U.S. patent application number 13/979884 was filed with the patent office on 2014-03-20 for method for producing coffee extract.
This patent application is currently assigned to SUNTORY BEVERAGE & FOOD LIMITED. The applicant listed for this patent is Hiroki Furuta, Morio Mitsuhashi, Makoto Nakajima, Yoshihiro Nakao, Kitaro Oka, Chiseko Sakuma, Hiroaki Shimizu, Yoshiaki Yokoo. Invention is credited to Hiroki Furuta, Morio Mitsuhashi, Makoto Nakajima, Yoshihiro Nakao, Kitaro Oka, Chiseko Sakuma, Hiroaki Shimizu, Yoshiaki Yokoo.
Application Number | 20140079855 13/979884 |
Document ID | / |
Family ID | 44592214 |
Filed Date | 2014-03-20 |
United States Patent
Application |
20140079855 |
Kind Code |
A1 |
Yokoo; Yoshiaki ; et
al. |
March 20, 2014 |
METHOD FOR PRODUCING COFFEE EXTRACT
Abstract
A method for manufacturing a coffee extract is provided which
method enables flavor ingredients of coffee to be extracted
separately from bitter ingredients. A coffee extract is obtained by
a method including a) a step of placing coffee granules in a
granule container part substantially sealed by a restraining
member, b) a step of guiding an extraction solvent from a first
direction into the granule container part for extraction, and c) a
step of retrieving, from the first direction, a coffee extract
stored in the granule container part.
Inventors: |
Yokoo; Yoshiaki;
(Kawasaki-shi, JP) ; Nakao; Yoshihiro;
(Kawasaki-shi, JP) ; Furuta; Hiroki;
(Kawasaki-shi, JP) ; Nakajima; Makoto;
(Kawasaki-shi, JP) ; Shimizu; Hiroaki;
(Kawasaki-shi, JP) ; Mitsuhashi; Morio;
(Atsugi-shi, JP) ; Oka; Kitaro; (Ohta-ku, JP)
; Sakuma; Chiseko; (Inagi-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Yokoo; Yoshiaki
Nakao; Yoshihiro
Furuta; Hiroki
Nakajima; Makoto
Shimizu; Hiroaki
Mitsuhashi; Morio
Oka; Kitaro
Sakuma; Chiseko |
Kawasaki-shi
Kawasaki-shi
Kawasaki-shi
Kawasaki-shi
Kawasaki-shi
Atsugi-shi
Ohta-ku
Inagi-shi |
|
JP
JP
JP
JP
JP
JP
JP
JP |
|
|
Assignee: |
SUNTORY BEVERAGE & FOOD
LIMITED
Tokyo
JP
|
Family ID: |
44592214 |
Appl. No.: |
13/979884 |
Filed: |
August 1, 2011 |
PCT Filed: |
August 1, 2011 |
PCT NO: |
PCT/JP2011/067625 |
371 Date: |
December 6, 2013 |
Current U.S.
Class: |
426/432 |
Current CPC
Class: |
A23F 5/262 20130101;
B65D 85/8043 20130101; A47J 31/407 20130101; A47J 31/44
20130101 |
Class at
Publication: |
426/432 |
International
Class: |
A23F 5/26 20060101
A23F005/26 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 17, 2011 |
JP |
2011-007366 |
Claims
1. A method for manufacturing a coffee extract, the method
comprising: a) a step of placing coffee granules in a granule
container part substantially sealed by a restraining member; b) a
step of guiding an extraction solvent from a first direction into
the granule container part for extraction; and c) a step of
retrieving, from the first direction, a coffee extract stored in
the granule container part.
2. The method according to claim 1, wherein, in step c), the coffee
extract is retrieved by guiding water from a second direction
opposite to the first direction.
3. The method according to claim 1, wherein, in step c), the coffee
extract is retrieved in such a manner that an extraction rate is
20% or less.
4. The method according to claim 1, wherein the restraining member
is a mesh member.
5. The method according to claim 1, wherein the coffee granules are
accommodated so as to accumulate in such a manner that the coffee
granules have a substantially rectangular cross-sectional shape in
a direction along an axis.
6. The method according to claim 1, wherein the restraining member
is positioned in abutting contact with or in close proximity to a
surface of deposited layers of the coffee granules which is
opposite to the first direction.
7. The method according to claim 1, wherein the first direction is
on a lower side of the deposited layers of the coffee granules.
8. The method according to claim 1, wherein, in step b), the
extraction solvent is injected up to a position substantially
aligning with a top surface of the deposited layers of coffee
granules.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for manufacturing
a coffee extract, in which excessive scorched bitterness involved
in the roasting of coffee beans is reduced.
BACKGROUND ART
[0002] Commonly coffee beverages include coffee extracts extracted,
using hot water or water, from granules into which roasted coffee
beans are ground (hereinafter referred to as coffee granules). The
coffee beverage is known to contain more than 300 types of flavor
ingredients and about 10 types of nutrient ingredients and serves
not only as a tasty beverage but also as a beverage with nutrient
function claims. Thus, obtaining a coffee extract liquid with an
excellent flavor is important for continuing to drink coffee
beverages in everyday life for a long period.
[0003] A concentrated coffee extract is known as a coffee extract
with an excellent flavor. The concentrated coffee extract refers to
the first several thick droplets of coffee during extraction. It
has been reported that the concentrated coffee extract is a thick
and flavory coffee liquid which gives a thick texture on the tongue
and which has an excellent aftertaste that disappears cleanly and
that the best coffee is obtained by making the most of the
attractive characteristics of the concentrated coffee extract (see
Non-Patent Literature 1).
[0004] In general, methods for extracting coffee are roughly
classified into a filtering method (drip type), a steeping method
(stirring or boiling type), and an espresso method (vaporization
type). For each of the extraction methods, various methods for
obtaining a coffee extract with an excellent flavor have been
proposed. For example, a steeping method (see Non-Patent Literature
2) involves limiting the amount of hot water and leaving a coffee
extract unchanged for a specific time, and a method involves
filling coffee granules into a glass pipe with opposite ends
thereof open and slowly dripping cool water in a glass container
into the glass pipe from above to collect eluate in the glass
container over a long time (this type of coffee is called Dutch
Coffee, cold-brew coffee, or drip coffee).
[0005] Furthermore, methods have been reported which suppress
extraction of offensive ingredients to improve the flavor of the
coffee extract. For example, a method involves filling coffee
granules into an extractor, injecting hot water into the extractor
from below the extractor, mixing the coffee granules with the hot
water, and then allowing a coffee extract to flow out from the
bottom of the extractor. This method has been disclosed to
sufficiently stir and mix the coffee granules and the extraction
solvent (hot water), enabling a reduction in time needed for
extraction and thus a reduction in offensive ingredients such as
harshness or astringency in a coffee bean which have been eluted in
the extract liquid as a result of the long extraction (see Patent
Literatures 1 and 2).
[0006] Moreover, methods for selectively removing offensive
ingredients to improve the flavor of the coffee extract have also
been reported. For example, a method involves selectively adsorbing
and removing macromolecular brown-black ingredients such as
chlorogenic acid polymers which make the coffee extract astringent,
utilizing, as an adsorbent, activated carbon with an average pore
radius distributed in the neighborhood of 30 to 100 .ANG. (Patent
Literature 3). Another method involves mixing an oxygen treatment
with an adsorption treatment with activated carbon, PVPP, activated
white earth or the like to reduce the bitterness and astringency of
tannin, caffeine, or the like (Patent Literature 4).
[0007] On the other hand, it is known that roasting coffee beans
allows a honeycomb structure to be formed. Partition walls of the
honeycomb structure have been reported to have a large surface area
comparable to the surface area of a porous gel and thus to have an
ingredient adsorptive capacity (see Non-Patent Literature 3).
CITATION LIST
Patent Literature
[0008] Patent Literature 1: Japanese Patent Laid-Open No. 01-148152
[0009] Patent Literature 2: Japanese Patent Laid-Open No.
2004-16586 [0010] Patent Literature 3: Japanese Patent No. 2578316
[0011] Patent Literature 4: Japanese Patent Laid-Open No.
