DRIP FILTER HEAD AND METHOD

Abstract

This invention provides a drip filter head for a beverage apparatus comprising a connected array of beverage extraction units, each unit comprising an extraction chamber, and further comprising at least one filter.

Claims

1. A drip filter head for a beverage apparatus comprising a connected array of beverage extraction units, each unit comprising an extraction chamber, and further comprising at least one filter.

2. The drip filter head of claim 1, wherein the drip filter head comprises between 2 and 8 extraction units.

3. The drip filter head of claim 1, wherein at least one extraction chamber has a volume of no more than 500 ml.

4. The drip filter head of claim 1, wherein the extraction chambers are laterally spaced apart and extending parallel with each other.

5. The drip filter head of claim 1, wherein the extraction units are spaced apart in a planar parallel array.

6. The drip filter head of claim 1, wherein at least one extraction chamber and/or extraction unit is removably attached to the connected array.

7. The drip filter head of claim 1, wherein each extraction unit comprises a filter.

8. The drip filter head of claim 1, wherein each extraction unit comprises the same volume, height and/or diameter.

9. The drip filter head of claim 9, wherein all extraction unit are physically substantially the same.

10. The drip filter head of claim 8, wherein the drip filter head comprises at least 4 extraction units and each extraction unit has a volume of no more than 500 ml.

11. The drip filter head of claim 1, wherein each extraction unit is different

12. The drip filter head of claim 1, wherein at least one beverage extraction chamber comprises an upper extraction chamber and a lower chamber separated by a filter; wherein the upper chamber comprises a perimeter wall and an inlet and the lower chamber comprises a perimeter wall and an outlet; and wherein the perimeter wall of the upper chamber adjacent to the filter tapers inwardly, towards the filter, by no more than 10 degrees and the perimeter wall of the lower chamber tapers inwardly from adjacent to or proximal to the filter.

13. The drip filter head of claim 12, wherein the perimeter wall of at least one upper extraction chamber is parallel-sided.

14. The drip filter head of claim 12 wherein the maximum diameter of the tapering perimeter wall of at least one lower chamber is between 25% and 95% the diameter of the perimeter wall of the upper chamber, adjacent to the filter.

15. The drip filter head of claim 1, wherein the drip filter head further comprises a water distribution device positioned to deliver water independently to the extraction units and/or extraction chambers, in use.

16. A method of preparing a beverage comprising, providing the drip filter head of claim 1, and comprising steps of: a) adding an extractable beverage material to at least two of the beverage extraction chambers; b) adding water to the beverage extraction chambers of step a); and c) combining and collecting the beverage extract from the beverage extraction units of steps a) and b).

17. The method of claim 16, wherein the total extraction time of steps b) and c) is between 2 and 5 minutes.

18. The method of claims 16, wherein the flow rate of beverage extract from each extraction unit over 80% of the total extraction time is between 1 ml/sec-1.6 ml/sec.

19. A drip filter apparatus comprising a water heater; the drip filter head of claim 1; a water distribution device for distributing water heated by the water heater between the extraction units and a container for gathering the output from the extraction units.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0096] In order that the invention may be more clearly understood embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

[0097] FIG. 1 is a perspective view of an embodiment of the first aspect of the invention, comprising four extraction units.

[0098] FIG. 2 is a perspective view of an embodiment of the fourth aspect of the invention comprising four extraction units.

[0099] FIGS. 3a, 3b and 3c are side cross-sectional views of embodiments of a single extraction unit of the first or second aspect of the invention.

[0100] FIGS. 4a, 4b, 4c and 4d are birds-eye views of arrangements and horizontal cross-sectional shapes of embodiments of drip filter heads comprising four extraction units of the first or second aspect of the invention.

[0101] FIG. 5 is a perspective view of an embodiment of the first aspect of the invention comprising three extraction units of different sizes.

[0102] With reference to FIG. 1, a first embodiment of a drip filter head (1) of the invention, comprises an array of four extraction units (2), each comprising an upper extraction chamber (4); a filter, in the form of a filter paper (6) (fourth filter not shown); and a lower chamber which acts as an extract channelling portion, in the form of an extract funnel (8) (fourth extract funnel not shown). Each upper extraction chamber (4) has a volume of 350 ml. Each upper extraction chamber (4) is positioned above a filter (6), which, in turn, is positioned above an extract funnel (8) in order that fluid may flow from upper extraction chamber (4) to extract funnel (8) under the force of gravity, in use. Also in use, an extractable material, preferably roasted and ground coffee, and then a liquid, preferably water, are loaded into at least one and preferably two of the upper extraction chambers (4) and over time liquid extract is collected from two or more the extract funnels (8).

