CA1172505A - Process for preparing aroma- and flavor-enriched soluble coffee - Google Patents

Abstract

PROCESS FOR PREPARING
AROMA- AND FLAVOR-ENRICHED SOLUBLE COFFEE

Judith A. Zaunbrecher and Richard G. Crooks Abstract A process for desorbing the volatile aroma and flavor components from roast and ground coffee having a particle size above about 1000 microns is disclosed. The roast and ground coffee particles are mixed with water or ice in a ratio of 0.1 to 0.9 parts of water per part of coffee in a fluidized mechanical mixer. The water/coffee mixture is then contacted with steam under vacuum (temperature of 32° to 125°F, about 5 to 100 mm mercury absolute pressure).
The resulting volatiles-laden steam is condensed, preferably in a two-stage operation. The first condenser removes most of the water and a fraction of the volatiles at 32°-125"F, and the remaining volatiles are condensed in a cryogenically cooled trap, preferably at liquid nitrogen temperature.
The moisture level of the coffee during devolatilization is from 15% to 65% by weight. The devolatilized roast and ground coffee can then be used in a conventional extraction column. The draw-off ratio of extract to column charge is from about 2.3 to about 3.2.
This produces a coffee extract having from 13% to about 26% solids.
The extract and the coffee-volatiles condensates provide the components of an improved highly aromatic and flavorful instant coffee.

Description

! 172505 PROCESS FOR PREPARING
AROMA- AND FLAVOR-ENRICHED SOLUaLE COFFEE

Judith A. Zaunbrecher and Richard G. Crooks Backqround of the Invention This invention relates to a process for preparing an improved soluble coffee product which has a brew-like aroma and flavor.
There are many processes for producing soluble coffee products. For the most part, these methods have been directed toward the provision of a coffee product capable of duplicating the desired flavor qualities of freshly prepared roast and ground coffee.
Various processes have been described as producing these soluble coffee products. Such methods are described in U.S. Patent 3,035,922, issued to Mbok et al, 1962 and U.S. Patent 4,072,761, issued to Mbrgolis et al, 1978.
Methods for producing an improved soluble coffee lS product having the favorable physical characteristics and preferred flavor attributes of freshly brewed roast and ground coffee are described in U.S. Patent 3,717,472, issued to Strobel (1973), U.S. Patent 3,997,685, issued to Strobel (1976), U.S. Patent 4,100,305, issued to Gregg (1978), and U.S. Patent 4,10û,3û6, issued to Gregg et al ~1978). These patents describe a process for desorbing the aroma and flavor volatiles from roast and ground coffees. The Strobel patents prepare aroma and flavor concentrates by pulsing or continuously passing ~et steam through roast and ground coffee which is in a column. The coffee substrate is preferably of a very fine grind. If very coarse coffee is used, a strong, harsh or stringent flavor is said to be produced.
The Gregg patents describe a method of steam stripping and recovering desirable volatiles from roast ..

! 17~505 and ground coffee particles in a mechanically fluidized }~ed. Ihe coffee particle size is preferably fr(m 5 to 800 m~crons.
In order to extract the solubles fro~nthis f~ne gr~nd coffee it must be slurry extracted which is an expensive process.
S It is an object of the presont invention to provide a process for preparing a soluble coffee product having flavor qualities preferred over commercially rnanufactured instant coffee. The process of the present invention will produce such a coffee via a gentle, but thorough steam distillation operation. Moreover, the process of the present invention utilizes roast and ground co~fee which can then be extracted in a conventional manner.
These and other objects and advantages of the present invention will become apparent from the detailed lS description provided hereinafter.
Detailed Description of the Invention ~ process for preparing a highly aromatic soluble coffee product having a stronger, more brew-like character is disclosed. The process comprises:
(1) wetting roast and ground coffee having a particle size of lûO0 microns to about 3500 microns with from about 0.1 to about 0.9 parts of water per parts of coffee;

(2) desorbing the wet roast and ground coffee in a fluidized bed, said wet roast and ground coffee having a moisture content of about 15,~ to 65%, a temperature of from 32F to 125F, and a pressure of from about 5 to 100 mm;

(3) condensing the volatiles separately at temperatures of from about 32F to about 125F
and at temperatures below 0F, and pressures of from about 5 to about 8,000 mm of mercury; and

(4) extracting the desorbed roast and ground coffee to form a coffee soluble solution from about 13 to about 26% solid concentration.
The extract may be dried in a conventional manner to provide a soluble coffee product.