2003-310162
Non-Patent Literature
[0011] [0012] Non-Patent Literature 1: Yukio Hirose et al.,
Kohigaku Kougi (Lecture on Science of Coffee), Ningen No Kagakusha
(Tokyo), 2003 [0013] Non-Patent Literature 2: Makoto Takagi,
Kohibunka Kenkyu (Study of Coffee Culture), 15, pp. 113-134, 2008
[0014] Non-Patent Literature 3: M. R. Jisha, et al., Mater. Chem.
Phys., 115, pp. 33-39, 2009
SUMMARY OF INVENTION
Technical Problem
[0015] Attempts have conventionally been made to reduce bitterness
and astringency, which are offensive ingredients. However, in some
cases, bitterness is successfully sufficiently removed, whereas
astringency fails to be sufficiently removed, or in other cases,
both bitterness and astringency are successfully removed but a rich
fragrance, a flavor, and a rich taste unique to coffee are
simultaneously removed to degrade the flavor of the coffee extract
itself.
[0016] An object of the present invention is to provide a method
for manufacturing a coffee extract which method allows a selective
reduction in an excessively bitter taste with preferable flavor
ingredients of coffee unchanged. Another object of the present
invention is to provide a method for manufacturing a coffee extract
with an excellent flavor for which excessive bitterness and
astringency are selectively reduced with preferable flavor
ingredients of coffee unchanged.
Solution to Problem
[0017] As is known with the concentrated coffee extract, the
surface of roasted beans has more aroma ingredients than the
interior of the roasted coffee beans, thus allowing a flavory
extract liquid to be efficiently obtained with a small amount of
extract. However, bitter ingredients produced during the final
stage of roasting are adsorbed on the outermost surface of the
coffee beans. Thus, an extract liquid of the surface of the roasted
beans gives an excessively bitter taste (sometimes referred to as
"scorched bitterness"), and thus, obtaining a coffee extract with
acidity, bitterness, and rich taste balanced is difficult.
[0018] The present inventors have earnestly studied methods for
selectively removing scorched bitterness from an extract liquid of
the surface of roasted beans, as methods for solving the
above-described problem. As a result, the present inventors have
found that the ingredients which show scorched bitterness has a
strong affinity for partition walls of the honeycomb structure of
the coffee beans. The present inventors have further found that a
coffee extract can be obtained by utilizing the affinity to adsorb
the scorched bitter ingredient on the partition walls of the coffee
beans to separate the scorched bitter ingredient by placing coffee
granules in a granule container part substantially sealed by a
restraining member and passing an extraction solvent through a
layer of accumulated coffee granules in such a manner that the
extraction solvent reciprocates through the layer. Thus, the
present invention has been completed. That is, the present
invention relates to the following.
1. A method for manufacturing a coffee extract, the method
including:
[0019] a) a step of placing coffee granules in a granule container
part substantially sealed by a restraining member;
[0020] b) a step of guiding an extraction solvent from a first
direction into the granule container part for extraction; and
[0021] c) a step of retrieving, from the first direction, a coffee
extract stored in the granule container part.
2. The method set forth in 1, wherein, in step c), the coffee
extract is retrieved by guiding water from a second direction
opposite to the first direction. 3. The method set forth in 1 or 2,
wherein, in step c), the extract liquid is retrieved in such a
manner that an extraction rate is 20% or less. 4. The method set
forth in any one of 1 to 3, wherein the restraining member is a
mesh member. 5. The method set forth in any one of 1 to 4, wherein
the coffee granules are accommodated so as to accumulate in such a
manner that the coffee granules have a substantially rectangular
cross-sectional shape in a direction along an axis. 6. The method
set forth in any one of 1 to 5, wherein the restraining member is
positioned in abutting contact with or in close proximity to a
surface of deposited layers of the coffee granules which is
opposite to the first direction. 7. The method set forth in any one
of 1 to 6, wherein the first direction is on a lower side of the
deposited layers of the coffee granules. 8. The method set forth in
any one of 1 to 7, wherein, in step b), the extraction solvent is
injected up to a position substantially aligning with a top surface
of the deposited layers of coffee granules.
Advantageous Effects of Invention
[0022] The method for manufacturing according to the present
invention allows easy obtainment of a coffee extract with a very
excellent flavor (particularly a coffee extract of the surface of
roasted beans) with the flavor and rich taste of coffee maintained
and with only the excessively bitter taste of coffee reduced. Thus,
for example, unprecedented coffee can be manufactured which has a
clean finish and significantly exhibits the characteristics of
coffee beans themselves even if the coffee is as thick as or
thicker than espresso. Furthermore, the coffee extract obtained by
the method for manufacturing according to the present invention has
the advantages of being clear and having high preservation
stability.
BRIEF DESCRIPTION OF DRAWINGS
[0023] FIG. 1 is a conceptual drawing of behavior of ingredients in
a method for manufacturing according to the present invention.
[0024] FIG. 2 is a diagram showing an example of an extraction
device that can be used for a method for manufacturing according to
the present invention (coffee extraction device 1).
[0025] FIG. 3 is a diagram showing a circular filter with a
diameter of 45 mm (FIG. 3A) and a restraining member 11 (FIG.
3B).
[0026] FIG. 4 is a diagram showing a mode in which deposited layers
of coffee granules M is wholly covered with a nonwoven cloth that
is the restraining member, that is, a granule container part 2 with
a bag-shaped restraining member.
[0027] FIG. 5 is a diagram of a case where the restraining member
11 is in the form of a lid member.
[0028] FIG. 6 is a diagram of a coffee extraction device 1 which is
similar to the coffee extraction device in FIG. 2 and which
includes an opening 2A formed at an upper end of the granule
container part 2 which end corresponds to a direction opposite to a
first direction and a conduit channel 5' connected to the opening
2A to guide water to the opening 2A.
[0029] FIG. 7 is a diagram illustrating a coffee extraction device
used in Test Example 1.
[0030] FIG. 8 is a diagram illustrating the coffee extraction
device used in Test Example 1.
[0031] FIG. 9 is a diagram illustrating a coffee extraction device
used in Example 4.
[0032] FIG. 10 is a diagram in which the logarithms of the relative
concentrations of ingredients are plotted for each fraction.
[0033] FIG. 11 is a diagram showing the results of analysis of
caffeine.
[0034] FIG. 12 is a diagram showing the results of analysis of
chlorogenic acid.
[0035] FIG. 13 is a diagram showing the results of measurement of
turbidity using extracts obtained using a CC method, a CD method,
and a PD method.
DESCRIPTION OF EMBODIMENTS
[0036] When coffee beans are roasted, moisture is evaporated from
the coffee beans. The internal cell tissues of the coffee beans are
hollowed to have a honeycomb structure. Carbon dioxide, aroma
ingredients, taste ingredients (water-soluble taste ingredients),
and the like in coffee are adsorbed on the protruding and recessed
surfaces (partition walls) of the hollowed cell membranes.
According to the present method for manufacturing, a small amount
of extraction solvent is passed through the aroma ingredients and
taste ingredients (water-soluble taste ingredients and bitter
ingredients) adsorbed on the surface of the honeycomb structure, to
temporarily desorb the aroma ingredients and the taste ingredients
to expose the surface of the honeycomb structure. Scorched bitter
ingredients, included in the desorbed ingredients, are then
selectively caught (resorbed) and thus removed in a separable
manner. The greatest characteristic of the method for manufacturing
according to the present invention is that roasted coffee beans
with the surface of the honeycomb structure exposed are utilized as
an adsorbent.
[0037] The present invention consecutively carries out a step of
exposing the surface of the honeycomb structure and a step of
adsorbing scorched bitterness on the exposed honeycomb structure
without the need for a cumbersome operation. Specifically, the
present invention adopts a method of passing an extraction solvent
through a layer of coffee granules packed (fixed) in a
substantially sealed manner so that the extraction solvent
reciprocates through the layer. When coming into the first contact
with the coffee granules (forward path), the extraction solvent
temporarily desorbs the aroma ingredients and taste ingredients
(water-soluble taste ingredients and bitter ingredients) adsorbed
on the surface of the honeycomb structure to expose the surface of
the honeycomb structure. The extraction solvent containing the
desorbed ingredients is brought into contact with the coffee
granules with the surface of the honeycomb structure exposed to
selectively resorb only the bitter ingredients in the extraction
solvent (see FIG. 1).
