CA1043155A - Pressure fixation of coffee grinder gas - Google Patents
Pressure fixation of coffee grinder gasInfo
- Publication number
- CA1043155A CA1043155A CA225,011A CA225011A CA1043155A CA 1043155 A CA1043155 A CA 1043155A CA 225011 A CA225011 A CA 225011A CA 1043155 A CA1043155 A CA 1043155A
- Authority
- CA
- Canada
- Prior art keywords
- glyceride
- vessel
- coffee
- frost
- aroma
- 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.)
- Expired
Links
Classifications
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23F—COFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
- A23F5/00—Coffee; Coffee substitutes; Preparations thereof
- A23F5/46—Coffee flavour; Coffee oil; Flavouring of coffee or coffee extract
- A23F5/48—Isolation or recuperation of coffee flavour or coffee oil
- A23F5/486—Isolation or recuperation of coffee flavour or coffee oil by distillation from beans, ground or not, e.g. stripping; Recovering volatile gases, e.g. roaster or grinder gases
Abstract
ABSTRACT OF THE DISCLOSURE
The concentration of volatile organics that can be in-corporated into a glyceride carrier is increased by the use of pressure in excess of 100 psia. Specifically coffee grinder gas aromatics are contacted with coffee oil in a pressure vessel.
The resulting aromatized oil is then combined with soluble coffee solids.
The concentration of volatile organics that can be in-corporated into a glyceride carrier is increased by the use of pressure in excess of 100 psia. Specifically coffee grinder gas aromatics are contacted with coffee oil in a pressure vessel.
The resulting aromatized oil is then combined with soluble coffee solids.
Description
11)43~55 This invention relates to a method for the manufacture of coffee aroma materials.
This invention is related to commonly assigned Patent Application, Serial No. lB2062 , wherein is disclosed a method for condensing the aromatic gases given off during the comminution of freshly roasted coffee in a vertically-mounted, scraped-wall heat exchanger which is cooled by means of liquid nitrogen. The condensed gases are collected at the bottom of the heat exchanger in the form of a fros~ or snow and this frost 0 i3 mixed with a liquid glyceride and then combined with a coffee extract prior to drying the extract (e.g., freeze drying) or com-bined with a soluble coffee powder.
Grinder gas, that is the gas which is released from roasted whole coffee beans when their internal cell structure is disrupted, such as during grinding of the beans and which also continues to be evolved from the disrupted and/or fractured bean f~r a short period thereafter, has long been recognized in the art as a highly desirable natural coffee aroma. The collection and stabilization of this aroma has how~ver proven to be a dif-ficult undertaking, especially when it is desired for use in a commercial-sized soluble coffee system.
The use of grinder gas as a means to enhance the jar aroma of a soluble coffee powder is disclosed in United States Patent No. 3,021,218 to Clinton et al. which aromatizes the jar headspace and United States Patent No. 2,306,061 to Johnston which condenses grinder gas aromatics onto chilled soluble coffee powder. The use of grinder gas condensates which are added to a liquid extract and dried in order to produce an improved cup aroma when the powder is dissolved in hot water is disclosed in United States Patent No. 3,244,533 to Clinton et al. which homogen-i~es coffee oil in extract and then adds condensed grinder gas aromatics. Condensed grinder gas frost can be mixed with a liquid glyceride which mixture is then processed to remove excess -1~43~5 water, such as by centrifugation, prior to being combined with soluble coffee solids (e.g., soluble powder).
; This invention is directed to fixing in a glyceride carrier aromatics contained in an aroma-bearing gas which has a high (e.g., above 80% by weight) carbon dioxide content, and which has been condensed as an aroma-bearing frost. This invention will be particularly described in terms of coffee grinder gas which contains in excess of 90% CO2 by weight;
however, it is to be understood that other aroma-bearing gases, such as percolator vent gas and roaster gas, may likewise be employed.
According to the invention there is provided a method for producing a coffee-aroma material which can be added to coffee solids wherein an aroma-containing frost with a carbon -dioxide content is condensed from a gas containing aroma, the frost is placed in a pressure vessel and is contacted under pressure while the vessel is isolated from the atmosphere with a liquid glyceride in the amount of 1 gram glyceride to 0.5 to 6 grams of frost, the pressure is released at a rate which avoids formation of liquid carbon dioxide and a glyceride material containing coffee-aroma is recovered.
In a specific embodiment there is provided a method for aromatizing soluble coffee comprising the steps of:
a) condensing, as a frost, an aroma-containing gas which ~-has a high carbon dioxide content;
b) placing the aroma-containing frost in a pressure vessel;
~, .
~43~5 c) contacting within said pressure vessel, under a pressure of at least 100 psia, the frost aromas and a liquid glyceride, said glyceride being present in the pressure vessel at a level of about one gram of glyceride to 0.5 to 6 grams of the frost;
d) removing the glyceride from the vessel and combining it with coffee solids.
The addition of the condensed aromatics to a glyceride carrier is a known method for attempting to stabilize the aromatics.
-2a-~ 043~S
Such glycerides as coffee oll, bland-tasting vegetable oils and triacetin have proven especially useful for this purposei how-ever other oils and low melting point fats may also be used. It has, however, been desired to maximize the amount of aromatics that are fixed in the glyceride carrier, since this would mini- -mize aroma loss and would reduce the amount of the glyceride which would be incorporated with the soluble coffee product to obtain a desired amount of aromatization.
