Abstract:
An apparatus and method useful for brewing a beverage. A brewing liquid, generally water, and in some cases brewing ingredients, are placed in a container having a bottom with openings that, due to surface tension of the liquid, do not allow the liquid to pass through the openings until the liquid approaches or reaches its boiling point. The liquid is heated to approach its boiling point by placing the apparatus in a microwave oven or by the use of an electrical resistance heater associated with the container. The brewed beverage is captured in a second, temporary container from which it may be consumed or served.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to beverage brewing systems. More particularly, it relates to systems and methods for rapidly and efficiently brewing beverages such as coffee, tea and hot chocolate, including systems that can do so using a microwave oven. 
     2. Prior Art 
     There are many systems that are being marketed for the brewing of beverages, including coffee. These items are ubiquitous in homes and offices. In general, they work well. If good quality ingredients are used, a good quality product is produced. However, there is a considerable amount of labor involved in placing the ingredients in a filter located in a brewing basket, measuring out the proper amount of water and pouring the water into the system. Some brewing apparatuses overcome some of these problems, such as eliminating the need to measure water, by connecting directly to a source of water such as the plumbing in a home or office, or to a purified water bottle. Such systems are expensive to install or may take up a great deal of space and require that large and heavy water bottles be handled. 
     Another disadvantage of these systems is that in general, the water is not heated instantaneously. Thus, there is a long delay between when the brewing of a new batch of beverage is initiated, and the time when it is completed. First, there is a time delay in heating the water. Then, there is a time delay as the water drips through the brewing ingredients and the containment filter (the filter, generally made of paper or another suitable material, that retains the brewing ingredients during brewing). It may take between five and eight minutes before a new batch of coffee is available. 
     Accordingly, there is a need for a brewing apparatus and a brewing method which reduces the labor required to brew the beverage, and brews the beverage quickly and efficiently. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a brewing apparatus and a brewing method that provide for brewing coffee or other beverages quickly and efficiently using an extremely simple and inexpensive system with no moving parts and that eliminate many of the components used to heat, pump, and maintain the beverage. 
     It is a further object of the invention to provide a brewing apparatus and method wherein the components are reusable. 
     It is yet another object of the invention to provide a brewing system and method which can be used in a microwave oven environment. 
     In accordance with one embodiment of the invention, the brewing system comprises a brewing basket in the form of a reservoir in which brewing ingredients are received. The reservoir has brewing ingredients supporting a lower surface having openings or pores therein in the order of 10 to 200 microns in diameter, and should be formed of a material that is slightly to significantly hydrophobic. The pores have characteristics so that surface tension of a brewing liquid (generally water) supports the liquid in the reservoir when the liquid is at an initial temperature (tap or room temperature), and allows the liquid to drain through the pores when the liquid is at a temperature which approaches or is at the boiling point of the liquid. The pores are sized, shaped and interconnected to perform this function. The supporting surface may be formed from a polymer and be in an integral part of the brewing basket. Alternatively, the supporting surface may be formed of a corrosion resistant metal such as 410 series or 316 series stainless steel having a thickness of approximately 0.75 mm. If the metal is imbedded at its edges in a polymer, ceramic, glass or other dielectric insulator material from which the brewing basket is formed, in general, the metal will not cause difficulties due to arcing or sparking when the apparatus is placed in a microwave oven. 
     The reservoir is preferably configured to be received directly by a beverage receiving container, such as a cup, mug or carafe. 
     In accordance with another embodiment of the invention, the reservoir, having the porous surface described above, receives the brewing liquid, but not the brewing ingredients. The reservoir is received above a brewing basket, which holds the brewing ingredients therein with a suitable screen, mesh or ingredient containment filter, of a type well known in the art. The brewing basket is in turn received in a beverage receiving container, such as a cup, mug or carafe. 
     In accordance with one aspect of the method of the invention, brewing ingredients (active flavor material) and a brewing liquid (generally water) are placed in a brewing basket or reservoir having the general structure set forth above. The brewing basket is placed over a second container to receive the brewed beverage product. Water is added to the brewing basket from the top, thus exposing the water to the brewing ingredients. The water is then heated by a heater associated with the brewing basket or by placing the entire apparatus in a microwave oven. As the water temperature increases and approaches the boiling point of water, its surface tension decreases significantly. The water, which up until this time is held within the brewing basket with the brewing ingredients so that the beverage can brew, then drains rapidly through the openings in the supporting surface, due to the much lower surface tension, and rapidly deposits the brewed liquid in the container for the brewed beverage. 
     In accordance with another aspect of the method of the invention, the reservoir receives only the brewing liquid. The reservoir is received directly above a brewing basket. The brewing ingredients are placed in a brewing basket, which in turn is received directly above a beverage receiving container. When the brewing liquid is heated and approaches or reaches its boiling point, it is released into contact with the brewing ingredients. The brewed liquid is then received in the beverage receiving container. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and other features of the present invention are explained in the following description, taken in connection with the accompanying drawings, wherein: 
         FIG. 1  is a cross-sectional view of a first embodiment of a brewing apparatus in accordance with the invention. 
