CA1054439A - Decaffeination process - Google Patents
Decaffeination processInfo
- Publication number
- CA1054439A CA1054439A CA260412A CA260412A CA1054439A CA 1054439 A CA1054439 A CA 1054439A CA 260412 A CA260412 A CA 260412A CA 260412 A CA260412 A CA 260412A CA 1054439 A CA1054439 A CA 1054439A
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- Canada
- Prior art keywords
- coffee
- drying
- surface solids
- water
- solids
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
IMPROVED DECAFFEINATION PROCESS
ABSTRACT OF THE INVENTION
Decaffeinated coffee of improved quality is achieved using a process wherein caffeine-containing green coffee is countercurrently extracted with a water solution of coffee solubles. The decaffeinated coffee removed from the extraction zone is treated to remove surface solids contained thereon and is then dried at temperatures not in excess of 200°F. The critical combination of a specified lower limit of surface solids on the coffee prior to drying and the drying temperature has been found to result in a decaffeinated coffee product of improved flavor.
ABSTRACT OF THE INVENTION
Decaffeinated coffee of improved quality is achieved using a process wherein caffeine-containing green coffee is countercurrently extracted with a water solution of coffee solubles. The decaffeinated coffee removed from the extraction zone is treated to remove surface solids contained thereon and is then dried at temperatures not in excess of 200°F. The critical combination of a specified lower limit of surface solids on the coffee prior to drying and the drying temperature has been found to result in a decaffeinated coffee product of improved flavor.
Description
This invention relates to coffee and more particularly to decaffeinated coffee.
The major concern of decaffeinated coffee producers has long been the desire to achieve rapid efficient removal of caffein from green coffee without deleteriously affecting the eventual coffee product produced from the decaffeinated coffee. Thus for example, while extremely high temperatures will generally increase decaffeination rates it is at the expense of damaging the flavor and aroma components of the green coffee resulting in a final coffee product which does not closely resemble its undecaffeinated counterpart.
Decaffeination processes employing an organic solvent for caffeine have the advantage of achieving caffeine removal in a relatively short time; however, direct contact of green coffee ;~
with solvent may be undesirable due to the possibility of amounts of solvent remaining in the coffee and thereby adversely altering the flavor of resultant coffee product. Further, caffeine- i solvents are also found to remove amounts of desirable waxes and oils from the green coffee which themselves contribute to the overall flavor and aroma of the coffee. -U.S. Patent 2,309,092 to Berry et al. issued January 26, - 1943 (see Canada Patent No. 432,659~ describes a no~able advance in the decaffeination art. According to this process, the extraction medium for caffeine is a water solution of green coffee water solubles, other than caffeine, at a concentration in equi- `
librium with the water soluble solids in the green coffee. This aquebus extract is continuously rec~cled through the green coffee `~
. .
and through a liquid-liquid extraction with a water-immiscible, c ~ organic caffeine solvent. This method produces decaffeinated ;~
. ' ' ' ~ ':.
; : ~
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`
` ` 1854~39 coffee of superior flavor and aroma for beverage purposes due to the fact that the organic caffeine solvent does not come in direct contact with the green coffee beans.
- Although the water extraction process described in U.S.
Patent 2,309,092 was a decided advance in the art, there still exists the need for further improving the quality of decaffeinated coffees such that coffee beverages prepared therefrom more nearly ~;~
approximate their undecaffeinated counterparts in flavor and aroma.
Accordingly this invention prepares decaffeinated coffees of improved quality.
Further this invention prepares decaffeinated coffees ``
of improved quality by improvement on the water extraction process described in U.S. Patent 2 r 309,092 (Canada 432,659). :~
The foregoing is accomplished in this invention by ,:
` improving the treatment of the decaffeinated green coffee produced by the water extraction process after the green coffee has been discharged from the extraction zone. Thus, the present . .
invention is a decaffeination process wherein caffeine-containing green coffee is added to one end of an extraction zone, and withdrawn from the other end of the extraction zone while a water solution of coffee solubles is flowed through said zone counter- ~i~
current to said coffee, the improvement comprising removing ~i surface solids from said withdrawn coffee such that less than about ' 0.3~ by dry weight remain thereon, and subsequentl~ dr~ing said , coffee at temperatures not in excess of 200F.
,~ According to the process of this invention caffeine-containing green coffee is decaffeinated using a water solution of green coffee water solubles other than caffeine according to .~ .
