GB2346800A

GB2346800A - Filter for infused beverage maker.

Info

Publication number: GB2346800A
Application number: GB9903802A
Authority: GB
Inventors: Vernon James Donnelly
Original assignee: Strix Ltd
Current assignee: Strix Ltd
Priority date: 1999-02-19
Filing date: 1999-02-19
Publication date: 2000-08-23
Also published as: GB9903802D0

Abstract

A beverage maker comprises an infusion chamber 2, for infusing particulate matter, e.g. coffee grounds, a filter 8 for filtering the particulate matter from the liquor, and means for varying the filtration. The means for varying the filtration may comprise means for adjusting the area of the filter through which the liquor flows, means for altering the mesh size of a filter, or means for controlling the amount of suction used to suck the liquor through the filter. The means for adjusting the area of the filter through which the liquor flows may comprise two overlapping, relatively rotatable filter plates (9, 10, Fig. 2) having a mesh part (13, 14 Fig. 2) and a solid part. The means for controlling the amount of suction used to suck the liquor through the filter may comprise a heater for controlling the rate at which steam generated in a liquor receiving chamber 3 is condensed.

Description

Electrical beverage making apparatus and method The present invention relates to beverage making aFpliances and in particular, but not exclusively, to coffee makers, and a method for making beverages and in particular, but not exclusively, coffee.

There are many known beverage makers, and in particular, a known coffee maker comprises a water heating chamber and an infusion chamber arranged above the water heating chamber in which ground coffee is placed and infused into the water. The chambers are connected by a passage which extends downwardly from the infusion chamber into the water heating chamber. A filter sits in an opening between the passage and the infusion chamber and allows water to flow into and out of the infusion chamber while retaining the ground coffee in the infusion chamber. In use, the water heating chamber is filled with cold or hot water and the water is heated in the water heating chamber by an external heater, for example a gas or spirit flame or an electric element arranged under the chamber. As the water is heated, pressure in the water heating chamber increases causing water to rise up the passage through the filter and into the infusion chamber where it infuses with the ground coffee. When the level of water in the water heating chamber falls below an opening through which water enters the passage, transfer of water into the infusion chamber stops and air and steam can escape, in the form of bubbles, through the beverage infusing in the infusion chamber. Heating continues for a few moments to drive air out of the water heating chamber so that the space within the water heating chamber contains mostly steam. Heating is then discontinued and, as the water heating chamber cools, steam begins to condense within the water heating chamber. This results in a reduction of pressure within the water heating chamber resulting in suction of the brewed coffee in the infusion chamber through the passage and the filter back into the water heating chamber. When all of the beverage has been sucked out into the water heating chamber, the infusion chamber is generally removable so that the beverage can be served from the water heating chamber.

Such appliances suffer from various problems, and in particular it is difficult to provide a beverage of consistent flavour. The present invention seeks to overcome such problems.

According to the present invention there is provided a method of preparing a beverage, the method comprising: infusing particulate matter with water to produce an infused beverage; filtering the beverage; and controlling the filtering to provide a beverage having a desired concentration of dissolved solids.

The applicant has identified that the amount of dissolved solids in an infused beverage strongly influences the taste of the beverage. In particular, as the amount of dissolved solids increases the flavour of coffee becomes more bitter, and as the amount of dissolved solids decreases the flavour of coffee becomes weaker.

Preferably, the concentration of dissolved solids is between 1.5 and 2%. Coffee containing 1. 5% to 2% dissolved solids has an optimum flavour. Thus, the invention allows coffee of an optimum flavour to be consistently produced.

Filtering may be controlled by providing a filter comprising a mesh having holes of a predetermined size.

Increasing the size of the holes decreases the time it takes to filter the beverage and hence decreases the amount of dissolved solids in the beverage. Reducing the size of the holes increases the amount of time it takes to filter the beverage and hence increases the amount of dissolved solids in the beverage.

A filter may be provided comprising plural meshes and each mesh may have holes of different size. The filter may be adjusted to selectively allow the beverage to pass through one or more of the meshes.

Furthermore, the area of mesh or meshes through which the beverage passes may be adjusted. The larger the area the more quickly the beverage passes through the filter and the less dissolved solids are contained in the beverage.

The method may further comprise: sucking the beverage through the filter in order to filter the beverage; and controlling the filtering by controlling the amount of suction used to suck the beverage through the filter.

Thus, filtering in known beverage makers, for example as described in the introduction of the specification above, can be controlled to provide a beverage of optimum flavour. The greater the suction, the smaller the time it takes to filter the beverage and the smaller the amount of dissolved solids in the beverage. The less the suction, the larger the time it takes to filter the beverage and the less the amount of dissolved solids in the beverage.

