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EP 1 882 431 B1
EUROPEAN PATENT SPECIFICATION
(12)
(45) Date of publication and mention
(51) Int Cl.:
A47J 31/00 (2006.01)
of the grant of the patent:
28.04.2010 Bulletin 2010/17
(21) Application number: 06015330.1
(22) Date of filing: 24.07.2006
(54) Method for delivering a long coffee extract from a capsule in a reduced flow time
Verfahren zum Ausgeben von langem Kaffee aus einer Kapsel mit verringerter Durchflusszeit
Procédé de distribution de café long à partir d’une capsule avec temps d’écoulement réduit
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR
HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI
SK TR
(43) Date of publication of application:
• Eichler, Paul
1009 Pully (CH)
• Koch, Peter
1350 Orbe (CH)
• Raetz, Ernest
1357 Lignerolle (CH)
30.01.2008 Bulletin 2008/05
(74) Representative: Borne, Patrice Daniel et al
(73) Proprietor: Nestec S.A.
1800 Vevey (CH)
Nestec S.A.
Avenue Nestlé 55
1800 Vevey (CH)
(72) Inventors:
EP 1 882 431 B1
• Ohresser, Sylvia
1350 Orbe (CH)
(56) References cited:
EP-A1- 0 844 195
US-A1- 2005 183 581
EP-A2- 1 566 127
Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent
Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the
Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been
paid. (Art. 99(1) European Patent Convention).
Printed by Jouve, 75001 PARIS (FR)
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EP 1 882 431 B1
Description
[0001] The present invention relates to a method for
delivering coffee beverages from capsules designed to
be extracted under pressure and containing a substance
for the preparation of a coffee beverage.
[0002] Coffee cups can be produced from filter coffee
machines. However, as a result of a "light" extraction of
the coffee, the resulting extract usually has low coffee
solids concentration, a low aroma profile, and little or no
"crema" on the top.
[0003] Capsules designed to be extracted under pressure and containing a substance for the preparation of a
beverage exist on the market. They provide a better extraction of coffee, i.e., a higher "extraction yield", more
aroma and a better "crema", more convenience in operation and they ensure freshness of the substance contained therein. As a result, the delivery of freshly extracted beverages of constant quality is better ensured.
[0004] For instance, the actual system commercialized
under the trademark "Nespresso®" is appreciated for producing good quality short cups of coffee and long cups
of coffee. A short cup of coffee is defined as containing
less than 50 grams of coffee liquid extract in the cup and
more specifically about 40 g for the espresso type and
about 25 g for the Ristretto type. Due to the high pressure
extraction conditions maintained in the capsule, in the
order of 10-20 bar, the liquid extract which is delivered
can be given desirable quality attributes in terms of coffee
yield, coffee solids and "crema" and within a delivery flow
time which is found acceptable for the user. Some consumers however, prefer to have the option to also prepare
a long cup of coffee with the existing capsules. A long
cup of coffee is defined as containing about 110 (+/- 10)
grams of coffee liquid extract in the cup. In order to deliver
a longer cup of coffee, a higher amount of water needs
to be sent through the capsule. Therefore, typically a
"long coffee" takes a too long time to be delivered, i.e.,
one minute or more, and the resulting beverage can taste
too bitter and harsh and might be slightly thin or watery.
The delivery time, which exceeds one minute, is also
unacceptable on a commercial standpoint and inconvenient to the consumer who wants to prepare several cups
in a row.
[0005] EP 1 566 127 A2 has proposed a solution for a
system adapted to deliver a short or long coffee using
the same coffee extraction device and the same capsule
format. The long coffee capsules have a retaining membrane of puncture resistance of from 0.6 to 1.1 mJ and
a coffee granulometry of from 300 to 600 microns.
[0006] The present invention aims at a significant improvement to the capsule system of the prior art. In particular, a main objective is to reduce flow time of the coffee
capsules to deliver a long coffee extract while at the same
time maintaining or even improving the quality attributes
of the coffee, in particular, a desirable strength (e.g. expressed by its "extraction yield") and also a sufficient
thickness and texture of crema.
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[0007] The invention is based on the general findings
that the pressure loss in the coffee bed of the capsule is
reduced compared to the prior art. At the same time, the
pressure loss at the membrane/opening plate interface
of the capsule can be increased compared to prior art.
Indeed, it was surprisingly found that the crema attribute
can be significantly increased by increasing the pressure
loss at the membrane/ opening plate interface. Decreasing of the pressure loss in the coffee bed itself can reduce
or at least maintain within desired limits the flow time for
the delivery of a long cup of coffee. However, reducing
the pressure loss in the coffee bed cannot be carried out
without reducing the extraction yield of coffee, which
would lead to a coffee with insufficient strength and/or
aroma. Therefore, the invention has found a solution to
maintain a high coffee extraction level providing relatively
less resistance in the coffee bed to the fluid flow as compared to prior art capsule systems in order to reduce the
overall coffee delivery time.