[0103] With reference to FIG. 2, where like numbers represent like components vis-à-vis FIG. 1, a first embodiment of a drip filter apparatus (20) ofthe invention, comprises a drip filter head (1), of the first or second aspect of the invention; a water distribution device, in the form of an water pipe with four outlets (21) a means for supplying water, in the form of a water tank (24); a drip filter apparatus body containing a water heater (26);

[0104] and a means of collecting liquid extract from the drip filter head (1), in the form of a jug (22). The water tank (24), water heater (26) and water distribution device (21) are connected together by pipework (not shown). The water distribution device (21) is located above the drip filter head (1) and configured to distribute water evenly between the extraction chambers of the drip filter head (1). The jug (22) is located below the drip filter head.

[0105] With reference to FIG. 3a, where like numbers represent like components vis-à-vis FIG. 1, a first embodiment of an extraction unit (2) of the first or second aspect of the invention comprises an upper extraction chamber (32) and a lower chamber (40) separated by a filter in the form of a porous mesh screen (36) and a paper filter (38). The upper extraction chamber (32) comprises a perimeter wall (34). The lower chamber (40) comprises a perimeter wall (42) and an outlet (44).

[0106] The upper extraction chamber perimeter wall (34) is non-tapering adjacent to the mesh screen (36). The mesh screen (36) is adjacent to and on top of the paper filter (38). In other embodiments, not shown, the vertical order of the mesh screen (36) and paper filter (38) may be reversed. The mesh screen (36) has a mesh size of 0.85 mm and thread diameter of 0.5 mm. The paper filter (38) has thickness of 1.1 mm, a low flow resistance and a diameter of less than the diameter of the upper extraction chamber (32) (approximately 80-90% of the diameter of the upper chamber (32)). The lower chamber (40) is adjacent to the paper filter (38). The perimeter wall of the lower chamber (42) tapers down away from the paper filter (38) at an angle of 45° to a minimum diameter of 15 mm over a length of 6.1 mm to meet the outlet (44). The total length from the top ofthe filter paper (38) to the end of the outlet (44) is 17 mm. The lower chamber (40) has a volume of 6 ml and the extraction chamber (32) a volume of 350 ml.

[0107] The tapering lower chamber wall (42) has a greatest diameter, adjacent to the filter (38) and mesh screen (36), of approximately 40% of the diameter of the upper extraction chamber (32).

[0108] The outlet (44) comprises a circular cross-sectional tube, having a diameter approximately 60-70% of the largest diameter of the lower chamber wall (42).

[0109] With reference to FIG. 3b, where like numbers represent like components vis-à-vis FIG. 1, a beverage extraction unit (2) comprises an upper extraction chamber (32) and a lower chamber (40) separated by a support in the form of a mesh screen (36) and a paper filter (38). The upper extraction chamber (32) comprises a perimeter wall (34). The lower chamber comprises an upper non-tapering perimeter wall section (41) adjacent to the filter (38) and mesh (36); a tapering lower perimeter wall section (42) and an outlet (44). The beverage extraction unit (2) of FIG. 3b is largely similar to the beverage extraction unit (2) of FIG. 3a; but differs by addition of the upper non-tapering perimeter wall section (41) of the lower chamber adjacent to the filter (38) and mesh screen (36) that acts to separate the tapering lower perimeter wall section (42) from the filter (38) by 5 mm; and the filter (38) extends across the full diameter of the upper extraction chamber (32) and upper extraction chamber perimeter wall (34).

[0110] With reference to FIG. 3c, in which like numbers represent like components vis-à-vis FIG. 1, a beverage extraction unit (2), comprises an upper extraction chamber (32) and a lower chamber (40) separated by a support in the form of a mesh screen (36) and a paper filter (38). The upper extraction chamber (32) comprises a perimeter wall (34). The lower chamber comprises a perimeter wall (42) and an outlet (44). The beverage extraction unit (2) of FIG. 3c is largely similar to the beverage extraction unit (2) of FIG. 1; but differs by the perimeter wall of the upper extraction chamber (34), having a taper of approximately 9° towards the filter (38).