         FIG. 2  is a cross-sectional view of a second embodiment of a brewing apparatus in accordance with the invention. 
         FIG. 3  is a cross-sectional view of a third embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , there is shown a cross-sectional view of an apparatus  10  incorporating features of the present invention. Although the present invention will be described with reference to the embodiments shown in the drawings and described below, it should be understood that the present invention can be embodied in many alternate forms of embodiments. In addition, any suitable size, shape or type of elements or materials could be used. 
     Brewing apparatus  10  includes a brewed beverage container  12  and a brewing basket  14 . While shown as being of a generally cylindrical shape or cup shape, container  12  can have a variety of shapes, such as that of a carafe, or that of a coffee pot. Container  12  of  FIG. 1  may have a handle  15  and a spout  16  to permit a beverage which has been brewed to be poured into another container, such as a drinking glass or cup (not shown) generally when brewing basket  14  has been removed from the top of container  12 . Alternatively, container  12  may be generally in the form of a simple mug or cup for receiving an appropriate quantity of beverage, and from which the consumer can drink directly. 
     Brewing basket  14  may be placed securely on top of container  12  by fitting within an annular shoulder  18  of container  12 . The fit of brewing basket  14  within shoulder  18  is such that brewing basket  14  is securely held, but is readily removed therefrom. Alternatively, if container  12  is generally in the form of a simple cup, brewing basket  14  may be formed with an annular shoulder (not shown), so as to be received securely in position over container  12 . 
     Brewing basket  14  has a cylindrical sidewall  20  and a bottom wall  22 . Bottom wall  22  is provided with a multitude of small apertures or pores  24 , each having a diameter of approximately 10 to 200 microns (or preferably 10 to 100 microns), and is slightly to significantly hydrophobic. In one construction, the sidewall  20  and bottom wall  22  are integrally formed, such as, for example, by injection molding of a polymer. The polymer can be a polymer, such as a polyolefin, and in particular polypropylene, or other suitable material. 
     Alternatively, the portion of bottom wall  22  having apertures  24  may be formed of a corrosion resistant metal insert or plate  25 . For example a 316 series or 410 series stainless steel insert, including a metal mesh with appropriate mesh size, may be provided. In general, the thickness of the bottom wall  22  will be approximately 0.25 mm to 2.0 mm. If a metal insert is used, it should be embedded in the polymer around its periphery so as to form a watertight seal and to prevent difficulties due to arcing or sparking when system  10  is placed in a microwave oven, to brew a beverage, in the manner described below. 
     In use, brewing basket  14  is placed in position on top of container  12 . A quantity of brewing ingredients  30 , such as, for example, ground coffee beans, is placed within brewing basket  14 . A quantity of water  32  appropriate for the amount of brewing ingredients  30 , is added up to a level  34 . 
     Apparatus  10  may then be placed within a microwave oven (not shown). The microwave oven may then be set to heat the brewing ingredients  30  and the water  32  for at least as long as it is a necessary for the temperature of water  32  to closely approach the boiling point of water. Water  32  will remain within brewing basket  14  for this pre-boiling period of time allowing brewing of the desired beverage to occur. The water is held within brewing basket  14  by surface tension. The relationship between the pressure of the head or column of water in brewing basket  14  and the size of the pores  24  is given by:
 
Δ p =(2 cos Φσ)/ r 
 
where:
         σ=surface tension of the water;   Φ=wetting contact angle;   r=pore radius; and   Δp=pressure generated by the water column of a height that will not penetrate a non-wetting pore.       

     In the case of a hydrophobic material, cos Φ=1. In accordance with this relationship, if the height of the water is increased by a factor of three, the radius of the pores must be reduced by a factor of three to support the water until it nears the boiling point. 
     When water  32  approaches (and especially when it reaches) its boiling point, its surface tension effectively decreases to a much smaller value. At that time, the brewed liquid is released through openings  24  into container  12 , because 2σ/r is then much lower than Δp (the head of water within the brewing basket  14 ). System  10  may be removed from the microwave oven. Brewing basket  14  is removed from the top of container  12  and container  12  may be used to pour the brewed beverage into cups or glasses for consumption. Brewing basket  14  may then be cleaned of the remainder of brewing ingredients  30  and is available for further use. 