[0008] The invention is thus based on the finding that
the granulometry of the coffee bed with a control of the
fines level in the coffee bed plays a key role in the reduction of the pressure loss in the coffee bed while maintaining the desired coffee extraction level. The invention is
also based on the principle of reducing the level of fines
in the ground coffee; such level of fines providing a faster
flow while not significantly affecting the extraction yield
of the resulting coffee extract.
[0009] Therefore, the present invention relates to a
method for delivering a long coffee extract from a capsule
containing ground coffee according to independent claim
1.
[0010] More preferably, the capsule contains ground
coffee having a controlled percentage of fines (F) depending on the particle size within the following limits:
F is comprised between 12 and 14% when D4,3 is
measured between 300 and 350 microns.
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[0011] A control of the level of fines as determined as
a function of the average particle size of the coffee grind
enables to decrease the pressure loss in the coffee bed,
consequently significantly reducing the flow time.
[0012] Preferably, a single grinding within the aforementioned specific ranges of D4,3, is dosed and filled in
the capsule to achieve the method of the invention.
[0013] According to the method of the invention, the
long coffee extract is preferably delivered in a flow time
reduced to less than 35 seconds. The flow time is reduced
while the extraction yield of the delivered coffee extract
is maintained of from 15 to 30%. More preferably, the
extraction yield of the delivered coffee extract is maintained between 20 and 26%.
[0014] In addition, the pressure loss at the membrane/
engaging means interface can be increased to provide
improved quality attributes, in particular, to improve the
production of crema. The flow time can be maintained or
even preferably reduced if the increase of pressure at
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the membrane is compensated by a reduction of the
fines. Preferably, a crema is formed on the top of the
coffee extract which experiences a stability at the sugar
test of more than 10 seconds. More preferably the crema
expericences a stability at the sugar test of between
about 11 and 15 seconds.
[0015] Pressure loss at the membrane/ engaging
means interface can be increased by having a membrane
which has a higher puncture resistance than a typical
membrane for delivering long coffee extracts. Preferably,
the membrane has a puncture resistance of at least 1.1
mJ. Even preferably the membrane has a puncture resistance of between 1.1 mJ and 3.5 mJ. Most preferably,
the membrane has a puncture resistance of between
1.35 and 3.2 mJ.
[0016] Another advantage of membranes having a relatively high puncture resistance is that the membrane
can be more reliably sealed to the capsule’s body. In
particular, there is a lower risk of defective seal that could
accidentally break during extraction under the pressure
of fluid and which would cause the coffee ground to dirty
the extraction device.
[0017] Pressure loss could also be controlled by other
means such as by choosing a specific design of the opening plate (e.g., more cutting or perforating design).
[0018] The membrane can be made of different material such as aluminium, aluminium alloy and/or plastic.
[0019] In a preferred example, when the membrane is
made of aluminium or aluminium alloy, the membrane
has a thickness comprised between 26 and 40 microns,
even more preferably of about 30 microns.
[0020] In order to obtain a reduction of fines in the capsules, one possible method may consist in grinding the
coffee beans (before filling the capsules) by using a grinder with at least one pair of rolls having radial corrugation
in the fine grinding section as opposed to longitudinal
corrugation. Good results have been obtained by grinding coffee using at least 3 stages, preferably 4 stages
with at least one roll being radially corrugated. The best
results have been obtained by at least 4 stages, most
preferably 6 stages, using only grinding rolls with radial
corrugation.
[0021] The coffee in the capsule can be filled in a loose
state in the capsule, i.e., without compacting step before
or after filling it in the capsule. Alternatively, the coffee
can be densified before the filling step using a densifying
device. However, the coffee is not compacted in a solid
block in the capsule but remains in a flowing state in the
capsule.
[0022] In a still a preferred example, the opening plate
for the delivery membrane is formed of a network of protruding reliefs, preferably, a number comprised between
20 and 50 ; each relief having a flat upper surface of
individual surface area comprised between about 0.5 and
5 mm2. More preferably, the upper surface of each individual surface area of the relief is comprised between
0.8 and 3 mm2. Such an opening arrangement may also
participate to generate a pressure loss that is sufficient
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to form a better crema.