~ - 2 - ~
' ~ .
~ ' , , ~ ' , , ; ' ~
10~4439 the process described in U.S. Patent 2,309,092. Hence, it is essential in order to understand the environment of this invention to refer to the above-mentioned patent wherein the - extraction of caffeine from green coffee is described and which further describes the subsequent treatment of the extraction medium to remove caffeine therefrom. The improved quality product of this invention is achieved by processing improve-ments performed on the decaffeinated coffee withdrawn from the extraction zones af-ter having been finally contacted with the 10 water extraction medium as described in Berry, et al.
According to this invention, the decaffeinated coffee withdrawn from the caffeine-extraction zone is treated to t remove surface solids remaining thereon and then dried at temperatures not in excess of 200F. It has been ound that - this combination of operating steps is critical in order to achieve an improved quality decaffeinated coffee. Thus, merely removing surface solids yet drying at temperatures above 200F.
does not result in any significant quality improvement. Con-` versely, drying temperatures below 200F. do not result in any 20 significant quality improvement if the surface solids on the coffee before drying are not lowered below the aforementioned ; level.
The decaffeinated coffee withdrawn from the extrac-tion zone contains solids adhering thereto as a r~sult of . contact with the water solution of coffee solubles during , extraction. Following the overall Berry et al. process wherein ;; the decaffeinated coffee is washed with an amount of water ., :
s~bstantially equal to the ' '',, ~
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volume of the extracting liquid absorbed by the coffee it has been found that surface solids do :in fact remain on the coffee generally in the order of about 1.0% to 1.8~ by dry weight of the coffee.
We have found that in order to obtain a decaffeinated coffee of improved quality it is necessary to remove surface solids such that the decaffeinated coffee contains less than about 0.3% surface solids by dry weight prior to being dried.
In the most preferred practice of this invention, substantially all the surface solids are removed fromthe decaffeinated green coffee. In practice~ this embodiment requires beans with less than about 0.1% surface solids by dry weight remaining thereon prior to drying.
A variety of methods may be employed to remove the requisite surface solids from the decaffeinated green coffee withdrawn from the extraction zone. Thus, wash water can be directed on the coffee in an amount and for a time sufficient to result in decaffeinated green coffee having surface solids below the above-mentioned leveI. The green coffee is then separated . ~ ~
from the resultant water solution, for example, by decantation - or washing the coffee on a screen. However, since the surface solids removed from the green coffee are generally recycled to the feed supply of the water extract to the extraction zone it has been found that due to the amount of water needed to remove . .
., ;: the requisite solids, the surface solids solution added back :~, to the feed supply of water extract may result in too substantial ' a dilution of the feed supply hence altering the substantial dynamic equilibrium between water extract solids and green coffee ;. , .
solids desired during extraction.
. , .
.;
.
.~, . ... .
; 1~354439 Accordingly, our most preferred means for achievin~ the requisite surface solids removal from the decaffeinated green coffee is by subjecting the coffee to the action of centrifugal force. Typically, a basket-type centrifuge is employed wherein the decaffeinated coffee withdrawn from the extraction zone is loaded into the centrifuge and during centrifugation the solids solution is forced through the basket apertures and directed into a suitable collection vessel from which the solution is pumped to the feed supply of water extract.
The coffee may be transferred directly from the extrac tion zone into the centrifuge apparatus and subjected to centri-. .
fugal force sufficient to remove the requisite amount of surface solids. Alternatively, the coffee may first be water washed with , ~ .
an amount of water insufficient to result in substantial dilutionof the feed supply of green extract when the aqueous effluent from the washing step is added thereto and then centrifuged to remove the additional surface solids needed to result in coffee having less than 0.3% surface solids by dry weight prior to drying.
Generally it is not necessary to add any aqueous wash -solution when centrifuging is employed making this means of solids removal particularly attractive since the aqueous effluent from -the centrifuge will not cause extensive dilution when added to the -feed supply of water extract to the extraction zone. However, it may be desirable to add minor amounts of water during centrifuga-tion to facilitate solids removal. A particularly preferred embodiment invo:Lves first centrifuging without adding water and then centrifuging again with minor amounts of added water. In any event the e:Efluent from the centrifuge is not so dilute so as ~' ~
to significantly adverseIy alter the concentration of the feed i . ' .
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water extract supply.