.1~, ' .. . . .. . . . . . .. . . .. .

! 1725~5 The condensates are added to a soluble coffee product in a manner in which the important aroma and flavor volatiles are retained. This may be done by addin3 coffee solubles to the aqueous condensate tG produce a coffee extract having from about 2û,~ to about 65,6 solubles, and then adding the frost to this at a cold temperature so that the important aroma and flavor volatiles do not evaporate.
The process of this invention represents an improvement over the devolatilization of the roast and ground coffee processing described in the Strobel and Gregg patents. The key to the process of this invention is the subjection of roast and ground coffee to a unique combination of devolatilization and conventional extraction techniques.
Gregg requires the use of slurry extraction to remove the soluble materials remaining in the desorbed coffees.
Slurry extraction is expensive and difficult to accomplish. Strobel's process requires more expensive equipment to achieve the same results.
The process of the present invention ha5 applicability to a variety of coffees, including blends of coffees. These may be classified for convenience and simplification as low-grade, intermediate grade, and high-grade coffees. Suitable examples of low-grade coffees include the natural Robustas such as the Ivory Coast Robustas and Angola Robustas; and the natural Arabicas such as the natural Perus and natural Ecuadors.
Suitable intermediate-grade coffees include the natural Arabicas from Brazil such as Santosl Paranas and Minas;
and natural Arabicas such as Ethiopians. Examples of high-grade coffees include the washed Arabicas such as Mexicans, Costa Ricans, Columbians, Kenyas, and New Guineas. Other examples and blends thereof are known in 35 the art and illustrated, for example, in U.S. Patent 3,615,667 (issued October 26, 1971 to Joffe).
Preferably, blends of intermediate and high_grade Arabicas will be used.

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. .. .. .... . = ..... . .. . .. . . .

! 17250S

The coffees are roasted in a conventional manner, either batchwise or continuously. Typical roasting equipment and methods for roasting coffee beans are described, for example, in Sivetz ,~ Foote, Coffee

5 Processinq ~echnology~ Avi Publishing Co., (Connecticut 1963, Vol. 1 at pp. 203-266).
Highly preferred roasting techniques for use herein are those which retain the volatiles within the roasted coffee. Such techniques include fast roasting followed 10 by liquid nitrogen quenching of the roasted beans.
The roasted coffee is ground to the desired particle s ize using any conventiorial grinding equipment. Typical grinding equipment is described, for example, in Sivetz &
Foote, _upra, pp. 239-25û. A highly preferred grinding 15 technique is cold grinding where the beans are embrittled by cooling with liquid carbon dioxide or liquid nitrogen.
In order to utilize the devolatilized roast and ground coffee in conventional extraction columns, the coffee must have a minimum particle size of about 1000 20 microns. Typically, the average coffee particle size will range from about 1000 to about 3500 microns, preferably from about 2400 to 2800 microns.
A typical particle size distribution when measured on standard U. S. sieves is:
Sieve Size Pe_cent On 6 39 On 8 36 On 20 21 Through 20 4 The r oast and ground coffee is then wet with from û .1 to 0.9 parts of water per 1 part of coffee. The wetting operation may be accomplished by mixing the roast and ground coffee with the water or by adding ice to the roast and ground coffee.
The temperature of the water used to wet the roast and ground coffee can be frorn about 32F to 125F, preferably from 32F to 40F. Control of the water temperature is important since high temperatures will degrade the coffee flavors and aroma.