Brief Description of the Drawings:
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[0023]
Figure 1 is a graphic showing the relation between
the average particle size and fines level according
to different grinding technologies;
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Figure 2 is a graphic showing the relation between
the average particle size and the extraction yield in
the delivery of long coffee extracts;
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Figure 3 is a graphic showing the relation between
flow time and the quality of crema in the delivery of
long coffee extracts;
Figure 4 is a graphic showing the relation between
the average particle size (D4,3) and flow time in the
delivery of long coffee extracts;
Figure 5 shows a schematic representation of the
system of the invention before insertion of the capsule;
Figure 6 shows a schematic representation of the
system; the device being closed and a cartridge being extracted in the device.
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Detailed Description of the Preferred Embodiments
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[0024] In the present application, terms are utilized for
which the definitions are given as a preamble below.
[0025] The "extraction yield" is defined as the weight
of total solids in the liquid extract divided by the total
weight of starting coffee ingredients in the capsule (e.g.,
roast and ground coffee). This value is typically expressed as a percentage. The extraction yield is representative of the strength of the coffee extract.
[0026] The "total solids" is defined as the weight of
extracted solids contained in the extract divided by the
total weight of the extract. This value is typically expressed as a percentage.
[0027] The "injection pressure" is defined as the maximal pressure expressed in bar and measured at the injection point(s) in the capsule during extraction.
[0028] The "flow time" is defined as the time from the
first moment of fluid dropping into the coffee cup to the
moment the extracts has been delivered into the cup with
the desired weight, strength and aroma.
[0029] "Long coffee extract" is defined as the liquid extract as obtained from the capsule with a weight of about
110 g (+/-10 g).
[0030] The average particle size "D4,3" represents the
mean volume diameter of the coffee grind as obtained
by laser diffraction method using a Malvern® optical instrument and butanol as dispersing agent for the parti-
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EP 1 882 431 B1
cles.
[0031] The "fines" are considered as being coffee particles having a diameter of less than 88.91 microns when
measured by the Malvern® laser diffraction method.
[0032] A "stage" for grinding coffee in a grinder represents a pair or rolls.
[0033] The "delivery membrane" is meant to be the
wall of the capsule from which the coffee is delivered
comprising at least one beverage outlet provided after
opening by any suitable method including cutting, puncturing and/or tearing or eventually a preformed beverage
outlet.
[0034] The "puncture resistance", expressed in milliJoules, is defined as the energy needed to puncture the
membrane of the capsule by using a MTS Synergie 400
tensile equipment supplied by Fuch Industrievertretungen (Switzerland) as further described in EP 1566127
A2; the content of which is included here by reference.
[0035] The "granulometry" of the ground coffee is defined as the diameter of the coffee particles as resulting
after grinding as explained in the examples.
[0036] The "crema" is defined as the head of foam created on the coffee extract with a texture of substantially
small bubbles. The crema attribute can be measured by
an empirical sugar test which consists in arranging a well
defined crystal sugar layer, i.e., sugar of average particle
size D4,3 of 660 microns on top of a freshly prepared cup
of coffee and measuring the elapsing time between the
start of overlaying and the main part of sugar’s sinking.
The "sugar test value" is thus a number of seconds.
[0037] The "engaging means" represents an element
of the extraction device or capsule having the function of
engaging in or pressing against the membrane to provide
a certain pressure loss that enables to delay the release
of coffee out of the capsule. The engaging means can
take various forms able to provide in conjunction with the
membrane a certain pressure loss such as a central needle or multiple needles or a plate with multiple protrusions
and/or bumps, or a filter plate.
[0038] The present invention relates to a system that
uses closed capsules and their attached benefits, as
aforementioned, to provide beverages of long volume.
[0039] Although the key quality attributes are generally
known for espresso-type coffee, there have been very
little studies able to determine precisely a definition of a
long cup of coffee, which corresponds to the consumers’
preference. For a long cup of coffee, key quality attributes
can be determined by different means such as by consumer tests and focus groups. Key quality attributes essentially encompass the extraction yield, the total solids
and crema. It has been found that the extraction yield
must preferably be maintained within a certain range. If
the extraction yield is too high, the coffee is usually considered as bitter and harsh because non-desirable compounds may have been extracted over a too long time of
extraction. Therefore, not only is it important to shorten
the delivery of a long coffee extract for the obvious reason
of reduction of the waiting time but also a shorter delivery
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time tends to avoid the problems linked to the over-extraction of the coffee. Conversely, if the extraction yield
is too low, the coffee tastes watery and is also not found
acceptable by the average consumer. Therefore, it has
been determined that an appropriate range of extraction
yield is usually of from 15 to 30%, more preferably 18
and 28%, most preferably 20 and 26%. Similarly, the
amount of total solids in the cup must be sufficient to
confer sufficient body and texture to the beverage otherwise the coffee tastes watery and does not find consumer
acceptance. Therefore, although it may also be a matter
of preference, the best concentration of total solids for a
long beverage has been determined to be within a range
of from 1.0 to 1.9 % wt, even more preferably 1.1 to 1.7%
wt, most preferably 1.1 to 1.5 % wt. Proper extraction
yields and total solids can be obtained with capsules containing about 5.5 and 7 grams of coffee, preferably, between 5.8 and 6.8 grams of coffee.