The process of this invention utilizes the principal of high pressure fixation to increase absorption of the volatile compounds present in an aroma-bearing carbon dioxide frost by a glyceride carrier. The process, which may be conducted as a simple batch operation in a suitable pressure vessel, or as a semi-continuous, countercurrent operation in a battery of pres-sure vessels, eliminates the need for laborious mixing of the frost and the glyceride. This mixing operation has proven to be troublesome in commercial operation, since contact between the condensed frost and the glyceride quickly congeals the glyceride thus making uniform mixing of the two components quite difficult.
If the mixture is allowed to warm to a point where the glyceride exists as a liquid, many of the desirable, condensed grinder gas aromatics will escape to the atmosphere.
According to this invention the aroma-bearing, carbon dioxide frost, which may be obtained from a liquid nitrogen-cooled scraped-surface heat exchanger, is contacted in a pressure vessel with a liquid glyceride phase at a ratio of grams of frost to grams of glyceride of about 0.5:1 to 6:1. The vessel is iso-lated from the atmosphere and the vessel contents are continuously supplied with heat by such means as a water jacket. Heat is supplied in sufficient quantities to raise or maintain the temp-erature of the glyceride above its congeal point, preferably the contents of the pressure vessel will reach at least room tempera-ture. As the temperature of the frost increases, a gaseous phase .
,: . - - .
1~43~S5 of increasing pressure is developed and as the temperature increas-es above about -69.9~F. the remaining condensed carbon dioxide is converted from a solid phase to a liquid phase. When the tempera-ture of the vessel contents is above the congeal point of the glyceride, aromatics are readily dissolved in the liquid glyceride phase. It may be desirable to hold the vessel contents at a par-ticular temperature above the congeal point of the glyceride in order to lengthen by an hour or more the contact time between the liquid glyceride and the aromatics. Agitation of the vessel con-tents, such as by means of an internal stirrer, may also be de-sirable in order to increase absorption of aromatic~ by the liquid glyceride.
After the contents of the vessel reach the desired temperature, preferably about room temperature, and possibly after a hold-up pexiod the aromatized glyceride is removed from the vessel. The resulting glyceride is found to contain more than twice the amount of aromatics obtained from manual mixing of the two components at atmospheric pressure. The aromatized glyceride should then be processed to remove excess water such as by centrifugation.
The aromatized glyceride may be combined with coffee solids either in the form of dry soluble coffee, such as by con-ventional spray plating or any of the techniques disclosed in United States Patent No. 3,769,032, or with a liquid coffee of coffee-like extract, prior to drying the extract. The aromatized glyceride may be solidified, such as by freezing, comminuted, such as by grinding, prior to being mixed with the soluble coffee powder, or prior to being combined with a liquid coffee extract, a slushed coffee extract, such as disclosed in commonly-assigned United States Patent No. 3,809,770, or a partially frozen slab of coffee extract, such as disclosed in commonly-assigned United States Patent No. 3,809,766.
The most readily available source of grinder gas may ,' , , -~ ' -11~43~ ~5 :
be obtained by enclosing or hooding coffee grinding equip-ment, such as the commercial grinders. The gases liberated from the ground coffee may be removed by a pump or rotary blower; additionally, when desired, a stream of inert, preferably moisture free, gas may be used to sweep gas from the coffee and to have the grinding operation take place in a substantially inert atmosphere. Such a process is described in United States Patent No. 2,156,212 which described a method of collecting gases evolved during roast-10 ing, but which can be equally applied to the collection of :~
gases evolved during the grinding or cellular disruption of whole freshly roasted coffee beans. If pumping is employed it may be desirable to cool the gas ahead of the pump so that the heat added by pumping will not deteriorate the ~ -aromatics contained in the gas.
The chemical composition of the evolved gas is largely carbon dioxide together with water vapor and the characteristic aromatic constituents of roasted coffee. The amount of moisture in the gas may be lowered by the use of dry roasting conditions and low-moisture or non-aqueous quenching mediums, such as cold, liquid or solid gases or liquid Freons . The evolved gas is preferably passed through a first condenser where it is cooled to between 35 and 50F. and where substantial quantities of water are removed. The relatively low-moisture gas is then fed to a condenser, such as a jacketed, vertically-mounted, scraped-wall hea~t exchanger, which is cooled by means of a liquid gas refrigerant.
Trademark ~ -5-, ~ .
, ~ : ' ' '; ' ~
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1~343~SS
Preferably the condenser is cooled by means of liquid nitrogen and the gas flow into the exchanger is maintained within the range of about 1 to 5 cubic feet per minute per square foot of heat exchange surface. The nitrogen gas that evolves from the cooling system is useful as an inert gas stream which might be used elsewhere in the soluble coffee process, such as sweeping grinder gas from the grinder or inert gas packaging of the soluble i; .
-5a-~ .
.
lS.~431S5 coffee product.