, Whenever wash water is employed to achieve surface solids removal it is preferred that the Water be relatively cold, thai is, less than about 100F. and preferably below 60F. so as ` to avoid the actual extraction of water soluble constituents from within the decaffeinated green coffee. It is also found that ,~ even treatment with cold water if for a long enough period of time .,, may also result in the extraction of soluble green coffee con-stituents. The washing time and water temperature can be easily optimized and counterbalanced to achieve only the removal of surface solids without any substantial extraction occurring. When centrifugation is employed it is rate that amounts of water or r';.
time of contact will be substantial enough to cause extraction making centrifuging an especially preferred method.
When employing centrifugation to remove the requisite surface solids from the decaffeinated coffee prior to drying it `
is preferred to operate at a centrifugal force in excess of about 180 G's and most preferably above about 500 G's. Under these conditions surface solids are efficiently removed from the decaf- -feinated coffee at a relatively rapid rate. While no criticality exists as to an upper limit it is generally unnecessary to exceed ,~-about 600-700 G's.
As previously stated, it is preferred to remove sub-stantially all of the surface solids from the decaffeinated coffee --prior to drying since we have found the quality improvement to be at its greatest when this condition is met. By substantially all is generally meant less than about 0.1% surface solids by dry weight remaining on the coffee. This condition is easily observed merely by washing the beans until a clear effluent appears. Similarly, where centrifuging is employed with wash , , .
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water added, the appearance of a clear effluent generally indicates the achievement of substantially complet`e removal. Where contri- t fuging is employed with no water added it is possible to visually observe the condition of complete solids removal.
Where it is not desired to remove substantially all of the surface solids, and irrespective of the particular means employed for removing surface solids from the decaffeinated green coffee prior to drying we have found that the measurement of the surface solids remaining on the coffee is best achieved using a centrifuge apparatus.
As an example of the use of his method, a sample portion of beans removed from the extraction zone are placed in a basket `
centrifuge and spun and washed until a clear effluent appears (indicating the removal of substantially all the surface solids).
The concentration of the total effIuent is measured and ~nowledge of the amount of effluent collected allows a calculation of the `
weight of surface solids removed which in turn is the weight of total surface solids on the beans removed from the extraction zone. ~;
: -:
When a batch of beans removed from the extraction zone is treated to remove surface solids, the solids removed are measured and then substracted from the total surface solids content, as calculated above, yielding the weight of surface solids remaining on the decaffeinated beans which can bhen be expressed as a percentage by dry weight.
As earlier mentioned, the provision of decaffeinated - ' green coffee having less than about 0.3% surface solids by dry weight and preferably less than 0.1% prior to drying is not itself -alone sufficient to achieve a significant quality improvement in . . . I .
the decaffeinatPd coffee. It is critical to this invention to dry ~ ~ .
. .
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the so treated coffee at drying tempera-tures not in excess of about 200F. Coffee having below the critical level of surface solids yet dried at temperatures above about 200F. does not dis-play the degree of quality improvement obtained by this invention.
Numerous drying techniques may be employed according to this invention so long as the temperatures involved do not exceed about 200F. It is preferred that the temperature be less than about 180F. (For example, freeze-drying may be employed or microwave drying). One preferred drying means are air dryers typically such as fixed-bed dryers wherein hot air is passed ;
through a fixed bed o coffee, belt dryers wherein a moving bed of coffee is continuously passed through an air drying chamber, ;
agitated dryers wherein coffee is continuously tumbled in a hot air-containing vessel e.g., a roaster, and fluidized bed dryers wherein coffee is contacted with an upward stream of air such that the coffee is agitated and constant particle to particle ;
contact is minimized allowing for more efficient drying of each individual ~article. Any such method may be employed so lGng as the drying temperature does not exceed 200F., howev~r, our most -preferred method employs a fluidized bed dryer utilizing an air inlet temperature of about 150F.
The following examples are provided to illustrate specific embodiments of this invention.
EXAMPLE I
Decaffeinated coffee beans withdrawn from the extraction zone according to the process described in U.S. Patent 2,309,092 and washed with water according to the above patent were collected and separated into three 3-3t4 pound samples. Samples III was given additional treatment by placing it in a basket centrifuge , : .i .
.
i(~S~39 for 30 seconds rotating at about 600 G's, and then rotated for an additional 30 seconds with the addition of a light spray of water at 58F. A clear effluent appeared and 1.8% surface solids by dry weight were found to have been removed. Sample I was given no additional treatment ~thus having 1.8~ surface solids thereon) and Sample II was treated via centrifuging such that 0.55%
surface solids by dry weight remained thereon.
