a method for preparing and delivering a beverage from a capsule that contains one or more beverage ingredients as well as the capsule for preparing and delivering the beverage in a brewing device. The present invention more particularly aims at providing a method for brewing tea from capsules and a beverage machine as well as a capsule adapted to deliver brewed tea, although other beverages can be successfully brewed by this method and in this capsule. 
       BACKGROUND 
       [0003]    Different beverage preparation methods using capsules to be brewed in a suitable beverage machine are known. Quality of a tea beverage is highly dependent on the quality of the leaf tea ingredients, i.e., the tea origin used (soil, drying, blending, etc.) and their storage conditions. For instance, tea ingredients are usually sensitive to oxygen and light. Preferred tea ingredients are taken from loose leaves, chiseled or broken in small fragments. However, brewing conditions are also important to take full advantage of the quality of the starting ingredients used. 
         [0004]    Another problem with tea beverages resides in that taste cross-contamination must be preferably avoided. Taste cross-contamination happens when two capsules are successively brewed in the machine and when a taste residue is left by the first capsule on permanent parts of the machine that can consequently affect the taste of the second capsule which is brewed just after the first capsule. For tea, this can be an issue with certain tea varieties that deliver a high aroma profile such as mint tea or other highly flavored varieties. Also tea residue may constitute a soil for bacterial growth and may lead to hygiene issues which need to be tackled. 
         [0005]    WO 2007/042414 A1 and WO 2007/042415 A1 propose a design of a capsule that promotes optimal conditions for the preparation of a tea beverage and the like. In particular they propose a capsule that is adapted to brew or infuse beverages in a beverage machine that may provide the following advantages: the quality of the tea beverage can be improved, in particular, in relation to the beverage concentration into the cup, the taste and the reduced turbidity. For these purposes the capsule comprises: an enclosure containing one or more beverage ingredients; a filtering wall delimiting at least one filtering side of the enclosure, wherein it comprises an overflow wall that is positioned in the path of the brewed liquid after the filtering wall and which comprises at least one overflow aperture. Since the production of such a capsule requests the assembly of different elements in a certain order—that is the positioning of a filter means through the capsule enclosure opening and then of an overflow wall on the filter means—the production of the capsule is complex and expensive. 
         [0006]    Therefore, there is a need for a capsule that is easier and less expensive to be produced while presenting a design that promotes optimal conditions for the preparation of a tea beverage and the like. 
         [0007]    In the present application, the terms “capsule” or “cartridge” or “package” are considered as synonymous. The term “capsule” will be preferentially used. The capsule can be a single use capsule hermetically closed before its use for the preparation of a beverage or it can be a reusable capsule that is openable to introduce desired food ingredients inside before use. The words “brewing” or “infusion” are used as synonymous. The term “brewing fluid” generally refers to the liquid that serves to infuse the beverage ingredients, more generally, hot water. The term “brewed liquid” generally refers to the liquid that has infused and submerged the beverage ingredients, more generally, tea or the like. 
         [0008]    In the present application, the term “tea” encompasses all type of leaf tea such as green tea, black tea, white tea, chai tea, flavored tea, herbal or fruit tea and combinations thereof. The term “leaf tea” or “leaf ingredient” refers to brewable tea or other ingredients in whatever form such as complete, cut or chiseled leaves, small fragments of leaves, powder or dust. 
       SUMMARY 
       [0009]    The present invention provides a new way to brew or infuse beverage from a beverage capsule in a beverage machine as well as a capsule that is adapted therefore and that provide the following advantages:
       the quality of the beverage can be maintained, in particular, in relation to the beverage concentration into the cup, a good taste and a reduced turbidity,   a capsule that is less complicated and less expensive to produce, and a method that involves the capsule   the beverage delivery is cleaner and it reduces or eliminates the taste cross-contamination and hygiene issues.       
 
         [0013]    For these purposes as well as many others possible, the invention according to a first aspect relates to a method for preparing a beverage through a capsule inserted in a beverage machine, the capsule comprising an enclosure containing one or more beverage ingredients, wherein a brewing fluid is introduced in the enclosure to brew the one or more beverage ingredients, and wherein a discharge wall is placed in association with the enclosure and the capsule is positioned in the machine during beverage preparation so that the discharge wall is vertically oriented. Further, according to the invention, the discharge wall comprises a discharge member that restrains the brewed liquid from being discharged from the capsule or limits the liquid flow in case the pressure inside the enclosure is below a predetermined value, and the discharge member enables the delivery of the brewed liquid in case the pressure exceeds the predetermined value. 