: The aroma bearing gas is condensed into the fcrm . .
of a frost as it comes into contact with the heat transfer wall of the condenser. The frost is removed from the condenser wall and collected for combination with a glyceride carrier. The frost may be held for a short period at low, such as liquid nitrogen, temperatures without - deteriorating; however, it is preferred to immediately combine the frost with a glyceride carrier in accordance with this invention. The glyceride, which preferably is coffee oil or a bland-tasting vegetable oil, such as cotton-seed, corn or coconut oil, is combined with the frost at a level of about 0.5 to 6 grams of frost per gram of glyceride, preferably at about 1 to 4 grams of frost per gram of glyceride.
According to this invention contact between the grinder gas frost and the glyceride occurs under pressure and in a pressure vessel. Conditions and operating pro-cedures useful for effecting the pressurized contact between the grinder gas and the glyceride are set forth below. The frost and the glyceride may be placed in the vessel before the initial isolation of the vessel. Alternatively, the glyceride may be added to the vessel subsequent to the frost and after the vessel has reached a desired temperature and/or pressure.
(A) The frost is placed in the vessel and the tempera-ture within the pressure vessel is raised above the congeal point of the glyceride and below about 85F. The glyceride may be added either with the frost or after the frost has ~ -6-A
.
... . . . .
.. ~ . ~ `. .
~5~4~55 been warmed, preferably to above the glyceride congealpoint. Then, possibly after a liquid glyceride phase-grinder gas contact period of up to several hours, the pressure is slowly released, preferably in such a manner that the glyceride is maintained in -6a-- . . . .
1~3433L55 a liquid state. Most preferably the temperature is raised to about room temperature and the pressure is released from the vessel isothermally. Pressure release may be conducted through a small diameter tube of sufficient length to pre-clude a rapid drop of pressure or temperature within the vessel. According to this co-pending application, it may also be desirable to regulate the amount of grinder gas frost which is placed into the vessel to a level where a saturated gas phase is present without the existence of a -- 10 liquid gas phase.
(B) With the frost and glyceride present, the tempera-ture within the vessel is raised or maintained above 87.8F., the critical temperature of liquid CO2, and the pressure is then, possibly after a hold-up period, slowly, preferably isothermally, released without the formation of liquid CO2.
(C) After the frost is placed in the vessel, the vessel is isolated and the contents are allowed to warm to a point where a pressure of about 100 psig. (about -55F., based on pure CO2) is developed. Liquid CO2 is then permitted to evaporate by venting the vessel and controlling pressure at about 100 psig. Once a substantial portion of the CO2 is removed, the vessel is again isolated and the contents warmed to above the congeal point of the glyceride, preferably about room temperature. An end pressure of 200 to 500 psig. should be obtained. Then with the glyceride present and preferably after a hold-up period, this pressure is slowly released.
~ -7-~4315S
(D) After the frost is placed in the vessel, the vessel is isolated and supplied with heat (e.g., 70-75F
water bath). The pressure is allowed to reach to between 75 and 120 psig., then the vessel is rapidly vented to 0 psig.
The vessel is repeatedly isolated, pressurized and vented until the residual pressure build-up is less than 100 psig.
at which point the vessel is allowed to warm to about room temperature. Thereafter, A -7a with the glyceride present, ~he vessel is completely vented. This process seeks to minimize the amount of volatiles which escape from the vessel with the CO2 when pressure is relièved. During rapid venting heat must be supplied to expand the gas, and this heat will be furnished almost entirely adiabatically with the re-sult that the remaining grinder gas frost, the volatiles contained therein and the glyceride that may be present are cooled. The repeated ventings seek to remove CO2, leaving a concentrated level of volatiles to dissolve or be dissolved in the glyceride.
(E) After the frost is placed in the ves~el, the vessel is isolated and supplied with heat. The temperature of the vessel contents is permitted to rise above the congeal point of the glyceride; however, before room temperature is reached, and with the glyceride present in the vessel, pressure is ~uickly released.
As a result of the rapid pressure release, the material remaining i9 a frozen, aroma-containing glyceride with additional grinder gas aromatics condensed onto its surface.
(F) The frost is placed in a vessel and CO2 is sublimed at atmospheric pressure (about -110F.). After a substantial por-tion of CO2 is removed, the vessel is isolated and the contentsraised to about room temperature and, with the glyceride present, the vessel is then vented. A 100 to 200 psig, pressure should be achieved prior to venting~
(G) The grinder gas frost i8 sealed in a pressure vessel and the pressure is allowed to rise to about 100 psig. The pres-sure i9 then rapidly reduced to 0 psig. and this cycle is repeated two to three more times. The vessel is then sealed and the con-tents heated to an internal temperature of about 70F. Then with the glyceride present, and po~sibly after a hold-up period, the vessel is vented. As an improvement of this process, it may be desirable to pass the sublimed frost gases through a column of liquid or li~uefied glyceride, which glyceride is then placed in the vessel.
1C~4~1~5 (H) Place both the grinder gas frost and the glyceride in the vessel. Seal the vessel and warm the contents up to about room temperature. Thereafter, cool to below 30F.
- and, if desired, to as low as -100F., then vent off ; residual CO2 pressure. The aromatized glyceride may be removed and used as a solid or else warmed and removed as a liquid.
As a preferred embodiment of this invention the vented or sublimed gas which may contain desirable aromatics is processed or handled in order to reclaim or recycle aromatics. Refluxing the vented or sublimed gas by means of an overhead packed column and partial condenser is possible. Venting the pressure vessel directly to the scraped-wall heat exchanger, to a bed of dry ice, or to another batch of liquid glyceride and/or grinder gas frost may also be desirable.
After the pressure within the vessel is released and/or reduced, the aromatized glyceride is removed from the vessel. This can be done by decanting or by draining the liquid through a valve in the bottom of the vessel. It would also be possible to permit residual pressure within . the vessel to force the liquid out of a vertical withdrawal : tube which protrudes through the upper portion of the vessel.
If the glyceride is removed from a pressurized vessel, any residual gas present in the vessel may be retained for use in a subsequent pressure fixation cycle. Preferably, the ;
aromatized glyceride phase and any water phase which may be present in the vessel are separated during removal from the vessel. Alternatively, since water _ .
.:
,' - ,. :'' . , ~: '. ' :
1~43~5S
: will be the heaviest material within the vessel, it would be -~ possible to remove the bottom liquid water phase from the vessel at any point in the pressure fixation cycle.
Removing water from the aromatized glyceride, : preferably down to a level of 0.5/0 by weight or less, appears to further ' .
. .
-9a-~ ,~ .
' . ~ . ' ' -: . .
.
~34~1~i5 stabilize the grirlder gas aromatics. As disclosed in the afore-mentioned application, Serial No. 252,883, centrifugation, ultra-centrifugation, molecular fract;onation, drying agents and li~e method have proved to be successful techniques for removing wa~er from the aromatized glyceride. As a further refinement of this water removal process, it is possible to separate any aromas from the removed water such as by vacuum distillation and to add these separated aromatics back to the aromatized glyceride.
The aromatized glyceride may be combined with soluble coffee powder or with coffee extract prior to drying the extract in accordance with any of the known prior art techniques. Typical levels of addition for the aromatized glyceride are 0.1 to 2% by weight glyceride based on the weight of soluble solids in the final product. The aromatized powder of this invention may con-stitute all or only a portion of the powder in the final product, as will be apparent to those skilled in the art.
The term coffee powder and coffee extract used in the description of this invention is meant to include materials con-taining in whole or in part coffee substitutes such as powders or extracts obtained in whole or in part from roasted cereals such as wheat, rye, barley and the like. One such item is the water extract and resulting dried powder of wheat, barley and molasses known as "Instant Postum", (Registered Trademark~.
This invention is fùrther described but not limited by the following example:
E X A M P L E
._ ~
A mixture of 130 grams of liquid nitrogen-condensed grinder gas frost and 110 grams of coffee oil were put in a high pressure stainless steel bomb and warmed up to 80F. A pressure of 700 psig. was obtained. The pressure was released and the residue that remained was stored at 0F. for fourteen days and then plated onto the surface of soluble coffee powder at a level of 0.5%.
- . ,
This invention is related to commonly assigned Patent Application, Serial No. lB2062 , wherein is disclosed a method for condensing the aromatic gases given off during the comminution of freshly roasted coffee in a vertically-mounted, scraped-wall heat exchanger which is cooled by means of liquid nitrogen. The condensed gases are collected at the bottom of the heat exchanger in the form of a fros~ or snow and this frost 0 i3 mixed with a liquid glyceride and then combined with a coffee extract prior to drying the extract (e.g., freeze drying) or com-bined with a soluble coffee powder.
Grinder gas, that is the gas which is released from roasted whole coffee beans when their internal cell structure is disrupted, such as during grinding of the beans and which also continues to be evolved from the disrupted and/or fractured bean f~r a short period thereafter, has long been recognized in the art as a highly desirable natural coffee aroma. The collection and stabilization of this aroma has how~ver proven to be a dif-ficult undertaking, especially when it is desired for use in a commercial-sized soluble coffee system.
The use of grinder gas as a means to enhance the jar aroma of a soluble coffee powder is disclosed in United States Patent No. 3,021,218 to Clinton et al. which aromatizes the jar headspace and United States Patent No. 2,306,061 to Johnston which condenses grinder gas aromatics onto chilled soluble coffee powder. The use of grinder gas condensates which are added to a liquid extract and dried in order to produce an improved cup aroma when the powder is dissolved in hot water is disclosed in United States Patent No. 3,244,533 to Clinton et al. which homogen-i~es coffee oil in extract and then adds condensed grinder gas aromatics. Condensed grinder gas frost can be mixed with a liquid glyceride which mixture is then processed to remove excess -1~43~5 water, such as by centrifugation, prior to being combined with soluble coffee solids (e.g., soluble powder).
; This invention is directed to fixing in a glyceride carrier aromatics contained in an aroma-bearing gas which has a high (e.g., above 80% by weight) carbon dioxide content, and which has been condensed as an aroma-bearing frost. This invention will be particularly described in terms of coffee grinder gas which contains in excess of 90% CO2 by weight;
however, it is to be understood that other aroma-bearing gases, such as percolator vent gas and roaster gas, may likewise be employed.
According to the invention there is provided a method for producing a coffee-aroma material which can be added to coffee solids wherein an aroma-containing frost with a carbon -dioxide content is condensed from a gas containing aroma, the frost is placed in a pressure vessel and is contacted under pressure while the vessel is isolated from the atmosphere with a liquid glyceride in the amount of 1 gram glyceride to 0.5 to 6 grams of frost, the pressure is released at a rate which avoids formation of liquid carbon dioxide and a glyceride material containing coffee-aroma is recovered.