[0040] Finally, crema is also considered in a long cup
of coffee as an important quality attribute and a long cups
of coffee should deliver a sufficiently thick and stable crema. The crema should be covering the whole surface of
the beverage in the cup without leaving any black holes.
This is particularly challenging since the surface of the
long coffee extract is usually much larger than that of the
short coffee extract (e.g., considering the difference between a coffee mug and an espresso cup). The crema
should also be creamy or velvety in texture, as opposed
to soapy or bubbly. Its colour should be brownish to reddish and not white. Therefore, the sugar test should show
a value of over 7 seconds and preferably more than 10
seconds.
[0041] Figures 5 and 6 schematically illustrate an exemplary system of the invention. The device D of the
invention comprises an extraction module 10 for extracting coffee from one capsule at a time. The extraction
module comprises receiving means in the form of a support base or collector 11 and an injection part 12. The
support base and injection part defines an internal volume upon closing of the two parts to receive the capsule.
In the support base is located engaging means 13 arranged to engage with a retaining part of the capsule
when pressure of fluid is built inside the capsule. The
engaging means 13 may be piercing means such as a
series of protruding elements such as pyramids, a network of elongated ribs or needles which are provided on
the surface of a plate. The coffee extract is primarily filtered by the very narrow spacing produced between the
protruding elements and the edges of the openings of
the membrane. The plate comprises a series of apertures
to drain the extract and eventually retain any solid coffee
particles. The apertures may be provided through the
plates in channels formed between the protruding elements or alternatively, be provided through the protruding
elements themselves.
[0042] The device further comprises at least one fluid
line 72 to which the fluid can be supplied in the capsule
via at least one injector 70. The injector may comprise
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EP 1 882 431 B1
one or more needles or blades, which create one or more
passages for water to enter in the capsule. The fluid is
supplied under pressure in the line by means of a pump
73. The pump may be an electromagnetic piston pump
or any suitable water pumping mechanism such as a diaphragm pump or pressurized head systems. A reservoir
of fluid 74 can be installed upstream the pump 73 to enable fluid to be supplied in sufficient amount for delivering
fluid to extract more than a capsule. Preferably, the reservoir holds more than 750 ml of water so as to eliminate
the inconvenience of repeatedly refilling the reservoir after a few extraction cycles. A heating system 75 can be
installed along the line between the reservoir and the
extraction module 10 to heat the fluid within a required
temperature range. The heater is configured to heat the
water to a temperature of extraction of between 70 to
100°C. It can be a thermoblock or an instant heating device such as ceramic heating cartridges. The reservoir
could also be such as a boiler that can keep the fluid
warm or hot. A control board with switches is also usually
helpful to automatically start the extraction cycle. Different controls can be added such as temperature sensors,
timers, flow meters, pressure sensors, vanes, probes and
so on for controlling and monitoring the extraction operations.
[0043] The coffee capsule L has a body 20 and a membrane 21 made of a material such as aluminium and/or
plastic. The capsule can take many different shapes without departing from the scope of the invention. The membrane could also be formed as the bottom of the body
itself. The membrane can take a predefined shape before
(e.g. convex or concave) and deforms against the engaging means 13 during extraction.
[0044] According to one important aspect of the invention, the capsule is filled with ground coffee of controlled
particle size and reduced level of fines.
[0045] The capsule may be flushed at a slight overpressure with an inert gas to increase the shelf life of the
coffee inside. The membrane can take a slight convex
shape as a result of the internal pressure of gas. Inert
gas is typically nitrogen but other inert gas could be used.
Carbon dioxide gas from the coffee also participates to
the inside building of gas pressure as a result of ground
coffee de-gassing inside the capsule after filling and sealing of the capsule. Therefore, the membrane should be
sufficiently resistant to withstand the internal pressure of
gas including the gas from de-gassing.
