Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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PROCESS FOR THE
PREPARATION OF DEACIDIFIED COFFEE
FIELD OF INVENTION
The field of this invention is coffee processing
and methods of treating coffee so that a brew made from
the roasted and ground coffee contains less acidity than
the untreated counterpart.
BACKGROUND OF THE INVENTION
Many people are concerned with the acidity of
their food and drink. A measure of this concern is the
extensive consumption of antacids in various forms.
According to a survey by Supermarket Business (46th Annual
lS Consumer Expenditures Study Vol 48 No.9 September 1993
p.83), a trade publication, the 1992 total sales in all
retail outlets, of antacids in across-the-counter non
prescription forms, was $1,082,262,000. This expenditure
included such forms as e~ervescent antacids, liquid
antacids, powder antacids, and antacid pills, gums, and
lozenges. Many such acidity concerned consumers deny
themselves full enjoyment of coffee beverages because of
the acid nature of coffees.
Coffees differ according to the variety, origin,
and processing. For variety, examples are Brazils,
Colombians, Centrals from Honduras, from Guatemala, and
from Mexico, Robustas from Africa, and Conillons from
Brazil. There are new crop, and old crop, and there are
several quality grades in each coffee. Coffees reach the
consumer as regular (undecaffeinated), decaffeinated and
partially decaffeinated, each with or without added
flavorings. Some people may find some of these
excessively acidic.
No one has provided to the public a roasted
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coffee, undecaffeinated or decaffeinated, which when
brewed combines the following features:
1. The beverage acidity is at a specified
reduced level, or is neutral, or is at a specified
alkaline level.
2. The consumer's coffee experience
substantially is characteristic of the particular type of
coffee when grinding the beans, brewing, and consuming the
beverage.
No one has demonstrated processes for the
reduction of coffee acidity using exclusively ammonia gas
and/or the ammonium ion quantitatively to result in a less
acid, a neutral, or an alkaline beverage.
It is an object of this invention to demonstrate
the use of ammonium ions and/or gaseous ammonia, as they
are available in a variety of physical states and
molecular compounds, to reduce the level of acidity of
coffee.
It is a further object of this invention that
only water where needed as a processing aid, and those
molecules, ions, or compounds functioning as neutralizers
of acidity, be the sole additives to coffee beans, or to
roasted and ground coffee.
It is a further object of this invention to
treat the coffee so that the beverage brewed from its
roasted and ground form is at a targeted reduced level of
acidity.
It is a further object of this invention to
treat coffee for a neutral beverage.
It is a further object of this invention to
treat coffee for a beverage at a targeted level of
alkalinity.
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SUMMARY OF INVENTION
This invention provides processes for the
reduction of co~fee acidity utilizing the respective
S acidity neutralizing capacities of ammonia, and/or
~mmon;um ions. Illustrative, non-limiting examples o~
sources of ~mmon; a and ammonium ions include:
1. Ammonia NH3
2. Strong Ammonia Water, such, for example, a
solution o~ 28~ to 29~ NH3 by weight in water;
3. Di~3mmon~ um hydrogen phosphate (NH4)2HPO4;
lS Ammonium carbonate, a mixture of ammonium
bicarbonate, NH4HCO3, and ammonium carbamate, NH2COONH4,
containing 30 to 34~ NH3 by weight;
5. Ammonium bicarbonate, NH4HCO3; and
6. Ammonium carbamate, NH2COONH4
In this invention cof~ee in various stages o~ preparation,
green, partially roasted, roasted, roasted and ground may
be treated to reduce their acidity.
Either undecaffeinated, and decaffeinated
cof~ees may be treated to reduce their acidity and coffees
before flavoring or a~ter flavoring may be treated.
In this invention each treatment may be combined
with other treatments. For example a particular lot of
r 30 roasted coffee beans may be divided into sublots for
treatments, ~or example, one sublot treated with Ammonia
gas, another sublot treated with Ammonium bicarbonate to
be blended at an appropriate point further in the cof~ee
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operations, as for example, roasted bean with roasted
bean, roasted bean with ground coffee, or ground coffee
with ground coffee.
In this invention an acid reduced coffee may be
blended with a non acid reduced coffee to standardize to a
target level of acidity.
In this invention the strong Ammonia Water may
be diluted to a lesser strength to be used for a desired
level of acidity reduction.
In this invention the solid compounds, for
example, Diammonium hydrogen phosphate, Ammonium
carbonate, or Ammonium bicarbonate may be used directly as
solids in contact with the coffee, or as water solutions
in contact with the coffees, or in comblnation of water
solution and solid in contact with the coffee.
On a particular lot of coffee a single one of
the acidity reducing substances may be used to reduce
coffee acidity or two or more may be used to accomplish
reduction of acidity.