         [0014]    Therefore, according to the first aspect of the method of the invention, and without willing to be bound to any theoretical model, an effect can be obtained to enable the beverage ingredients to be submerged by the fluid, therefore avoiding bypassing areas and ensuring that the mass of ingredient fully interacts with the brewing fluid, and thus, a well mixed brewed liquid can leave the capsule and becomes dispensed once the pressure exceeds the predetermined value. 
         [0015]    According to a first embodiment, the discharge member can be a discharge opening which may comprise a hole which increases its section when the pressure inside the enclosure is rising. In this case, the discharge wall is preferably made up of a flexible, preferably resilient or elastic, material such as a silicone membrane to enable the increase in section while at the same time forming a watertight wall being impermeable in its discharge opening portions as long as the pressure is below the predetermined value. It can also be an elastic fibres woven material or the like. Hence, the discharge wall, or better the discharge member in the wall limits the flow of fluid to the outlet when a low fluid pressure is applied thereon, and the flow of fluid to the outlet can be increased when the pressure inside the capsule increases. That is when the capsule enclosure is full of water and the water pump goes on introducing water in the enclosure, the pressure raises, the discharge member increases its section and the liquid flow thus slowly increases as well, such that the ingredients will have been thoroughly submerged until the predetermined pressure value has been reached. 
         [0016]    According to a second embodiment, the discharge member may comprise a flexible valve such as a bicuspid-like valve, a tricuspid-like valve or a tetracuspid-like valve. The discharge wall of the second embodiment can be made up of the same material as the discharge wall according to the first embodiment. Additionally or alternatively, both the discharge opening and the flexible valve, i.e., the before-mentioned discharge member, can be contracted to close the discharge member, i.e., thus closing the discharge wall, when the pressure is below the predetermined value, and the discharge member can be expanded to open the discharge member, i.e., thus opening the discharge wall, when the pressure exceeds the predetermined value. An advantage of these two first modes is that at the end of the preparation of the beverage, the water pump stops introducing water in the enclosure of the capsule then the pressure inside the capsule decreases and either the hole section decreases or the valve closes. Then the discharge wall is closed and prevents the liquid that is still inside the capsule to leak therefrom during the ejection of the capsule from the beverage machine which makes the beverage preparation method cleaner. 
         [0017]    According to a third embodiment, the discharge member is a discharge opening comprising a hole with fixed diameter sufficiently small to create a watertight wall when brewing fluid is introduced without pressure, and to let brewed liquid flow there through when the pressure exceeds the predetermined value. In this case, the discharge wall can be made of a plastic material comprising the at least one hole. It can also be a plastic, paper or textile filter. By means of the feature, the ingredients can be thoroughly submerged before the predetermined pressure value has been reached and the water, i.e., the brewed beverage is forced to exit the enclosure via the discharge member, i.e., the holes when the predetermined value has been exceeded. 
         [0018]    Preferably, the discharge wall extends substantially along a whole transversal section of the enclosure, more preferably substantially from the bottom of the enclosure to the top of the enclosure. The discharge wall thus creates a sufficiently large surface for the brewed liquid that favors a lower brewing pressure in the enclosure and a slow flow velocity while the flow rate can stay within the acceptable range. Thus, the predetermined pressure can be adjusted and set more accurately and the ingredients can be thoroughly submerged. Preferably the discharge wall presents a valve opening section or a hole section (i.e. discharge member) sufficiently small to act as a filter and prevent solid food ingredients like tea leaves to go through them. 
         [0019]    By the method of the invention, the brewing fluid enters the enclosure at a relative pressure below 0.2 bar, preferably, below 0.1 bar and most preferably from atmospheric pressure to a value below 0.1 bar. 
         [0020]    In the present context, the “relative pressure” is meant to be the pressure that is measured just outside of the fluid inlet of the capsule (and downstream an eventual backpressure valve) and refers to the value of pressure above the ambient atmospheric pressure. 
         [0021]    According to the method of the invention, the brewed liquid can be conducted downward from the discharge member through a beverage conduit to a beverage outlet. Therefore, the brewed liquid can be dispensed properly and hygienically into the recipient (cup, mug, . . . ) while keeping a simple capsule construction and promoting an easy handling of the capsule in the machine. 
