Note: Descriptions are shown in the official language in which they were submitted.
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-1-
SINGLE SERVE CAPSULE FOR IMPROVED EXTRACTION EFFICIENCY AND
FLAVOR RETENTION
BACKGROUND OF THE INVENTION
1. Field of the Invention
100011 The invention relates generally to improved single serve capsules,
and more
particularly to single serve capsules having improved extraction efficiency
and reduced
loss of flavor components.
2. Description of the Related Art
100021 In recent years single serve coffee capsules have become very
popular, due to the
offered convenience and flexibility. Consumers of single serve coffee capsules
have come
to appreciate the possibility of enjoying freshly brewed coffee of a preferred
flavor on the
spur of the moment.
100031 Manufacturers of coffee brewers for single serve coffee capsules
have uniformly
opted for short brewing times, typically less than 90 seconds, and frequently
60 seconds or
less, because market research shows that brewing times significantly longer
than 90
seconds are not accepted by the broad consumer population, as being an
anathema to the
convenience aspect of the on-demand single serve concept. However, short
brewing times
result in sub-optimal extraction of the ground roast coffee.
100041 The single serve approach lends itself well for espresso style
coffees, which are
traditionally prepared in single serve format, with relatively short brewing
times. The
espresso brewing process compensates for the short brewing time by using a
very fine
grind size (typically about 300 gm). Pressurized hot water at 8-10 bar is used
to force the
hot water through the compacted finely ground coffee. The resulting coffee is
very strong,
and has a characteristic taste profile that certain consumers dislike. The
strength can be,
and sometimes is reduced by dilution with hot water, but dilution does not
change the taste
profile.
100051 Many consumers prefer the more mellow taste of drip filter coffee
over the more
bitter taste of espresso style coffees. Single-serve capsules have been
developed that mimic
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-2-
the drip filter brewing process. These capsules contain ground roast coffee in
a first
chamber, and a second chamber that is empty. A filter medium separates the
second
chamber from the first chamber. During the brewing process hot water is
injected into the
first chamber. Brewed coffee is collected in the second chamber, and from
there it is
channeled to a beverage container, such as a cup or mug. The filter medium
prevents
coffee grounds from being entrained with the brewed coffee.
100061 In North America these filter style capsules are far more popular
than capsules for
espresso style coffees. Filter style capsules suffer from two important
drawbacks. Firstly,
the short brewing times used in single serve machines results in a sub-optimal
extraction of
the ground roast coffee. Secondly, the filter material, which typically is
made of paper,
removes and retains important flavor components from the brewed coffee.
[00071 The present invention addresses these problems by providing a single
serve
coffee capsule enabling improved extraction efficiency of ground roast coffee,
while
reducing the loss of flavor components through absorption by the filter
medium.
100081 Another aspect of the invention comprises a process for brewing
coffee using the
inventive capsule.
100091 Yet another aspect of the invention is brewed coffee produced by the
process of
the invention.
BRIEF SUMMARY OF THE INVENTION
100101 The invention relates to a single serve coffee capsule comprising a
first chamber
comprising ground roast coffee having an average particle size in the range of
from 300 to
800 gm; and a second chamber; said first chamber being separated from the
second
chamber by a filter medium made of a synthetic polymeric material.
[00111 Another aspect of the invention is a process of brewing coffee using
the single
serve coffee capsule of the invention, said process comprising passing hot
water through
the ground roast coffee during a brew time of from 20 to 90 seconds.
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-3-
100121 Yet another aspect of the invention is coffee produced by the
process of the
invention.
DRAWINGS
[00131 The drawings included herewith are for illustrating various examples
of articles,
methods, and apparatuses of the present specification and are not intended to
limit the
scope of what is taught in any way. For simplicity and clarity of
illustration, where
considered appropriate, reference numerals may be repeated among the drawings
to
indicate corresponding or analogous elements.