All three samples were dried in a fluidized bed dryer utilizing an air temperature of about 151F. Coffee brews were prepared by separately roasting and grinding the three samples A
- and percolating them. An expert flavor panel preferred Sample III.; in that it was cleaner and stronger than either Sample I or Sample II. Sample II displayed no signigicant improvement over i Sample I.
h EX~PLE II
Decaffeinated green coffee recovered after washing according to the Berry, et al. process were divided into four samples. Sample I was given no additional treatment and contained approximately 1.5% surface solids bv dry weight. Sample II
through IV were centrifuged with the addition of water at about 600 G's until subs-tantially all the surface solids were removed (less than about 0.1% by dry weight~. `
Sample I was dried using a ROTO-LO W RE* Dryer having an inlet air temperature of 350F. This type dryer is a rotating .... ... .. . ... .. ... .. . .
vessel described in Chemical Engineers Handbook, 20 - 29, 4th ed.
(McGraw-~ill 19631. 5amples II through IV were dried in a fluidized bed dryer at air temperatures of 150F., 180F. and 220F. All samples were then brewed under identical conditions.
, . r , *Trademark . _ 9 - ; ., - ,.:: ,, `~ 105~43~
An expert taste panel found Sample I to be t~in and underdeveloped with low aromatics and similar characteristics for Sample IV. Samples II and III were preferred by the tasters in that the brews were cleaner, smoother, more full-bodies and higher in aromatics.
. While the above examples.illustrate specific preferred . embodiments of the invention they are not intended to th~reby limit the present invention. Various other modifications and : operating parameters are believed ascertainable by those s~illed- ..
: in-the-art without departing from the scope and spirit of the invention as defined by the claim= herein.
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The major concern of decaffeinated coffee producers has long been the desire to achieve rapid efficient removal of caffein from green coffee without deleteriously affecting the eventual coffee product produced from the decaffeinated coffee. Thus for example, while extremely high temperatures will generally increase decaffeination rates it is at the expense of damaging the flavor and aroma components of the green coffee resulting in a final coffee product which does not closely resemble its undecaffeinated counterpart.
Decaffeination processes employing an organic solvent for caffeine have the advantage of achieving caffeine removal in a relatively short time; however, direct contact of green coffee ;~
with solvent may be undesirable due to the possibility of amounts of solvent remaining in the coffee and thereby adversely altering the flavor of resultant coffee product. Further, caffeine- i solvents are also found to remove amounts of desirable waxes and oils from the green coffee which themselves contribute to the overall flavor and aroma of the coffee. -U.S. Patent 2,309,092 to Berry et al. issued January 26, - 1943 (see Canada Patent No. 432,659~ describes a no~able advance in the decaffeination art. According to this process, the extraction medium for caffeine is a water solution of green coffee water solubles, other than caffeine, at a concentration in equi- `
librium with the water soluble solids in the green coffee. This aquebus extract is continuously rec~cled through the green coffee `~
. .
and through a liquid-liquid extraction with a water-immiscible, c ~ organic caffeine solvent. This method produces decaffeinated ;~
. ' ' ' ~ ':.
; : ~
~:
`
` ` 1854~39 coffee of superior flavor and aroma for beverage purposes due to the fact that the organic caffeine solvent does not come in direct contact with the green coffee beans.
- Although the water extraction process described in U.S.
Patent 2,309,092 was a decided advance in the art, there still exists the need for further improving the quality of decaffeinated coffees such that coffee beverages prepared therefrom more nearly ~;~
approximate their undecaffeinated counterparts in flavor and aroma.
Accordingly this invention prepares decaffeinated coffees of improved quality.
Further this invention prepares decaffeinated coffees ``
of improved quality by improvement on the water extraction process described in U.S. Patent 2 r 309,092 (Canada 432,659). :~
The foregoing is accomplished in this invention by ,:
` improving the treatment of the decaffeinated green coffee produced by the water extraction process after the green coffee has been discharged from the extraction zone. Thus, the present . .
invention is a decaffeination process wherein caffeine-containing green coffee is added to one end of an extraction zone, and withdrawn from the other end of the extraction zone while a water solution of coffee solubles is flowed through said zone counter- ~i~
current to said coffee, the improvement comprising removing ~i surface solids from said withdrawn coffee such that less than about ' 0.3~ by dry weight remain thereon, and subsequentl~ dr~ing said , coffee at temperatures not in excess of 200F.