[0046] When the extraction module 10 is closed
around the capsule 2 and the capsule is positioned in the
module, as shown in figure 6, the retaining member, i.e.,
hereafter called "membrane", is positioned adjacent or
at a short distance from the engaging means 13 of the
device. The membrane of the capsule is not opened until
a certain opening pressure is built within the capsule by
virtue of water coming in the capsule. The membrane
and engaging means are so arranged to not create an
accidental opening before extraction begins. Therefore,
as water is entering within the capsule pumped by the
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pump means 75, the internal pressure builds up inside
the capsule which forces the membrane 21 to deform
and press on the engaging means 13 up to a point where
it becomes pierced or torn open. The capsule starts opening at a certain opening pressure but pressure usually
continues increasing due to the compaction of the bed
of ground coffee inside the capsule and also due to the
pressure drop created by the narrow openings torn or
pierced through the membrane of the capsule. Then, the
pressure level usually flattens to a pressure of extraction,
which is typically of several bars and then drops when
the pump is shut off. The overall pressure loss is usually
the addition of the pressure loss created by the compacted coffee bed and the pressure loss created by the conjunction of the small openings through the membrane
and the engaging plate 13 of the device. The water pressure of extraction reaches a value higher than 11 bar at
the injection side in the capsule. It can be noted that the
engaging plate could be a part of the capsule itself. It can
be noted that the membrane of the capsule can be preopened before water injection such as by one or more
needles of the engaging plates.
[0047] The pump has a fixed performance characteristic curve which means that it delivers a certain flow rate
of water when downstream the pump has to overcome
a certain pressure depending on the characteristics of
the capsule (granulometry, membrane, etc.).
[0048] The invention is based on the principle that the
pressure loss in the coffee bed has been significantly
reduced as compared to the pressure loss of the coffee
bed in the capsules of the existing systems while at the
same time substantially maintaining the coffee extraction
characteristics (i.e., the extraction yield).
[0049] For that, the granulometry of the coffee ground
in the capsule has been modified with a reduced level of
fines. Preferably, the percentage of fines (F) is related to
the measured range of particle size (D4,3). When the particle size increases, the amount of fines usually inversely
decreases. The finer the coffee is ground, the more fines
are created. According to the invention, the percentage
of fines F is determined as a function of D4,3 within the
following preferred limits:
F is between 12 and 16% when D4,3 is measured
from 300 to 349 microns,
F is between 14 and 18% when D4,3 is measured
from 299 to 250 microns.
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[0050] Preferably, the capsule is filled with one single
selected grinding having a selected particle size D4,3. In
other words, two or more grindings having different particle sizes (D4,3) are not mixed for filling a capsule.
[0051] Even more preferably, the percentage of fines
(F) of the capsule for delivering a long coffee extract is
comprised between 12 and 14% when D4,3 is measured
from 300 and 350 microns, therefore allowing to deliver
a long coffee extract in less than 45 seconds, preferably
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EP 1 882 431 B1
in about 35 seconds. It has been found that above 350
microns, extraction of the coffee mass is less effective.
It is supposed that the surface of contact between the
extraction fluid and the coffee particles is reduced thus
affecting the extraction principle. Too large particles also
require a longer degassing time for the coffee after grinding during the manufacturing. Below 300 microns, the
flow time may also be accelerated as well but the coffee
extraction may be less effective due to uneven distribution of the water in the coffee bed, called channeling.
[0052] The granulometry with a reduced level of fines
enables to control the flow time for long coffee extract.
[0053] The following examples further illustrate the invention in a non-limiting manner.
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3. Impact of flow time, grinding technology and membrane thickness on crema:
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[0056] The graphic of Figure 3 shows the impact of
flow time and membrane thickness on the quality of crema. The results show that a capsule extracted with a
thicker membrane (i.e., 30 microns) provides a better crema than a capsule extracted with a thinner membrane
(i.e., 20 microns) at substantially the same flow time. The
results also show that an axial corrugation generating
higher level of fines provided a faster flow (with 20-micron
instead of 30-micron membrane) but with less crema.
Finally, grinding with radial corrugation provided an improved crema at 35 seconds flow time when a thicker
membrane is utilized (i.e., 30 microns).
Examples:
4. Impact of granulometry (average particle size / fines)
on flow time:
1. Grinding technology:
[0054] The graphic of figure 1 illustrates the relation
between the average diameter D4,3 and the percentage
of fines considering different grinding technologies. A
grinding technology utilizing six stages representing 6
pairs of radially corrugated rolls has led to obtain a reduced level of fines as compared to a grinding technology
using only axially corrugated rolls or a mixed corrugation
(i.e., both radial and axial rolls on one or two stages of
the fine grinding section). The graph also shows that the
use of a grinder having mixed rolls provides a lower level
of fines as compared to axial corrugation only.
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2. Impact of particle size (D4,3) and membrane thickness
on extraction yield:
[0055] The graphic of Figure 2 shows the impact of the
average particle size on the coffee extraction yield when
extracting long coffee extracts from the capsules with
different thicknesses of the aluminium delivery membrane. Tests have been done, respectively, with 20-micron and 30-micron aluminium membranes. The average
puncture resistance of the 20-micron membrane was
measured at about 0.7 mJ and its maximal puncture resistance was measured at about 0.81 mJ. The average
puncture resistance of the 30-micron membrane was
measured at about 1.45 mJ and its minimal puncture resistance was measured at about 1.1 mJ. Tests also encompass different grinding technologies, respectively,
using full radial corrugation (6 stages as defined in Example 1) or, alternatively, full axial corrugation. Radial
corrugation led to a significantly reduced level of fines as
compared to axial corrugation as exemplified in Fig.1.