         [0022]    For this, the method of the invention contemplates the positioning of the capsule substantially vertically and the carrying of the beverage from the discharge member to the beverage outlet in a downward direction. As a result, fluid can be collected and mixed in the enclosure, and after being discharged through the discharge member when exceeding the predetermined pressure value inside the enclosure, beverage is then dispensed downwards while the capsule can be positioned vertically in the machine. This approach provides significant advantages over the existing systems that prone a horizontal arrangement of the capsule in the machine. In the present invention, not only the flow can be controlled more slowly through the capsule for a better infusion quality but the whole capsule system is greatly simplified and the handling of the capsule is easier. Indeed, as the capsule can be placed vertically, capsule insertion and capsule removal is facilitated since the capsule can be inserted vertically from the top of the machine and it can be removed during opening of the machine along the same axis or direction by simple gravity and without need for complicated ejection devices and/or user&#39;s intervention. 
         [0023]    In a preferred embodiment, the beverage conduit and the beverage dispense outlet are parts of the capsule and the beverage flows out of the capsule without direct contact with machine parts. This provides the additional benefits that cleaning or rinsing of the machine part is no longer required and taste cross-contamination can be so eliminated 
         [0024]    If necessary, an additional filter media can be used to prevent fines of food ingredients to go through the discharge openings of the discharge member. 
         [0025]    In an embodiment, fluid can be introduced in the capsule through an entry wall of the enclosure that is opposed to the discharge wall. Again, contrary to the teaching of the prior art, fluid can be introduced on any possible side of the capsule. Preferably, the fluid is introduced from the opposed side while keeping all the benefits of the invention, i.e., slow flow for high quality infusion, controlled guidance of the beverage to the cup, reduced cross-contamination and easy handling of the capsule in the machine. This “opposed side” approach is even preferred because first it ensures that water can traverse fully though the ingredients and it also leaves more room for placing the injection fluid system on one side and it so contributes to the compactness of the capsule system (both capsule and machine). 
         [0026]    The invention according to a second aspect relates to a capsule for the preparation of a beverage in a beverage machine comprising an enclosure containing one or more beverage ingredients to be brewed, and a discharge wall that is positioned in the path of the brewed liquid (i.e., in association with the enclosure) and which comprises a discharge member configured to restrain the brewed liquid from being discharged from the capsule or limit the liquid flow in case the pressure inside the enclosure is below a predetermined value, and configured to enable the delivery of the brewed liquid in case the pressure exceeds the predetermined value. 
         [0027]    According to a first embodiment, the discharge member can be a discharge opening preferably comprising a hole configured to increase its section when the pressure inside the enclosure is rising. 
         [0028]    According to a second embodiment, the discharge member can comprise a flexible valve such as a bicuspid-like valve, a tricuspid-like valve or a tetracuspid-like valve. 
         [0029]    Additionally or alternatively, the discharge member is preferably designed such that it is contracted to close the discharge member, i.e., thus closing the discharge wall, when the pressure is below the predetermined value, and expanded to open the discharge member, i.e., thus opening the discharge wall, when the pressure exceeds the predetermined value. 
         [0030]    According to the before-mentioned embodiments, the discharge wall can be made up of a flexible or elastic or resilient material such as a silicone membrane or the like. 
         [0031]    According to a third embodiment, the discharge wall can comprise a textile material, paper or plastic filter having the at least one discharge member, wherein the discharge member is a discharge opening comprising a hole with fixed diameter being designed to be sufficiently small to create a watertight wall when brewing fluid is introduced without pressure, and brewed liquid is able to flow through the at least one hole when the pressure exceeds the predetermined value. 
         [0032]    Preferably, the discharge wall extends substantially from the bottom of the enclosure to the top of the enclosure. 
         [0033]    Preferably, the capsule comprises a shell and the discharge wall closes the shell. More preferably, the capsule comprises a cover that is attached to the shell and faces the discharge wall. 
         [0034]    Preferably, the cover comprises a beverage flow guiding means configured to guide the beverage flow to a beverage outlet of the capsule. 
         [0035]    Therefore, the brewed liquid can be dispensed properly and hygienically into the recipient (cup, mug, . . . ) while keeping a simple capsule construction and promoting an easy handling of the capsule in the machine. 
         [0036]    Preferably, the at least one ingredient is tea. 
         [0037]    Additionally, the enclosure can be impermeable to gas and light. 
         [0038]    The discharge wall thus comprises at least one discharge member. The discharge wall can be internal to the capsule and protected by an outer closing membrane. The closing membrane can close the capsule in a gastight manner to improve the maintenance of freshness of the ingredients contained in the enclosure. 
