United States Patent 0
1
3,373,041
Patented Mar. 12, 1968
1
‘
3,373,041
METHOD OF PREPARING BREWED COFFEE
Jack Bloom and Leroy W. Brown, Chicago, Ill., assignors
to Continental ‘Coffee Company, a corporation of Illinois
No Drawing. Filed Jan. 23, 1964, Ser. No. 339,596
6 Claims. (Cl. 99-68)
This invention relates to beverages. More particularly,
it relates to coffee prepared as a brew of roasted and com
minuted coffee beans. Still more particularly, it relates to 10
dry, ground coffee bean compositions adapted for brew
ing with softened water.
In accordance with the present invention a comminuted
coffee bean composition is prepared, the ?avor of whose
brew is similar irrespective of brewing with hard Water 15
or ‘with softened water. In preparing the coffee bean com
position, the coffee beans are subjected to special degrees
of roasting and ground to a critical particle size distribu
tion pattern. An organic food grade acid is incorporated
odically withdrawing samples for a brew test which in
volves grinding the roasted bean to a particle size such that
all material passes a No. 30 screen, adding two grams
of this ground coffee to 100 cc. of boiling distilled water
and continuing the boiling for exactly .?ve minutes, trans
ferring the resultant suspension of coffee and water to a
100 ml. volumetric ?ask, cooling the decoction to 68° F.,
and adding distilled Water to make the volume up to the
100 ml. mark. The cooled suspension is ?ltered through
?lter paper using a ?lter aid. The clear ?ltrate is placed
in a 10 mm. cuvette and the optical density of the solution
is read at 550 millimicron Wave length in a spectrophotom
eter, such as Coleman 6A spectrophotometer. When opti
cal density of the clear filtrate is in the range between
about 0.35 and 0.45 and preferably between about 0.38
and 0.42, the roasting is terminated and the roasted beans
are cooled in accordance with conventional coffee bean
handling procedure.
Coffee beans roasted to the above explained degree,
with the bean material in quantities to produce in a brew 20
if they are to exhibit a brewing time such that the pres
thereof a pH in the range .between about 4.8 and 5.4.
ence of bitterness and off-?avors in the brews are to be
Conventional, drip, regular, etc. grinds of coffee beans
avoided, must be comminuted to a critical size range.
when brewed ‘with untreated water, i.e., tap water of acid-1
A brew time is determined by placing 85 grams of
ity in the range of pH 6.0 to 8.0, produce a brew having
ground coffee in the bottom of a tapered aluminum
a pleasing aroma, pleasant taste and a medium brown 25 cylinder supported on a cloth ?lter on the bottom, said
color.
?lter having a diameter of 5 inches. 64 ?uid ounces of
It is known and generally accepted in the trade that
when the conventional, drip, regular, etc. grinds of coffee
water at a temperature of 200° F. are poured over the
coffee in this cylinder and the time required for 58 ?uid
beans are brewed with softened water, such softening usu~
ounces of brew to collect is recorded. In such a test, hard
ally being the result of substitution of sodium ions for 30 water
is simulated by dissolving 400 parts per million
the calcium ions normally present, the coffee beverage has
poor quality in terms of ?avor and appearance. The poor
quality is attributable to changes in the coffee grounds
whereby they produce a ?lter blend of slower ?ltration
action, to reaction with the tannin-like and/or partially
decomposed carbohydrate materials in the coffee beans
productive of a very dark coloring matter in the coffee
solution and to alteration effects upon the naturally occur
ring ?avoring components of the coffee beans. The effects
(p.p.m.) of calcium chloride and 200 parts per million
(p.p.rn.) of sodium bicarbonate in distilled water. To
simulate brewing with softened water, 500 ppm. of
sodium bicarbonate is dissolved in distilled Water.
Generally a brew time of 360 seconds or less is deemed
an acceptable period. A brew time is attained for con
ventional grinds of coffee, for example, a conventional
grind consisting of a coffee of a particle size showing
2.3% retained on a No. 16 US. Standard Screen, 29.9%
resulting from the use of softened water are so apparent 40 on a No. 20 US. Standard Screen, 45.1% on a No. 30
that the average coffee drinker recognizes the differences
simply from visual observation and testing the vapor for
aroma.
Now it has been discovered that a ground coffee bean
product can be prepared which will meet the commonly
accepted standard for brews even though prepared with
softened water. This dry, ground coffee bean composition
is prepared by roasting coffee beans, preferably a blend
US. Standard Screen, 22.5% passing a No. 30 US.