100141 Figure 1 is a sectional view of a single serve capsule in accordance
with the
present invention disposed in a schematic representation of a brew chamber for
a beverage
preparing machine;
100151 Figure 2 is enlarged schematic view of a section of filter for a
single serve
capsule in accordance with the present invention;
100161 Figure 3 is an enlarged schematic sectional view of a multi-
component fiber for
the filter shown in Figure 2; and
100171 Figure 4 is a sectional view of a single serve capsule in accordance
with the
present invention showing the multilayered material and the process for
forming the filter.
DETAILED DESCRIPTION OF THE INVENTION
100181 The following is a detailed description of the invention.
100191 In one aspect the invention provides a single serve capsule 10
comprising a body
12, filter 14, ingredients 16 and cover 18. Body 12, filter 14 and cover 18
are all formed of
food grade materials (meaning materials that are considered to be safe for
preparation of
food products). Body 12 and cover 18 are each formed of multilayered materials
that
include one or more barrier layers providing barriers against one or more
environmental
factors such as light, oxygen, and moisture.
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-4-
[0020] Body 12 includes a side wall 20 and an end wall 22 together defining
an interior
space 24. An opening 26 is defined at one end of body 12. A flange 28 extends
around the
perimeter of opening 26. End wall 22 includes an extraction region 32 adapted
for being
pierced by an extraction needle 34 of a beverage preparing machine 36.
[0021] Filter 14 is adapted to be disposed within body 12 to define at
least one
ingredients chamber 46 in an upper region of the interior space 24 for
receiving one or
more ingredients 16 and at least one extraction chamber 48 exterior to the
ingredients
chamber 46 in the interior space 24 for receiving beverage from the at least
one ingredients
chamber 46 prior to extraction using the extraction needle 34.
[0022] Filter 14 includes a gasket portion 50 that is adapted to be
disposed between
flange 28 and cover 18. Filter 14 also includes a filter portion 52 located
inwardly from
gasket portion 50 that is adapted to be molded to a desired shape for
filtering a beverage
from ingredients 16.
[0023] In an alternative embodiment (not shown), body 12 does not include a
side wall
20 and end wall 22 that define interior space 24. Body 12 instead comprises a
structure that
is adapted to support filter 14 and also support capsule 10 in beverage
preparing machine
36 without fully enclosing filter 14. The structure may comprise flange 28
either on its
own or in combination with a partial side wall 20.
[0024] Filter 14 may be secured to either the top of flange 28 (preferable)
or to side wall
20. Flange 28 may be sized to support capsule in beverage preparing machine
36. Cover 18
may be secured to flange 28, directly or over filter 14, as described herein.
[0025] Referring to Figures 2 and 3, filter 14 is formed of a moldable non-
woven fabric
70 having a basis weight in the range of 40 to 150 grams per square meter
(gsm) and more
preferably between 60 to 120 gsm.
[0026] Fabric 70 is comprised of filaments or fibers 72 (referred to as
fibers 72 hereafter)
having a single component (homo-component) or multiple components (multi-
component).
Multi-component fibers 72 may have components arranged in configurations such
as
islands-in-the-sea, sheath-core or segmented pie. Preferably, fibers 72
comprise two
components (bi-component) formed of a first material 74 and a second material
76. The bi-
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-5-
component fiber 72 may be arranged in an islands-in-the-sea configuration with
first
material 74 forming islands and second material 76 forming a sea as shown in
Figure 3. It
will be seen that multiple strands of first material 74 form islands within
the sea formed by
second material 76.
[0027] First material 74, preferably has a higher tensile strength than
second material 76
to provide sufficient integrity and strength to fabric 70. First material 74
also preferably
has a higher melt temperature than the melt temperature of second material 76.
First
material 74 also preferably has a higher melt temperature than the melt
temperature of the
sealing layer of body 12 and the sealing layer of cover 18.
[0028] This allows gasket portion 50 of filter to be secured to flange 28
and cover 18 by
way of a heat seal that melts second material 76 and the sealing layer of
flange 28 while
maintaining a web of first material 74 defining channels 78. Channels 78 are
adapted to
receive molten material from sealing layers for flange 28 and cover 18 during
heat sealing
to sandwich and seal gasket portion 50 of filter 14 between flange 28 and
cover 18.