[0111] With reference to FIGS. 4a, 4b, 4c and 4d, in which like numbers represent like components vis-à-vis FIG. 1, birds-eye views of various drip filter heads (1) of the invention are depicted comprising some suitable arrangements and shapes of extraction units (2), although other suitable arrangements and shapes exist.

[0112] With reference to FIG. 5, an embodiment of a drip filter head of the invention (1) with different sized extraction units (52, 54 and 56) is shown. The drip filter head is substantially the same as that of FIG. 1 differing in the fact that the extraction units are of different sizes. The first extraction unit (52) has a volume sufficient to produce one cup of beverage extract, the second extraction unit (54) has a volume sufficient to produce two cups of beverage extract; and the third extraction unit (56) has a volume sufficient to produce 4 cups of beverage extract. It will be understood that this sequence of extraction units could extend indefinitely in order to provide a drip filter head capable ofproducing n number of cups of extract. Drip filter heads suitable for normal consumer use may comprise extraction units comprising volumes of one, two, four and eight, or eight and sixteen cups. Variants of this embodiment may have a smallest extraction unit of two or four cups.

EXAMPLE 1

Preparation of a Beverage Using a Drip Filter Head of the Invention

[0113] A beverage was prepared using the drip filter head (1) of FIG. 1 by the following steps: [0114] a) Each extraction unit (2) contained a standard coffee filter paper (6) shaped to fit flat across the full diameter of each extraction chamber (4) and the drip filter head (1) was positioned over a container; [0115] b) 12 g of roast and ground coffee (Aroma Rood® produced by Jacobs Douwe Egberts) was loaded into each of the four extraction chambers (4) on top of the filter (6); [0116] c) Each extraction chamber (4) was then filled with 234 ml of water heated to 80-100° C. and the beverage extract allowed to drip through the head (1) under gravity, and; [0117] d) The beverage extract from the drip filter head (1) was collected in a single container.

[0118] The time taken from first addition of water to the drip filter head (1) until the flow of beverage extract from the drip filter head (1) had substantially stopped was 4 minutes 15 seconds. The flow of extract from the drip filter head (1) was rapid at first and slowed over the extraction time.

EXAMPLE 2

Preparation of a Beverage Using Enhanced Extraction Units

[0119] A beverage was prepared using the drip filter head (1) of FIG. 1 comprising the extraction units (2) of FIG. 3a by the following steps: [0120] a) Each of the four extraction chambers (32) was loaded with 12 g of roast and ground coffee (Aroma Rood®, produced by Jacobs Douwe Egberts), each extraction unit (2) fitted with a Senseo® chocolate filter paper, code UPC05A and the drip filter head (1) supported above a beverage container; [0121] b) 234 ml of water heated to 80-100° C. was then added at a rate of 2.6 ml/sec to each extraction chamber at a steady rate over 1 minute 30 seconds at the same time. During this time the volume of water in each extraction chamber (32) built to a maximum i.e. the flow rate of heated water into each extraction chamber (32) was the same as the flow rate of the beverage extract from each outlet (44); and [0122] c) After the addition of water stopped, the drip filter head (1) was then left to drain until the beverage extract stopped flowing from each outlet (44). Approximately 3 minutes 15 seconds after the start of water addition to the extraction chambers.

[0123] The drip filter head (1) of FIG. 1 with the extraction units of FIG. 3a is configured such that, in use, the flow rate of beverage extract is between 1 ml/s and 1.6 ml/s throughout the extraction process. The flow rate of extract from the drip filter head (1) was slower than the flow rate of water into it.

[0124] The flow rate through each beverage extraction unit (2) is largely determined by the combination of resistances between the filter (38), mesh (36) and geometry of the lower chamber (40). The major contributors to the overall flow resistance through the head (1) of Example 1 are, without wanting to be bound by theory: [0125] From the upper extraction chamber (32), the beverage extract undergoes a portion of horizontal flow through the filter (38) and mesh (36) in order to reach the smaller diameter lower chamber (40), maximising the resistance provided by the low resistance filter paper (38). [0126] Upon traversing through the mesh (36) and filter paper (38) the beverage extract forms a meniscus under the mesh (36), held by surface tension and supported by the geometry of the shoulders provided by the tapering perimeter wall (or tapering section ofthe perimeter wall) of the lower chamber (36). This meniscus provides additional flow resistance below the extraction chamber. [0127] The outlet (44) is configured (with a non-tapering perimeter wall) to provide little or no resistance to the flow of beverage extract.