The results on the extraction of capsule having different
fine levels show that the extraction yield is finally not significantly affected. It also shows that a finer grinding, i.e.,
between 200 and 300 microns, gives a slightly higher
extraction yield as compared to coarser grinding (i.e.,
above 300 microns).
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[0057] The graphic of Figure 4 shows the impact of the
average particle size (D4,3), grinding technology (related
to fine levels) and membrane thickness on the flow time.
[0058] Three different coffee beans blends for long
cups, respectively, "Blend 1", "Blend 2" and "Blend 3"
were tested. The coffee beans were ground using either
axial or radial corrugation grinding technologies. The
capsules were filled with the resulting ground coffee and
were tested with different membrane thicknesses, respectively 20 and 30 microns.
[0059] The results show that flow time can be significantly reduced when the ground coffee has a reduced
level of fines (i.e., radial corrugation grinder used) compared to coffee ground of typical level of fines. This also
shows that the flow time is significantly reduced when
both the fines level is reduced and the membrane is made
thicker (i.e., 30 microns). In some instances, flow time
can even be reduced below 30 seconds at a particle size
comprised between 260 and 320 microns.
[0060] It must also be noted that the coffee origin(s),
the blend is made of, can also impact significantly on the
flow time. Therefore, for a same blend using same origin
(s), the invention provides a significant improvement of
the flow time.
5. Granulometry:
[0061] The particle size distribution (D4,3) and fines
level (F) were determined by laser diffraction using a
"Mastersizer S" instrument from Malvern® equipped with
a 1000mm optical lens. 1-2g of powder are dispersed in
1 litre of butanol and recirculated in front of the laser
beam in order to obtain an obscuration between 15 and
20%. The particle size distribution is obtained by Fraunhofer approximation of the diffraction pattern. The complete experiment is repeated 3 times (or until the StDev
< 5%) and the results are averaged.
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6. Sugar Test for crema measurements:
[0062] The mechanised sugar test device is composed
of a small sugar-containing silo. The prismatic V-shape
of this silo comprising a defined slit (2mm x 40mm) at the
bottom edge can create a uniform sugar curtain as long
as the slit is free and a minimum of sugar remains in the
silo. This silo can be moved horizontally, with controlled
speed (~40 mm/s) from one point "A" to a point "B" (distance between A and B is 20 cm). In the end position at
both points a baffle prevents the sugar from flowing out
if the device is in stand-by mode. When the silo is moved,
the sugar curtain is produced all the way between the
two points "A" and "B". The crema in a cup that is placed
at 60 mm below this path within the two points will be
toped with a uniform layer of sugar when the silo passes
over it. The chronograph is started when the sugar layer
is positioned on the foam’s layer. The amount of sugar
(a thickness of the layer to obtain a precise weight of 5
g of sugar) deposed in the cup is adjustable by varying
the speed of the silo or the dimensions of the slit. The
sugar is crystal sugar of D4,3 equal to 660 microns.
[0063] A precise waiting period (i.e., 10 sec. for long
cups) must be observed between the end of extraction
and the start of the sugar test.
[0064] The sugar layer remains some time on top of
the crema. Later, when the main part of the sugar sinks
suddenly the observing operator must stop the chronograph.
[0065] The "sugar test value" is the number of seconds
shown by the chronograph.
depending on the average particle size (D4,3)
within the following limits:
F is between 12 and 16% when D4,3 is
measured from 300 to 349 microns,
F is between 14 and 18 % when D4,3 is
measured from 250 to 299 microns,
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2.
Method according to claim 1, wherein the percentage
of fines (F) of the capsule for delivering a long coffee
extract is comprised between 12 and 14% when D4,3
is measured from 300 and 350 microns.
3.
Method according to any of the preceding claims,
wherein the pressure loss at the interface of the
membrane/engaging means is increased by selecting a membrane made of aluminium of a thickness
comprised between 26 and 40 microns.
20
4.
Method according to claim 3, wherein the pressure
loss at the interface of the membrane/engaging
means is increased by selecting a membrane of a
thickness of about 30 microns.
25
5.
Method according to any of the preceding claims,
wherein the level of fines is controlled by having coffee beans ground before the filling in the capsule
using a grinder comprising at least one pair of radially
corrugated rolls in the fine grinding section.
6.
Method according to claim 5, wherein coffee is
ground using only radially corrugated rolls.
7.