Standard Screen and 12% passing through a 100 mesh
screen, of 274 seconds with hard water. The same grind
of coffee brewed with soft water will not ?lter in a period
which meets the speci?cation of 360 seconds or less but
gives a ‘brew time of 560 seconds, alperiod which is so
long and extended that the brew has bitterness and off
?avors.
of African, Central American, South-American, etc., cof
- To attain an acceptable brew time when the coffee brew
fees to a temperature in the range between about 375° F. 50 is to be prepared with softened water, it is necessary that
and about 425° F., preferably between about 390° F. and
the coffee beans, roasted as above described, be com
about 410° F., until a brew thereof prepared according
minuted to particles of reasonably uniform size and fall
to a brew test and measured by a spectrophotometer at
within a critical range of dimensions. ‘To meet the re
550 millimicron wave length shows an optical density in
the range between about 0.35 and 0.45, and irrespective of 55 quirements, it is necessary that about 95% to 100% of
a grind pass through a No. 16 US. Standard Screen and
the order of the following steps, grinding the beans to
that less than 10% and preferably less than 6% be ?nes
produce a comminuted coffee of a relatively uniform
passing through a No. 100 US. Standard Screen.
particle size such that preferably 95% thereof will pass
A material of such uniform particle size may be at
through a No. 16 US. Standard Screen, and less than about
10% will be ?nes capable of passage through a No. 100 60 tained by careful grinding in conventional coffee grinders
and, if necessary, by screening to limit the end product
Standard Screen, and incorporating an edible or food grade
to a maximum of 10% of ?nes.
organic acid in amounts between 0.1% and 0.5% by
weight of the dry, comminuted coffee beans.
Roasting conditions and grinding conditions, are not in
Coffee beans useful for the purposes of this invention
and of themselves su?icient to insure acceptable ?avor
fall into the broad categories of Brazils,'Central American, 65 and aroma. It is necessary to maintain an acidity in the
Colombian, East African Arabica and African Robusta
brews in the pH range between about 4.8 and 5.4. To
coffees.
accomplish this result, an edible organic acid is incor
Green coffee beans either of a single variety or a blended
porated into the coffee composition. Suitable acids are
mixture are roasted in conventional roasters at tempera
citric acid, tartaric acids, malic acid, lactic acid and the
70
tures in the range between about 375° F. and 425° F.
like. An acid, for example, citric acid may be mixed in
The termination point for roasting is determined by peri
powder form into a ground coffee or incorporated by
3,373,041
.
4
3
and approximately 6% passes a No. 100 U.S. Standard
Screen.
beans or a ground coffee.
This product was tested for brewing time. With hard
A typical solution for spraying coffee beans contains
water, the product had a brew time of 238 seconds. With
between about one and about two pounds of citric acid
per quart of water. Acid, in solid or solution form is in in softened water, the product had a brew time of 251 sec
onds. The pH of the brew prepared with softened water
corporated into the coffee bean material in quantities
was approximately 5.1.
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to have 0.1% to 0.5%, preferably between 0.15% and
The coffee compositions show to advantage irrespective
0.25% of citric acid, based upon the weight of the coffee
of the brewing method, although some property such as
beans. Tartaric acid in approximately the same amounts
will produce approximately the same pH in a softened 10 color or taste may show greater enhancement than the
spraying a solution of the acid onto either the coffee
other, but the advantages in all properties are particular
ly apparent when subjected to “drip-type” brewing or
water brew of a grind of coffee beans.
The invention will be more fully illustrated by ‘the
when using pressure in a closed system.
following examples of the method of preparation of a
The foregoing description is given for clearness of
grind of coffee beans and the character of the coffee
understanding and no unnecessary limitation should be‘
drink prepared using softened water, which are given by
understood therefrom because modifications will be un
way of illustration and without any intention that the
derstood by those skilled in the art.
'
invention be limited thereto.