,~ According to the process of this invention caffeine-containing green coffee is decaffeinated using a water solution of green coffee water solubles other than caffeine according to .~ .
~ - 2 - ~
' ~ .
~ ' , , ~ ' , , ; ' ~
10~4439 the process described in U.S. Patent 2,309,092. Hence, it is essential in order to understand the environment of this invention to refer to the above-mentioned patent wherein the - extraction of caffeine from green coffee is described and which further describes the subsequent treatment of the extraction medium to remove caffeine therefrom. The improved quality product of this invention is achieved by processing improve-ments performed on the decaffeinated coffee withdrawn from the extraction zones af-ter having been finally contacted with the 10 water extraction medium as described in Berry, et al.
According to this invention, the decaffeinated coffee withdrawn from the caffeine-extraction zone is treated to t remove surface solids remaining thereon and then dried at temperatures not in excess of 200F. It has been ound that - this combination of operating steps is critical in order to achieve an improved quality decaffeinated coffee. Thus, merely removing surface solids yet drying at temperatures above 200F.
does not result in any significant quality improvement. Con-` versely, drying temperatures below 200F. do not result in any 20 significant quality improvement if the surface solids on the coffee before drying are not lowered below the aforementioned ; level.
The decaffeinated coffee withdrawn from the extrac-tion zone contains solids adhering thereto as a r~sult of . contact with the water solution of coffee solubles during , extraction. Following the overall Berry et al. process wherein ;; the decaffeinated coffee is washed with an amount of water ., :
s~bstantially equal to the ' '',, ~
' ~. .
1~ ~:
, ~
~, ~ ,:
:. :
:~` 10~443~31 .
volume of the extracting liquid absorbed by the coffee it has been found that surface solids do :in fact remain on the coffee generally in the order of about 1.0% to 1.8~ by dry weight of the coffee.
We have found that in order to obtain a decaffeinated coffee of improved quality it is necessary to remove surface solids such that the decaffeinated coffee contains less than about 0.3% surface solids by dry weight prior to being dried.
In the most preferred practice of this invention, substantially all the surface solids are removed fromthe decaffeinated green coffee. In practice~ this embodiment requires beans with less than about 0.1% surface solids by dry weight remaining thereon prior to drying.
A variety of methods may be employed to remove the requisite surface solids from the decaffeinated green coffee withdrawn from the extraction zone. Thus, wash water can be directed on the coffee in an amount and for a time sufficient to result in decaffeinated green coffee having surface solids below the above-mentioned leveI. The green coffee is then separated . ~ ~
from the resultant water solution, for example, by decantation - or washing the coffee on a screen. However, since the surface solids removed from the green coffee are generally recycled to the feed supply of the water extract to the extraction zone it has been found that due to the amount of water needed to remove . .
., ;: the requisite solids, the surface solids solution added back :~, to the feed supply of water extract may result in too substantial ' a dilution of the feed supply hence altering the substantial dynamic equilibrium between water extract solids and green coffee ;. , .
solids desired during extraction.
. , .
.;
.
.~, . ... .
; 1~354439 Accordingly, our most preferred means for achievin~ the requisite surface solids removal from the decaffeinated green coffee is by subjecting the coffee to the action of centrifugal force. Typically, a basket-type centrifuge is employed wherein the decaffeinated coffee withdrawn from the extraction zone is loaded into the centrifuge and during centrifugation the solids solution is forced through the basket apertures and directed into a suitable collection vessel from which the solution is pumped to the feed supply of water extract.
The coffee may be transferred directly from the extrac tion zone into the centrifuge apparatus and subjected to centri-. .
fugal force sufficient to remove the requisite amount of surface solids. Alternatively, the coffee may first be water washed with , ~ .
an amount of water insufficient to result in substantial dilutionof the feed supply of green extract when the aqueous effluent from the washing step is added thereto and then centrifuged to remove the additional surface solids needed to result in coffee having less than 0.3% surface solids by dry weight prior to drying.
Generally it is not necessary to add any aqueous wash -solution when centrifuging is employed making this means of solids removal particularly attractive since the aqueous effluent from -the centrifuge will not cause extensive dilution when added to the -feed supply of water extract to the extraction zone. However, it may be desirable to add minor amounts of water during centrifuga-tion to facilitate solids removal. A particularly preferred embodiment invo:Lves first centrifuging without adding water and then centrifuging again with minor amounts of added water. In any event the e:Efluent from the centrifuge is not so dilute so as ~' ~
to significantly adverseIy alter the concentration of the feed i . ' .
i :- . .. . . . , . , . . ... . , . , ,: .