     Referring to  FIG. 2  (wherein like components have like reference numerals to those described with reference to  FIG. 1 ) a system  38 , in accordance with the invention, but not designed for use in a microwave oven environment, is illustrated. An alternative means for heating the water  32  is provided. In particular, a heating coil  40  may be associated with wall  20  of a brewing basket  14 A, which can be of an all-metal, ceramic, glass or other construction, including a construction having a metal interior liner, a polymer exterior, and an insulating layer therebetween. A conventional power cord  42  may be connected to an electrical outlet to provide power to heating coil  40  to heat water  32 . The operation of this modified system is identical to that disclosed above, except that a microwave oven is not required. However, this modified system may require a slightly longer amount of time in order for the water  32  to reach its boiling point, and for the beverage to be brewed. 
     A heating element may also be associated with bottom wall  22 . The temperature of the water near bottom wall  22  can thus most closely approach the boiling temperature of the water, while the remainder of the water is at a slightly lower temperature, which maybe more advantageous for brewing of a product with optimal taste. 
     It will be recognized that it may be convenient to provide a system  10  including a microwave brewing basket  14  which does not include a heating coil  40 , and a separate brewing basket  14 A to be used without a microwave oven and thus including a heating coil  40 . 
     Referring to  FIG. 3 , a system  50  in accordance with another embodiment of the invention includes a water reservoir  52 , having a porous bottom wall or an inset or plate  25 , as described above. A brewing basket  54 , that is designed to hold brewing ingredients  30 , is configured to receive at its top, reservoir  52 . Brewing basket  54  has at its bottom a filter or a mesh  56 , of a type well known in the art, having a generally concave shape to provide a region that supports brewing ingredients  30 , but permits the passage of a brewed liquid. Alternatively, at least one opening through which the brewed beverage may pass is provided, and a brewing ingredient containment filter  57 , generally formed of paper, may be provided. A beverage receiving container  58  upon which brewing basket  54  may be placed, receives brewed beverage from brewing basket  54 , which has passed through mesh  56 . 
     System  50  is used by first placing brewing ingredients into brewing basket  54 . Brewing basket  54  is then placed on top of container  58 . Reservoir  52  is then placed over brewing basket  54 . Water at room or tap temperature, in an amount appropriate for brewing with brewing ingredients  30 , is then placed in reservoir  52 . The entire assembly is then placed in a microwave oven, and the microwave oven is turned on. When the temperature of the water approaches or reaches its boiling point, water is released from reservoir  52  into brewing basket  54 , as described above with respect to the embodiments of FIG.  1  and FIG.  2 . Although brewing does not begin until water is released from reservoir  52  into brewing basket  54 , the brewing time is not lengthened appreciably because the water is heated rapidly by the microwave oven, and quickly comes into contact with brewing ingredients  30 . 
     In summary, the present invention provides an apparatus to quickly and efficiently brew a beverage. No moving parts are used. The flow of the brewing liquid does not follow a tortuous path as in some brewing equipment, but moves directly downward under the influence of gravity. The apparatus is reusable. In at least one embodiment, most of the brewing takes place at a temperature below boiling, while the brewing liquid is being heated, generally from room, or faucet tap temperature, because the brewing liquid and the brewing ingredients are in the brewing basket while the brewing liquid is being heated. As soon as the temperature of the brew approaches boiling, it is available for immediate consumption, without further delay. The apertures of the porous member are precisely engineered to assure that the brewing liquid is at a selected temperature, or within a closely controlled temperature range, during the time that the brewing liquid is in contact with the brewing ingredients. 
     Various modifications of the invention are possible. The pores or openings in the surface of the lower wall of the brewing basket may be of various geometries. Rather than being circular, as assumed by the analysis set forth above, the openings maybe rectangular, such as those found in a filter mesh, or may have the shape of other regular or irregular polygons. Further, the cross sectional area may vary as a function of depth through the material. For example, the openings may be tapered to be larger toward the top than at the bottom. It is also possible that the openings be tapered to have the largest cross sectional area at the top and at the bottom, with the cross sectional area being reduced at approximately the center of the thickness of the material. 
     The ratio of the area that is open to that of the surrounding material may be adjusted. For example, the openings may be of hexagonal shape so that the material appears to have a honeycomb structure with the ends of the cells being at the upper and lower surfaces of the member. In this case the percentage of open area may be large, thus facilitating rapid flow of the brewing liquid once the surface tension is reduced due to heating. For enhanced control, the cross sectional area of the cells may also be tapered, as described above. 
     The openings or pores may also be arranged in various geometrical patterns such as rings and the size and shapes of the openings in one ring may be different than that in another. This may be especially useful if different brewing liquids are to be used at different temperatures. A single brewing basket or withholding reservoir may thus be useful for a series of different applications. 
     In yet another variation, rather than being planar, the lower wall (or a plate  25  or member therein) may have a curved, cone shaped, or other geometry. Again, the size and shape of the pores may be varied with position thus increasing the versatility of the brewing basket or water reservoir. Bands of openings interspersed with regions without openings may be provided. If the lower wall of the brewing basket has a plate  25  or a mesh, it may be made by a variety of methods well known in the art, including electroforming. 
     It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims.