GB2386543A

GB2386543A - Tea production

Info

Publication number: GB2386543A
Application number: GB0202617A
Authority: GB
Inventors: Nicholas Middleton
Original assignee: STEAM TEA Co Ltd
Current assignee: STEAM TEA Co Ltd
Priority date: 2002-02-05
Filing date: 2002-02-05
Publication date: 2003-09-24
Also published as: GB0202617D0

Abstract

A method for production of tea beverage is disclosed. The method comprises forcing a quantity of hot or cold liquid, typically water, under pressure through a quantity of tea particles to form a tea beverage. Infusion occurs over a short time period in the range 0.5 to 60 seconds with infusion of liquid and tea particles occurring at a temperature in the range 50 to 100{C for production of hot beverage and 0 to 50{C for production of cold beverage. Liquid pressures range from 2.03 x 10<5>Pa to 10 x 10<5>Pa. An optional pre-infusion cycle comprises directing a quantity of steam towards the tea particles prior to forcing liquid through the tea particles.

Description

-1 IMPROVEMENTS TO TEA PRODUCTION

Field of the Invention

The present invention relates to methods and apparatus for the production of tea beverages and particularly, although not exclusively, to the production of a tea beverage having consistently reproducible quality characteristics.

Background to the Invention

Tea beverages are known in the prior art to be produced by an infusion

To process comprising the interaction of water with tea particles over a prolonged period of time.

It is known in the prior art that in order to make a cup of tea of high quality,

such high quality being defined by aspects of clarity, consistency, taste and as aroma of the infusion, that it is necessary to place boiling water in contact with either loose leaf tea or tea granules contained within a water permeable bag for a period of typically 3 to 5 minutes. Importantly, it is necessary for the water applied to the tea to be boiling, that is water that has reached a temperature of 100 C and has then been directly applied to the tea particles. Further, it is necessary to 2 o maintain the bolted water in contact with the tea particles for a sufficient period of time to allow for infusion. In the prior art, this infusion process comprises the

diffusion of water and tea particle extracts such as to impart to the water a tea flavor and colour. Traditional tea making methods place particular importance on this relatively long duration for which contact between the tea and boiling water must be maintained.

Traditionally, tea beverages have been made by one of three techniques. A. *.

. first technique comprises placing a quantity of loose leaf tea in a vessel, typically. a.

a teapot, to which boiling water is added. The mixture of loose leaf tea and so boiling water is allowed to stand for a period in the region of three minutes or.

more. During this time gentle agitation of the mixture e.g. by stirring with a spoon a ' À - À:-: À À À À.

or gently rotating the pot can optionally be conducted to speed up the mixture of water and tea. Using the first technique it is necessary to pour the infused tea beverage through a strainer in order to remove the loose leaf tea from the beverage. A second technique is a variation on the first technique wherein loose leaf tea is placed into a infusion ball, typically comprising two hemispheric elements connected about a hinge. The hinge enables the ball to be opened and loose leaf tea placed inside. The ball is then closed and placed in a suitable vessel to which boiling water is added. A plurality of small apertures in the infusion ball are designed to enable water to mix with the tea contained within the o infusion ball whilst preventing excessive release of loose leaf tea particles into the surrounding water. Use of an infusion ball is intended to overcome the need to use a strainer to remove the loose leaf tea from the infused beverage. A third technique comprises the production of tea beverage by the use of teabags. A teabag typically comprises a paper or material bag formed of water permeable material which enables water to mix with tea particles contained within the bag whilst preventing release of the tea particles to the surrounding fluid. As with the first and second techniques it is generally necessary, in order to produce a quantity of tea beverage, to soak the bag in boiling water for at least three minutes. By applying an external mixing force to mix together tea particles and water by any one of the prior art techniques described above a cup of tea can be

produced more quickly. However, the quality of the tea produced by applying an additional mixing step in order to reduce the length of time over which infusion is 25 occurring generally reduces the quality of the tea beverage produced. Whilst mixing together of tea and water, e.g. with a spoon, can encourage release of colours to the liquid an ideal extraction of flavour, required to produce a high quality cup of tea, does not occur using this method unless the tea and water are allowed to infuse together for a period typically of at least three minutes and o certainly greater than two minutes.

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There is therefore a problem with prior art tea production techniques in that

extraction of flavour from the tea to the water in order to produce a high quality tea beverage does not occur unless the tea and water are allowed to mix for a long period of time. This problem makes production of tea to high quality in cafes, restaurants and the like a slow process which in turn limits the amount of tea which can be served over a time period, thus either increasing the cost of the tea beverage to the consumer or decreasing the efficiency and cost effectiveness of the serving and selling of tea to the vendor.

To Even where a strict infusion regime is adhered to, such a regime for example comprising infusing tea particles with boiling water for a defined time period in the region of 3 to 5 minutes, it is extremely difficult to maintain a consistent texture, flavor, consistency, clarity and overall quality of the tea beverage produced. This difficulty in consistently producing tea of a particular quality presents a particular problem to tea vendors, e.g. cafe owners.

in contrast to traditional prior art methods of producing tea beverages,

coffee beverages are known to be made by passing hot water through a quantity of coffee grains such that the water percolates through a layer of coffee grains, 2 o the water being infused to form a coffee beverage. One particular form of prior art

coffee beverage production comprises formation of espresso coffee where hot water at a temperature in the range 95 to 96 C is passed, under a pressure of between 8.3 x 105 Pa and 9.12 x105 Pa (corresponding to between 8.2 and 9 bar), through a layer of coffee particles typically in the form of ground coffee 25 beans. This method is used in order to extract the maximum flavor from the coffee whilst leaving behind the excess acids and caffeine. Production of a shot of espresso coffee so as to reproducibly maintain a set of quality characteristics....

between shots is a difficult process required to be undertaken by a Barista, being a person trained in the skills and techniques associated with espresso coffee A 3 o preparation. Production of espresso coffee requires controlled water temperature.

and pressures. A low temperature of the brewing water can cause the espresso -: C c À* to be sour, an over-temperature brewing water will bum the coffee oils and create A- À e À:: À À À À.

-4 either flat flavors or a bitter, burnt after-taste. Additionally, differing coffee roasts can require varied brewing conditions to achieve an ideal extraction required to produce a coffee beverage of high quality.

The Barista produces espresso coffee by using an espresso machine.

Espresso machines are known in the prior art (e.g. as illustrated in Fig. 1 herein)

and typically comprise at least one boiler for boiling water under pressure and producing steam. The main features of an espresso machine include a means to deliver water at a consistent temperature and under a consistent pressure to the To coffee, a stable pump pressure which can be maintained throughout the brewing cycle, a pre-infusion cycle allowing for the espresso coffee to be saturated with brewing water before pressurized hot water contacts the coffee to cause the main extraction, pre-infusion lasting typically 1 to 2 seconds.

Apparatus and methods describing prior art techniques for the production of

espresso coffee are described in "Espresso Coffee-Professional Techniques" David C Schomer, Peanut Butter Publishing, first edition February 1996.

Prior art tea beverage production techniques rely on a random diffusion of

no water with tea in an infusion process. The quality characteristics of the tea produced are difficult to reproduce between infusions. The infusion time period required is greater than 2 minutes and the quality of tea produced is variable.

Coffee beverages have been produced using espresso methods for many years.

However, the known prior art tea beverage production techniques teaches the

:5 skilled man in the art that in order to produce high quality tea beverages it is necessary for a prolonged infusion period to be provided for. The strong flavours present in ground coffee permit the rapid percolation of water through a packed layer of coffee for extraction of flavours sufficient to produce espresso coffee.

The man skilled in the art of tea production would not consider this rapid infusion so process to be sufficient for the flavour extraction from tea required in the production of high quality tea beverages.. - Is act. À eee. Àe À À À À.

-5 Summarv of the Invention Surprisingly, the inventors have found that tea beverage can be consistently and reproducibly formed to have high quality characteristics by the passage of hot water, below boiling point and under pressure, through a quantity of tea 5 particles. Not only is the tea beverage produced of high quality but allows for production of a quantity of tea beverage in under 30 seconds.

The inventors have provided a method of consistently producing a quantity of tea beverage having consistent quality characteristics, such quality 10 characteristics including, but not limited to texture/consistency, clarity, flavour, colour and aroma. The inventors have further provided for the production of such tea beverage rapidly such that a quantity of tea, e.g. a cup of tea, can be produced in a format ready to drink in under 60 seconds, this period being inclusive of the time required for preparation of the tea.

The methods of the present invention comprise the transfer or passage of hot or cold water, the brewing water, under pressure through a quantity of tea particles, typically in the form of a packed layer, in a short time period.

Preferably, the duration of the passage of water under pressure through said go quantity of tea in order to produce a quantity of tea beverage ready for consumption is in the overall range 0.1 to 120 seconds and preferably in the range of 1 to 60 seconds and more preferably in the range 1 to 30 seconds.

The time period for transfer of a quantity of brewing water through the tea particles to form a quantity of tea beverage defines an infusion time.

During passage of water under pressure through the quantity of tea the water is allowed to saturate the tea, steeping the tea in the water in order to effect the infusion process. By applying an even pressure of water to a surface of the 30 tea, and throughout the layer of tea, a substantially uniform infusion process occurs. Where hot, tea beverage is produced, the water saturating the quantity Off, À.e À e-e. Àe - À À e À ae

of tea is at a temperature in the range of 50 to 100 C, preferably in the range 77 to 87 C and more preferably at 82 C.

An optional pre-infusion cycle can be incorporated wherein hot brewing water or steam is directed to the quantity of tea particles for a predetermined time period prior to passage of water under pressure, comprising the main brewing water, to the tea particles for infusion. This pre-infusion process occurs in a time in the range 0.5 to 30 seconds.

JO For the production of hot tea beverage the pre-infusion cycle preferably occurs in a time in the range 0.5 to 5 seconds and more preferably in a time in the range 1 to 3 seconds.

For the production of a cold tea beverage, the pre-infusion cycle preferably :s occurs in a time in the range 0.5 to 30 seconds and more preferably in a time in the range 15 to 25 seconds.

Production of tea in accordance with the methods of the present invention provides an efficient and rapid process for the reproducible production of tea go beverage having high quality characteristics. The random aspect of diffusion used in prior art tea beverage production techniques is overcome by use of

pressurised water evenly distributed through a quantity of tea particles to maximise the flavour extraction whilst minimising the duration of the infusion process. The quantity of tea particles used in a single brewing operation and z quantity of water directed through the quantity of tea particles is variable in accordance with the required quantity of tea to be produced. Further, both the temperature and pressure at which the brewing water is delivered to the tea can further be varied.

3 o Brewing water delivered to a quantity of tea for infusion is required to be at a pressure greater than atmospheric pressure. In particular, brewing water pressures suitable for use in the method of the present invention are preferably

greater than 2.03 x 105Pa (2 bar), more preferably in the range 7 - 10 x 105Pa and still more preferably in the range 8.31 to 9.12 x 105Pa (8.2 to 9 bar).

The inventors have further identified that an optimal ratio of tea particles to brewing water is in the range 3 to 5 grams of tea particles per 200 to 460ml of brewing water and more preferably in the range 3.3 to 4.5 grams of tea particles to 285 to 400ml of brewing water. These ratios may be varied to produce a tea beverage having particular quality characteristics desired by a specific consumer and further may be varied as required depending upon the tea blend being used.

According to a first specific method of the present invention there is provided a method of producing a quantity of tea beverage, said tea beverage comprising an infusion, said method characterized by comprising the step of forcing a quantity of hot liquid under pressure through a quantity of tea particles thereby infusing said liquid and tea particles, wherein: transfer of a quantity of said hot liquid, sufficient to form a quantity of said tea beverage, through said quantity of tea particles occurs in a time in the range 0.5 to 60 seconds, infusion of said liquid and tea particles occurring at a temperature in the range 50 to 1 00 C.

According to a further specific method of the present invention there is 2s provided a method of producing a quantity of tea beverage, said tea beverage comprising an infusion, said method characterized by comprising the step of forcing a quantity of cold water liquid under pressure through a quantity of tea particles thereby infusing said liquid and tea particles, wherein: . o transfer of a quantity of said cold liquid, sufficient to form a quantity of said tea beverage, through said quantity of tea particles, occurs in a time in the range. i 'e 0.5 to 60 seconds, . À :..'

-8 infusion of said liquid and tea particles occurring at a temperature in the range O to 50 C.

Preferably, said method further comprises the step of directing a first quantity of steam or hot liquid towards said quantity of tea particles prior to said step of forcing said liquid through said tea particles.

For production of hot tea beverage said first quantity of steam or hot liquid is To preferably directed towards said quantity of tea particles for a time period in the range 0.1 to 5 seconds and more preferably in the range 1 to 3 seconds.

For production of cold tea beverage said first quantity of steam or hot liquid is preferably directed towards said quantity of tea particles for a time period in the range 0.1 to 30 seconds and more preferably in the range 15 to 25 seconds.

Preferably, said hot liquid is forced through said quantity of tea particles at a pressure greater than 2.03 x 105 Pa, more preferably in the range 7 - 10 x 105 Pa and still more preferably in the range 8.31 to 9.12 x105 Pa.

For production of hot tea beverage transfer of brewing liquid through said quantity of tea particles preferably occurs in a time in the range 1 to 25 seconds, more preferably in the range 15 to 20 seconds.

For production of cold tea beverage transfer of brewing liquid through said quantity of tea particles preferably occurs in a time in the range 1 to 45 seconds, more preferably in the range 15 to 30 seconds.....

i, For production of hot tea beverage infusion of said liquid and tea particles 'I 30 preferably occurs at a temperature in the range 77 to 87 C, more preferably in the range 80 to 85 C and still more preferably at 82 C., -,.

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-9 - For production of cold tea beverage infusion of said liquid and tea particles preferably occurs at a temperature in the range 1 to 1 5 C.

Preferably, said quantity of tea particles is retained in a filter means, said 5 filter means enabling passage of infused liquid through said filter means, said filter means preventing passage of tea particles through said filter means.

Preferably, said method further comprises the steps of: To loading a quantity of tea particles into a filter means; engaging said filter means at a means to dispense pressurised liquid; activating said means to dispense pressurised liquid to force a quantity of liquid under pressure through said quantity of tea particles so as to infuse said liquid with said tea particles.

Preferably, following the step of loading a quantity of tea particles into said filter means the loaded tea particles are packed in said filter means by application 20 of pressure to a main surface of said quantity of tea particles to provide a substantially uniform density of tea particles retained in said filter means.

Preferably, said method further comprises the step of collecting filtered tea beverage in a receptacle.

Preferably, said liquid is forced through a said quantity of tea in the ratio 3.0 to 4.5 grams of tea particles per 285 to 400ml of hot liquid.

. According to one aspect of the present invention there is provided; Hi: o apparatus for use in producing a quantity of tea beverage in accordance with the specific methods of the present invention, said apparatus comprising means to., ace. À --e À- À À.e

-10 retain said quantity of tea particles during forcing of liquid through said quantity of tea particles, said apparatus characterized by comprising; a receiving basket to retain said tea particles, said basket comprising a 5 first filter portion; a second filter portion configured to be positioned substantially adjacent said first filter portion, To wherein said second filter portion comprises a fine mesh member, said first and second filter portions allowing transfer of infused liquid and configured to prevent transfer of tea particles of a predetermined size.

Preferably, said second filter portion is mounted on at least one sealing 5 member. Preferably, said apparatus further comprises a receiving basket mounting means configured to engage a group head on an espresso machine, said receiving basket mounting means configured to house said receiving basket and o said second filter portion.

Preferably, said second filter portion is mounted on a first sealing member at a base region of said receiving basket mounting means, said receiving basket located above said second filter portion and mounted on a second sealing member such that material filtered through said first filter portion is immediately further filtered through said second filter portion, said sealing members directing infused liquid through said filters.

. Preferably, said sealing members comprise a polymer ring. '-.' 2 Preferably, said liquid is water...DTD: .

-11 Brief Description of the Drawinns

For a better understanding of the invention and to show how the sanne may be carried into effect, there will now be described by way of example only, specific embodiments, methods' and processes according to the present 5 invention with reference to the accompanying drawings in which: Fig. 1 illustrates diagrammatically an espresso machine of a type known in the prior art;

To Fig 2 illustrates in cross-section a group head of an espresso machine with a portafilter containing packed dry tea engaged at the group head; Fig 3 illustrates diagrammatically a receiving basket, sealing members, second filter portion and receiving basket mounting means (portafilter), suitable 15 for retaining tea particles and filtering the tea beverage produced; Fig 4 illustrates diagrammatically a prior art Italian flat packer for packing tea

into a receiving basket; 20 Fig 5 illustrates diagrammatically the steps involved in hard packing and polishing tea particles in a receiving basket; Fig 6 illustrates schematically a flow diagram illustrating the steps involved in producing hot tea beverage in accordance with the present invention; 25 _ Fig 7 illustrates schematically a flow diagram of selected method steps involved in producing hot tea beverage in accordance with the present invention; i,. Fig 8 illustrates schematically a flow diagram illustrating the main method -

. steps involved in producing cold tea beverage in accordance with the present 3 o invention.

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-12 Detailed Description of the Best Mode for Carrvinn Out the Invention

There will now be described by way of example the best mode contemplated by the inventors for carrying out the invention. In the following description numerous specific details are set forth in order to provide a thorough

understanding of the present invention. It will be apparent however, to one skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to unnecessarily obscure the present invention.

o In this specification the term infusion used in relation to the production of tea

beverage relates to the steeping or soaking of tea particles in/with liquid so as to saturate the tea particles with said liquid and resulting in the extraction of material from said tea particles into said liquid to form a tea beverage.

Infusion of liquid and tea particles results in extraction of chemical components from the tea particles, which mix with the liquid to form the tea beverage. These chemical components impart properties to the tea beverage determining the quality characteristics of the tea beverage. These quality characteristics include, but are not limited to texture/consistency, flavour, colour, o clarity, aroma and tannin content of the tea beverage.

In this specification the terms tea beverage and tea based beverage relate

to tea flavoured drinks.

In this specification the term tea particle(s) relates to tea grains, leaves, or

parts thereof, or other material comprising tea leaves or a derivative thereof, including, but not limited to, so-called "black tea", and useful in production of a tea beverage.

c. 30 In this specification the term hot liquid comprises liquid of a temperature -.

greater than or equal to 50 C and the term cold liquid comprises liquid of a c en. temperature less than 50 C..,2

-13 Referring to Fig. 1 herein there is illustrated in diagrammatic form an espresso machine 100 of a type known in the prior art. The espresso machine

100 comprises a body 101 housing boiler apparatus and steam generating 5 apparatus. Body 101 is furtherformed into a tray portion 106 upon which cups, mugs or other vessels can be mounted in order to receive a quantity of beverage.

A steam wand 102 for preparation of steamed milk to accompany the espresso coffee is typically provided.

JO In operation, hot water under pressure is passed through a group head 104 towards a portafilter 103 which is releasably mounted at the group head 104. A plurality of control means 105, including buttons and dials, are provided to control the temperature, pressure and release of hot water under pressure through the group head 104.

Espresso machines of a type known in the prior art and illustrated in figure 1

herein are configured to produce "shots" of espresso coffee. The exact quantity of coffee beverage contained in the shot can be varied, but in general a single shot comprises a quantity of beverage produced by infusing a quantity of hot o water under pressure with a quantity of the material to be infused, in the present invention this material comprising tea particles.

Referring to Fig. 2 herein there is illustrated in cross section an enlarged view of a group head 201 and portafilter 202. Pressurised hot water 204 is delivered from the espresso machine through the group head 201 via a dispersion screen 207. The portafilter comprises a mounting means for mounting a receiving basket 206. The receiving basket 206 typically comprising a metal cup À, shaped basket having a base region formed into a mesh providing a filter. In the first embodiment of the present invention, tea particles e.g. ground black tea, are 30 placed in the receiving basket and packed down to provide a layer of tea of -; substantially uniform density through which hot water under pressure may be,;; c passed during the infusion process. Ideally a gap of approximately 3mm (205) is rat 3

-14 maintained between the dispersion screen 207 of the group head 201 and the packed dry tea 203. The receiving basket 206 can be formed in different sizes to accommodate varying amounts of tea required to produce, for example, one, two or three shots of tea beverage.

Further referring to Fig. 2, operation of the espresso machine causes pressurised hot water 204 to be evenly distributed over the packed tea particles 203 via group head 201 and dispersion screen 207. The mesh base of the retaining basket 206 comprises a plurality of apertures, e.g. in the form of JO diamond-shaped apertures, having chamfered edges, the apertures forming a filter substantially preventing transfer of tea particles through the retaining basket 206. The pressurised hot water is infused with the packed tea particles forming tea beverage which passes through the filter portion formed at the base of the retaining basket 206 towards outflow portion 208 where the tea beverage is collected in a form suitable for consumption.

Referring to figure 2 and figure 3 herein, the portafilter comprises a cup shaped portion 304 forming a mounting means to support receiving basket 206, 301. The cup shaped body of a portafilter generally comprises a substantially so cylindrical body having a cylindrical wall portion. This wall portion is open at a first end in order to receive receiving basket 206, 301. At a second end of the wall portion the portafilter is substantially closed by a closing end wall portion.

The closing wall portion further provides a means of directing liquid out of the portafilter for collection and consumption. This means for directing fluid typically : comprises an aperture formed in the base of the portafilter wherein the portafilter is designed to funnel liquid through said aperture, the aperture forming a pathway.2, 208 for direction of fluid to a fluid collection vessel e.g. a cup. The portafilter.: further comprises a handle portion 306 which enables the user to manipulate the combined portafilter, mesh 303, sealing rings 302, 305 and receiving basket 301 I . 3 o combination.

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-15 Referring to Fig. 3 herein there is illustrated in diagrammatic from an expanded illustration of the portafilter and receiving basket. Receiving basket 301 comprises a substantially cylindrical cup shaped vessel, typically formed from metal e.g. stainless steel to provide a hygienic surface. The underside (not illustrated) of the receiving basket 301 is formed into a mesh providing a first filter portion. Receiving basket 301 is configured for loading with tea particles which may be packed down to a uniform density. The first filter portion formed on the base of the receiving basket 301 prevents loss of packed tea from the receiving basket 301. Between the portafilter 304, into which receiving basket 301 is 10 mounted, and the receiving basket 301 an intermediate second filter portion 303 is provided. Intermediate second filter portion 303 is formed of an ultra fine mesh of circular shape. A first sealing member 302, comprising a polymer ring, is provided between the receiving basket 301 and ultra fine mesh 303. Mesh 303, sealing member 302, andreceiving basket 301 all comprise a substantially identical circumference. A further sealing member 305 of identical or similar construction to sealing member 302 can optionally be provided and mounted in.

the base of portafilter 304 to sandwich the ultra fine mesh 303 between the two sealing members.

o Second filter portion 303, comprising an ultra fine mesh, can be manufactured from a thin layer of sheet metal or alternatively from a polymer or plastics material e.g. nylon. Ultra fine mesh 303 is mounted in the base of the portafilter 304. In the case where a further sealing member 305 is provided, ultra fine mesh 303 is separated from the internal base of portafilter 304 by sealing s member 305. Sealing member 302 is mounted upon the upper surface of second filter portion 303 and the receiving basket 301 is further mounted on top is.

Of the sealing member 302..: Optionally, the one or both of the sealing members may be omitted. s 30 - cc The effect of providing a first filter portion in the base of the receiving basket.;.

301 and a second filter portion provided by the ultra fine mesh 303 is to prevent.ó,

-16 tea leaf dust or residue escaping the receiving basket from being carried by the infused water into the tea beverage of the final product. By utilising sealing members 302, 305 having a substantially elliptical or circular cross-section or profile a single ring shaped sealing member can be used to fit a range of 5 portafilter sizes. Figure 3 illustrates an enlarged view of the cross-section of sealing member 302. Either a flattened, elliptical cross-section 307 or a circular cross-section 308 of the polymer ring may be used. The weight of the receiving basket and the pressure of the optional packing step acts to compress each polymer ring to effect a seal with the adjacent surfaces. This flattening enables o each polymer ring to be used over a range of sizes of portafilter 304, mesh 303 and receiving basket 301. Polymer ring 302, 305 is typically manufactured from a synthetic polymer or plastics material but may also be manufactured from a natural or synthetic rubber or latex material.

s Fig. 4 illustrates a traditional Italian flat packer of a type known in the prior art for use in packing coffee granules into a receiving basket. The packer 401 comprises a handle portion and packing element of different size, suitable for varying sizes of receiving basket, disposed at either end of the handle portion.

2 o Fig. 5 illustrates in diagrammatic form the steps involved in distributing, hard packing and polishing tea granules in a receiving basket 506. initially, loose tea particles 501 are dispensed into a receiving basket 506. The Barista distributes the tea within the receiving basket to an approximately even form. This is performed by hand. The flat packer 401 is then used to hard pack and polish the 2 5 tea. This involves applying a uniform pressure to the tea to evenly distribute the tea and provide a consistent density in the receiving basket 503. As the flat.

packer 401 is released it is twisted through 360 degrees to polish the surface of.:' the tea. This prevents the formation of pits in the tea surface. A pit in the tea surface provides a path of least resistance for the pressurised water to pass o 3 o through the tea contained in the receiving basket. This has the effect of reducing. 6 the efficiency of infusion and therefore the quality of tea beverage produced. À, O À. O

tic

-17 Hard packed and polished tea 503 contained in receiving basket 506 is then mounted in a portafilter and engaged at the group head where pressurised hot water 504 is passed through the hard packed and polished tea 503 providing ideal extraction conditions for production of tea beverage 505.

In order to produce tea beverage in accordance with the present invention it is necessary to load and prepare the tea particles in the receiving baskets. Tea particles, typically in the form of loose leaf tea or tea granules 501 are initially loaded into the receiving basket by hand. A predetermined quantity of tea is To loaded into a receiving basket in accordance with the number of shots of tea which are required to be produced. Typically, between three and five grams of tea particles are loaded per 250 to 450ml of water to be passed through the packed tea.

15 To enhance the quality of the tea and to ensure production of tea in a consistent manner an optional step of packing the tea in the receiving basket is recommended. This involves use of a packing element e.g. a prior art type Italian

flat packer as illustrated in figure 4. The packing element is placed on the loose leaf tea contained in the receiving basket and a pressure is applied by hand go evenly across the tea to pack the tea to a substantially uniform density. By twisting the packer during the release of the packing element from the tea particles a polished surface is presented. A polished surface comprises a substantially uniform surface layer wherein water under pressure applied to the layer is evenly distributed through the tea. If the polishing step is not applied a pit may form in the tea at a point of weakness in the tea layer. Formation of a pit generally forms a line of least resistance which allows the pressurised hot water to pass through the tea without saturating the tea and without achieving a maximized extraction. As the pressurised hot water is passed through the tea layer the water saturates the tea. This saturation occurs rapidly, generally within 3 o 1 to 5 seconds of first contact of the pressursied hot water with the upper surface of the packed tea. Where the tea has been correctly packed and polished the hot water passes through the tea in an approximately uniform manner, steeping

-18 the tea in the water and producing a maximum flavour extraction in a short period of time, typically in the range 1 to 25 seconds.

Fig. 6 illustrates schematically the main method steps for producing hot tea beverage in accordance with the present invention. The first step comprises assembly of the portafilter and receiving basket 601. As illustrated in figure 3 herein an ultra fine mesh member 303 and sealing members 302, 305 are inserted into the portafilter 304 prior to insertion of the receiving basket 301. This prevents any loss of tea particles from the receiving basket and hence keeps the o tea beverage produced free of particulate matter. A quantity of tea is then placed in the receiving basket 602 and packed using a traditional flat packer as known in the prior art for packing of coffee during preparation of espresso coffee. Once the

tea has been packed in the receiving basket and polished the portafilter can be connected to the group head of an espresso machine 603. Whilst an espresso machine provides an ideal supply of hot water under pressure which can be directed evenly over packed tea, any supply of hot pressurised water which can be controllably supplied in an even manner to a layer of tea could be used.

The espresso machine is then operated to pass hot water under pressure o through the packed and polished tea layer 604. Infusion of the water with the tea occurs such as to extract from the tea flavors and colour into the water thereby producing a tea beverage. This tea beverage is filtered by the first filter portion of the receiving basket 301 and the second ultra fine mesh portion 303 disposed between receiving basket 301 and portafilter 304 base. The filtered and infused water is collected 605. The tea beverage so produced is then ready to be served and consumed 606. À.

In general use, to obtain maximum extraction of tea flavours, acids and components for production of tea beverage in accordance with the present 30 invention a single quantity of tea contained in a receiving basket is used only À i once for the production of tea beverage. Following the passage of hot water -;r under pressure through the tea 604 the portafilter is removed from the group Us,.

-19 head and the receiving basket is emptied of water-saturated tea particles 607. A short rinsing step to remove tea particles adhering to the receiving basket may optionally be included. The receiving basket is then ready to be reloaded with tea and packed 602 ready for production of a further shot of tea beverage.

The tea beverage produced by this method comprises hot black tea produced by the infusion of hot water under pressure with a layer of tea particles.

Sugar and milk can be added according to the users desired taste. By using water which, during infusion of the tea is below boiling point a maximum JO extraction can be produced rapidly whilst further providing for a product which is at a temperature ready to drink immediately.

The first specific method of the present invention therefore provides a method of producing a quantity of hot tea beverage by the infusion of hot water :s under pressure with tea. The method is characterized by the passage of hot water under pressure through a packed quantity of tea over a short time period.: In particular by using an espresso machine the infusion period, during which hot water and packed tea are in contact, is typically in the range 1 to 25 seconds go and more typically in the range 15 to 20 seconds. The time period of infusion is dependent upon the temperature and pressure of the water used and therefore in certain circumstances an extended infusion duration is required, this being typically no more than 60 seconds. Accordingly, the specific method of the present invention provides a rapid means of producing tea beverage compared to the traditional brewing time of approximately 3 to 5 minutes.

Whereas traditional tea brewing methods require boiling water to be added. : to either loose leaf tea or tea bags, the method of the present invention provides for hot water under pressure to be infused with tea at temperatures below 1 00 C.

30 and more specifically, infusion typically occurs at a water temperature in the.

range 50 to 100 C. More typically the water temperature is in the range 77 to ale, 87 C and optimally at 82 C. A.

-20 The infusion temperatures recited above relate to the temperature of water during contact of the water with tea particles during the infusion process. An espresso machine suitable for delivery of hot water under pressure will boil water 5 under pressure, thus superheating the water. However, during delivery through the group head the water temperature is allowed to decrease and once the water has saturated the tea the effective infusion temperature is below boiling point.

The temperature of water during passage through the tea, i.e. during infusion, is measurable by inserting a temperature probe into the tea following saturation of o the tea with hot water. This temperature is best measured within the middle 60% of the infusion time period i.e. the period during which substantially all of the tea is saturated with water and the infusion process is well established.

It is further possible to vary the pressure at which the hot water is delivered.

15 The hot water is required to be delivered to the packed tea under pressure.

Pressures greater than local atmospheric pressure are required and pressures greater than 2.03 x 105Pa (2 bar) are desirable and in particular pressures in the range 7- 10 x 105Pa and more typically in the range 8.31 to 9.12 x 105 Pa (8.2 to 9 bar) are required in order to obtain optimal quality of tea beverage produced.

The inventors have identified through experiment that an optimal ratio of quantity of tea per quantity of hot water is in the range 3.0 to 4.5g, and particularly 3.3g, of loose leaf tea per 285 to 400ml of hot water under pressure discharged through the packed tea.

A method of production of tea beverage by the passage of hot water under pressure through a quantity of tea particles is provided. The method comprises the steps of heating hot water under a pressure greater than atmospheric pressure. The heated, pressurised water is then directed to a pre-determined : So quantity of pre-prepared tea. During direction of the heated, pressurized water i c" towards the tea and during passage of said water through said tea the applied in pressure is substantially maintained to force the water through the quantity of tea.

-21 rapidly whilst extracting a maximum colour and flavour from the tea into the water. Infusion of water with the tea occurs by saturating the tea with the pressurized, heated water. The temperature of the infusion mixture is below 100 C being typically in the range 50 C to 100 C and optimally at 82 C. The infusion process is rapid, providing for the formation of tea beverage with an optimized flavour extraction wherein the infusion process occurs within 0.5 to 60 seconds and more typically within 15 to 20 seconds. The result is a tea beverage which can be reproduced consistently by use of the same method so as to produce a quantity of tea of high quality in a short time period.

According to a second specific method of the present invention there is further provided a pre-infusion cycle to the method steps of the first specific method described above. Pre-infusion occurs prior to passage of hot water under pressure through the packed tea. Following mounting of the portafilter at the 15 group head on an espresso machine the packed tea contained in the receiving basket therein is saturated with brewing water or steam just before the main body of pressurised infusion water impacts at the packed tea. This pre-infusion cycle typically lasts for 1 to 5 seconds resulting in tea beverage being produced typically within 15 to 30 seconds of the user activating the espresso machine.

Fig. 7 illustrates schematically a flow diagram in accordance with the second specific method of the present invention. The portafilter containing packed tea is mounted at the group head. The user activates the espresso machine wherein a pre-infusion cycle 701 commences. The preinfusion cycle z saturates the packed tea with steam or brewing water for 1 to 5 seconds. This has the effect of sealing the uppermost layer of packed tea to prevent the D pressurised water causing formation of a pit in the top of the tea layer. Further,.:.

pre-infusion acts to further release flavours from the tea improving the quality of the tea beverage produced. Following pre-infusion superheated water under 30 pressure is transferred through the tea, typically for an infusion duration of - -

between 1 and 25 seconds 702. The tea beverage is filtered and collected 703 u; and is then ready to drink. *..

-22 The pre-infusion cycle prepares the packed tea by passage of a shot of steam through the packed tea. This acts to warm the packed tea preventing scolding of the tea upon impact of the pressurised hot water delivered from the group head. This has the effect of ensuring that the flavours in the tea are not degraded or destroyed upon impact of the brewing water. Upon impact of the brewing water infusion occurs between the water and tea steeping the water in tea particles so as to saturate the tea particles with water.

JO A further specific method of the present invention for the production of cold tea (also known as "ice-tea") is now described. Referring to Fig. 8 herein, tea particles are placed in a receiving basket and packed 801 as described above.

The receiving basket is assembled in a portafilter in accordance with Fig. 3 herein, wherein the sealing members 302, 305 are omitted and the fine mesh 15 filter 303 is substituted with a blank portion substantially preventing passage of liquid from the receiving basket 301. The blank typically comprises a circular disc placed between the receiving basket 301 and the base of the portafilter. The assembled portafilter is engaged at a group head on an espresso machine or at other available steam supply means. Pre-infusion comprises saturation of the tea o particles held within the receiving basket with steam for a time in the range 0.5 to 30 seconds, and typically in the range 5 to 20 seconds. The blank prevents escape of any liquid which may form through condensation of the steam with the tea particles. The pre-infusion cycle saturates the tea particles with steam so as to expand the hydroscopic particles. This expansion of the tea particles enhances extraction of tea flavours by cold water during the subsequent infusion process. In production of ice- tea the pre-infusion process is not entirely essential but improves the extraction of tea flavours by the cold brewing water. Following the pre- infusion cycle, the blank is removed and a fine mesh filter is inserted in replacement as appropriate. The reassembled portafilter is then engaged at a G I 30 water supply means, e.g. group head, wherein cold water under pressure is o passed through the pre-infused quantity of tea particles 803, filtered cold tea (ice- - -; C tea) collected and served 804.. *,

-23 The production of iced tea in accordance with the present invention is suitable for production on an espresso machine wherein pre-infusion takes advantage of the steam pressure built up in such machines and wherein the machine is adapted to supply refrigerated cold water under pressure through one of the group heads for the infusion process.