DETAILED DESCRIPTION OF THE INVENTION
The treatments of the invention substantially
retain the essential nature of the coffee experience. By
this is meant providing the various styles of roasted
coffee, for example, regular, decaffeinated, flavored
regular, and flavored decaffeinated in typical forms,
including beans to be custom ground in the store, to be
ground on consumer premises, or prepackaged, roasted and
ground, to be followed by customary domestic or
institutional brewing procedures, and any modes of
consumption, for example, black, or with whitener, with or
without sugar, or in a variety of recipes.
The respective acidity reducing treatments of
the invention are compatible with delivering the coffee to
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the consumer in all packaging modes, for example, can,
paper bag, gas barrier vacuum packed, gas barrier film
package with prior nitrogen or other gas flush, or gas
barrier film package with a special valve which exhausts
gas pressure from within the package but does not allow
S gas from the outside to flow into the package.
The invention provides acidity reducing
treatments for any appropriate stage, ranging from beans
as green, partially roasted, fully roasted, and fully
roasted and ground coffees.
Methods are provided that are adjustable to
achieve any desired level of acidity reduction, ranging
from slight reduction of beverage acidity, to alkaline
beverages.
Reduction in acidity literally means reduction
IS in the concentration of hydrogen ions which impart
acidity. In a water solution a hydrogen ion is an atom of
hydrogen with a positive charge due to a loss of an
electron. It is designated as H+. To measure H+
concentration an electrode is immersed in the water
solution, to give a reading in pH units. Examples of pH
are pH 1 for a 0.36~ solution of hydrochloric acid,
(muriatic acid), a strong acid, and pH 13 for a 0.40~
solution of sodium hydroxide (soda lye), a strong base. A
pH of 7 is neutral, under pH 7, acid, and over pH 7
alkaline. Vinegar has a pH of about 3; milk 6.5 to 7;
pure water, completely neutral at pH 7, sea water, on the
alkaline side, pH 8.5 to 10.
The pH is defined as the logarithm, to the base
10, of the reciprocal of the hydrogen ion concentration.
Mathematically this is expressed as follows:
pH = log 1 .
lOCH+]
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The brackets[] signify concentration. Since pH is an
exponential function, what appears to be a small numeric
change may represent a very large change in the
concentrations o~ hydrogen ions, the ions o~ acidity, as
compared to [OH-], hydroxyl ions, the ions o~ alkalinity.
This can be seen from the ~ollowing.
pHRatio o~ [H+] or [OH-]
ValueConcentration to that
o~ Pure Water at 22~C
o 1 1,000,000
Acid side 2 100,000
(excess 3 10,000
[H+] ions) 4 1,000
100
6 10
Neutrality 7
...... 8 10
9 100
1, 000
11 10,000
Alkaline 12 100,000
side 13 1,000,000
(excess
[OH-]
ions)
The change in acidity resulting from a particular
treatment may be expressed as a percentage. In the
examples o~ acidity reduction treatments the pH o~ the
beverage made ~rom the treated co~ee is compared to the
pH of the beverage ~rom the untreated co~ee. The brewing
method in these examples is standardized to 65 U.S. fluid
ounces o~ hot water per 60 grams o~ ground co~fee.
Brewing is by passing hot water through the ground co~ee
on a paper ~ilter. A portion o~ beverage ~rom the
untreated co~ee is allowed to cool to 25~C and the pH is
-
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determined by glass electrode. Similarly taken is the pH
of beverage from the treated coffee. The percent
reduction in acidity is calculated as in the following
example:
s
Untreated Coffee
Beverage pH = 5.3
Calculation of hydrogen ion concentration, [H+]:
pH = log 1 = 5.3
10 [H+]
1 = antilog 5.3 = 199526.23
[H+]
[H+] = 0.000005012
Treated Coffee
Beverage pH = 6.5
Calculation of hydrogen ion concentration, [H+]:
pH = log 1 = 6.5
10 [H+]
1 = antilog 6.5 = 3162277.7
[H+]
[H+] = 0.000000316
Calculation of ~ reduction in aciditY:
Regular Coffee, [H+] 0.000005012
Treated Coffee, [H+] 0.000000316
Di~ference [H+] 0.000004696
(reduction in acidity)
Percent reduction = 0.000004696 X 100= 93.7
0.000005012
of course where the beverage of a treated coffee
is neutral, pH 7, there is 100~ reduction in acidity.
Where the beverage of a treated co~fee is
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alkaline, for example, pH 7.3, the treatment has proceeded
beyond the l00~ reduction in acidity to an excess of
hydroxyl ion [OH-] concentration.
EXAMPLES
s
The following examples illustrate certain
embodiments of the present invention. The examples are
not meant to limit the invention beyond what is claimed
below.