[0038] The "reciprocation of the extraction solvent" as used herein
refers to the flow of the extraction solvent in which, for example,
the extraction solvent reciprocates in the direction of gravity or
a horizontal direction with respect to the layer of the coffee
granules, and means that the extraction solvent temporarily flows
in one direction and subsequently in the opposite direction. For
example, the reciprocation of the extraction solvent refers to the
flow of water (extraction solvent) in which if the extraction
solvent guided in to desorb the ingredients adsorbed on the
honeycomb structure flows in an antigravitational direction through
the coffee granule layer, an extract liquid of the surface of the
resultant roasted beans flows in the direction of gravity.
[0039] The method for manufacturing according to the present
invention will be described below in connection with specific
embodiments based on the drawings. However, the present invention
is not limited to these embodiments.
[0040] FIG. 2 shows a coffee extraction device 1 in a vertical
orientation. The coffee extraction device 1 includes a granule
container part 2 with an upper opening 2A formed at an upper end
thereof, a lower opening 2B (which serves both as an injection port
and as a takeout port) formed at a lower end thereof, and an
extraction section E storing coffee granules M, a lid member 3 that
can be freely installed on and removed from the upper opening 2A, a
conduit channel 8 that is in communication with the lower opening
2B in the granule container part 2, an extraction solvent tank 4, a
supply channel 5 that injects the extraction solvent from the
extraction solvent tank 4 into the lower opening 2B, and a liquid
feed channel 7 that transfers a coffee extract from the lower
opening 2B to a storage tank 6. The conduit channel 8 is connected
to the supply channel 5 and the liquid feed channel 7 by a
three-way valve 9.
[0041] (Step a)
[0042] When the apparatus shown in FIG. 2 is used, first, coffee
granules are placed in the extraction section E so as to be
substantially sealed by a restraining member according to the
present method for manufacturing. As described above, the present
invention utilizes roasted coffee beans with the surface of the
honeycomb structure exposed as an adsorbent. To make the most of
the effects of the adsorbent, it is important to accommodate coffee
granules in the granule container part in a substantially sealed
manner. The term "substantially sealed" as used herein refers to a
state in which, when the extraction solvent is passed through the
coffee granules, the coffee granules are prevented from moving
around inside the granule container part and means that the
deposited layers of the coffee granules are enclosed by walls of
the granule container part, a filter member, the lid member and the
like. In FIG. 2, a lower filter member 10 (first filter medium) is
installed on the lower side of the granule container part 2 (in a
first direction), coffee granules M are accommodated on an upper
surface of the lower filter member 10, and a restraining member
(second filter member) 11 is positioned in abutting contact with or
in close proximity to an opposite surface (uppermost surface) of
the deposited layers of the coffee granules M. That is, the coffee
granules M are accommodated in the extraction section E of the
granule container part 2 in a substantially sealed manner by a
right wall surface and a left wall surface present in a direction
along the axis of the granule container part 2, the lower filter
member 10, and the restraining member 11. In the specification, the
extraction section E corresponds to a portion of the coffee granule
container part 2 in which the coffee granules M are accommodated in
a substantially sealed manner, that is, the interior of an area
between the position of the lower filter member 10, provided at the
lower end position of the granule container part 2, and the
position of the restraining member 11, removably provided above the
lower filter member so as to internally contact the granule
container part 2.
[0043] The coffee granules M, an extraction material according to
the present invention, may be granules obtained by grinding roasted
coffee beans. A tree species grown for the coffee beans is not
particularly limited and may be, for example, an Arabica species or
a Robusta species. The method according to the present invention is
characterized by obtaining a coffee extract having a clean finish
even when the coffee is thick and exhibiting significant
characteristics, and using much of the Robusta species leads to an
excessively emphasized Robusta smell. Thus, particularly the
Arabica species is preferably used. Furthermore, the coffee brand
is not particularly limited and may be, for example, Mocha, Brazil,
Columbia, Guatemala, Blue Mountain, Kona, Mandheling, or
Kilimanjaro. A plurality of coffee brands may be blended together
to be used.
[0044] The degree of roasting (normally expressed as light roast,
medium roast, and extra roast in order of increasing degree of
roasting) is also not particularly limited. In general, coffee
beans roasted at the light level and at the extra level are known
to have the following features. Coffee beans roasted at the light
level fail to exhibit the rich characteristics of the coffee beans
themselves, and serve to reduce a scorched smell resulting from
roasting but are not heated up to the interior of the beans and
tend to give an unfavorable taste or an acid taste. Coffee beans
roasted at the extra level serve to increase a scorched smell on
the surface, but give a bitter taste which is unique to coffee and
which results from roasting as well as a spicy fragrance rising
therefrom, leading to an attractive flavor. The medium roast and
the extra roast are preferred because these types of roasts serve
to make the most of the characteristic of the present invention
that the present invention produces a coffee extract with scorched
bitterness restrained and significant characteristics exhibited. In
terms of an L value, the range from 15 to 24 is preferable, the
range from 16 to 22 is more preferable, and the range from 16 to 20
is particularly preferable. The L value is a numerical value for
the surface color of coffee granules into which roasted coffee
beans are ground and is indicative of lightness (0 is indicative of
black, and 100 is indicative of white). The L value of the coffee
granules can be measured using, for example, a color-difference
meter. The use of coffee beans roasted at the extra level also
advantageously improves the efficiency of extraction of nutrient
ingredients.
[0045] The degree of grind of roasted coffee beans (normally
classified into coarse grind, medium grind, fine grind and the
like) is not particularly limited, and ground beans with different
grain size distributions can be used. However, an excessively low
degree of grind is likely to cause the first filter member to be
clogged, increasing time needed for extraction to cause
over-extraction. Thus, in particular, the medium grind and/or the
coarse grind is a preferred aspect of the present invention. In
terms of average grain size after grind, the range from about 0.1
mm to about 2.0 mm is preferable, the range from about 0.5 mm to
about 2.0 mm is more preferable, and the range from about 1.0 mm to
about 1.5 mm is particularly preferable. The term "over-extraction"
as used herein refers to a phenomenon in which the extraction
solvent comes into excessive contact with the coffee granules to
extract an astringent taste and an unfavorable taste from inside
the coffee beans.
[0046] The first filter member is installed in order to prevent the
coffee granules from falling and mixing into the coffee extract.
Any filter member that meets this object may be used. Specific
examples of the first filter member may be mesh members such as a
metal mesh, a nonwoven cloth (e.g. flannel cloth or lint cloth),
and a paper filter. A filter member with an excessively small mesh
size is likely to be clogged, increasing time needed for extraction
to cause over-extraction. Thus, for a metal mesh, the mesh size is
preferably about 20 to about 200 in terms of American mesh size.
Furthermore, a nonwoven cloth is preferably used because the
nonwoven cloth can adsorb and remove oil contained in the coffee
extract.
[0047] In step b described below, the coffee granules M are
deposited and accommodated in the granule container part 2 shaped
to have an approximately uniform inner diameter in the advancing
direction (in FIG. 1, the antigravitational direction (down-up
direction)) of the extraction solvent so that the extraction
solvent comes into even contact with the coffee granules M. That
is, the coffee granules M are deposited in the form of a cylinder
or a rectangular parallelepiped (including a cubic) so as to have a
substantially rectangular cross-sectional shape in a direction
along the axis of the deposited layers of the coffee granules M.
The present invention utilizes the coffee granules as an adsorbent,
and the shape (the relation between the cross-sectional area and
the height) of the extraction section E is important in making the
most of the adsorption effect. Although depending on the
characteristics of the coffee granules such as the grain size, the
coffee granules M are generally preferably accommodated in the
extraction section E so that, in a substantially rectangular
cross-sectional shape in the direction along the axis of the
extraction section E, the ratio (H/L) of the width (L) to height
(H) of the rectangle is in the range of 0.1 to 10, preferably 2 to
6, and more preferably 3 to 6. Above these ranges, the extraction
may take much time or clogging may occur, leading to
over-extraction. Furthermore, below the ranges, the adsorption
effect of the present invention may not sufficiently be
produced.