[0029] First material 74 is preferably selected from polyamide (PA) such as
nylon,
polyethylene terephthalate (PET) and polyester such as polybutylene
terephthalate (PBT)
or polylactic acid (PLA). More preferably first material 74 is formed from
PBT. Second
material 76 is preferably selected from polyethylene (PE), polypropylene (PP)
and PA.
More preferably second material is formed from PE. It is preferable that first
material 74
comprises at least 50 % of the fibers 72 and more preferable that first
material 74
comprises at least 70% of the fibers 72.
[0030] Fabric 70 preferably comprises undrawn or partially drawn fibers 72
in order that
fibers 72 have the capability to be drawn sufficiently during the filter
molding process to
form a desired depth of filter 14. Fibers 72 may for instance be formed by
melting and
spinning selected polymers at low air drawing and/or low spinning speeds. It
is preferred
that a lower spinning speed is selected to optimize the amount of undrawn or
partially
drawn fibers.
[0031] Referring to Figure 4, an exploded sectional view of a single serve
capsule 10 in
accordance with the present invention is shown.
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-6-
[00321 Single serve capsule 10 includes body 12 formed of a conventional
multilayered
material MM1 that includes a barrier layer B1 preferably formed of ethylene
vinyl alcohol
(EVOH) and a sealing layer Si preferably formed of polyethylene (PE). As well,
body 12
may include outer base layer 01 preferably formed of polyolefin or polyester
or other
materials adapted to cover and protect barrier layer B.
[00331 Single serve capsule 10 further includes cover 18 formed of a
conventional
multilayered material MM2 that includes a barrier layer B2 preferably formed
of aluminum
foil or metalized polyester or EVOH and a sealing layer S2 preferably formed
of
polyolefin. As well, cover 18 may include an outer base layer 02 preferably
formed of
polyolefin or polyester and a graphics layer G2 preferably formed of ink.
100341 Filter 14 is formed by disposing fabric 70 over opening 26 of body
12. Gasket
portion 50 of filter 14 engages sealing layer Si disposed on the top surface
of flange 28
and filter portion 52 extends across opening 26. Gasket portion 50 is then
sealed with a
heat sealer (not shown) to sealing layer Si disposed on the top surface of
flange 28. A
portion of the sealing layer Si on top surface of flange 28 and a portion of
second material
76 of fabric 70 is melted by heat sealer and flows into channels 78 within
gasket portion 50
of fabric 70. Once the melted material sufficiently cools to support gasket
portion 50 on
flange 28, then filter 14 may be molded for instance by engaging filter
portion 52 using a
heated mandrel (not shown) to mold filter portion 52 to a desired shape within
interior
space of body 12 to form the ingredients chamber 46. Then ingredients 16 are
disposed
within ingredients chamber 46 of filter 14 and cover 18 is positioned over
gasket portion
50 to cover opening 26.
100351 Cover 18 may then be partially sealed to gasket portion 50 using a
heat sealer. A
portion of the sealing layer S2 on bottom surface of cover 18 and a portion of
second
material 76 of fabric 70 is melted by heat sealer (not shown) and flows into
channels 78 of
gasket portion 50. The air within interior space 24 of capsule 10 may then be
evacuated
and replaced with an inert gas such as nitrogen. Cover 18 may then be fully
sealed to body
12 over gasket portion 50 to seal the interior space 24 of capsule 10. In
particular, cover 18
may be heated to the melt temperature of sealing layer S so that the material
of sealing
layer S2 and second material 76 of fabric 70 at least partially flows into
channels 78 of
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-7-
gasket portion 50 to form a seal upon cooling. Fibers 72 may be bonded
together
mechanically, thermally or chemically. Preferably, fibers 72 are mechanically
bonded
through hydroentanglement or needle punching. More preferably, fibers 72 are
mechanically bonded through hydroentanglement.
100361 In one aspect, a single serve coffee capsule 10 is provided with a
first chamber 46
comprising ground roast coffee having an average particle size in the range of
from 300 to
800 tim. First chamber 46 being separated from the second chamber 48 by a
filter medium
14 made of a synthetic polymeric material.