EXAMPLE 1
To 200 grams of roasted undecaffeinated
Colombian coffee beans 5.2 grams of water were added to
raise bean moisture to 6.0~. The moistened beans were
transferred to a vessel which then was sealed, followed by
opening an inlet valve to feed in l.7 grams of ammonia
gas. The valve then was closed and the vessel was held,
sealed, at 23~C room temperature for l.5 hours. Then the
vessel was opened, and the coffee beans were spread on a
screen in a 100~C hot air oven for l.25 hours. The coffee
beans then were removed, cooled to room temperature and
ground. Beverage brewed as described and cooled to 25~C
read pH 6.97. The corresponding untreated coffee beverage
read pH 5.41. Accordingly the decrease in acidity
calculates to 97.2~.
EXAMPLE 2
In 200 grams of roasted decaffeinated Colombian
coffee beans 5.2 grams of water was added to raise bean
mois~ure to 6.0~. The moistened beans were transferred to
a vessel which then was sealed, followed by opening an
inlet valve to feed in l.6 grams of ammonia gas. The
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valve then was closed and the vessel held, sealed, at 23~C
room temperature for 1.5 hours. Then the vessel was
opened and the coffee beans spread on a screen in a 100~C
hot air oven for 1.25 hours. The coffee beans then were
~ removed, cooled to room temperature and ground. Beverage
S brewed as described, and cooled to 25~C read pH 6.76. The
corresponding untreated decaf~einated co~:Eee beverage read
pH 5.25. Accordingly the decrease in acidity calculates
to 96.9~.
EXAMPLE 3
To 200 grams of roasted and ground
undecaffeinated Colombian coffee 5.2 grams of water were
added to raise moisture to 6.0~. The moistened ground
coffee was trans:f~erred to a vessel which then was sealed
followed by opening an inlet valve to feed in 1.6 grams of
ammonia gas. The valve then was closed and the vessel
held, sealed, at room temperature o:E 23~C for 0.5 hours.
Then the vessel was opened and the ground co~ee spread on
a screen in a 100~C hot air oven for 0.5 hours. The
ground coff~ee then was removed and cooled to room
temperature. Beverage brewed as described, and cooled to
25~C read pH 6.56. The corresponding untreated co~fee
read pH 5.41. Accordingly the decrease in acidity
calculates to 93.2~.
EXAMPLE 4
Two hundred grams of Central American green
undecaffeinated cof~ee beans were sealed in a vessel which
then was opened to a vacuum pump, subjecting the beans to
30 pounds per square inch gage of vacuum. The vacuum pump
connection was sealed o:Ef and an ammonia gas inlet opened
to feed in 4.7 grams of~ ammonia gas. The ammonia valve
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then was closed and the sealed system held at room
temperature of 23~C for 2.5 hours. The vessel then was
opened and the green beans spread on a screen in a 100~C
hot air oven for 0.5 hours. The beans then were removed
to cool to room temperature, and then transferred to an
S air quench roaster to be roasted, and then ground.
Beverage brewed as described, and cooled to 25~C read pH
6.15. The corresponding untreated green Central was
similarly roasted, ground, and brewed for a beverage pH at
25~C o~ pH 5.41. Accordingly the decrease in acidity
calculates to 81.8~.
EXAMPLE 5
To 200 grams of roasted undecaffeinated
Colombian coffee beans 7.7 milliliters of strong ammonia
water solution (29~ by wt. o~ ammonia gas) were added and
the container sealed. The contents were shaken i~requently
until all free liquid was absorbed. After 3.0 hours the
container was opened, the beans spread onto a screen which
then was held in a 100~C air oven for 1.5 hours. The
beans were removed, cooled to room temperature, and
ground. Beverage brewed as described, and cooled to 25~C
read pH 6.85. The corresponding untreated co:E~ee beverage
read pH 5.26. Accordingly the decrease in acidity
calculates to 97.5~6.
EXAMPLE 6
To 1500 grams of roasted and ground
30 undecaf~einated co~ee 59.6 milliliters of strong ammonia
water solution (29~ by wt. of ~mm~rl; a gas) were added and
the container sealed. The contents were shaken :Erequently
until all free liquid was absorbed. A~ter 3.0 hours the
container was opened, the ground coffee spread onto a
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~ screen which then was held in a 100~C air oven for 1.5
hours. The ground coffee then was removed, and cooled to
room temperature. Beverage brewed as described and cooled
to 25~C read pH 6.80. The corresponding untreated ground
coffee beverage read pH 5.53. Accordingly the decrease in
acidity calculates to 94.6~.