! 172505 The wetted coffee particles are subjected to mechanical fluidization durirg the steam stripping or devol2tilization step. ~echanical fluidization provides uniform devolatilization bv allGwing intimate contact of the steam with the coffee particles. The operation can also be conducted at lower temperatures and under vacuum without excessive pressure drops across the coffee bed if the coffee remains in a state of mechanical fluidization.
The term "fluidization~ refers to a process where fine, solid par~ cles are made to behave in a fluid-like manner. A dense phase fluidized bed, such as a bed of particulated coffee solids, behaves much like that of a boiling liquid.
Mechanical fluidization is a rapid agitation with a mechanical mixing system which provides a fluidized bed of substrate. In mechanical fluidization, the substrate is continuously hurled and ~hirled so as to create the fluidized system normally formed by gaseous fluidization.
To achieve mechanical fluidization in the process of the present invention, certain types of mixers are used.
For example, one suitable mixer employs an impeller in the form of a centrally rotating shaft having a plurality of radially extending arms attached thereto.
Crescent-shaped scoops are attached to the ends of the arms. See U.S. Patent 3,273,863 to Lodige et al, issued September 20, 1966 "~lhich discloses a mixer employing an impeller having such crescent-shaped scoops. Another suitable mixer employs an impeller which has scoops in the form of double-bladed plows. See U.S. Patents 3,018,059 issued January 23, 1962; 3,û27,102 issued March 27, 1962; and 3,i62,428 issued December 22, 1964 to Lodige et al.
Typically, the mixer can be filled to about 20% to about 7û% of its capacity with the wetted roast and ground coffee.
The fluidized wetted coffee particles are devolatilized at a bed temperature of from 32F to 125F
and an absolute pressure of from about 5 mm to 100 mm iA~ . ' . , . .. . . . . ..... _ . .. . .... .. . .

~ 172503 Hg. The moisture level of the coffee particles during the desorption process must be maintained at a level of from about 15% to 65%, and preferably from 20% to 55%, most preferably from 30% to 50~. The maintenance of this moisture level is critical to effectively desoro the volatiles from the coffee.
This process described herein can remove and recover from 60% to 100~, of the volatiles from the roast and ground coffee.
The moisture level is best maintained by passing steam through the fluidized bed of roast and ground coffee.
The mechanically fluidized wetted coffee particles are contacted with from about û.05 to about 0.50 parts of steam under an absolute pressure of from about 5 to about 100 mm of mercury. The temperature of the steam is controlled so that the coffee bed is at a temperature of from about 10F to about 125F. Preferably, this steam~coffee mixture will be at a temperature of from 20 70F to 125F and the pressure will be from about 20 to about 100 mm of mercury.
The contact time for the steam varies from about 10 to about 120 minutes. The time will be dependent upon particle size distribution of the coffee being desorbed.
The wetting and steam-stripping can be done simultaneously or sequentially. As noted above, the key to this process is the maintenance of the bed moisture level above about 15%, for sufficient time to devolatilize the coffee.
The volatiles-laden steam which is generated hy the devolatilization or desorption of the roast and gTound coffee is drawn from the mixing device and collected.
The amount of water collected should be from .05 to 0.50 parts of water per part of coffee desorbed.
Preferably these volatiles are condensed in a two-stage operation. The first condensation consists of passing the volatiles vapor stream through a condenser which reduces the stream temperature to about 32-125F, preferably 32F to 70F, most preferably 32F to ~5F.
This proce~ure removes the water and a fraction of the volatiles from the vapor stream. Preferably ~his first condensation is at a pressure of 5 to 100 mm of mercury.
The rem2ining volatile and flavor compounds and the desorbed carbon dioxide are then collected as a frost in a cryogenically cooled trap. This trap must be contained at a temperature of from about ~lû0F to about -320F and an absolute pressure of from about 1 to about lûO mm of mercury-Alternatively, the volatiles are first condensed asabove by passing the volatile laden stream through a condenser at 32-125F, preferably 32-45F, and the water collected. The remaining fraction is compressed to pressures o, from 760 to 8000 mm Hg and collected in a cold trap at temperatures of from 0F to -320F.
In a second method, the volatiles-laden steam can be cûllected in a single condenser in the form of a frost.
Under these conditions, however, the condenser must be maintained at from about -100F to about -32ûF and an absolute pressure of from about 4 to 8û rnm of mercury.
The first condensate can be cryofied by miY~ing it with liquid nitrogen in a high shear mixer. Tl~is cryofied extract can be used as a substrate on which the second fraction of the condensate is collected. The cryofied extract would be held at temperatures of from -100F to -320F.
The desorbed wet roast and ground coffee can be charged to conventional coffee extraction columns at about 90-98~' of the normal loading weight on a dry basis because of the water which swells the coffee from 2%-10~.
Any conventional percolation equipment and processing can be used. For a description of percolation extraction methods, see Sivetz & FGote, supra, pp. 261-31~.
8ecause the roast and ground coffee is pre-wetted, the draw-off ratio must be adjusted to achieve the same yield of solids. The draw-off ratio is the amo~lnt of ~1 .... . . . .. . .. . . . .. . . .