In a specific embodiment there is provided a method for aromatizing soluble coffee comprising the steps of:
a) condensing, as a frost, an aroma-containing gas which ~-has a high carbon dioxide content;
b) placing the aroma-containing frost in a pressure vessel;
~, .
~43~5 c) contacting within said pressure vessel, under a pressure of at least 100 psia, the frost aromas and a liquid glyceride, said glyceride being present in the pressure vessel at a level of about one gram of glyceride to 0.5 to 6 grams of the frost;
d) removing the glyceride from the vessel and combining it with coffee solids.
The addition of the condensed aromatics to a glyceride carrier is a known method for attempting to stabilize the aromatics.
-2a-~ 043~S
Such glycerides as coffee oll, bland-tasting vegetable oils and triacetin have proven especially useful for this purposei how-ever other oils and low melting point fats may also be used. It has, however, been desired to maximize the amount of aromatics that are fixed in the glyceride carrier, since this would mini- -mize aroma loss and would reduce the amount of the glyceride which would be incorporated with the soluble coffee product to obtain a desired amount of aromatization.
The process of this invention utilizes the principal of high pressure fixation to increase absorption of the volatile compounds present in an aroma-bearing carbon dioxide frost by a glyceride carrier. The process, which may be conducted as a simple batch operation in a suitable pressure vessel, or as a semi-continuous, countercurrent operation in a battery of pres-sure vessels, eliminates the need for laborious mixing of the frost and the glyceride. This mixing operation has proven to be troublesome in commercial operation, since contact between the condensed frost and the glyceride quickly congeals the glyceride thus making uniform mixing of the two components quite difficult.
If the mixture is allowed to warm to a point where the glyceride exists as a liquid, many of the desirable, condensed grinder gas aromatics will escape to the atmosphere.
According to this invention the aroma-bearing, carbon dioxide frost, which may be obtained from a liquid nitrogen-cooled scraped-surface heat exchanger, is contacted in a pressure vessel with a liquid glyceride phase at a ratio of grams of frost to grams of glyceride of about 0.5:1 to 6:1. The vessel is iso-lated from the atmosphere and the vessel contents are continuously supplied with heat by such means as a water jacket. Heat is supplied in sufficient quantities to raise or maintain the temp-erature of the glyceride above its congeal point, preferably the contents of the pressure vessel will reach at least room tempera-ture. As the temperature of the frost increases, a gaseous phase .
,: . - - .
1~43~S5 of increasing pressure is developed and as the temperature increas-es above about -69.9~F. the remaining condensed carbon dioxide is converted from a solid phase to a liquid phase. When the tempera-ture of the vessel contents is above the congeal point of the glyceride, aromatics are readily dissolved in the liquid glyceride phase. It may be desirable to hold the vessel contents at a par-ticular temperature above the congeal point of the glyceride in order to lengthen by an hour or more the contact time between the liquid glyceride and the aromatics. Agitation of the vessel con-tents, such as by means of an internal stirrer, may also be de-sirable in order to increase absorption of aromatic~ by the liquid glyceride.
After the contents of the vessel reach the desired temperature, preferably about room temperature, and possibly after a hold-up pexiod the aromatized glyceride is removed from the vessel. The resulting glyceride is found to contain more than twice the amount of aromatics obtained from manual mixing of the two components at atmospheric pressure. The aromatized glyceride should then be processed to remove excess water such as by centrifugation.
The aromatized glyceride may be combined with coffee solids either in the form of dry soluble coffee, such as by con-ventional spray plating or any of the techniques disclosed in United States Patent No. 3,769,032, or with a liquid coffee of coffee-like extract, prior to drying the extract. The aromatized glyceride may be solidified, such as by freezing, comminuted, such as by grinding, prior to being mixed with the soluble coffee powder, or prior to being combined with a liquid coffee extract, a slushed coffee extract, such as disclosed in commonly-assigned United States Patent No. 3,809,770, or a partially frozen slab of coffee extract, such as disclosed in commonly-assigned United States Patent No. 3,809,766.
The most readily available source of grinder gas may ,' , , -~ ' -11~43~ ~5 :
be obtained by enclosing or hooding coffee grinding equip-ment, such as the commercial grinders. The gases liberated from the ground coffee may be removed by a pump or rotary blower; additionally, when desired, a stream of inert, preferably moisture free, gas may be used to sweep gas from the coffee and to have the grinding operation take place in a substantially inert atmosphere. Such a process is described in United States Patent No. 2,156,212 which described a method of collecting gases evolved during roast-10 ing, but which can be equally applied to the collection of :~
gases evolved during the grinding or cellular disruption of whole freshly roasted coffee beans. If pumping is employed it may be desirable to cool the gas ahead of the pump so that the heat added by pumping will not deteriorate the ~ -aromatics contained in the gas.