~05~43~
, - .
water extract supply.
, Whenever wash water is employed to achieve surface solids removal it is preferred that the Water be relatively cold, thai is, less than about 100F. and preferably below 60F. so as ` to avoid the actual extraction of water soluble constituents from within the decaffeinated green coffee. It is also found that ,~ even treatment with cold water if for a long enough period of time .,, may also result in the extraction of soluble green coffee con-stituents. The washing time and water temperature can be easily optimized and counterbalanced to achieve only the removal of surface solids without any substantial extraction occurring. When centrifugation is employed it is rate that amounts of water or r';.
time of contact will be substantial enough to cause extraction making centrifuging an especially preferred method.
When employing centrifugation to remove the requisite surface solids from the decaffeinated coffee prior to drying it `
is preferred to operate at a centrifugal force in excess of about 180 G's and most preferably above about 500 G's. Under these conditions surface solids are efficiently removed from the decaf- -feinated coffee at a relatively rapid rate. While no criticality exists as to an upper limit it is generally unnecessary to exceed ,~-about 600-700 G's.
As previously stated, it is preferred to remove sub-stantially all of the surface solids from the decaffeinated coffee --prior to drying since we have found the quality improvement to be at its greatest when this condition is met. By substantially all is generally meant less than about 0.1% surface solids by dry weight remaining on the coffee. This condition is easily observed merely by washing the beans until a clear effluent appears. Similarly, where centrifuging is employed with wash , , .
. - ,:
,, - 6 -., :.
. :, ~;. , ~os4439 ~
water added, the appearance of a clear effluent generally indicates the achievement of substantially complet`e removal. Where contri- t fuging is employed with no water added it is possible to visually observe the condition of complete solids removal.
Where it is not desired to remove substantially all of the surface solids, and irrespective of the particular means employed for removing surface solids from the decaffeinated green coffee prior to drying we have found that the measurement of the surface solids remaining on the coffee is best achieved using a centrifuge apparatus.
As an example of the use of his method, a sample portion of beans removed from the extraction zone are placed in a basket `
centrifuge and spun and washed until a clear effluent appears (indicating the removal of substantially all the surface solids).
The concentration of the total effIuent is measured and ~nowledge of the amount of effluent collected allows a calculation of the `
weight of surface solids removed which in turn is the weight of total surface solids on the beans removed from the extraction zone. ~;
: -:
When a batch of beans removed from the extraction zone is treated to remove surface solids, the solids removed are measured and then substracted from the total surface solids content, as calculated above, yielding the weight of surface solids remaining on the decaffeinated beans which can bhen be expressed as a percentage by dry weight.
As earlier mentioned, the provision of decaffeinated - ' green coffee having less than about 0.3% surface solids by dry weight and preferably less than 0.1% prior to drying is not itself -alone sufficient to achieve a significant quality improvement in . . . I .
the decaffeinatPd coffee. It is critical to this invention to dry ~ ~ .
. .
~ 7 -;...................................................................... .
~
.
,; . . ' , ' . . -. , : .
: ~05~3~ :
.
the so treated coffee at drying tempera-tures not in excess of about 200F. Coffee having below the critical level of surface solids yet dried at temperatures above about 200F. does not dis-play the degree of quality improvement obtained by this invention.
Numerous drying techniques may be employed according to this invention so long as the temperatures involved do not exceed about 200F. It is preferred that the temperature be less than about 180F. (For example, freeze-drying may be employed or microwave drying). One preferred drying means are air dryers typically such as fixed-bed dryers wherein hot air is passed ;
through a fixed bed o coffee, belt dryers wherein a moving bed of coffee is continuously passed through an air drying chamber, ;
agitated dryers wherein coffee is continuously tumbled in a hot air-containing vessel e.g., a roaster, and fluidized bed dryers wherein coffee is contacted with an upward stream of air such that the coffee is agitated and constant particle to particle ;
contact is minimized allowing for more efficient drying of each individual ~article. Any such method may be employed so lGng as the drying temperature does not exceed 200F., howev~r, our most -preferred method employs a fluidized bed dryer utilizing an air inlet temperature of about 150F.