' 17250~

extract withdrawn from the fresh extraction column during one cycle compared to the average dr~J weight of coffee in the individual extraction columns. Preferably, a draw-off ratio of about 2.3 to about 3.2 is employed.
This gives a solids yield of about 13% to about 26% by weight Typically "/hen the same load oF dry coffee is charged into the extraction column, a draw-off ratio of about 2.1 is employed.
Another method of preparing a soluble coffee extract which comprises a two-stage counter-current extraction is described in U.S. Patent 3,700,466 issued to Bergeron et al (October 1972). In this process one stage is a hydrolyzing stage and is operated at lemper2tures of from 330 to 355F. The second stage is a cold, fresh lS extraction stage operated at temperatures of from 32 to 180F and at a pressure of not less than about 200 psig. This process may also be used herein.
After emission from the extraction system, the extract contains from about 13% to about 26% coffee solubles. The extract is preferably concentrated to at least 35~ solubles concentration and preferably up to 50%
solubles concentration, and then dried by well-known spray drying, freeze drying, or drum drying techniques.
The condensed volatiles and volatile-laden steam whether condensed as one fraction or two, are combined with soluble coffee materials to produce a highly aromatic and flavorful soluble coffee product. The combination of the condensates with the solubles can be accomplished by several methods.
One method involves adding from about ~0% to about 50% soluble solids to the aqueous condensate (the first fraction) to produce a soluble coffee extract. This extract is then cryofied by mixing with liquid nitrogen under high shear and added to the frost or second condensate at cryogenic temperatures.
A second method involves adding solids to the frost and equilibrating these materials. This frost/solids mixture is then added to the aqueous condensate to ! 172505 produce a coffee extract having from about 20% to about 50% solids. This a~ueous ext.act can then be freeze dried.
A third method involves the collection of the frost 5 on cryofied aqueous condensate to which coffee solids are added later, or on cryofied aqueous condensate to which from 25% to 5û% coffee solubles have been added.
The extract condensate mixture is prepared at cryogenic temperatures, i.e. -100F to about -320F.
10 This mixture is then equilibrated to allow the carbon dioxide to volatilize while retaining the key volatiles which make up the frost and condensate.
The equilibration can be accomplished at atmospheric pressure or at pressures up to 8000 mm mercury 15 (150 psi). The key is to keep the solution at or above the sublimation temperature of carbon dioxide for only the length of time required to rerrove the carbon dioxide. As soon as the carbon dioxide is removed, the extract should be processed through freeze drying to 20 minimize the loss of the aroma and flavor materials.
Atmospheric pressure equilibration is conducted under the following conditions. The cryofied extract and frost mixture which is usually at liquid nitrogen temperatures, i.e. -320F, is placed in a container which is open to 25 the atmosphere. The mixture is allowed to equilibrate, that is, the carbon dioxide is allowed to sublime from the mixture. At atmospheric pressure the carbon dioxide sublimes at a temperature of about -108F. It is preferable to keep the vessel containing the cryofied 30 extract and frost at temperatures below about -40F, preferably below about -80F, during this sublimation process.
During the sublimation of the carbon dioxide, the temperature of the extract will remain at -108F. The 3s t emperature of the extract must be carefully monitored.
ûnce the temperature of the cryofied extract starts to rise above -108F, the processing, i.e. the melting and mixing of the materials prior to freeze drying, ! 172505 should be started. The atmospheric sublimation usually requires about 24 hours.
The pressure equilibration is conducted somewhat differently. The cryofied extractJfrost mixture is placed in a pressure vessel at -320F. The pressure in the vessel is allowed to build up to 8000 mm mercury.
This is usually accomplished by warming the vessel. The carbon dioxide is then vented from the vessel to maintain the pressure. The heat of vaporization will keep the cryofied extract/frost mixture cold. Again, the temperature of the cryofied extract/frost mixture is monitored such that as soon as it begins to rise above the sublimation point of carbon dioxide, the equilibration is stopped, the product melted under carefully controlled conditions to form a homogeneous mixture, then freeze dried.
The cryofied extract/frost mixture is melted after equilibration at as close to the melt temperature as possible, preferably at the melt temperature. The 2û extract~frost mixture is melted in a sealed vessel with agitation. It is advantageous to keep the vessel sealed so that the aroma/flavor volatiles will not be lost during this melting/mixing operation.
The extract/frost mixture is then slowly frozen to 2s about -~0F in order to produce large ice crystals. This mixture is then ground to the desired particle size range and freeze dried.
Convertional freeze drying may be used. In order to retain the volatiles within the extract/frost mixture during freeze drying, it is very important that the particles not be allowed to melt during the freeze-drying operation. Therefore, the temperature must be controlled to maintain the frozen material in a solid state. The final moisture level is from about 1% to about 7%.
rhe freeze-dried material is the aroma/flavor concentrate which can be mixed with other soluble coffees to produce a soluble coffee beverage.