The chemical composition of the evolved gas is largely carbon dioxide together with water vapor and the characteristic aromatic constituents of roasted coffee. The amount of moisture in the gas may be lowered by the use of dry roasting conditions and low-moisture or non-aqueous quenching mediums, such as cold, liquid or solid gases or liquid Freons . The evolved gas is preferably passed through a first condenser where it is cooled to between 35 and 50F. and where substantial quantities of water are removed. The relatively low-moisture gas is then fed to a condenser, such as a jacketed, vertically-mounted, scraped-wall hea~t exchanger, which is cooled by means of a liquid gas refrigerant.
Trademark ~ -5-, ~ .
, ~ : ' ' '; ' ~
- .. ~, ,. . ~:
1~343~SS
Preferably the condenser is cooled by means of liquid nitrogen and the gas flow into the exchanger is maintained within the range of about 1 to 5 cubic feet per minute per square foot of heat exchange surface. The nitrogen gas that evolves from the cooling system is useful as an inert gas stream which might be used elsewhere in the soluble coffee process, such as sweeping grinder gas from the grinder or inert gas packaging of the soluble i; .
-5a-~ .
.
lS.~431S5 coffee product.
: The aroma bearing gas is condensed into the fcrm . .
of a frost as it comes into contact with the heat transfer wall of the condenser. The frost is removed from the condenser wall and collected for combination with a glyceride carrier. The frost may be held for a short period at low, such as liquid nitrogen, temperatures without - deteriorating; however, it is preferred to immediately combine the frost with a glyceride carrier in accordance with this invention. The glyceride, which preferably is coffee oil or a bland-tasting vegetable oil, such as cotton-seed, corn or coconut oil, is combined with the frost at a level of about 0.5 to 6 grams of frost per gram of glyceride, preferably at about 1 to 4 grams of frost per gram of glyceride.
According to this invention contact between the grinder gas frost and the glyceride occurs under pressure and in a pressure vessel. Conditions and operating pro-cedures useful for effecting the pressurized contact between the grinder gas and the glyceride are set forth below. The frost and the glyceride may be placed in the vessel before the initial isolation of the vessel. Alternatively, the glyceride may be added to the vessel subsequent to the frost and after the vessel has reached a desired temperature and/or pressure.
(A) The frost is placed in the vessel and the tempera-ture within the pressure vessel is raised above the congeal point of the glyceride and below about 85F. The glyceride may be added either with the frost or after the frost has ~ -6-A
.
... . . . .
.. ~ . ~ `. .
~5~4~55 been warmed, preferably to above the glyceride congealpoint. Then, possibly after a liquid glyceride phase-grinder gas contact period of up to several hours, the pressure is slowly released, preferably in such a manner that the glyceride is maintained in -6a-- . . . .
1~3433L55 a liquid state. Most preferably the temperature is raised to about room temperature and the pressure is released from the vessel isothermally. Pressure release may be conducted through a small diameter tube of sufficient length to pre-clude a rapid drop of pressure or temperature within the vessel. According to this co-pending application, it may also be desirable to regulate the amount of grinder gas frost which is placed into the vessel to a level where a saturated gas phase is present without the existence of a -- 10 liquid gas phase.
(B) With the frost and glyceride present, the tempera-ture within the vessel is raised or maintained above 87.8F., the critical temperature of liquid CO2, and the pressure is then, possibly after a hold-up period, slowly, preferably isothermally, released without the formation of liquid CO2.
(C) After the frost is placed in the vessel, the vessel is isolated and the contents are allowed to warm to a point where a pressure of about 100 psig. (about -55F., based on pure CO2) is developed. Liquid CO2 is then permitted to evaporate by venting the vessel and controlling pressure at about 100 psig. Once a substantial portion of the CO2 is removed, the vessel is again isolated and the contents warmed to above the congeal point of the glyceride, preferably about room temperature. An end pressure of 200 to 500 psig. should be obtained. Then with the glyceride present and preferably after a hold-up period, this pressure is slowly released.
~ -7-~4315S
(D) After the frost is placed in the vessel, the vessel is isolated and supplied with heat (e.g., 70-75F
water bath). The pressure is allowed to reach to between 75 and 120 psig., then the vessel is rapidly vented to 0 psig.
The vessel is repeatedly isolated, pressurized and vented until the residual pressure build-up is less than 100 psig.
at which point the vessel is allowed to warm to about room temperature. Thereafter, A -7a with the glyceride present, ~he vessel is completely vented. This process seeks to minimize the amount of volatiles which escape from the vessel with the CO2 when pressure is relièved. During rapid venting heat must be supplied to expand the gas, and this heat will be furnished almost entirely adiabatically with the re-sult that the remaining grinder gas frost, the volatiles contained therein and the glyceride that may be present are cooled. The repeated ventings seek to remove CO2, leaving a concentrated level of volatiles to dissolve or be dissolved in the glyceride.
(E) After the frost is placed in the ves~el, the vessel is isolated and supplied with heat. The temperature of the vessel contents is permitted to rise above the congeal point of the glyceride; however, before room temperature is reached, and with the glyceride present in the vessel, pressure is ~uickly released.
As a result of the rapid pressure release, the material remaining i9 a frozen, aroma-containing glyceride with additional grinder gas aromatics condensed onto its surface.