         [0039]    The invention also relates to a beverage capsule system for preparing a beverage comprising:
       a beverage capsule comprising an enclosure containing one or more beverage ingredients and a discharge wall placed in association with the enclosure,   a brewing device comprising capsule handling members that maintain the capsule in a determined brewing position where the capsule discharge wall is vertically oriented.       
 
         [0042]    Further the discharge wall comprises a discharge member that restrains the brewed liquid from being discharged from the capsule or limits the liquid flow in case the pressure inside the enclosure is below a predetermined value, and the discharge member enables the delivery of the brewed liquid in case the pressure exceeds the predetermined value. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0043]    Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
           [0044]      FIG. 1  is a schematic illustration of a capsule brewing system before brewing for carrying out the method according to the invention; 
           [0045]      FIG. 2  is a schematic illustration of the capsule brewing system of  FIG. 1  during brewing of the capsule; 
           [0046]      FIG. 3A  is a perspective view of a discharge wall according to a first aspect; 
           [0047]      FIG. 3B  is a perspective view of the discharge wall of  FIG. 3A  when enabling the delivery of the liquid; 
           [0048]      FIG. 4A  is a perspective view of a discharge wall according to a second aspect; 
           [0049]      FIG. 4B  is a perspective view of the discharge wall of  FIG. 4A  when enabling the delivery of the liquid; 
           [0050]      FIG. 5A  is a perspective side view of a discharge wall according to a third aspect; 
           [0051]      FIG. 5B  is a perspective side view of the discharge wall of  FIG. 5A  when enabling the delivery of the liquid; and 
           [0052]      FIG. 6  is a perspective view of a discharge wall according to a fourth aspect. 
       
    
    
     DETAILED DESCRIPTION 
       [0053]    The general principle of the method of the invention will now be explained in relation to  FIGS. 1 and 2 . 
         [0054]    A capsule system  1  is provided that comprises a capsule  2  and a beverage brewing device  10 . For simplicity, the beverage brewing device is only schematically depicted and may, in reality, comprise additional technical features within the normal knowledge of the person skilled in the art. The capsule comprises an enclosure  20  containing beverage ingredients  5  such as leaf tea and the like. The enclosure  20  is demarcated by a cup-shaped housing or shell  21  and a discharge wall  3 . 
         [0055]    The enclosure  20  is preferably impermeable to gas and light. The housing  21  may encompass different cross sections such as a circular, ellipsoid, square, rectangular or polygonal section that determine as a matter of fact the general profile of the discharge wall  3 . The enclosure  20  is sized to accommodate a dose of leaf beverage ingredient  5  of typically about between 1 to 10 grams, preferably 2 to 5 grams. The dose of leaf ingredient  5  may depend on the final volume of beverage to produce. For an individual cup of tea, a typical dose can be of about 2 grams whereas for a tea pot, a typical dose can be of about 8 to 10 grams. As clearly apparent in  FIG. 1 , the capsule  2  is positioned relative to the brewing device  10  so that the discharging wall  3  extends substantially vertical and from substantially the bottom of the enclosure  20  to the top of the enclosure  20 . For this, the capsule  2  is preferably positioned in a “vertical” arrangement in the brewing device  10 . The cup-shaped housing  21  can be so oriented with its large opening and its bottom oriented in a vertical position. 
         [0056]    The capsule  2  is preferably closed by the discharge wall  3  that closes the enclosure  20 . The discharge wall  3  is attached, for instance, to a peripheral outer rim  24  of the cup-shaped housing  21 . 
         [0057]    The capsule  2  can further comprise a cover member  4  that is also attached to the rim  24  of the housing and overlaps the discharge wall  3 . The cover  4  forms an internal channel (beverage conduit)  40  that terminates at its side end by an outlet (beverage outlet)  41 . According to a preferred embodiment, the beverage conduit  40  and the beverage outlet  41  are parts of the capsule  2 . Therefore, the brewed liquid can be dispensed properly and hygienically into the recipient (cup, mug, . . . ) while keeping a simple capsule  2  construction and promoting an easy handling of the capsule  2  in the machine. However, it is also possible that both the beverage conduit and the beverage outlet are parts of the beverage machine. 
         [0058]    The shape of the capsule  2  is not very critical. Preference is given to a trunconical, ellipsoidal or hemispherical shapes for different reasons. This allows a larger surface for the exit of the beverage through the discharge wall  3  and a reduction of the inside pressure. The housing  21  can also be manufactured industrially at lower cost by plastic thermoforming or aluminum or aluminum-plastic deep drawing. This shape with smoother corners also favors the removal of handling members  30 ,  31  of the brewing device  10  and so the ejection of the capsule  2 . 