[00371 The invention addresses the flavor deficiencies of prior art filter
style single serve
coffee capsules in two ways: (i) by optimizing the extraction process; and
(ii) by
minimizing the loss of flavor components through absorption by the filter
medium.
100381 With at least about 800 flavor components present in roast ground
coffee, the
flavor profile of coffee is far from completely understood. But a few general
rules can be
stated nevertheless. The world's most important coffee species are Arabica and
Robusta.
Of the two, Arabica is considered having the fuller and more pleasant flavor
profile. Coffee
beans contain a significant amount of lipids; 15-18% in the case of Arabica; 8-
12% in the
case of Robusta.
100391 Many components of the lipids fraction are flavor components in
their own right.
The roasting process contributes to the flavor profile by chemical conversion
of such
components, for example esterification. Other, more volatile flavor components
are not
part of the lipid fraction, but are soluble in the lipid fraction.
100401 Brewing coffee involves extraction of flavor and other components
from ground
roast coffee, using hot water as the extractant liquid. The water temperature
is generally in
the range of 85 to 100 C, more typically between 90 and 95 C. This
temperature is high
enough for the water to extract a major portion of the lipids from the ground
roast coffee.
The lipids in the brewed coffee contribute to the flavor experience in three
distinct ways.
Firstly, the lipids play a major role in defining the mouth feel and texture
of the brewed
coffee. Secondly, many of the lipids, in particular the esters, are flavor
components in their
own right. Thirdly, the lipids act as a solvent for many of the coffee flavor
components,
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-8-
thereby aiding in the extraction of these components from the ground roast
coffee, and
preventing their premature evaporation from the brewed coffee. From this
perspective it is
not surprising that Arabica, which has the higher lipid content, is also the
more flavorful.
[00411 The extractable solids of ground roast coffee are defined as all non-
volatile
components of the ground roast coffee that can be removed by extraction. This
term
includes the non-volatile lipids. Many of the extractable solids can be
extracted with hot
water, although some require extensive boiling in water to become extracted.
Yet other
extractible solids require an organic solvent, such as hexane, for extraction.
Some of the
more difficultly extracted components impart unpleasant flavors, such as
bitter notes and
astringent notes, to the brewed coffee.
100421 The maximum amount of solids in roast coffee that can be dissolved
in water is
about 30%. For the best coffee flavor the extraction should be sufficient to
capture all the
desirable flavor components in the brewed coffee, yet should be gentle enough
to avoid
over-extraction of the unpleasant bitter and astringent flavor components. It
has been found
that the best flavor profile of the brewed coffee is obtained in a brewing
process whereby
from 18 to 22% of the solids are extracted from the ground roast coffee.
Extraction within
this range will be referred to as "optimum extraction." Extraction resulting
in less than
18% of the extractible solids being extracted will be referred to as
"underdeveloped."
Extraction resulting in more than 22% of the extractible solids being
extracted will be
referred to as "over extraction." Together with the amount of water used to
extract the
coffee solids, the coffee strength, which is the ratio of dissolved coffee
solids to water in
the finished coffee, need to be optimal (1.0-1.5%) in order to achieve a
good/gold cup of
coffee with the optimum balance of strength and extraction.
[0043j In the context of filter style single serve coffee capsules it is
difficult to
accomplish extraction within the optimum range because the brewing times are
kept short
for reasons of, real or perceived, consumer preference. The present invention
optimizes
extraction efficiency by using ground roast coffee having an average particle
size in the
range of from 300 to 800 gm. Preferably the average particle size is in the
range of 400 to
600 gm.
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-9-
[0044] Desirably the ground roast coffee has a narrow particle size
distribution, with at
least ¨ 80% of the particles having a particle size within two standard
deviations of the
average particle size. The preferred ground coffee particle size is designed
to work with the
selected filter and limited brew time to maximize a desirable extraction ¨ if
coffee is too
fine, over extraction is readily induced while under optimal extraction occurs
if coffee is
too coarse.
[0045] It will be understood that an optimized particle size within the
ranges defined
herein does not necessarily result in optimum extraction. Other factors, such
as water
temperature, water hardness, and the like also play a role. The optimized
particle
size/distribution in any event moves the extraction process closer to the
optimum, and
thereby contributes to the flavor of the brewed coffee.