Pre-infusion of tea particles for production of ice-tea occurs over a time in the range 0.1 to 30 seconds.

Infusion of the pre-infused tea particles following pre-infusion occurs over a time in the range 0.5 to 60 seconds and more typically over a time in the range 15 to 30 seconds. Cold water comprises water at a temperature in the range O to 50 C and more typically in the range 1 to 15 C. Cold water is supplied at pressures as described for the production of hot tea beverage above.

:;. In preferred embodiments, tea beverage produced by any of the specific methods described comprises the passage of water under pressure through a quantity of tea to produce tea beverage, the said quantity of tea then disposed of go as waste. In a further alternative embodiment, a quantity of tea particles contained in a receiving basket is used to produce a first quantity of tea beverage. The quantity of tea particles contained in the receiving basket is then set aside for a first interval, typically in the range 30 to 180 seconds, following which the tea particles contained in the receiving basket are re-engaged at a 25 group head or other supply of pressurised water and a second quantity of hot or cold tea beverage is produced. The previously infused tea particles may then be further put to one side for a second time interval, again typically in the range 30 to 180 seconds, after which a third quantity of tea beverage is produced from the same quantity of tea particles. The inventors have identified that allowing the 3 o infused tea to stand between production of quantities of tea beverage allows the tea particles to relax such that they may be reused in a further infusion process without compromising the extraction of tea flavours to produce a high quality of

-24 tea beverage. The number of times which a particular quantity of tea particles can be reused is dependent upon the type of tea particles used but is typically no less than three consecutive occasions without significant loss in quality of the resulting tea beverage.

Tea beverage produced through any one of the specific methods described is of measurable higher quality than tea beverage produced by prior art

techniques. This distinction in quality is measurable by an analysis of the tannin content of tea particles produced by prior art methods compared to tea beverage

o produced in accordance with the present invention. The inventors have identified that the tannin or tannic acid levels, which produce a characteristic bitter taste, are significantly reduced in tea produced by the methods of the present invention.

Wherein a same predetermined quantity of tea particles is used to produce a quantity of tea beverage in accordance with a prior art technique of either directly

infusing loose leaf tea with water or use of a tea bag, compared to a quantity of tea beverage produced in accordance with the present invention the level of tannins in the resulting tea beverage is up to 50% lower in the tea beverage produced in accordance with the present invention.

go In order to facilitate reliable reproduction of tea beverage produced in accordance with the present invention the inventors have further provided a sachet for providing a predetermined quantity of tea particles for use in producing a predetermined quantity of tea beverage. The sachet comprises a paper or plastics pouch, having a polyethylene inner lining surrounding tea particles Q contained within a sachet. The sachet is sealed during storage such as to prevent moisture contacting the tea particles held within. The vendor tears open the sachet and pours a predetermined quantity of tea into the receiving basket In this way, consistent high quality tea beverage can be produced in accordance with the methods described above.

The methods disclosed describe the steps involved in producing tea beverage reproducibly to a high quality comprising an optimised extraction of

i -25- flavours from tea particles by an infusion process which occurs rapidly and generally within 60 seconds. The methods involve the application of hot or cold water under pressure to a quantity of tea. By using pressurised water tea particles can be saturated rapidly, the pressure applied enhancing the infusion process to extract tea flavours and colours from the tea particles rapidly.

Whereas conventional tea making methods rely on infusion processes requiring boiling water and infusion periods lasting for several minutes the present methods enable the production of tea beverage of high quality enabling full extraction of tea flavours within a short time period.

. et: --

a. . i ..

Claims

-26 Claims:

1. A method of producing a quantity of tea beverage, said tea beverage comprising an infusion, said method characterized by comprising the step of forcing a quantity of hot liquid under pressure through a quantity of tea particles 5 thereby infusing said liquid and tea particles, wherein: transfer of a quantity of said hot liquid, sufficient to form a quantity of said tea beverage, through said quantity of tea particles occurs in a time in the range 0.5 to 60 seconds, infusion of said liquid and tea particles occurring at a temperature in the range 50 to 1 00 C.

2. A method as claimed in claim 1, said method further comprising the 5 step of directing a first quantity of steam or hot liquid towards said quantity of tea particles prior to said step of forcing said hot liquid through said tea particles.

3. A method as claimed in claim 2, wherein said first quantity of steam or hot liquid is directed towards said quantity of tea particles for a time period in the 2 o range 0.1 to 5 seconds.

4. A method as claimed in claim 2, wherein said first quantity of steam or hot liquid is directed towards said quantity of tea particles for a time period in the range 1 to 3 seconds.

5. A method as claimed in any of claims 1 to 4, wherein said hot liquid is, forced through said quantity of tea particles at a pressure greater than 2.03 x 105 At'' Pa. o 6. A method as claimed in any of claims 1 to 4, wherein said hot liquid is t forced through said quantity of tea particles at a pressure in the range 7 - 10 x;; 105 Pa.

-27 7. A method as claimed in any of the claims 1 to 4, wherein said hot liquid is forced through said quantity of tea particles at a pressure in the range 8.31 to 9.12 x105 Pa.

8. A method as claimed in any of claims 1 to 7, wherein said transfer of hot liquid through said quantity of tea particles occurs in a time in the range 1 to 25 seconds.

To 9. A method as claimed in any of claims 1 to 7, wherein said transfer of hot liquid through said quantity of tea particles occurs in a time in the range 15 to 20 seconds.

10. A method as claimed in any of claims 1 to 9, wherein said infusion of said liquid and tea particles occurs at a temperature in the range 77 to 87 C.