[0128] There is also a contribution to overall resistance from the coffee bed and a slow increase in resistance due to the clogging of filter pores by coffee particles during extraction, but this is a far lower proportion of the total resistance through the device than in devices of the prior art, such as in Comparative Example 1, below.

[0129] By configuring the majority of the flow resistance through each beverage extraction unit (2) to be present below the coffee bed and top surface of the filter (38), each unit (2) of Example 2 benefits from a consistent flow rate throughout the extraction rather than the steadily decreasing flow rate of the prior art, such as Comparative Example 1 (below), where the flow rate through the extraction device is largely determined by the compacting coffee bed and clogging top surface of the filter. With volumes ofwater and coffee sufficient to create more than 2 beverages this effect is very significant through the extraction time.

[0130] The configuration of the upper extraction chamber (32) with a substantially parallel, non-tapering circumferential wall and the difference in flow rate into and out of each extraction unit enabled the creation of convection and turbulence in the extraction chamber of each extraction unit such that the coffee particles formed at least a partial suspension in the water during the preparation ofthe beverage—enhancing the extraction of the slow extracting coffee fractions.

[0131] Further, the geometry of the upper extraction chamber yields a sufficiently high fill height for a given volume ofwater, and so enhances convection; a lower deposition of coffee grounds on the sides ofthe container, compared to a chamber with steeply tapering sides; an even deposition of coffee grounds in the coffee bed upon draining the upper extraction chamber, facilitating even extraction; a small footprint; a smaller liquid surface to facilitate lower heat loss during the preparation of the beverage extract.

EXAMPLE 3

Preparation of a Beverage Using Enhanced Extraction Units within an Appliance

[0132] A beverage extract was prepared using a by loading the drip filter head (1) of FIG. 1, comprising the extraction units of FIG. 3a, into an Excellent lOSN drip filter appliance manufactured by Douwe Egberts to create the beverage preparation apparatus (20) of FIG. 2 by the following steps: [0133] a) 12 g ofroast and ground coffee was added to each extraction chamber (32) of the drip filter head (1); [0134] b) Cold water was added to the water reservoir (24) of the apparatus (20); and [0135] c) The apparatus (20) was switched on to provide a steady flow of 234 ml of hot water, to each of the four extraction chambers, at a rate of 2.6 ml/sec over 1 minute 30 seconds and the beverage extract collected from the outlets (44).

[0136] The beverage extract flow rate was identical to that of Example 2 and the beverage had the same profile under sensory analysis as that of Example 2. The beverage preparation ceased after approximately 3 minutes 15 seconds from the start of water addition to the extraction chambers.

COMPARATIVE EXAMPLE 1

Standard Drip Filter 8 Cups

[0137] A beverage was prepared using a standard Excellent 10SN machine (Manufactured by Douwe Egberts) by the following steps: [0138] a) A standard filter paper and 48 g of roast and ground coffee (Aroma Rood®, produced by Jacobs Douwe Egberts) were fitted to the extraction basket of the machine; [0139] b) 1872 ml of cold water was added to the water reservoir of the machine; [0140] c) The machine was switched on to provide a steady flow of hot water to the extraction basket until the reservoir was empty; and [0141] d) The beverage extract was collected until the flow of extract had substantially stopped after 8 minutes 30 seconds.

Comparison of Attributes of Beverage Produced in Each Example

[0142] A key indicator of optimum beverage extraction in a drip filter extraction method is the time that the coffee and water are in contact—coffee:water contact time. In general, if this time is too long, then the beverage extract will be over-extracted and bitter in taste; too short and the extract is under extracted and weak.

[0143] The beverage extract produced in Comparative Example 1 took over 8 minutes to produce. The first extract produced had insufficient coffee:water contact time and as a result the first extract was weak and under-extracted by the end of the extraction process, 8 minutes later, the filter paper had become clogged with coffee particles and the flow through the system was very slow. As a result, the last extract was very over extracted and bitter in flavour. This portion of slowly produced extract made up a significant portion of the total extract, this, coupled with the overall variation in quality ofthe extract throughout the process, resulted in a sub-optimal, over-extracted flavour in the whole collected beverage extract.