[0048] In FIG. 2, the restraining member 11, removably positioned
above the lower filter member so as to internally contact the
granule container part 2, allows the coffee granules M to be
accommodated in a substantially sealed manner. Normally, during
coffee extraction, the coffee granules move around (flows) in
response to injection of the extraction solvent. For example, in
the drip extraction, the coffee granules float up close to the
liquid surface or move along the path through which the extraction
solvent is injected. In the steeping extraction, the coffee
granules float up close to the liquid surface or flow swiftly due
to natural convection or stirring. According to the present
invention, the restraining member 11 is positioned in abutting
contact with or in close proximity to the uppermost surface of the
coffee granules M to hold the coffee granules M in a substantially
sealed manner. This prevents the coffee granules from moving around
during extraction. The coffee granules prevented from moving around
enable the target bitter ingredient to be resorbed on the partition
walls of the exposed coffee honeycomb structure.
[0049] Thus, the material, shape, and the like of the restraining
member 11 are not particularly limited provided that the
restraining member 11 can hold the coffee granules M in a
substantially sealed manner and internally contact the granule
container part 2. An example of the restraining member may be a
mesh member (hereinafter sometimes referred to as a second filter
member) similar to mesh member of the first filter member. If a
mesh member is used restraining member, then preferably a
peripheral portion of the mesh member is formed of an elastic
material (for example, cotton flannel) and the restraining member
11 is brought into pressure contact with the inner surface of the
granule container part 2 to enhance the braking function (see FIG.
3). Furthermore, FIG. 4 shows a mode in which the whole deposited
layers of the coffee granules M are covered with a nonwoven cloth
serving as the restraining member, that is, the granule container
part 2 with a bag-shaped restraining member. In this mode, the
first filter member and the second filter member are not
distinguished from each other, and the restraining member functions
as the first filter member. Moreover, it is assumed that the
present invention includes a mode in which the restraining member
11 is in the form of a lid member as shown in FIG. 5.
[0050] The restraining member is positioned in abutting contact
with or in close proximity to the uppermost surface of the
deposited layers of the coffee granules M in a dry state so as to
substantially seal the coffee granules M. The position where the
restraining member 11 is in close proximity to the coffee granules
M refers to a position where, when the coffee granules M are wetted
with the extraction solvent, the restraining member is separated
from the uppermost surface of the deposited layers of the coffee
granules M by a distance corresponding to the amount of natural
bulging (void) of the coffee granules. Specifically, the position
refers to the interior of the area between the position where the
coffee granules are slightly compressed (so as to reduce the volume
of the coffee granules to about nine-tenths) and a position which
corresponds to the approximately doubled volume of the coffee
granules (preferably the original volume multiplied by about 1.5)
and which is used taking into account the bulging of the coffee
granules after contact with the extraction solvent.
[0051] (Step b)
[0052] Subsequently to step a described above, the extraction
solvent is guided into the extraction section E for extraction from
the first direction (step b). In the apparatus shown in FIG. 2, the
"first direction" as used herein is shown as the lower side of the
deposited layers of the coffee granules.
[0053] The present inventors have confirmed that the method for
manufacturing according to the present invention is effective in
reducing scorched bitterness at any temperature of the extraction
solvent. However, an elevated temperature of the extraction solvent
allows the rich fragrance, flavor, and rich taste unique to coffee
to be more appropriately extracted and also allows the rich
characteristics of coffee beans themselves to be more appropriately
exhibited. Thus, water at 15.degree. C. to 10.degree. C. or
preferably hot water at 50.degree. C. to 98.degree. C. is
preferably used as the extraction solvent. In particular, the
present inventors have confirmed that the use of hot water at
60.degree. C. to 95.degree. C. allows a coffee extract with a
strong odor and a sweet taste to be obtained.
[0054] In step b, water (preferably hot water) is brought into
contact with the coffee granules M placed in the granule container
part in a substantially sealed manner in step a) to temporarily
desorb the ingredients (aroma ingredients and taste ingredients
produced mainly during roasting) adsorbed on the partition walls of
the honeycomb structure of roasted coffee beans. Thus, the surfaces
of the partition walls of the honeycomb structure are exposed. That
is, preparation is made to carry out efficient separation of bitter
ingredients utilizing the coffee granules as an adsorbent, which is
characteristic of the present invention.
[0055] Any amount of extraction solvent may be passed in step b
provided that the amount enables the ingredients adsorbed on the
partition walls of the honeycomb structure to be temporarily
desorbed. The amount is equal to the volume of the coffee granules
M multiplied by about 0.3 to about 2 or preferably about 0.5 to
about 1.5 or is more preferably such that the extraction solvent is
injected substantially up to the upper surface of the deposited
layers of the coffee granules M. In step b, the use of a small
amount of extraction solvent can produce an extract liquid of the
surface of the roasted beans having rich aroma ingredients and rich
taste ingredients. Feeding an amount of extraction solvent
exceeding the above-described range may reduce the efficiency with
which scorched bitter ingredients are separated in step c described
below or may cause an unfavorable taste to be extracted from inside
the coffee beans to degrade the flavor of the extract. The amount
of extraction solvent injected may be controlled by a level gauge
provided in the granule container part or calculated from the
volume of the coffee granule layer. An example of a calculation is
illustrated below. In general, the bulk specific gravity of coffee
granules resulting from the medium roast and medium grind is 0.3 to
0.5. For example, if 10-g coffee granules are filled into a glass
pipe with an inner diameter of 55 mm, the volume of the extraction
section is approximately 25 mL, and the volume of the extraction
solvent needed to fill the extraction section up to the upper
surface thereof is 15 mL per 10-g granules.
[0056] The extraction solvent the amount of which falls within the
above-described range is passed through the granule container part
2 at a velocity SV (Space Velocity)=about 3 to about 100. Then, the
ingredients adsorbed on the coffee granules M can be effectively
desorbed. A more preferable liquid passage rate SV is about 5 to
about 70, preferably about 5 to about 50, or more preferably about
6 to about 40.
[0057] (Step c)
[0058] In step c, the extraction solvent (water or preferably hot
water) is brought into contact with the coffee granules. Then, it
is expected that strong bitter ingredients produced during the
final stage of roasting and adsorbed on the uppermost surface of
the partition walls are first desorbed and that a solution
containing a high concentration of these ingredients is temporarily
transferred toward a direction opposite to the first direction (in
FIG. 2, the upper side of the deposited layers of the coffee
granules M) (see FIG. 1(b)). The resultant coffee extract is
retrieved from the direction opposite to the first direction toward
the first direction (step c). It is expected that the coffee
extract passes through the deposited layers of the coffee granules
M with the partition walls of the honeycomb structure exposed,
allowing the excessively bitter ingredients to be resorbed on the
partition walls of the honeycomb structure for separation (see
FIGS. 1(c) and 1(d)).
[0059] Means for retrieving the coffee extract from the first
direction is not particularly limited. Examples of the means
include (i) a method of retrieving the coffee extract by suction
with a pump or the like from the first direction (in FIG. 2, the
lower side of the extraction section), (ii) a method of retrieving
the coffee extract by introducing air or the like from the
direction opposite to the first direction (in FIG. 1, the upper
side of the extraction section) to pressurize the coffee extract,
that is, retrieving the coffee extract by pressurization, and (iii)
a method of retrieving the coffee extract by injecting water from
the direction opposite to the first direction (in FIG. 2, the upper
side of the extraction section) to push the coffee extract (this
method is hereinafter sometimes referred to as "water drive"). The
pressurization methods (methods (i) and (ii)) may cause bitter
ingredients adsorbed on the partition walls to be desorbed
depending on the magnitude of the pressure. Thus, the method of
retrieving the coffee extract by water drive is simple and easy and
is a preferred aspect.
[0060] FIG. 6 shows a coffee extraction device 1 which is similar
to the coffee extraction device in FIG. 2 and which includes an
opening 2A formed at an upper end of a granule container part 2
which end corresponds to the direction opposite to the first
direction and a conduit channel 5' connected to the opening 2A to
guide water to the opening 2A. The method of retrieving the coffee
extract by water drive will be described in detail based on FIG. 6.