The following examples are provided to illustrate specific embodiments of this invention.
EXAMPLE I
Decaffeinated coffee beans withdrawn from the extraction zone according to the process described in U.S. Patent 2,309,092 and washed with water according to the above patent were collected and separated into three 3-3t4 pound samples. Samples III was given additional treatment by placing it in a basket centrifuge , : .i .
.
i(~S~39 for 30 seconds rotating at about 600 G's, and then rotated for an additional 30 seconds with the addition of a light spray of water at 58F. A clear effluent appeared and 1.8% surface solids by dry weight were found to have been removed. Sample I was given no additional treatment ~thus having 1.8~ surface solids thereon) and Sample II was treated via centrifuging such that 0.55%
surface solids by dry weight remained thereon.
All three samples were dried in a fluidized bed dryer utilizing an air temperature of about 151F. Coffee brews were prepared by separately roasting and grinding the three samples A
- and percolating them. An expert flavor panel preferred Sample III.; in that it was cleaner and stronger than either Sample I or Sample II. Sample II displayed no signigicant improvement over i Sample I.
h EX~PLE II
Decaffeinated green coffee recovered after washing according to the Berry, et al. process were divided into four samples. Sample I was given no additional treatment and contained approximately 1.5% surface solids bv dry weight. Sample II
through IV were centrifuged with the addition of water at about 600 G's until subs-tantially all the surface solids were removed (less than about 0.1% by dry weight~. `
Sample I was dried using a ROTO-LO W RE* Dryer having an inlet air temperature of 350F. This type dryer is a rotating .... ... .. . ... .. ... .. . .
vessel described in Chemical Engineers Handbook, 20 - 29, 4th ed.
(McGraw-~ill 19631. 5amples II through IV were dried in a fluidized bed dryer at air temperatures of 150F., 180F. and 220F. All samples were then brewed under identical conditions.
, . r , *Trademark . _ 9 - ; ., - ,.:: ,, `~ 105~43~
An expert taste panel found Sample I to be t~in and underdeveloped with low aromatics and similar characteristics for Sample IV. Samples II and III were preferred by the tasters in that the brews were cleaner, smoother, more full-bodies and higher in aromatics.
. While the above examples.illustrate specific preferred . embodiments of the invention they are not intended to th~reby limit the present invention. Various other modifications and : operating parameters are believed ascertainable by those s~illed- ..
: in-the-art without departing from the scope and spirit of the invention as defined by the claim= herein.
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Claims (12)
1. In a decaffeination process wherein caffeine-containing green coffee is added to one end of an extraction zone, and withdrawn from the other end of the extraction zone while a water solution of coffee solubles is flowed through said zone counter-current to said coffee, the improvement comprising removing surface solids from said withdrawn coffee such that less than about 0.3% by dry weight remain thereon, and subsequently drying said coffee at temperatures-not in excess of 200°F.
2. The process of claim 1 wherein said drying is performed in an air fluidized-bed dryer.
3. The process of claim 2 wherein said drying temperature is less than about 180°F.
4. The process of claim 1 wherein said drying is performed by freeze-drying.
5. The process of claim 1 wherein said drying is performed by subjecting the coffee to the action of microwave energy.
6. The process of claim 1 wherein said surface solids are removed by subjecting said coffee to the action of centrifugal force.
7. The process of claim 6 wherein said centrifugal force is at least 185 G's.
8. The process of claim 7 wherein water is added to said coffee during centrifugation.
9. The process of claim 8 wherein said drying is performed in an air fluidized-bed dryer.
10. The process of claim 9 wherein less than 0.1%
surface solids by dry weight remains on said coffee before drying.
surface solids by dry weight remains on said coffee before drying.
11. The process of claim 10 wherein said drying temperature is less than about 180%F.
12. The process of claim 1 wherein said surface solids are removed by contacting said coffee with water and separating said coffee from the resultant water solution of solids.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA260412A CA1054439A (en) | 1976-09-02 | 1976-09-02 | Decaffeination process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA260412A CA1054439A (en) | 1976-09-02 | 1976-09-02 | Decaffeination process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1054439A true CA1054439A (en) | 1979-05-15 |
Family
ID=4106772
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA260412A Expired CA1054439A (en) | 1976-09-02 | 1976-09-02 | Decaffeination process |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1054439A (en) |
-
1976
- 1976-09-02 CA CA260412A patent/CA1054439A/en not_active Expired
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