! 172505 If 2 more concentrated aroma/flavor concentrate is preferred, the condensates can be mixed with lesser amountS of soluble coffees. However, it is then necessary to freeze-concentrate or evaporatively concentrate these materials to a coffee extract soluble c-oncentration of 25o to 50,' which is the desired range for freeze drying.
_XAMPLE I
Forty-six pounds of a green coffee blend consisting of washed Arabicas are batch roasted in a Probat Roaster to a photovolt color of 70. A minimal amount of water is used to quench the roasting process (0.25 gal.). ~ithin 5 minutes of discharge from the roaster the coffee is then additionally cuenched with about 46 pounds of liquid nitrogen. This operation serves to cool the ~Yhole roasted beans to a maximum temperature of -40F.
~ he cold enbrittled beans are then ~round using a precooled hammermill type grindern(Fitz~'Mill). The particle size distribution of the roast and ground coffee 20 is: -Sieve Size on 6 39 on 8 36 on 2û 21 through 20 4 The yield through grinding is about 40 pounds of roaste~d and ground coffee. ~lost of this loss is due to shrinkage during the roasting operation.
The 40 pounds of cold roast and ground coffee are loaded into a mechanical mixer"(Littleford"Model FM-130D) fitted to run under vacuum. The system is then evacuated to an absolute pressure of about 20 mm of mercury. At this time, 17 pounds of 40F water are sprayed at a uniform rate over a 10-minute period into the mixer and onto the mechanically fluidized bed of roast and ground coffee. This process serves to increase the moisture content of the coffee from about 2% to about 32%.