         [0059]    As described above, the housing has the peripheral rim  24  that extends as a flange to constitute a substantially flat sealing portion onto which can be sealed the discharge wall  3  and snap fitted and/or sealed the cover member  4 . 
         [0060]    At the rear of the housing  21 , the wall of the housing  21  can comprise a raising zone that constitutes the injection region for the introduction of the fluid in the capsule  2 . The raising zone is so conceived to resist to compressive forces of an injection device  38  and to puncture at its center more easily. 
         [0061]    Turning to the brewing device  10 , it comprises the capsule handling members  30 ,  31  that are configured to hold the capsule  2  in the “vertical” arrangement as defined. These handling members  30 ,  31  can be machine jaws or any suitable mechanical enclosing means that can open and close about the capsule  2  and can maintain it firmly in place. There is no need for providing high closing forces since the involved fluid pressure in the capsule  2  remains relatively low and, preferably, as close as possible to the atmospheric pressure. Also, since the capsule  2  can withstand the low brewing pressure therefore the capsule  2  does not necessarily need to be entirely enclosed but simply held water tightly in place during brewing. This participates to a simplification of the machine and reduces machine costs. 
         [0062]    The brewing device  10  comprises a water supply  32 , such as a water tank, a water pump  33 , a heater  34  and a hot water injection line  35  that is managed through the handling member  30 . The brewing device  10  may also comprise a controller and a user interface board (not shown) to manage the beverage preparation cycles as known in the art. A backpressure valve  36  can be provided to lower the pressure at the entry side or injection member  38  (such as a needle(s) or blade(s) and a water inlet) in the capsule  2 . Of course, the backpressure valve  36  could be omitted and a low pressure pump could be used that delivers fluid at low pressure. Medium to high pressure pump may however be preferred because of their robustness and reliability and so used in combination with a backpressure valve  36 . 
         [0063]    Importantly, in the brewing operation shown in  FIG. 2 , the capsule  2  comprises discharge means  100  (as will be described later on in detail) such as discharge openings or flexible valves placed at predefined positions on/in the discharge wall  3 . 
         [0064]    According to the invention, the discharge wall  3  is positioned in association with the enclosure  20  in the path of a brewed liquid and comprises the discharge means  100  configured to restrain the brewed liquid from being discharged from the capsule  2  or limit the liquid flow in case the pressure inside the enclosure  20  is below a predetermined value, and enable the delivery of the brewed liquid in case the pressure exceeds the predetermined value. 
         [0065]    Hence, the beverage ingredients can be thoroughly submerged by the fluid, therefore avoiding bypassing areas and ensuring that the mass of ingredient fully interacts with the brewing fluid, and thus, the liquid can be well mixed due to the rising pressure. Finally, well mixed brewed liquid leaves the capsule  2  via the discharge means  100  once the pressure exceeds the predetermined value. 
         [0066]    With respect to  FIGS. 3 to 6  there will be now described four embodiments of a discharge wall or discharge means, respectively, according to the invention. 
         [0067]    In a preferred embodiment according to  FIGS. 3A and 3B , a discharge wall  300  according to a first embodiment will be described. The discharge wall  300  comprises a discharge means being formed as a discharge opening  301 . The discharge opening  301  comprises a hole  302  being designed such that it increases its section “D” when the pressure inside the enclosure  20  is rising. Therefore, the discharge wall  300  is preferably made up of an elastic or resilient material such as a silicone membrane or an elastic fibers woven material. Hence, the discharge means  301  comprises holes  302  which have a section or diameter such that no liquid or only a limited flow of liquid is dispensed when a low fluid pressure is applied on the discharge wall  300 , i.e., is present inside the enclosure  20  (see  FIG. 3A ). Thus, the ingredients can be thoroughly submerged while only a low pressure is applied. In case the pressure increases when the capsule enclosure  20  is full of brewing fluid like water and the water pump goes on introducing water in the enclosure  20 , the discharge wall can deform itself due its elastic nature and becomes rounded. This deformation also deforms the holes  302  of which section increases. Then, the discharge means  301  can open or (slowly) increase the liquid flow when exceeding the predetermined value thus dispensing the thoroughly submerged, brewed and mixed beverage (see  FIG. 3B ). 
         [0068]    Even if a specific number of discharge openings  301  are shown in this embodiment, the invention is not limited to the number and particular arrangement thereof. In fact, the discharge wall  300  may comprise at least one or a plurality of the discharge openings  301  being arbitrarily or evenly distributed. 