Coffee granules are accommodated in an extraction section E of the
cylindrical granule container part 2 in a vertical orientation so
that an upper surface and a lower surface of the coffee granules M
are pressed by the respective filters to substantially seal the
coffee granules M. An operation of opening a three-way valve 9 is
performed to inject an extraction solvent (water or preferably hot
water) from a medium tank 4 (for example, a hot water tank) to the
opening 2B. Thus, the extraction solvent is filled from the lower
side of the deposited layers of the coffee granules M substantially
up to the upper surface of the deposited layers of the coffee
granules M. At this time, no extract liquid is retrieved until the
extraction solvent substantially reaches the upper surface of the
deposited layers of the coffee granules M, maintaining a silent
hold state. When the extraction solvent is injected up to a
predetermined position, an operation of opening a supply valve 5A'
is performed to inject the extraction solvent (water or preferably
hot water) from the extraction solvent tank 4 to the upper opening
2A in the granule container part 2 via an opening 3A formed in a
lid part 3. Then, a coffee extract is retrieved through the lower
opening 2B in the granule container part 2 by water drive. The
temperature and the like of the water injected through the opening
2A are not particularly limited provided that the water can be used
for water drive.
[0061] The present inventors' studies indicate that bitter
ingredients have the following property. That is, the bitter
ingredients adsorbed on the uppermost surface of the partition
walls during roasting are easily desorbed by being brought into
contact with water (particularly hot water), but the bitter
ingredients resorbed on the exposed partition walls of the
honeycomb structure have a strong affinity for the partition walls
and are unlikely to be desorbed even when brought into contact with
hot water. In general, an extraction residue of the coffee granules
is expected to contain extract liquid ingredients which have the
same concentration as that of extract liquid ingredients in the
coffee extract and which are equivalent to or larger than residual
solids in amount. Thus, extract liquid ingredients contained in the
extraction residue of the coffee granules can be efficiently
extracted by retrieving, by water drive, an extract liquid of the
surface of the roasted beans obtained in step a and then continuing
to inject the extraction solvent (water) into the extraction
section E through the opening 2A to continue the extraction with
the water. Thus, the temperature or amount of water injected
through the opening 2A may be set as appropriate depending on the
purpose of retrieving an extract liquid of the surface of the
roasted beans by water drive or extracting extract liquid
ingredients from the extraction residue of the surface of the
roasted beans. The temperature of the water may be changed in
stages. For the purpose of extracting extract liquid ingredients
with an excellent flavor from the extraction residue of the surface
of the roasted beans, the temperature of water guided from the
second direction according to the present invention is 15.degree.
C. to 100.degree. C., preferably 50.degree. C. to 98.degree. C., or
more preferably 60.degree. C. to 95.degree. C.
[0062] The present inventors' examinations indicate that
unfavorable ingredients of the coffee extract include not only
excessively bitter ingredients (scorched bitterness) adsorbed on
the uppermost surface of the partition walls of the coffee beans
but also astringent ingredients eluted during the middle and last
periods of extraction and left on the tongue. In step c, in the
method of retrieving a coffee extract by water drive, a coffee
extract with a better flavor can be efficiently obtained by
controlling the extraction such that the retrieval of the
astringent ingredients is avoided which are eluted during the
middle and last periods of extraction and which are left on the
tongue. Specifically, the sampled amount of coffee extract
retrieved through the lower opening 2B in the granule container
part 2 by water drive is equal to the volume of the coffee granules
M multiplied by about 0.5 to about 5, preferably about 1 to about
3, or more preferably about 1 to about 2. When the sampled amount
is more than five times as large as the volume of the coffee
granules M, the astringent ingredients in the extract liquid are
perceived.
[0063] Such extraction results in a coffee extract extraction rate
of 20% or less or preferably 15% or less.
[0064] Coffee extraction rate (%)={weight of extract
(g)}.times.{Brix of extract (%)}/{weight of coffee granules (g)}
(Brix is indicative of soluble solids measured with a
refractometer. An example of the refractometer may include a
digital refractometer RX-5000.alpha. manufactured by ATAGO CO.,
LTD.)
[0065] In step c, the coffee granules with the surface of the
partition walls of the honeycomb structure exposed are used as an
adsorbent and an extract liquid of the flavory surface of the
roasted beans obtained in step b is passed through the coffee
granules to resorb scorched bitter ingredients in the extract
liquid on the coffee granules. In this case, for efficient
adsorption, the liquid passage rate is important. In step c, the
velocity (SV (Space Velocity) at which the extraction solvent is
passed through the coffee granules is preferably about 3 to about
100, more preferably about 5 to about 70, further more preferably
about 5 to about 50, or particularly preferably about 6 to about
40.
[0066] In step b, when the extraction solvent is injected into the
extraction section E, bubbles sealed in the coffee granules are
released into the extraction section E, in which the bubbles stay.
The flow velocity of the extract liquid is significantly impacted
by the bubbles present in the extraction section E. Thus, the
bubbles in the extraction section are preferably removed before
step c and/or simultaneously with step c in order to facilitate the
control of the flow velocity and to prevent astringent ingredients
from being eluted (over-extracted) due to an excessively long time
needed for extraction. Means for removing the bubbles in the
extraction section is not particularly limited. The extraction
section may be degassed by a publicly-known method before or after
the coffee granules are placed in the granule container part 2.
Examples of the publicly-known degassing method include a
decompression process, a method of carrying out degassing by
applying a physical stimulus such as vibration to the extraction
section E, a method of carrying out degassing by ultrasound, and a
method of carrying out degassing using an inserted degassing pipe.
The present inventors have confirmed that when the column of the
extraction section is slightly vibrated from outside the extraction
section using a commercially available handy vibrator (THRIVE
(registered trade mark) manufactured by DAITO ELECTRIC MACHINE
INDUSTRY CO., LTD.), bubbles in the granule layer move upward and
are removed from the mesh member 11.
[0067] In the method for manufacturing a coffee extract according
to the present invention, water (preferably hot water) passes, in a
reciprocating manner, through the layer of the coffee granules
deposited in a substantially sealed manner. That is, water
(preferably hot water) is passed from the first direction to the
opposite direction (second direction) and then discharged from the
second direction toward the first direction. The first amount of
coffee extract discharged from the extraction section has not
substantially passed through the layer of the coffee granules, and
is thus a very dilute solution. Preferably, an extract liquid is
retrieved after the first solution is disposed of. However, the
first solution does not contain any bitter ingredient or any
astringent ingredient, which is left on the tongue, and may thus be
retrieved along with the subsequent extract. The liquid discharged
as the dilute solution is a liquid discharged during the very
initial period of extraction and corresponding to an extraction
rate of about 1%.
EXAMPLES
[0068] The present invention will be described below in detail
based on examples. However, the present invention is not limited to
the examples.
Test Example 1
[0069] FIG. 7 is a diagram illustrating a coffee extraction device
1 according to an embodiment of the present invention which was
used in Test Example 1. The coffee extraction device 1 includes a
substantially cylindrical granule container part 2 with an upper
opening and a lower opening (2A and 2B) (the inner diameter of the
upper opening: 55 mm and the length of the upper opening: 250 mm),
and has an extraction pipe (glass pipe/chromatography pipe) 8
formed at a lower end of the granule container part 2 and having a
three-way cock, and a hot water container (glass pipe) 4 having an
inner diameter of 50 mm and a length of 100 mm and connected to the
three-way cock 9 of the extraction pipe 8 via a tube 5.
[0070] A filter 10 was installed in a bottom portion of the granule
container part 2, and 40-g coffee granules (Arabica coffee beans
grown in Ethiopia and roasted in an Italian manner were ground at
the medium level) were placed on an upper surface of the filter 10.
A restraining member 11 for braking the flow of the coffee granules
was placed slightly away from an upper surface of the deposited
layers of the coffee granules (placed at a position where, when the
coffee granules are bulged as a result of contact with an
extraction solvent, the upper surface of the deposited layers of
the bulged coffee granules comes into abutting contact with the
restraining member 11). The filter 10 was a circular filter (FIG.
3A) with a diameter of 45 mm including six lint clothes sewed
together in an overlapping manner, an O ring sealed in the sewed
lint clothes and formed of wire with a diameter of 1 mm and having
a diameter of 35 mm, and an appropriate amount of small pieces of
lint cloth sealed in the sewed lint clothes so as to increase the
thickness of a central portion thereof. The restraining member 11
included a ring member having an outer diameter of 58 mm and an
inner diameter of 37 mm and including an O ring formed of wire with
a diameter of 1 mm and having a diameter of 47 mm and sewed on
eight overlapping ring-like lint clothes, an inner diameter portion
of the ring member being sealed with (a piece of) cotton gauze
(FIG. 3B).