Method according to claim 6, wherein coffee is
ground using between 4 to 6 stages of radially corrugated rolls.
8.
Method according to claim 6, wherein coffee is
ground using radially and axially corrugated rolls.
9.
Method according to any of the preceding claims,
wherein the extraction yield of the delivered coffee
extract is comprised between 15 and 30%.
10
15
30
Claims
35
1.
Method for delivering a long coffee extract from a
capsule containing ground coffee within a flow time
of less than 35 seconds per 110mL extract by injection of water under pressure within the capsule,
wherein the capsule is filled with ground coffee and
has a delivery membrane;
wherein the capsule is extracted in a coffee extraction device and pressurized water is injected in the
capsule under pressure;
wherein the coffee beverage is released through the
beverage delivery membrane of the capsule with engaging means engaging in and/or against the membrane,
wherein the pressure loss at the interface of the
membrane/engaging means is increased by selecting a membrane of a puncture resistance of between
1.1 and 3.5 mJ,
characterized in that:
the pressure loss is reduced in the coffee bed
by providing in the capsule coffee ground having
an average particle size of less than 350 microns, and a controlled percentage of fines (F)
12
40
45
50
10. Method according to claim 9, wherein the extraction
yield of the delivered coffee extract is comprised between 20 and 26%.
11. Method according to claim 10, wherein the total solids is comprised between 1.0 and 1.9% wt.
12. Method according to claim 11, wherein the total solids is comprised between 1.1 and 1.7% wt.
55
7
13. Method according to any of the preceding claims,
wherein the water pressure of extraction reaches a
value higher than 11 bar at the injection side in the
capsule.
13
EP 1 882 431 B1
Patentansprüche
1.
2.
Verfahren zur Ausgabe eines langen Kaffeeextrakts
aus einer gemahlenen Kaffee enthaltenden Kapsel
innerhalb einer Durchflusszeit von weniger als 35
Sekunden pro 110 ml Extrakt durch Einspritzen von
Wasser unter Druck in die Kapsel,
worin die Kapsel mit gemahlenem Kaffee gefüllt ist
und eine Ausgabemembran aufweist;
worin die Kapsel in einer Kaffeeextraktionsvorrichtung extrahiert wird und unter Druck gesetztes Wasser in die Kapsel unter Druck eingespritzt wird;
worin das Kaffeegetränk durch die Getränkeausgabemembran der Kapsel mit Eingreifmitteln, die in
und/oder gegen die Membran eingreifen, freigesetzt
wird,
worin der Druckverlust an der Grenzfläche Membran/Eingreifmittel erhöht wird, indem eine Membran
mit einer Durchstoßfestigkeit von zwischen 1,1 und
3,5 mJ gewählt wird,
dadurch gekennzeichnet,
dass der Druckverlust im Kaffeebett verringert wird,
indem in der Kapsel Kaffeemehl mit einer durchschnittlichen Teilchengröße von weniger als 350 Mikrometer vorgesehen wird und eine gesteuerte Prozentzahl feiner Teilchen (F) in Abhängigkeit der
durchschnittlichen Teilchengröße (D4,3) innerhalb
folgender Grenzen eingehalten wird:
5
4.
5.
7.
Verfahren nach Anspruch 6, worin der Kaffee unter
Anwendung von zwischen 4 bis 6 Phasen radialgeriffelter Walzen gemahlen wird.
8.
Verfahren nach Anspruch 6, worin der Kaffee unter
Anwendung radial- und axialgeriffelter Walzen gemahlen wird.
9.
Verfahren nach einem der vorangegangenen Ansprüche, worin die Extraktionsausbeute des aus gegebenen Kaffeeextrakts zwischen 15 und 30 % beträgt.
10. Verfahren nach Anspruch 9, worin die Extraktionsausbeute des ausgegebenen Kaffeeextrakts zwischen 20 und 26 % beträgt.
11. Verfahren nach Anspruch 10, worin die Gesamtfeststoffe zwischen 1,0 und 1,9 Gewichtsprozent betragen.
25
12. Verfahren nach Anspruch 11, worin die Gesamtfeststoffe zwischen 1,1 und 1,7 Gewichtsprozent betragen.
F ist zwischen 12 und 16 %, wenn für D4,3 300
bis 349 Mikrometer gemessen werden,
F ist zwischen 14 und 18 %, wenn für D4,3 250
bis 299 Mikrometer gemessen werden.
30
Verfahren nach Anspruch 1, worin die Prozentzahl
feiner Teilchen (F) der Kapsel zur Ausgabe eines
langen Kaffeeextrakts zwischen 12 und 14 % beträgt, wenn für D4,3 300 bis 350 Mikron gemessen
werden.