[0144] The beverage extract produced by Example 1 had an improved balance in extent of extraction between the first and last portion of extract that was produced. The overall extraction time was reduced from over 8 minutes to 4 minutes 15 seconds compared with Comparative Example 1, and the amount of over-extracted extract towards the end ofthe preparation time was greatly reduced.

[0145] The beverage extract produced by Example 2 provided an even further improvement over that of Comparative Example 1. The total extraction time was 3 minutes 15 seconds. This total extraction time provides the even more optimum coffee:water contact time for a particular coffee flavour preference through the extraction process. The extract produced in Example 3 showed precisely the same improvement in extract quality and attributes as Example 2 with the additional advantage of the convenience and user experience associated with the combination with a drip filter appliance.

Further Examples of Embodiments of the Invention with Alternate Extraction Units

[0146] With reference to FIG. 3a, when in use, the beverage extraction unit (2) provides a fluid flow path for the beverage extract from upper extraction chamber (32) to lower chamber (40). All of: the route ofthe fluid flow path from extraction chamber (32) to outlet (44), the filter paper (38) and/or mesh (36) properties and the meniscus size and shape formed below the filter (38) and mesh (36) have an impact on the flow resistance and therefore coffee:water contact time and quality of the extracted beverage. The meniscus size and shape can be adjusted by variation in the maximum diameter of lower chamber perimeter wall (42). The tapering perimeter wall (42) ofthe lower chamber (40) of device (2) of FIG. 3a has the preferred maximum diameter of 40-50% the diameter of the perimeter wall of the extraction chamber (32) whereas, embodiments of an extraction unit (2) of the invention (not shown) exist that benefit from at least one of the advantages of FIG. 3a where the maximum diameter ofthe tapering perimeter wall (42) of the lower chamber of the device (2) of FIG. 3a is between one quarter to three quarters the diameter of the perimeter wall of the extraction chamber chamber(32). Further, the meniscus size and shape can be adjusted by variation in the angle ofthe taper of the perimeter wall of the lower chamber (40). In further embodiments of a beverage extraction unit (2) of the invention (not shown) the taper of the perimeter wall of the lower chamber (40) of FIGS. 3a-c may be between 35° and 55°, for example, and maintain at least one of the benefits of the invention.

[0147] FIGS. 3b and c show examples of alternative beverage extraction units (2) that may be used in conjunction with the drip filter head of FIG. 1. Each exhibits sufficient flow resistance below the coffee bed and top surface of the filter to secure the additional benefits associated with the beverage extraction unit (2) of Example 2 or 3.

[0148] Further to variations of FIG. 3a, the meniscus formation below the filter (38) and its impact on flow resistance through the extraction unit (2) can also be manipulated by spacing the tapered perimeter wall of the lower chamber (42) away from the filter (38). With reference to FIG. 3b, the short upper non-tapering perimeter wall section (41) of the lower chamber (40) provides additional volume to the lower chamber (42) without significantly hindering the formation of the coffee extract meniscus below the filter (38) and the resistance to flow through the extraction unit (2) this provides when in use. The lower non-tapering perimeter wall section (41) of the lower chamber (40) is spaced 5 mm from the filter (38).

[0149] With reference to FIG. 3c, the small taper in the perimeter wall (34) of the upper extraction chamber (32) provides an increase in volume to the extraction chamber (32) and a larger opening at the top ofthe perimeter wall (34) for ease of adding beverage material into the extraction chamber (36). No negative impact was seen, compared to the benefits associated with the device of FIG. 3a, by the inclusion of a small taper to the circumferential wall of the extraction chamber. A turbulent, convection of the coffee/water suspension was still created, there was little deposition of coffee grounds on the circumferential wall, the coffee bed was deposited evenly across the filter and the heat loss from the upper chamber was largely unaffected.

[0150] Each of the extraction units (2) of FIG. 3b or c may be used in Example 2 or 3 in place ofthe extraction unit (2) of FIG. 3a without loss or detriment to the additional benefits associated with the original Example 2 or 3.

[0151] The above embodiment is/embodiments are described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.