[0071] With the three-way cock 9 closed, 100-mL hot water
(95.degree. C.) was added to the hot water container 4. A lower tip
of the hot water container 4 was fitted into an upper end (the
position of the restraining member 11) of an extraction section E,
and an operation of opening the three-way cock 9 was performed to
inject hot water from the lower side of the apparatus (first
direction) into the extraction section E (FIG. 8A). When a surface
of the hot water flowing upward through the granule layer in the
extraction section E comes into contact with the restraining member
11, the cock 9 was closed and subsequently 400-mL hot water
(90.degree. C.) was injected toward the extraction section E
through the upper opening 2A, located on the upper side of the
deposited layers of the coffee granules (second direction) (FIG.
8B). An operation of opening the cock 9 was performed to retrieve
and inject an outflow coffee extract into a 100-mL graduated
cylinder (FIG. 8C). When bubbles generated during extraction caused
clogging, an aligning string 1g attached to the restraining member
18 was operated to remove bubbles. Thus, outflow velocity was
adjusted. The extract liquid was fractionated into 20-mL fractions,
and 12 fractions were retrieved. Then, a 0.5-mL extract liquid of
each fraction was placed in an NMR measurement pipe, and 0.58-mmol
TSP-d4 (3-(trimethylsilyl)propionic-2,2,3,3-d.sub.4 acid sodium
salt) was added as an internal standard substance, to the extract,
which was then stirred well. Measurement was carried out by a
1D-NOESY-presaturation pulse sequence technique using a nuclear
magnetic resonance apparatus (Avance 600 apparatus manufactured by
Bruker Biospin in Switzerland). Then, the standard signal of TSP-d4
and the particular signal of each ingredient were compared with
each other in terms of height, the signals being observed at a
chemical shift 0.00 ppm in an NMR spectrum. The particular signals
of the respective ingredients were a singlet at 3.23 ppm for
caffeine, a singlet at 1.95 ppm for acetate salt, a singlet at
8.45-ppm for formate, a singlet at 9.11 ppm for trigonellin, a
doublet at 8.79 ppm for N-methyl pyridinium cation, a singlet at
8.95 ppm for nicotine acid, and a singlet at 9.65 ppm for a bitter
ingredient with an unknown structure. The ratio of each of these
signal heights to the signal height for TSP-d4 was determined to be
the relative concentration of the corresponding ingredient relative
to the internal standard TSP-d4. The logarithm of the relative
concentration was then plotted for each fraction, with results
shown in FIG. 10 obtained. FIG. 10 shows that main nutrient
ingredients of coffee can be very efficiently extracted, that is,
extracted with no waste in a short time, by retrieving fractions 1
to 7, preferably fractions 2 to 7, or more preferably fractions 2
to 5.
[0072] Furthermore, the fractions of the extract liquid obtained
from the present test was subjected to a sensory rating by expert
panelists (ten persons). In the sensory rating, the favorableness
of the flavor was evaluated on a scale of 1 to 5 based on the
mutual consent of the panelists through a comparison with an
extract liquid (control) obtained by the conventional drip method
(KALITA dripper, model number: 102D, for two to four persons) using
40 g of the same roasted beans as those in the present test
(roasted beans ground under the same conditions) and 200 mL of hot
water. The results are shown in Table 1. The results clearly show
that a total of 40-mL fractions 2 and 3 had very excellent flavors,
and even when diluted by a factor of 5, gave a better flavor than
the control extract liquid obtained by the drip method.
Furthermore, the fraction 1 did not taste bad but was watery and
undrinkable. The fractions 4 and 5 fell well short of the fractions
2 and 3 but had a better flavor than the control. Additionally, the
fractions 6 and 7 had a flavor comparable to the flavor of the
control, and the other fractions had astringent ingredients and
were undrinkable. Thus, it has been found that, according to the
method for manufacturing according to the present invention, a
coffee extract with a dramatically excellent flavor can be obtained
by retrieving the fractions 1 to 7 (extraction rate of 1% to 20%),
preferably the fractions 2 to 7 (extraction rate of 5% to 20%), or
more preferably the fractions 2 to 5 (extraction rate of 5% to
15%).
[0073] The above-described results suggest that the appropriate
flavor ingredients of roasted coffee can be extracted separately
from astringent ingredients eluted during the latter half of the
extraction and left on the tongue, by the method of carrying out
the extraction with separation according to the present invention
to avoid the retrieval of the astringent ingredients. The results
also suggest that the method allows the extraction of not only the
appropriate flavor ingredients of coffee but also nutrient
ingredients that prevent possible lifestyle-related diseases with
high efficiency.
TABLE-US-00001 TABLE 1 Rating Corresponding fractions Very
excellent 2, 3 Excellent 4, 5 Same as the drip method 6, 7 Watery
and undrinkable 1 Undrinkable 8, 9, 10, 11, 12
Example 1
[0074] A coffee extract was manufactured using 30-g Arabica beans
grown in Guatemala and roasted and ground at the medium level. As
an extraction device, a coffee extraction device was used which was
of the same type as that shown in FIG. 7 and in which a granule
container part 2 had an inner diameter of 25 mm (this method is
hereinafter referred to as a CC method: Column Chromatography). A
flannel cloth was used as a lower filter member 10, and as a
restraining member (upper filter member) 11, a metal mesh of about
80 m/s was used around which silicon packing was installed to allow
the metal mesh to tightly contact the column. The lower filter
member 10 and the restraining member 11 were positioned in abutting
contact and in alignment with a lower surface and an upper surface,
respectively, of deposited layers of coffee granules. A three-way
cock 9 was operated to inject 90-mL hot water (90.degree. C.) from
the lower side of the apparatus to an extraction section E at SV=1.
When the surface of the hot water flowing upward through the coffee
granule layer comes into contact with the upper filter member 11,
the cock 9 was closed. Subsequently, 1,200-mL hot water (90.degree.
C.) was injected toward the extraction section E through an upper
opening 2A. The resultant extract liquid was then retrieved at SV=1
at extraction rates of 10%, 15%, 20% and 25%, and was evaluated for
the flavor thereof. For comparison, a coffee extract was obtained
by a unidirectional extraction method using the same amount of the
same roasted beans (roasted beans ground under the same conditions)
and the coffee extraction device shown in FIG. 1 (CD method: Column
Drip). Furthermore, a coffee extract was obtained using an
extraction device of a conventional drip type (KALITA dripper,
model number: 102D, for two to four persons), the same amount of
the same roasted beans (roasted beans ground under the same
conditions), and similar hot water (PD method: Paper Drip).
[0075] Table 2 shows the results of a sensory rating. With
extraction based on the conventional CD method and PD method,
astringency or bitterness was perceived from the initial period of
the extraction. In contrast, the CC method according to the present
invention achieved extraction so as to allow separation of
astringency or bitterness perceived during the initial period of
the extraction, and produced a flavory and sweet coffee extract. On
the other hand, it has been found that no method can separate
astringency eluted during the middle and last period of the
extraction, that is, when the extraction rate is about 25%, and
left on the tongue. This indicates that a reduced extraction rate
is effective in removing the astringency left on the tongue.
TABLE-US-00002 TABLE 2 Extrac- tion rate CC method CD method PD
method 10% Tastes moder- Tastes coarse Tastes sharply ately sweet
and astringent bitter and Flavory and no Too bitter to astringent
bitterness or drink Too bitter to astringency drink 15% Tastes
sweet Tastes slightly Tastes bitter No bitterness less coarse and
and astringent or astringency astringent Too bitter to but clean
Too bitter to drink drink 20% Tastes clean Tastes slightly Tastes
bitter clean and astringent 25% Astringency left Astringency left
Tastes bitter on tongue starts on tongue starts and astringent to
be felt to be felt
Example 2
[0076] As is the case with Example 1, coffee extracts were obtained
by the conventional CD method and PD method and the CC method
according to the present invention. The coffee extracts were
compared with one another in terms of the amounts of caffeine and
chlorogenic acid obtained per unit solid with an extraction ratio
(the ratio of the coffee extract to the extraction material=the
coffee extract/extraction material) varied. For analysis, the
coffee extracts as samples were filtered (0.45-.mu.m filter) and
subjected to HPLC analysis. HPLC analysis conditions are as
follows.