35
13. Verfahren nach einem der vorangegangenen Ansprüche, worin der Wasserextraktionsdruck höher
als 11 bar an der Einspritzstelle in der Kapsel erreicht.
Revendications
1.
Verfahren nach einen der vorangegangenen Ansprüche, worin der Druckverlust an der Grenzfläche
Membran/Eingreifmittel erhöht wird, indem eine
Membran aus Aluminium mit einer Dicke zwischen
26 und 40 Mikrometer gewählt wird.
45
Verfahren nach Anspruch 3, worin der Druckverlust
an der Grenzfläche Membran/Eingreifmittel erhöht
wird, indem eine Membran mit einer Dicke von etwa
30 Mikrometer gewählt wird.
50
Verfahren nach einem der vorangegangenen Ansprüche, wobei der Gehalt an feinen Teilchen gesteuert wird, indem man vor dem Füllen in die Kapsel
die Kaffeebohnen mahlt, wobei ein Mahlwerk, das
mindestens ein Paar radialgeriffelter Walzen aufweist, im Feinteilchenmahlbereich verwendet wird.
Verfahren nach Anspruch 5, worin der Kaffee unter
Anwendung von nur radialgeriffelten Walzen gemahlen wird.
15
40
3.
6.
10
20
14
55
8
Procédé de distribution d’un extrait de café long à
partir d’une capsule contenant du café moulu dans
un temps d’écoulement de moins de 35 secondes
par 110 mL d’extrait par injection d’eau sous pression dans la capsule,
où la capsule est remplie de café moulu et a une
membrane de distribution;
où la capsule est extraite dans un dispositif d’extraction de café et de l’eau pressurisée est injectée dans
la capsule sous pression;
où la boisson de café est libérée à travers la membrane de distribution de boisson de la capsule avec
des éléments d’engagement engageant dans et/ou
contre la membrane,
où la perte de pression à l’interface de la membrane/
éléments d’engagement est augmentée en sélectionnant une membrane ayant une résistance de perforation entre 1,1 et 3,5 mJ,
caractérisé en ce que
la perte de pression est réduite dans la couche de
café en pourvoyant dans la capsule du café moulu
15
EP 1 882 431 B1
ayant une taille moyenne de particules de moins de
350 microns, et un pourcentage contrôlé de fines (F)
qui dépend de la taille moyenne des particules (D4,3)
dans les limites suivantes:
totaux sont compris entre 1,1 et 1,7% en poids.
5
F est entre 12 et 16% quand D4,3 est mesurée
de 300 à 349 microns,
F est entre 14 et 18% quand D4,3 est mesurée
de 250 à 299 microns.
10
2.
Procédé selon la revendication 1, où le pourcentage
de fines (F) de la capsule pour distribution d’un extrait
de café long est compris entre 12 et 14% quand D4,3
est mesurée entre 300 et 350 microns.
3.
Procédé selon l’une quelconque des revendications
précédentes, où la perte de pression à l’interface de
la membrane/éléments d’engagement est augmentée en sélectionnant une membrane faite en aluminium d’une épaisseur comprise entre 26 et 40 microns.
15
4.
5.
Procédé selon la revendication 3, où la perte de pression à l’interface de la membrane/éléments d’engagement est augmentée en sélectionnant une membrane d’épaisseur d’environ 30 microns.
Procédé selon l’une quelconque des revendications
précédentes, où le taux de fines est contrôlé en ayant
des graines de café moulues avant le remplissage
dans la capsule en utilisant un moulin comprenant
au moins une paire de rouleaux ondulés radialement
dans la section de moulage des fines.
6.
Procédé selon la revendication 5, où le café est moulu en utilisant seulement des rouleaux ondulés radialement.
7.
Procédé selon la revendication 6, où le café est moulu en utilisant entre 4 et 6 sections de rouleaux ondulés radialement.
8.
9.
Procédé selon la revendication 6, où le café est moulu en utilisant des rouleaux ondulés radialement et
axialement.
20
25
30
35
40
45
Procédé selon l’une quelconque des revendications
précédentes, où le rendement d’extraction de l’extrait de café distribué est compris entre 15 et 30%.
50
10. Procédé selon la revendication 9, où le rendement
d’extraction de l’extrait de café distribué est compris
entre 20 et 26%.
11. Procédé selon la revendication 10, où les solides
totaux sont compris entre 1,0 et 1,9% en poids.
16
55
12. Procédé selon la revendication 11, où les solides
9
13. Procédé selon l’une quelconque des revendications
précédentes, où la pression d’extraction de l’eau atteint une valeur plus haute que 11 bar du côté d’injection dans la capsule.
EP 1 882 431 B1
10
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11
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12
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13
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REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European
patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be
excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description
•
EP 1566127 A2 [0005] [0034]
15