10046] It has been found that the pore size of the filter medium also
contributes to the
extraction efficiency. Preferred are filter media having an average pore size
in the range of
from 50 to 100 p.m.
[0047] The coffee dosage is also critical in order to achieve gold standard
cup based on
preferred strength, cup size and extraction level.
100481 According to consumers' preference on brew strength, the ideal
coffee dosage is
determined through the following equation (the calculation is based on a
determined
brewing system, i.e., water temperature, pressure, volume, and dispensing
pattern are
fixed):
-1) Xs
x= ____________________________________________
[00491 Here, x is the dosage level, v is brew volume, s is preferred total
dissolved solid
strength, and e is the extraction yield.
[00501 Yet another important variable for extraction efficiency is the
ratio of the surface
area, A, of the filter medium, and the weight W of the ground roast coffee
contained in the
capsule. Preferably the ratio A/W is in the range of 1 to 10 cm2/g, more
preferably from 3
to 7 cm2/g.
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-10-
[00511 Many of the advantages of an optimized extraction efficiency are
lost if major
flavor components are subsequently lost from the brewed coffee. It has been
found that
paper, which is commonly used as filter medium in filter style single serve
coffee capsules,
acts to remove and/or retain a significant portion of the flavor components
from the brewed
coffee due to the high absorbing capability of cellulose fibers and the
relative large filter
surface area compared to the packed coffee weight in a single capsule. The
pores with filter
paper becomes smaller as well especially with expanded cellulose fibers in hot
water,
which stops desirable molecules including flavor compounds and lipids from
passing
through the filter. This is, in fact surprising. Although it has been known
for some time that
filter paper is capable of removing coffee components by absorption, the
impact of filter
paper on the flavor of single serve coffee has been misunderstood and
underappreciated.
[00521 This point is illustrated by the disclosures of US Patent
Application Publication
2005/0051478 to Karanikos et al. This patent application, which is assigned to
North
America's leading manufacturer of single serve coffee capsules, seeks to
increase the
flavor impact of the brewed coffee by using a pleated paper filter instead of
a smooth paper
filter. Of course, the use of a pleated filter increases the amount of paper,
resulting in an
increased loss of flavor components through absorption.
100531 The capsule 10 of the present invention uses a filter medium 14 made
of a
synthetic polymeric material. It has been found that brewed coffee made with a
capsule 10
of the invention contains on average 100% more lipid than brewed coffee made
with a
comparable capsule containing a conventional paper filter.
100541 The filter medium 14 can be any type of porous structure. Non-
limiting examples
include: a nonwoven web of synthetic fibers; a molded filter basket; a cage of
structurally
rigid material, covered with a porous polymer web or file; and the like. Any
food grade
polymer material can be used for the filter medium 14. Preferred materials
include
polyolefin fibers; polyester fibers, polyamide fibers, and combinations of
aforementioned
fibers. The fiber here is a generic term which can be short fibers (fibers) or
long fibers
(filaments). The filter medium can also be a continuous polymeric sheet/film
with
perforated holes. Preferred materials also include polyolefin, polyamide and
polyester. The
synthetic filter material is also preferred more hydrophobic than cellulose
fibers, through
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-11-
which the filter creates more resistance or back pressure to extractant water.
Therefore,
more turbulence is generated in a capsule that allows more uniform and
efficient
extraction.
[0055] The filter medium 14 is particularly suitable for the preparation of
beverages and
other liquid food items, such as sauces and soups. In general, the filter
medium 14 serves
to retain solid food items from which flavor components; natural colorants;
and/or
nutritional components are extracted by a liquid. The liquid can be water, in
particular hot
water. It is also possible to use ethanol as the extracting liquid in the
preparation of
flavored alcoholic beverages.
[0056] There is no limit to the type of solid items from which components
can be
extracted. Examples for beverage preparation include tea leaves, tea cuts and
ground roast
coffee. Examples for food item preparation include dried vegetables, such as
onions,
garlic, carrots, or the like, for the preparation of soups or broths; solid
preparations
containing food additives, such as vitamins or so-called nutritionals, for the
preparation of
fortified liquid food items; and pharmaceutically active materials. For
example, the filter
medium 14 can contain cold medication, such as aspirin and ephedrine,
optionally fortified
with vitamin C, for the preparation of a hot drink for use in battling the
symptoms of the
common cold.