Preferably, controlling the suction comprises controlling a reduction in pressure achieved in a chamber for receiving the filtered beverage. The reduction in pressure may be controlled by a pressure relief valve. Alternatively, the reduction in pressure may be controlled by selective heating of the chamber.

Filtering may still be additionally be controlled by varying the size of the holes in the filter mesh or the area of the mesh through which the infused beverage passes.

Also according to the present invention there is provided a beverage maker comprising: an infusion chamber in which particulate matter is infused with water; a filter for filtering the infused beverage; and means for controlling or setting the filtering to provide a beverage having a desired strength.

Preferably, at the desired strength the beverage has concentration of dissolved solids between 1.5k and 2%.

Preferably the means for controlling the filtering comprises means for adjusting the area of the filter through which the beverage may pass. Reducing the filter area increases the time it takes for the beverage to be filtered and increasing the filter area reduces the time it takes for the beverage to be filtered.

Preferably, the means for adjusting the area of the filter comprises a frame for mounting the filter. The frame may comprise two members having radial slots, and the filter may comprise two meshes, each mesh mounted over the slots of one of the members, wherein the members are rotatable with respect to one another to increase the area of the slots and respective meshes through which the beverage may flow.

Alternatively, the means for adjusting the area of the filter may comprise an iris.

The beverage maker may further comprise: means for applying suction to the filter to draw the beverage through the filter; and the means for controlling the filtering may comprise means for controlling the suction to control the amount of dissolved solids in the beverage.

The beverage maker may further comprise a chamber in which the suction is generated by a reduction of pressure within the chamber, and the means for controlling the amount of suction may comprise a pressure relief valve for controlling the reduction in pressure in the chamber.

The chamber may be a water heating chamber in fluid communication with the infusion chamber and the beverage maker may further comprise a heater for heating water in the water heating chamber.

When the water is heated, pressure in the water heating chamber increases and drives the heated water into the infusion chamber. When the water heating chamber is subsequently cooled, a partial vacuum is created in the water heating chamber by the condensation of steam, and this sucks the infused beverage through the filter into the water heating chamber.

The means for controlling the amount of suction may then comprise means for controlling the heater to control the production or condensation of steam. The reduction of pressure in the water heating chamber and the suction is therefore controlled.

According the broadest aspect of the invention there is therefore provided a coffeemaker having a variable filter.

The filter is varied by altering the cross sectional area through which the beverage flows or the mesh size of filter. The filtering effect can also be varied by altering the pressure by which the beverage is drawn through the filter.

Preferred embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a cross sectional view of a coffee maker according to the invention; Figure 2 is a plan view of two members of a filter for a coffee maker according to the invention; and Figure 3 is a cross sectional view of the filter in position.

Referring to Figure 1, a coffee maker 1 has an infusion chamber 2 removably mounted on a water heating chamber 3. The water heating chamber 3 rests on a contact plate 4 mounted on a stand 5. The contact plate 4 contacts one or more heating elements 6 for heating water in the water heating chamber 3.

A passage 7 fluidically connects the water heating chamber 3 with the infusion chamber 2. In this example a filter 8 is provided around the passage 7. The filter 8 comprises a generally planar annulus 8.

Alternatively, the filter 8 comprises a disc and the passage 7 ends below the filter 8.

Referring to Figure 2, a filter 8 comprises a first member 9 and a second member 10. The members 9 and 10 are planar disks having radial slots 11 and 12 respectively. Slots 11 of the first member are provided with a first mesh 13 and slots 12 of the second member are provided with second mesh 14. The first mesh 13 has larger holes than the second mesh 14.

The first member 9 is mounted above the second member 10 in the infusion chamber 2, as shown in Figure 3. The members 9 and 10 are rotatably connected about their central axis. The filter 8 is secured in the infusion chamber 2 by a restraining member 15 which is removably connectable to the passage 7. This may connect, for example, to the lip 16 at the bottom of the passage 7.

In use, water is heated in the water heating chamber 3 by the heater or heaters 6. As the temperature of the water rises, steam is produced and the water is pushed up through the passage 7 into the infusion chamber 2, where it mixes with coffee grounds (not shown) resting on the filter 8. When the level of water falls below the lip 16 of the passage 7, water stops rising into the infusion chamber 2.

As described in our co-pending application No.

9825961.7, heating may be continued in order to control the amount of air and steam remaining in the water heating chamber 3 and to vary the amount of time for which the beverage continues infusing in the infusion chamber 2.