We claim:
EXAMPLE I
1. The method of preparing a coffee adapted for use
A commercial blend of green coffee beans is prepared 20 with softened water which comprises roasting green coffee
beans to a temperature in the range between about 375°
by mixing on a weight basis, 40% of a Santos IV coffee,
F. and 425° F. until the ?ltrate obtained by brewing 2
40% of a Central American coffee and 20% of Colom
ounces of comminuted roasted beans of a particle size
of 100% passing a 30 mesh standard screen to 100 cc. of
bian coffee. 500 pounds of the blended green beans are
roasted to a temperature of approximately 400° F. in
a so-called Thermalo roaster, manufactured by Jabez
boiling distilled water and boiling for ?ve minutes, cool
ing the decoction to 68° F., diluting with distilled water
Burns and Company, until the optical density of a brew
of a sample of the roasted beans was 0.4 by the spectro
photometer test.
to a volume of 100 ml., and ?ltering, when read on the
spectrophotometer at a 500 millimicron wavelength, has
an optical density between 0.35 and 0.45, and irrespective
The roasted beans were cooled to room temperature
and the beans sprayed with one quart of solution con 30 of order, the steps of incorporating an organic food acid
in an amount between about 0.1% and about 0.5% by
taining one pound of citric acid so as to incorporate ap
weight of the coffee and comminuting the roasted beans
whereby a particulate material is recoverable of a particle
size such that at least 95% passes through a No. 16 U.S.
Standard Screen and the maximum amount of particles
passing a No. 100 U.S. Standard Screen is less than about
6%.
2. The method according to claim 1 in which the
proximately 0.2% by weight of citric acid.
. The citric acid impregnated coffee was ground to a
particle size such that 100% passed through a No. 116
U.S.
U.S.
U.S.
only
Standard Screen, 45% was retained on a No. 20
Standard Screen, 45% was retained on a No. 30
Standard Screen, 10% passed the No. 30 screen and
4% passed a No. 100 U.S. Standard Screen as ?nes.
organic food acid is citric acid.
This product was tested for brewing time. With hard
3. The method according to claim 1 wherein the coffee
water; the product had a brew time of 221 seconds. With 40
beans are roasted to a temperature in the range between
softened water, the product had a brew time of 247 sec
about 390° F. and 410° F.
onds. The pH of the brew prepared with softened water
4. The method according to claim 1 wherein the optical
was approximately 5.2.
density is in the range between about 0.38 and about‘
In tests of coffee brews prepared using softened water,
a statistically signi?cant number of testers usually con 45 0.42.
5. The method according to claim 1 wherein the or
stituting better than 85% of the test panel and often con
ganic food acid is added as a water solution and applied
stituting 100% of the test panel picked the coffee brew
prepared from the coffee composition prepared as de
by spraying onto roasted coffee beans after the cooling
scribed in this example as the preferred brew, for ex
thereof.
ample, in a test using a panel of 16, at least 14 preferred 50
6. The method according to claim 1 wherein the or
the brew prepared from the coffee of this example.
ganic food acid in pulverulent form is mixed with com
minuted coffee beans.
EXAMPLE II
A blend of green coffee beans is prepared by mixing
on a weight basis, 60% of Santos coffee, 30% Colombian 65
coffee and 10% of African Robusta. 500 pounds of the
1,946,398
blended green beans are roasted to a temperature of ap
proximately 396° P. so that an optical density of a brew
of a sample to the roasted beans was 0.38 by the spectro<
photometer test.
The roasted beans were cooled to room temperature
and the beans sprayed with one quart of solution con
taining one pound of citric acid so as to incorporate ap
proximately 0.2% by weight of citric acid.
References Cited
UNITED STATES PATENTS
2/1934
Gilbreath ___________ __ 99-68
OTHER REFERENCES
60
Lockhart, Ernest E., “Water, Coffee, and Beverage
Preparation,” publ. by Coffee Brewing Inst, Inc. New
York, publication No. 56, April 1966, pp. 4 and 9 re
lied on.
Vogel, Edward H., J12, et al., “The Practical Brewer,”
The citric acid impregnated coffee was ground to a 65 publ. by Master Brewers Assoc. of America, St. Louis,
1964, p. 5.
particle size such that 2% is retained on a No. 16 U.S.
Standard Screen, 32% is retained on a No. 20 U.S.
MAURICE W. GREENSTEIN, Primary Examiner.
Standard Screen, 46% is retained on a No. 30 U.S. Stand
ard Screen, 20% passes the No. 30 U.S. Standard Screen 70 A. LOUIS MONACELL, Examiner.
UNITED STATES PATENT OFFICE
CERTIFICATE OF CORRECTION
Patent No. 3,373,041
‘ March 12, 1968
Jack Bloom et :11.
It is certified that error appears in the above identified
patent and that said Letters Patent are hereby corrected as
shown below:
Column 4, line 23, "ounces" should read -- grams 1--.
Signed and sealed this 29th day of July 1969.
(SEAL)
Attest:
Edward M. Fletcher, Jr.
Atiesting Officer
WILLIAM E. SCHUYLER, JR.
Commissioner of Patents