. 11. A method as claimed in claim 10, wherein said infusion of said liquid and tea particles occurs at a temperature in the range 80 to 85 C.

To 12. A method as claimed in claim 11, wherein said infusion of said liquid and tea particles occurs at a temperature of 82 C.

13. A method as claimed in any of claims 1 to 12, wherein said quantity of tea particles is retained in a filter means, said filter means enabling passage of s infused liquid through said filter means, said filter means preventing passage of tea particles through said filter means...

14. A method as claimed in any proceeding claim, wherein said method further comprises the steps of: +' 30: loading a quantity of tea particles into a filter means;,,,

-28 engaging said filter means at a group head of an espresso machine; activating said machine to force a quantity of hot liquid under pressure through said quantity of tea particles so as to infuse said liquid with said tea particles. 15. A method as claimed in claim 14, wherein following the step of loading a quantity of tea particles into said filter means the loaded tea particles are packed in said filter means by application of pressure to a main surface of said quantity of tea particles to provide a substantially uniform density of tea particles retained in said filter means.

16. A method as claimed in any of claims 1 to 15, further comprising the step of collecting filtered tea beverage in a receptacle.

17. A method as claimed in any of claims 1 to 16, wherein said hot liquid is forced through a said quantity of tea in the ratio 3.0 to 4.5 grams of tea particles per 285 to 400ml of hot liquid.

To 18. A method of producing a quantity of tea beverage, said tea beverage comprising an infusion, said method characterized by comprising the step of forcing a quantity of cold liquid under pressure through a quantity of tea particles thereby infusing said liquid and tea particles, wherein: ss transfer of a quantity of said cold liquid, sufficient to form a quantity of said tea beverage, through said quantity of tea particles, occurs in a time in the range..

0.5 to 60 seconds,.

infusion of said liquid and tea particles occurring at a temperature in the o range O to 50 C. ': I

-29 19. A method as claimed in claim 18, said method further comprising the step of directing a first quantity of steam or hot liquid towards said quantity of tea particles prior to said step of forcing said cold liquid through said tea particles.

20. A method as claimed in claim 19, wherein said first quantity of steam or hot liquid is directed towards said quantity of tea particles for a time period in the range 0.1 to 30 seconds.

21. A method as claimed in claim 19, wherein said first quantity of steam or o hot liquid is directed towards said quantity of tea particles for a time period in the range 15 to 25 seconds.

22. A method as claimed in any of claims 18 to 21, wherein said cold liquid is forced through said quantity of tea particles at a pressure greater than 2.03 x 15 105 Pa.

23. A method as claimed in any of claims 18 to 21, wherein said cold liquid is forced through said quantity of tea particles at a pressure in the range 7 - 10 x 1 o5 Pa.

24. A method as claimed in any of claims 18 to 21, wherein said cold liquid is forced through said quantity of tea particles at a pressure in the range 8.31 to 9.12 x 105 Pa.

2 25. A method as claimed in any of claims 18 to 24, wherein said transfer of cold liquid through said tea particles occurs in a time in the range 1 to 45, seconds.. 26. A method as claimed in any of claims 18 to 24, wherein said transfer of 3 o cold liquid through said quantity of tea particles occurs in a time in the range 15 to.

30 seconds.....

e e: À..

-30 27. A method as claimed in any of claims 18 to 26, wherein said infusion of said liquid and tea particles occurs at a temperature in the range 1 to 1 5 C.

28. A method as claimed in any of claims 18 to 27, wherein said quantity of tea particles is retained in a filter means, said filter means enabling passage of infused liquids through said filter means, said filter means preventing passage of tea particles through said filter means.

29. A method as claimed in any of claims 18 to 28, wherein said method o further comprises the steps of: loading a quantity of tea particles into a filter means; engaging said filter means at a means to dispense pressurised cold liquid; activating said means to dispense pressurised cold liquid to force a quantity of cold liquid under pressure through said quantity of tea particles so as to infuse said cold liquid with said tea particles.

2 o 30. A method as claimed in claim 29, wherein following the step of loading a quantity of tea particles in said filter means, the loaded tea particles are packed in said filter means by application of pressure to a main surface of said quantity of tea particles to provide a substantially uniform density of tea particles retained in said filter means.

31. A method as claimed in any of claims 18 to 30, further comprising the. .

step of collecting filtered tea beverage in a receptacle..: 32. A method as claimed in any of claims 18 to 31, wherein said cold liquid So is forced through a said quantity of tea in the ratio 3.0 to 4.5 grams of tea c.

particles per 285 to 400ml of cold liquid. 0.

:.'.

-. -31 33. Apparatus for use in producing a quantity of tea beverage according to the methods as claimed in any of claims 1 to 32, said apparatus comprising means to retain said quantity of tea particles during forcing of liquid through said quantity of tea particles, said apparatus characterized by comprising; a receiving basket to retain said tea particles, said basket comprising a first filter portion; a second filter portion configured to be positioned substantially adjacent o said first filter portion, wherein said second filter portion comprises a fine mesh member, said first and second filter portions allowing transfer of infused liquid and configured to prevent transfer of tea particles of a predetermined size.

34. Apparatus as claimed in claim 33, wherein said second filter portion is mounted on at least one sealing member.

35. Apparatus as claimed in claim 33 or 34, further comprising a receiving 20 basket mounting means configured to engage a group head on an espresso machine, said receiving basket mounting means configured to house said receiving basket and said second filter portion.

36. Apparatus as claimed in claim 35, wherein said second filter portion is mounted on a first sealing member at a base region of said receiving basket mounting means, said receiving basket located above said second filter portion..

and mounted on a second sealing member such that material filtered through, said first filter portion is immediately further filtered through said second filter portion, said sealing members directing infused liquid through said filters.

30 TO

37. Apparatus as claimed in any of claims 34 to 36, wherein said sealing; 'O members comprise a polymer ring.

-32 38. Methods and apparatus in accordance with any of claims 1 to 37, wherein said liquid is water.

39. A quantity of tea beverage produced in accordance with the method and/or apparatus as claimed in any of claims 1 to 38.

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