(F) The frost is placed in a vessel and CO2 is sublimed at atmospheric pressure (about -110F.). After a substantial por-tion of CO2 is removed, the vessel is isolated and the contentsraised to about room temperature and, with the glyceride present, the vessel is then vented. A 100 to 200 psig, pressure should be achieved prior to venting~
(G) The grinder gas frost i8 sealed in a pressure vessel and the pressure is allowed to rise to about 100 psig. The pres-sure i9 then rapidly reduced to 0 psig. and this cycle is repeated two to three more times. The vessel is then sealed and the con-tents heated to an internal temperature of about 70F. Then with the glyceride present, and po~sibly after a hold-up period, the vessel is vented. As an improvement of this process, it may be desirable to pass the sublimed frost gases through a column of liquid or li~uefied glyceride, which glyceride is then placed in the vessel.
1C~4~1~5 (H) Place both the grinder gas frost and the glyceride in the vessel. Seal the vessel and warm the contents up to about room temperature. Thereafter, cool to below 30F.
- and, if desired, to as low as -100F., then vent off ; residual CO2 pressure. The aromatized glyceride may be removed and used as a solid or else warmed and removed as a liquid.
As a preferred embodiment of this invention the vented or sublimed gas which may contain desirable aromatics is processed or handled in order to reclaim or recycle aromatics. Refluxing the vented or sublimed gas by means of an overhead packed column and partial condenser is possible. Venting the pressure vessel directly to the scraped-wall heat exchanger, to a bed of dry ice, or to another batch of liquid glyceride and/or grinder gas frost may also be desirable.
After the pressure within the vessel is released and/or reduced, the aromatized glyceride is removed from the vessel. This can be done by decanting or by draining the liquid through a valve in the bottom of the vessel. It would also be possible to permit residual pressure within . the vessel to force the liquid out of a vertical withdrawal : tube which protrudes through the upper portion of the vessel.
If the glyceride is removed from a pressurized vessel, any residual gas present in the vessel may be retained for use in a subsequent pressure fixation cycle. Preferably, the ;
aromatized glyceride phase and any water phase which may be present in the vessel are separated during removal from the vessel. Alternatively, since water _ .
.:
,' - ,. :'' . , ~: '. ' :
1~43~5S
: will be the heaviest material within the vessel, it would be -~ possible to remove the bottom liquid water phase from the vessel at any point in the pressure fixation cycle.
Removing water from the aromatized glyceride, : preferably down to a level of 0.5/0 by weight or less, appears to further ' .
. .
-9a-~ ,~ .
' . ~ . ' ' -: . .
.
~34~1~i5 stabilize the grirlder gas aromatics. As disclosed in the afore-mentioned application, Serial No. 252,883, centrifugation, ultra-centrifugation, molecular fract;onation, drying agents and li~e method have proved to be successful techniques for removing wa~er from the aromatized glyceride. As a further refinement of this water removal process, it is possible to separate any aromas from the removed water such as by vacuum distillation and to add these separated aromatics back to the aromatized glyceride.
The aromatized glyceride may be combined with soluble coffee powder or with coffee extract prior to drying the extract in accordance with any of the known prior art techniques. Typical levels of addition for the aromatized glyceride are 0.1 to 2% by weight glyceride based on the weight of soluble solids in the final product. The aromatized powder of this invention may con-stitute all or only a portion of the powder in the final product, as will be apparent to those skilled in the art.
The term coffee powder and coffee extract used in the description of this invention is meant to include materials con-taining in whole or in part coffee substitutes such as powders or extracts obtained in whole or in part from roasted cereals such as wheat, rye, barley and the like. One such item is the water extract and resulting dried powder of wheat, barley and molasses known as "Instant Postum", (Registered Trademark~.
This invention is fùrther described but not limited by the following example:
E X A M P L E
._ ~
A mixture of 130 grams of liquid nitrogen-condensed grinder gas frost and 110 grams of coffee oil were put in a high pressure stainless steel bomb and warmed up to 80F. A pressure of 700 psig. was obtained. The pressure was released and the residue that remained was stored at 0F. for fourteen days and then plated onto the surface of soluble coffee powder at a level of 0.5%.
- . ,
Claims (7)
1. A method for aromatizing soluble coffee comprising the steps of:
a) condensing, as a frost, a coffee aroma-containing gas given off during comminution of freshly roasted coffee which has a carbon dioxide content in excess of 80%, b) placing the aroma-containing frost in a pressure vessel, c) contacting within said pressure vessel, under a pressure of at least 100 psia, and at a temperature of 70-75°F, the frost aromas and a liquid glyceride, said glyceride being present in the pressure vessel at a level of about one gram of glyceride to 0.5 to 6 grams of the frost, d) cooling the contents of the vessel to below 30°F, venting the vessel to the atmosphere and removing the glyceride from the vessel and combining it with coffee solids.
a) condensing, as a frost, a coffee aroma-containing gas given off during comminution of freshly roasted coffee which has a carbon dioxide content in excess of 80%, b) placing the aroma-containing frost in a pressure vessel, c) contacting within said pressure vessel, under a pressure of at least 100 psia, and at a temperature of 70-75°F, the frost aromas and a liquid glyceride, said glyceride being present in the pressure vessel at a level of about one gram of glyceride to 0.5 to 6 grams of the frost, d) cooling the contents of the vessel to below 30°F, venting the vessel to the atmosphere and removing the glyceride from the vessel and combining it with coffee solids.