When heating is stopped, the steam in the water heating chamber 2 condenses on the walls of the water heating chamber 2, creating a partial vacuum. This sucks the infused beverage through the filter 8 and the passage 7 back into the water heating chamber 3. The rate at which the beverage flows through the filter 8 is dependent on the size of the holes in the filter meshes 13 and 14 and the area of the meshes 13 and 14 through which the beverage can flow.

The filter can therefore be adjusted to alter the rate at which the beverage returns to the water heating chamber 3. When the slots 11 and 12 only partially overlap, the area of the meshes 13 and 14 through which the beverage can flow is small. This increases the time it takes for the beverage to flow through the filter 8 and hence increases the amount of dissolved solids which mix with the beverage as it is drawn through the filter 8 and the coffee grounds which rest on the filter 8.

When the slots 11 and 12 overlap to a greater extent, the area of the meshes 13 and 14 through which the beverage can flow is increased, and the time it takes for the beverage to flow through the filter is decreased.

Thus, the filter can be adjusted to vary the amount of dissolved solids in the beverage. It has been found that the preferable concentration is between 1.5% and 2%.

Alternatively, the reduction in pressure in the water heating chamber may be controlled by heating the water left in the water heating chamber 3 when the level of the water in the chamber 3 falls below the lip 16 of the passage 7. This is described in our co-pending application no. 9825961.7, a copy of which is attached hereto as Appendix 1. Controlling the reduction in pressure allows the suction through the filter to be controlled and the amount of dissolved solids in the beverage to be varied. When the suction is increased, the rate of flow through the filter is increased and the' amount of dissolved solids in the beverage reduced.

Yet another alternative is to provide a pressure relief valve in the water heating chamber. This also allows the reduction in pressure in the water heating chamber to be controlled.

The strength of the beverage can therefore be seen to depend on not only the time that the beverage is infused in the infusion chamber, but also on the rate at which it flows or is drawn through the filter.

Claims

CLAIMS 1. A method of preparing a beverage, the method comprising : infusing particulate matter with water to produce an infused beverage; filtering the beverage; and controlling the filtering to provide a beverage having a desired concentration of dissolved solids.
2. The method of claim 1, wherein the desired concentration of dissolved solids provided is between 1.5% and 2%.
3. The method of claim 1 or claim 2, wherein the filtering is controlled by varying the size of holes in the filter mesh.
4. The method of claim 1 or claim 2 wherein the filtering is controlled by varying the area of the mesh through which the infused beverage passes.
5. The method of claim 1 or claim 2 wherein the method further comprises sucking the beverage through the filter and wherein the filtering is controlled by controlling the amount of suction used to suck the beverage through the filter.
6. The method of claim 5, wherein controlling the suction comprises controlling a reduction in pressure achieved in a chamber for receiving the filtered beverage.
7. The method of claim 5, wherein the reduction in pressure is controlled by a pressure relief valve.
8. The method of claim 6, wherein the reduction in pressure is controlled by selective heating of the chamber.
9. A beverage maker comprising: an infusion chamber in which particulate matter is infused with water; a filter for filtering the infused beverage; and means for controlling or setting the filtering to provide a beverage having a desired strength.
10. The beverage maker of claim 9, wherein the means for controlling the filtering comprises means for adjusting the area of the filter through which the beverage may pass.
11. The beverage maker of claim 10, wherein the means for adjusting the area of the filter comprises a frame for mounting the filter.
12. The beverage maker of claim 11, wherein the frame comprises two members having radial slots, and the filter comprises two meshes, each mesh mounted over the slots of one of the members, wherein the members are rotatable with respect to one another to increase the area of the slots and respective meshes through which the beverage may flow.
13. The beverage maker of claim 10, wherein the means for adjusting the area of the filter comprises an iris.
14. The beverage maker of claim 9 or claim 10 further comprising means for applying suction to the filter to draw the beverage through the filter and wherein the means for controlling the filtering comprises means for controlling the suction.
15. The beverage maker of claim 14 further comprising a chamber in which the suction is generated by a reduction of pressure within the chamber, and wherein the means for controlling the amount of suction comprises a pressure relief valve.
16. The beverage maker of claim 14, further comprising a water heating chamber in fluid communication with the infusion chamber and a heater for heating water in the water heating chamber, and wherein the means for controlling the amount of suction comprises means for controlling the heater to control the production or condensation of steam.
17. A coffeemaker having a variable filter.
18. The coffeemaker of claim 17, wherein the filter is varied by altering the cross sectional area through which the beverage flows.
19. The coffeemaker of claim 17, wherein the filter is varied by altering the mesh size of the filter.
20. The coffeemaker of claim 17, wherein the filter is varied by the filtering effect being varied by altering the pressure by which the beverage is drawn through the filter.