         [0069]    According to another embodiment as shown in  FIGS. 4A and 4B , the discharge wall  310  comprises a discharge means comprising a flexible valve  311 . The flexible valve is preferably formed as a multiplecuspid-like valve such as a bicuspid-like valve  312 , a tricuspid-like valve  313 , a tetracuspid-like valve  314  and/or a heptacuspid-like valve  315 . For the sake of simplification, there are many different types of multiplecuspid-like valves shown in  FIGS. 4A and 4B . However, there is preferably used only one type of such valves per discharge wall  310 ; but the invention is not limited thereto. Moreover, the invention is also not limited to the number and arrangement of the valves as shown in the embodiment, but there can be provided at least one or a plurality of valves of any of the before-mentioned types being arbitrarily or evenly distributed. 
         [0070]    The (multiplecuspid-like) flexible valve  311  can be designed such that it is sealably closed in case a liquid acts on the valve  311  with a pressure being below a predetermined pressure value (see  FIG. 4A ). Moreover, the valve  311  can be adjusted such that it opens when the liquid pressure exceeds the predetermined value (see  FIG. 4B ). In this case, the valve  311  can create a comparatively large opening such that the brewed liquid, after having thoroughly submerged the ingredients, can be easily and quickly dispensed from the machine. 
         [0071]    According to a further embodiment of the invention as shown in  FIGS. 5A and 5B , the discharge means of the discharge wall  320  preferably comprises a discharge valve  321 , which discharge means  321  is designed such that it is contracted to close the discharge means  321  (and thus the discharge wall  320 ) when the pressure is below the predetermined value, and expands to open the discharge means  321  (and thus the discharge wall  320 ) when the pressure exceeds the predetermined value. Such valves  321  are also known from bottles being stored containing viscous liquids or spreads such as honey or ketchup; preferably having an outlet portion  322  designed as a multiplecuspid-like valve according to the second embodiment or with a small hole according to the first embodiment. 
         [0072]    In the contracted state, the discharge valve  321  preferably everts such that its outlet portion  322  is directed to the enclosure  20  and thus against the liquid pressure (see arrow “A”) such that it is even better sealably closed (see  FIG. 5A ). When exceeding the predetermined pressure value, the discharge valve  321  expands and everts the other way round such that its outlet portion  322  expands away from the enclosure  20  and thus forming a channel  323  for guiding the brewed liquid to the outlet portion  322  (e.g. a tricuspid-like valve) where the liquid can be easily discharged. 
         [0073]    Again, the number and arrangement of the discharge means or discharge valves  321  as shown in the embodiment of  FIGS. 5A and 5B  is not restrictive, but there can be provided at least one or a plurality of such valves  321  being arbitrarily or evenly distributed. 
         [0074]    According to another embodiment as shown in  FIG. 6 , the discharge means of the discharge wall  330  is a discharge opening  331  comprising a hole  332  with fixed diameter “d”. The diameter “d” of the hole  332  is, however, sufficiently small to create a watertight wall when brewing liquid is introduced without pressure. When the pressure exceeds the predetermined value—preferably below 0.2 or even below 0.1 bar—liquid (e.g. a brewed beverage like tea) is able to flow through the at least one hole  332 , i.e., the liquid is forced through the openings  331  when exceeding the predetermined pressure value. The discharge wall  330  according to this embodiment preferably comprises a watertight material so that the liquid can only flow through the openings under pressure. The material can be a plastic filter having the at least one discharge opening  331 . The material can also be a plastic, paper or textile filter, either woven or non woven, with a low permeability to water so that water cannot permeate through its holes if the water flow does not reach a certain pressure. The number and arrangement of the discharge openings  331  as shown in the embodiment is not restrictive, but there can be provided at least one or a plurality of such openings  331  being arbitrarily or evenly distributed. 
         [0075]    In a preferred embodiment, the discharge wall presents a valve opening section or a hole section (=discharge means) sufficiently small to act as a filter and prevent solid food ingredients like tea leaves to go through them. If necessary, an additional filter media can be used to prevent fines of food ingredients to go through the openings of the discharge means. The filter media can be, for instance, fixedly attached to a peripheral inner step  23  of the housing  21 . 
         [0076]    The capsule and the method of the present invention can be used with a beverage preparation machine such as described in WO 2007/134960 A1. 
         [0077]    The principle of the brewing method according to  FIGS. 1 and 2  encompasses different variants and equivalences and is not limited by the embodiments described above as long as they are covered by the following claims.