[0057] Another aspect of the invention is a process for brewing coffee
using the single
serve coffee capsule of the invention, said process comprising passing hot
water through
the ground roast coffee during a brew time of from 20 to 90 seconds. It will
be understood
that larger brew sizes require longer brewing times. The brew time is not a
critical portion
of this invention, as it is governed by taste preferences, local habits,
available brewing
equipment and the like.
100581 It should be noted that the process can be carried out with a
conventional single
serve brewing apparatus as available on the market for filter style single
serve coffee. The
advantages of the present invention can be achieved without requiring a change
in
consumer habits or any modification to standard brewing equipment.
100591 Preferably the hot water temperature is in the range of from 90 to
95 C.
CA 02902231 2015-08-24
WO 2014/127467
PCT/CA2014/000147
-12-
100601 In an embodiment the process results in extraction of 18 to 22% of
the extractible
solids from the ground roast coffee.
100611 In an embodiment the process results in a brewed coffee that meets
the
international standard for brewed coffee known as the SCAA Gold Cup Standard.
100621 Another aspect of the invention is brewed coffee produced by the
process of the
invention.
Example
100631 Several batches of coffee were brewed, using a commercially
available single-
serve coffee maker (Keurig B150). In each test a side-by-side comparison was
made
between a capsule having a filter made of paper, and a capsule made of a
nonwoven web of
polyolefin/polyester composite fibers. The brew sizes were varied between
tests, but kept
constant within each test run so as to provide comparisons having the filter
material as the
only variable.
100641 Samples of brewed coffee were analyzed for fat content by two
different
methods.
A. Total Fat
100651 A sample of brewed coffee is extracted with an organic solvent, such
as n-hexane.
After extraction the two phases are allowed to separate, after which the
organic phase is
collected. The organic solvent is evaporated, and the resulting residue is
weighed. The
result is reported as grams per 100 grams of brewed coffee. It will be
recognized that the
weighed residue may contain components that are soluble in the organic
solvent, but are
not "fats" in the scientific meaning of this term.
B GC Fat
100661 A sample of brewed coffee is injected into a gas chromatograph
("GC").
Components of the brewed coffee travel through a packed column in the gas
chromatograph at different speeds, as a result of differences in volatility
and differences in
affinities to the column material. Coffee components leaving the column are
detected by a
detector located at the outlet of the column. This method permits qualitative
analysis of the
CA 02902231 2015-08-24
-13-
[00011 various components of the brewed coffee, based on their
retention times within
the column, and quantitative analysis of each component based on the
integrated detection
signal for each component.
100021 It will be recognized that GC Fat analyzes fats that are
true fats, and that are
sufficiently volatile to be analyzable in a gas chromatograph. As a
consequence the number
for "GC Fat" should be expected to be lower than the number for "Total Fat".
Also, the
number for "GC Fat" is believed to provide a better correlation to flavor
components than
does "Total Fat."
100031 Table 1 provides side-by-side comparisons of the fat
contents of brewed coffee
samples (fat contents are in g/100g):
[00041 Table 1
SAMPLE TOTAL GC FAT FILTER MATERIAL
FAT
j
12F46498-1 0.10 0.01 Paper
12F46498-2 0.15 0.02 Nonwoven
12F46498-3 0.18 0.01 Paper
12F46498-4 0.29 0.02 Nonwoven
100051 Sample 12F46498-1 contains more Total Fat and more GC
Fat than sample
12F46498-2. Sample 121746498-3 contains more Total Fat and more GC Fat than
sample
12F46498-4. Both samples brewed with a nonwoven polyolefin/polyester filter
contain
more GC Fat than the samples brewed with a conventional paper filter.
100061 The scope of the claims should not be limited by the
preferred embodiments set
forth in the examples, but should be given the broadest interpretation
consistent with the
description as a whole.
I