2. The method of claim 1, wherein the aromatized glyceride is added to soluble coffee powder.
3. The method of claim 1, wherein the aroma-containing gas is condensed in a jacketed, vertically-mounted, scraped-wall heat exchanger.
4. The method of claim 1, wherein the temperature within the vessel is raised to about room temperature.
5. The method of claim 1, wherein the aroma-containing gas is passed through a condenser where water is removed, prior to being passed into the scraped-wall heat exchanger.
6. The method of claim 1, wherein the aroma-bearing gas is obtained by disrupting the cellular structure of freshly roasted coffee beans.
7. A method for producing coffee-aroma material which can be added to coffee solids wherein an aroma-containing frost with a carbon dioxide content in excess of 80% is condensed from a gas containing aroma, said gas given off during comminution of freshly roasted coffee, the frost is placed in a pressure vessel and is contacted under a pres-sure of at least 100 psia and as a temperature of 70-75°F
while the vessel is isolated from the atmosphere with a liquid glyceride in the amount of 1 gram glyceride to 0.5 to 6 grams of frost, the pressure is released at a rate which avoids formation of liquid carbon dioxide and a glyceride material containing coffee-aroma is recovered.
while the vessel is isolated from the atmosphere with a liquid glyceride in the amount of 1 gram glyceride to 0.5 to 6 grams of frost, the pressure is released at a rate which avoids formation of liquid carbon dioxide and a glyceride material containing coffee-aroma is recovered.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/471,630 US3979528A (en) | 1974-05-20 | 1974-05-20 | Pressure fixation of coffee grinder gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1043155A true CA1043155A (en) | 1978-11-28 |
Family
ID=23872398
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA225,011A Expired CA1043155A (en) | 1974-05-20 | 1975-04-18 | Pressure fixation of coffee grinder gas |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US3979528A (en) |
| CA (1) | CA1043155A (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4551345A (en) * | 1983-03-21 | 1985-11-05 | General Foods Corporation | Process for preparing a liquid aroma and aromatizing a dry coffee substrate with same |
| US4551344A (en) * | 1983-03-31 | 1985-11-05 | General Foods Corporation | Method for aromatizing soluble coffee |
| EP0213247B1 (en) * | 1985-09-04 | 1989-11-02 | General Foods Corporation | Improved method for aromatizing soluble coffee |
| US4556575A (en) * | 1983-03-31 | 1985-12-03 | General Foods Corporation | Method for aromatizing soluble coffee |
| US4574089A (en) * | 1985-04-24 | 1986-03-04 | General Foods Corporation | Process for preparing a liquid coffee aroma |
| US5043177A (en) * | 1986-04-08 | 1991-08-27 | Nestec S.A. | Aromatics recovery and transfer |
| JPH0687741B2 (en) * | 1986-07-17 | 1994-11-09 | 味の素ゼネラルフーヅ株式会社 | Stable immobilization method for coffee and aromatic substances |
| US5792505A (en) * | 1992-09-22 | 1998-08-11 | Mccormick & Company, Inc. | Flavor encapsulation |
| WO1994023593A1 (en) | 1993-04-16 | 1994-10-27 | Mccormick & Company, Inc. | Encapsulation compositions |
| US5342639A (en) * | 1993-11-18 | 1994-08-30 | The Procter & Gamble Company | Making dry coffee aroma gas with improved aroma characteristics |
| US5756136A (en) * | 1995-06-02 | 1998-05-26 | Mccormick & Company, Inc. | Controlled release encapsulation compositions |
| AU4985497A (en) | 1996-10-25 | 1998-05-22 | Mccormick & Company, Inc. | Fat-coated encapsulation compositions and method for preparing the same |
| US6444246B1 (en) | 1997-12-16 | 2002-09-03 | Mccormick & Company, Inc. | Cake-resistant, hygroscopically sensitive materials and process for producing the same |
| DE60335264D1 (en) * | 2003-10-09 | 2011-01-20 | Kraft Foods R & D Inc | Flavored particles containing coffee flavorings |
| US8043645B2 (en) | 2008-07-09 | 2011-10-25 | Starbucks Corporation | Method of making beverages with enhanced flavors and aromas |
| US9669326B2 (en) | 2013-01-25 | 2017-06-06 | Geoff Todosiev | Vapor trap |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2680687A (en) * | 1950-06-16 | 1954-06-08 | Lemonnier Pierre | Coffee product and process therefor |
| US3021218A (en) * | 1959-01-21 | 1962-02-13 | Gen Foods Corp | Producing a stable coffee aroma product |
| US3535118A (en) * | 1964-12-31 | 1970-10-20 | Kroger Co | Method of making aromatized oil |
| US3823241A (en) * | 1970-09-21 | 1974-07-09 | Procter & Gamble | Cryogenic aromatization of instant coffee |
| US3783163A (en) * | 1972-04-28 | 1974-01-01 | Procter & Gamble | Aromatizing edible oils |
| US3836682A (en) * | 1972-05-12 | 1974-09-17 | Gen Foods Corp | Method for enhancing soluble foodstuffs |
-
1974
- 1974-05-20 US US05/471,630 patent/US3979528A/en not_active Expired - Lifetime
-
1975
- 1975-04-18 CA CA225,011A patent/CA1043155A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US3979528A (en) | 1976-09-07 |
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