[0077] HPLC conditions:
[0078] Column: TSK-gel ODS-80TsQA (4.6 mm.phi..times.150 mm, TOSOH
CORPORATION)
[0079] Mobile phase: Liquid A:water:acetonitrile:trifluoroacetic
acid=900:100:0.5 Liquid B:water:acetonitrile:trifluoroacetic
acid=200:800:0.5
[0080] Flow velocity: 1.0 mL/min
[0081] Column temperature: 40.degree. C.
[0082] Gradient condition; analysis start to a lapse of 5 minutes:
remains 0% on the gradient of Liquid B.
Lapse of 5 minutes to 11 minutes: increases up to 8% on the
gradient of Liquid B Lapse of 11 minutes to 21 minutes: increases
up to 10% on the gradient of Liquid B Lapse of 21 minutes to 22
minutes: increases up to 100% on the gradient of Liquid B Lapse of
22 minutes to 30 minutes: maintained at 100% on the gradient of
Liquid B Lapse of 30 minutes to 31 minutes: decreases to 0% on the
gradient of Liquid B
[0083] Detection: A280 nm
[0084] The results of analysis of caffeine and chlorogenic acid are
shown in FIG. 11. FIG. 11 shows values in terms of the amounts of
caffeine and chlorogenic acid per soluble solid (Brix). FIG. 11
clearly shows that a coffee extract obtained by the CC method
according to the present invention contains caffeine and
chlorogenic acid similar in amounts to caffeine and chlorogenic
acid in coffee extracts obtained by the conventional PD method and
CD method, without depending on the extraction ratio. The analysis
results, in combination with the sensory rating results in Example
1, suggest that the CC method according to the present invention
allows manufacture of a coffee extract with an excellent flavor for
which excessive bitterness and astringency are selectively reduced
with ingredients such as caffeine and chlorogenic acid unchanged,
the ingredients contributing significantly to the flavor.
Example 3
[0085] The coffee extract manufactured by the CD method in Example
1 was treated using an ultrafiltration membrane with a cut-off
molecular weight of about 100,000 (VIVA SPIN 20 manufactured by
SARTORIUS K.K.; cut-off molecular weight: 100,000), and the
resultant liquid was retrieved and compared, in terms of flavor,
with the coffee extract obtained by the CC method in Example 1. The
results are shown in Table 3. When the coffee extract obtained by
the conventional CD method was treated by the ultrafiltration
membrane, the bitterness and astringency perceived during the
initial period of the extraction were removed. This suggests that
the CC method according to the present invention allows efficient
removal of macromolecular bitter and astringent ingredients with a
molecular weight of about 100,000 or more. As is apparent from
Table 3, the CC method according to the present invention is
superior to the CD method with the ultrafiltration membrane
treatment in terms of sweetness.
TABLE-US-00003 TABLE 3 Extraction rate CC method CD method 10%
Tastes moderately sweet Flavory and tastes clear Flavory and tastes
clear 15% Tastes sweet Tastes clean and clear Tastes clean and
clear 20% Tastes clean and clear Tastes clean and clear 25% Starts
to taste astringent Starts to taste astringent
Example 4
[0086] As is the case with Example 1, coffee granules were placed
in a granule container part 2 in a substantially sealed manner, and
hot water or water was injected from the lower side of the
extraction section E until the coffee granules were completely
dipped in the water. Subsequently, hot water or water was injected
through the upper opening 2A to produce a coffee extract
(extraction rate: 14.1%) (CC method). Furthermore, for comparison,
the same roasted coffee beans (ground under the same conditions)
were filled in a commercially available coffee dripper
(manufactured by KALITA CO., LTD.), and hot water or water was
injected from the upper side of the coffee dripper to produce a
coffee extract (extraction rate: 13.7%) (PD method). These coffee
extracts were subjected to a sensory rating by six expert
panelists. The coffee extracts were evaluated on a scale of 1 to 5
in terms of bitterness, fragrance, and taste ingredients
(bitterness: bitterness decreases with increasing scale value,
fragrance: the level of fragrance increases consistently with scale
value, and taste ingredients: the number of (favorable) taste
ingredients increases consistently with scale value).
[0087] The results are shown in Table 4. The CC method according to
the present invention removed approximately all of the bitterness
and produced favorable taste ingredients. In particular, it has
been found that, when the temperature of water is high (about
90.degree. C.) during steps b and c, a coffee extract can be
manufactured which has a much better fragrance than a coffee
extract obtained by the conventional water drip (extraction at
about 20.degree. C. by the PD method). Furthermore, if a first
extraction (step b) and a second extraction (step c) are carried
out at 20.degree. C. by the CC method, a larger amount of coffee
extract can be manufactured in a shorter time than in the case of
extraction at 20.degree. C. by the PD method. This indicates that
the CC method according to the present invention is a high-yield
method for manufacturing.
TABLE-US-00004 TABLE 4 Step b Step c From lower From upper Taste
side to side to Bitter- Fra- ingre- upper side lower side ness
grance dient CC method Hot water Hot water 4 5 5 (present (about
90.degree. C.) (about 90.degree. C.) invention) Water Water 5 2 4
(about 20.degree. C.) (about 20.degree. C.) PD method -- Hot water
1 5 5 (conven- (about 90.degree. C.) tional -- Water 5 2 3
technique) (about 20.degree. C.)
Example 5
[0088] Commercially available coffee beans were coarsely ground,
and 15 g of the ground coffee beans were used for extraction by the
CC method, the CD method, and the PD method. For the CC method, the
same apparatus as that used in Example 1 (and the same lower and
upper filter members as those used in Example 1) was used, and hot
water (about 90.degree. C.) was injected from the lower side of the
extraction section E until coffee granules were completely dipped
in the water. Then, hot water (about 90.degree. C.) was injected
through the upper opening 2A, and the resultant extract liquid was
retrieved. For the CD method, coffee granules were placed in an
apparatus similar to that used for the CC method, hot water (about
90.degree. C.) was injected through the upper opening 2A, and the
resultant extract liquid was retrieved through the lower opening
2B. For the PD method, a conventional drip extractor (KALITA
dripper, model number: 102D, for two to four persons) was used, and
coffee granules were filled into a commercially available coffee
filter (manufactured by KALITA CO., LTD.). Hot water was injected
from the upper side of the coffee filter, and the resultant extract
liquid was retrieved. Table 5 shows the amount of extract liquid
retrieved (the amount of extract liquid sampled: g), the Brix (%)
of the extract, and the extraction rate (%) of the extract liquid
(the Brix is a value measured using a digital refractometer
RX-5000.alpha. manufactured by ATAGO CO., LTD.).
TABLE-US-00005 TABLE 5 Amount of extract Brix Extraction liquid
sampled (%) rate (%) Column chromatography 40.1 5.46 14.6 Column
drip 40.8 4.51 12.3 Paper drip 40.4 5.44 14.7
[0089] Water was added to extracts obtained by the CC method, the
CD method, and the PD method so as to adjust the Brix of each
extract liquid to 2.0%. The extracts were filtered using filter
paper (no. 2), and the NTU turbidity of each of the extracts was
measured using a NTU turbidimeter (2100AN) manufactured by HACH.
The results are shown in FIG. 13. FIG. 13 clearly shows that the
extract liquid according to the present invention has the lowest
turbidity and the highest clarity. This also suggests that the
coffee extract according to the present invention has high
preservation stability.
Example 6
[0090] Arabica coffee beans were roasted so that the L value was
18, and were ground so that the average grain size was about 1.5 mm
to produce coffee granules. Extraction was carried out by the CC
method according to the present invention using an extraction
device shown in FIG. 7. As is the case with Example 1, a flannel
cloth was used as a lower filter member 10, and as a restraining
member (upper filter member) 11, a metal mesh of about 80 m/s was
used around which silicon packing was installed to allow the metal
mesh to tightly contact the column. The lower filter member 10 and
the restraining member 11 were positioned in abutting contact and
in alignment with a lower surface and an upper surface,
respectively, of deposited layers of the coffee granules and to
place the coffee granules in a substantially sealed manner. At this
time, the amount of the coffee granules was 100 g, and the
cross-sectional shape of a substantial rectangle in a direction
along the axis of an extraction section E was such that the ratio
(H/L) of the width (L) to height (H) of the rectangle was about 4.
A three-way cock 9 was operated to inject 90-mL hot water
(90.degree. C.) from the lower side of the apparatus to the
extraction section E at SV=1. When the surface of the hot water
flowing upward through the coffee granule layer comes into contact
with the upper filter member 11, the cock 9 was closed.