EXAMPLE 7
To 200 grams of roasted decaffeinated Colombian
coffee beans 7.7 milliliters of strong ammonia water
solution (29~ by wt. of ammonia gas) were added and tne
container sealed. The contents were shaken frequently
until all free liquid was absorbed. After 3.0 hours the
container was opened, the beans spread onto a screen which
then was held in a 100~C air oven for 1.5 hours. The
beans were removed, cooled to room temperature, and
ground. Beverage brewed as described and cooled to 25~C
read pH 6.87. The corresponding untreated decaffeinated
coffee beverage read pH 5.25. Accordingly the decrease in
acidity calculates to 97.6~.
EX~iMPLE 8
Sixty grams of roasted and ground
undecaffeinated Colombian coffee were mixed with 1.67
grams of di~mmn~;um hydrogen phosphate powder. A beverage
was brewed as described above and cooled to 25~C to read
pH 6.51. The corresponding untreated roasted and ground
coffee beverage read pH 5.3 8. Accordingly the decrease in
acidity calculates to 92.6~.
EX~MP~E 9
-
One hundred grams of undecaffeinated roasted
Colombian beans were mixed in a closed container with 2.6
-
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milliliters of water. The contents were shaken frequently
until free liquid was absorbed. After 45 minutes the
moistened beans were ground. The ground coffee was mixed
in a closed container with 3.4 grams of Ammonium
bicarbonate for 45 minutes, followed by brewing as
S described above. The cooled, 25~C beverage tested pH
7.39, an alkaline coffee. The beverage made from the
corresponding untreated coffee tested pH 5.47.
EXAMPLE 10
To 100 grams of roasted undecaffeinated
Colombian coffee beans 2.6 milliliters of water were added
followed immediately by Ammonium bicarbonate powder. The
container was closed and placed in a 100~C oven for 20
lS minutes, and then held, closed, for 25 minutes at 24~C.
The contents were ground and a beverage was brewed as
described above, cooled to 25~C, giving a test reading of
pH 6.64. The corresponding untreated coffee beverage
tested pH 5.47. Accordingly the percent reduction in
acidity calculates to 93.2~.
EXAMPLE 11
Two hundred grams of roasted, undecaffeinated
Colombian coffee beans were mixed in a closed container
with 5.2 grams of water for 45 minutes. The contents were
shaken frequently until free liquid was absorbed.
~mmon; um carbonate lumps were broken to a fine powder and
5.4 grams were added to the beans with thorough mixing by
shaking the closed container. The sealed container was ,
placed in an oven at 80~C. After one hour the powder
visually decreased. At two hours, the container obviously
was under high pressure stress. The container was opened
to relieve the pressure and then resealed to return to the
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80~C oven for an additional two hours by which time the
powder had disappeared. The beans then were transferred
to screens and placed in a 100~C oven for 75 minutes. The
contents then were cooled to room temperature, ground, and
a beverage brewed as described above. Cooled to 25~C the
beverage tested pH 6.80. The beverage from the
corresponding untreated bean tested pH 5.47. Accordingly
the percent reduction in acidity calculates to 95.3~.
EXAMPLE 12
A portion of the roasted and ground,
undeca~einated, treated Colombian coffee of EXAMPLE 1 was
held 28 days at room temperature in a loosely sealed bag.
Similarly, untreated, undecaf~einated roasted and ground
lS Colombian coffee was held 28 days at room temperature in a
loosely sealed bag. Beverages made as described above
tested pH 6.97 for the treated coffee, and pH 5.21 for the
untreated coffee. To demonstrate that precise levels of
acid reduction may be achieved by blending treated co~ee
of high pH with more acid, untreated cof~ee of low pH, a
75/25 blend was made o~ the two coffees as follows:
Treated Cof~ee pH 6.97 17.3 grams
Untreated Cof~ee pH 5.21 5.7 grams
The blended mixture was brewed as described
above. The resulting beverage when cooled to 25~C tested
pH 6.49. Relative to pH 5.21, pH 6.49 represents a 94.8
reduction in acidity.
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o
ALL EXAMPLES
In each of the examples, EXAMPLES 1 TO 12
inclusive, the essential nature of the coffee experience
was retained including the quality of the treated roasted
beans, the quality of treated roasted and ground beans,
and the quality at each step thereafter, grinding,
brewing, and the cup aroma and taste. This applied
whatever the acidity reducing treatment point, green
beans, roasted beans, or ground roasted co~fee,
undeca~feinated or decaffeinated.
Each of the roasted coffee bean and/or roasted
and ground co~fee bean final products of each of the
treatments in EXAMPLES 1 to 12 was packageable in any mode
with full lowering of acidity retainable through normal
shelf conditions of time and temperature. This includes
but is not limited to can, paper bag, gas barrier vacuum
packed, gas barrier film package with prior nitrogen or
other gas flush, or gas barrier ~ilm package with a
special valve which exhausts gas pressure from within the
package but does not allow gas from the outside to ~low
into the package.