Subsequently, 1,200-mL hot water (90.degree. C.) was injected
toward the extraction section E through an upper opening 2A, and
the resultant extract liquid was retrieved at SV=1.
[0091] Basic conditions were set as described above, and the
following were varied to be examined: the degree of grind of the
coffee granules (average grain size), the shape of the extraction
section, the temperature of water injected from the first direction
multiplied by SV, and the temperature of water injected from the
second direction multiplied by SV.
[0092] The results are shown in Table 6. In Table 6, circles denote
a flavor equivalent to a flavor obtained under the basic
conditions, and double circles denote a flavor better than the
flavor obtained under the basic conditions.
TABLE-US-00006 TABLE 6 Average grain size ~0.1 ~0.5 ~1.0 ~1.5 ~2.0
of beans (mm) .DELTA. .largecircle. .circleincircle.
.circleincircle. .largecircle. Aspect ratio of 0.1 2 4 6 10 12 20
beans (h/w) .DELTA. .largecircle. .circleincircle. .circleincircle.
.largecircle. .largecircle. .DELTA. Water temperature 30 60 90
(.degree. C.) .largecircle. .largecircle. .circleincircle. Flow
from first direction Flow velocity 3 7 10 20 30 50 100 (space
velocity sv) .largecircle. .circleincircle. .circleincircle.
.largecircle. .largecircle. .largecircle. .largecircle. Amount of
liquid 0.3 0.5 1 1.5 2 transferred (bean volume ratio)
.largecircle. .circleincircle. .circleincircle. .largecircle.
.DELTA. Flow from second direction Flow velocity 3 7 10 20 30 50
100 (space velocity sv) .largecircle. .circleincircle.
.circleincircle. .largecircle. .largecircle. .largecircle.
.largecircle. Amount of liquid 0.3 0.5 1 1.5 2 3 5 transferred
(bean volume ratio) .largecircle. .circleincircle. .circleincircle.
.circleincircle. .circleincircle. .largecircle. .DELTA.
Example 7
[0093] A coffee extraction device 1 was used which was similar to
the coffee extraction device used in Test Example 1. Thirty-gram
Robusta coffee beans grown in Indonesia and roasted in a French
manner were ground at the medium level, and the ground coffee beans
were placed in a granule container part 2. With a three-way cock 9
closed, 100-mL hot water (95.degree. C.) was injected into a hot
water container 4. A lower tip of the hot water container 4 was
fitted into an upper end (the position of a restraining member 11)
of an extraction section E, and an operation of opening the
three-way cock 9 was performed to inject hot water into the
extraction section E through a lower opening 2B. When a surface of
the hot water flowing upward through the granule layer in the
extraction section E passes through the restraining member 11 and
reaches a position 10 mm above the restraining member 11, the cock
9 was closed. Subsequently, 350-mL hot water was injected through
an upper opening 2A in the granule container part, the cock 9 was
opened, and a colorless portion and a faint yellow portion of an
outflow liquid (extraction rate: about 1%) were disposed of. When
the outflow liquid turned brownish, the outflow liquid started to
be retrieved with the flavor thereof checked. When the outflow
liquid became cervine and the color was subsequently lightened
again, the outflow liquid continued to be retrieved with the flavor
thereof similarly checked until the "very excellent" fractions
completed flowing out. Then, the retrieval container was changed,
and the retrieval was continued. When the "excellent" fractions
completed flowing out, the retrieval was ended. The amount of
extract liquid retrieved was 60 mL for the "very excellent"
fractions (Extract 1 according to the present invention) and 40 mL
for the "excellent" fractions (Extract 2 according to the present
invention).
[0094] For comparison, extraction was carried out on the same
roasted beans as those in the Example 7 (roasted beans ground under
the same conditions) by the drip method (KALITA dripper, model
number: 102D, for two to four persons) using 350-mL hot water
(95.degree. C.) so that the extraction rate was about 15%
(Comparative Example 1). Six expert panelists compared, in terms of
flavor, Comparative Example 1 with each of Extract 1 according to
the present invention, Extract 2 according to the present
invention, and a mixture of a total amount of Extracts 1 and 2
according to the present invention (Extract 3 according to the
present invention). All the panelists determined that all of
Extracts 1 to 3 according to the present invention has much better
flavors than Comparative Example 1. Extracts 1 to 3 according to
the present invention were thick and flavory coffee liquids without
excessively strong bitterness and had a very clean aftertaste and
no astringent aftertaste left on the tongue, and were thus coffee
with an excellent flavor.
Example 8
[0095] A coffee extract was manufactured in a manner similar to the
manner of Example 7 except that 30-g each of granules were obtained
by roasting, in an Italian manner, Arabica coffee beans grown in
Indonesia and having the lowest market price and then grinding the
roasted beans at the medium level and that a different amount of
extraction solvent was injected from the lower side of an
extraction section E. The amount of extraction solvent was set in
two ways: the amount needed for a surface of hot water flowing
upward through the granule layer in the extraction section E to
come into contact with the restraining member 11 and the amount
needed for the surface of the hot water flowing upward through the
granule layer in the extraction section E to pass through the
restraining member 11 and reach a position 10 mm above the
restraining member 11. Six expert panelists evaluated the flavor of
a retrieved liquid and all of the panelists determined that the
bitterness and astringency were significantly suppressed, making
the coffee extract tasty.
Example 9
[0096] Thirty grams of commercially available brand coffee beans
shown to have been roasted at the highest level for iced coffee
were ground at the medium level. A technique similar to the
technique in Example 7 was used to carry out extraction on the
ground beans to obtain a 60-mL "very excellent" coffee extract and
a 40-mL "excellent" coffee extract. The 60-mL "very excellent"
coffee extract was diluted to 300 mL with cold water, and the
diluted coffee extract was cooled in a refrigerator (5.degree. C.)
(Extract 4 according to the present invention).
[0097] For comparison, 30 g of the same coffee granules as those
used in Example 9 were placed in a French press coffee pot
manufactured by Bodum (500-mL type), and hot water at 95.degree. C.
was injected into the French press coffee pot. Four minutes later,
an extract liquid was separated from the liquid to produce 300 mL
of coffee extract, which was then cooled in the refrigerator
(5.degree. C.) (Comparative Example 2). Extract 4 according to the
present invention and Comparative Example 2 were evaluated for
flavor by six exert panelists. Iced coffee corresponding to Extract
4 according to the present invention was tasty coffee having
moderate bitterness and a rich fragrance even when drunk black. In
contrast, Comparative Example 2 was very bitter and did not taste
directly drinkable.
Example 10
[0098] As an extraction device, a coffee extraction device was used
which included a substantially cylindrical glass pipe (inner
diameter: 50 mm and length: 150 mm) having an upper opening and a
lower opening (2A and 2B) and serving as a granule container part 2
as shown in FIG. 9. The lower opening 2B in the granule container
part 2 included an extraction pipe (glass pipe/chromatography pipe)
with a two-way cock 9'. The same lower filter member 10 as that
used in Example 7 was installed, and 30 g of coffee granules
obtained by roasting, in an Italian manner, Arabica coffee beans
grown in Ethiopia and grinding the roasted coffee beans at the
medium level were placed on an upper surface of the lower filter
member. A restraining member 11 with an outer diameter of 54 mm was
installed on the coffee granules and included an O ring formed of
wire with a diameter of 1 mm and having a diameter of 40 mm and
sewed on four overlapping lint clothes. A safety pipetter 13 was
installed above the granule container part 2 via a joint 12. A
beaker with 50-mL hot water (95.degree. C.) was placed at a
retrieval port 8 at the lower part of the granule container part 2.
The retrieval port 8 was inserted into the hot water, and the
two-way cock 9' and the safety pipetter 13 were operated to suck
the hot water up to an upper end of an extraction section E. Then,
the two-way cock 9' was closed, and the safety pipetter 13 was
removed. One hundred-mL hot water (about 90.degree. C.) was
injected into the extraction section E through an upper opening 2A
of the granule container part 2. The safety pipetter 13 was
installed again, and air pressure is applied to the granule
container part 2. Then, the two-way cock 9' was opened, the first
10 mL of outflow liquid was disposed of, and the next 60 mL of
outflow liquid was retrieved. The flavor of the retrieved liquid
was checked and determined to belong to the "very excellent"
class.
* * * * *