* Trademark ~' .1 .

.

' 172505 At the conclusion of the ~ater wetting operation, steam flow is begun into the mixer at a uniform rate over a 65-minute period so that the coffee is contacted with about 9.2 pounds of steam. During the 75 minute desorption cycle time the pressure within the mixer is controlled to from 20 mm to 100 mm of mercury so that the vapor temperatur is maintained from about 7û to 125F.
The volatiles and carbon dioxide released from the coffee during the desorption process and the steam passed through the mixer are condensed in a two-stage operation.
This stream is first passed through a heat exchanger which cools the vapor to about 35F. Most of the w2ter and some of the volatiles are condensed by this operation. The non-condensed volatiles and carbon dioxide are collected as a frost by subsequent condensation in a liquid nitrogen cooled trap.
The pressure within the heat exchanger is varied in conjunction with the pressure in the desorption vessel.
The pressure within the cryogenic trap, however, is controlled at a uniform 10 mm of mercury.
At the conclusion of the 75-minute desorption cycle, the ~later condensed at 35F (about 8.0 lbs.) is mixed with about 4.31 lbs. of spray-dried soluble coffee po~der to form a 35~ solids extract. This extract is then added to liquid nitrogen using a high-speed mixer ("Chemineer~)*
This cryofied extract is added to the frost and placed in a -4ûF freezer for 24 hours or until the temperature of the mixture rises to just above -103F. This insures that all the carbon dioxide has been vented, i.e. sublimed from the system.
The extract/frost mixture is then melted, mixed to produce a homogeneous mixture and refrozen at temperatures below -25F for freeze drying. The mixture is ground (at -4ûF) and sieved so that the particles pass through an 3; 8-mesh screen and are retained on a 2û-mesh screen. This material is then freeze dried in a conventional batch freeze-drying unit for 7 hours using a steam temperature of 90F.

* Trademark ~i The roast and ground coffee desorbed to added solubles ratio is 9.3:1.
The GC counts for this product are about 1,950,ûûO as measured by the method described below. About 32~ of the area (636,100 counts) of the gas chromato~raph appear within the first 11 minutes of the spectrum. This part of the gas chromatograph is dominated by two peaks, one having about 3.5 minutes and one having about 5.8 minutes retention time.
Gas Chromatograph Analysis of an Aroma/Flavor Cuncentrate Retention Area (counts) Area (%) Time 0.77 1455 0.07 0.88 392 0.02 15 1.00 338 0.02 1.15 289 0.02 1.57 11330 0.06 2.89 7558 0.4 3.54 158700 8.1 20 5.29 9550 0.5 5.83 341200 17.5

6.07 18350 0.9 6.55 36310 1.9

7.27 13690 0.7 25 7.65 22740 1.2

8.14 14210 0.7 10.89 2698 0.1 13.û5 123900 6.4 13.56 25760 1.3 30 14.78 62460 3.2 15.81 124900 6.4 17.68 74840 3.8 18.77 34~200 17.8 19.90 548100 28.2 35 Total 1946970 For cornparative purposes, the gas chromatograph of soluble coffee used to make the aroma/flavor concentrate is reproduced below.
Retention Time Area (Counts) Area (%) _ 40 0.77 1550 1.98 0.88 370 0.47 1.57 3052 3.90 5.83 2629 3.38 13.05 38200 48.87 45 15.81 11300 14.46 19.90 21060 26.94 ! 1 725~

The devolatilized roast and sround coffee remaining after the desorption process is charged to a conventional extraction column. 8ecause of the high moisture content of this material (about 35%), a dra~.v-off ratio of 2.7 is ~sed. The extract emanating from the columns contains about 16.5% solids concentration. Evaporation is used to increase the solids concentration to 48~' prior to spray drying.
Gas Chromatography Anal~sis A suitable technique for measuring the coffee volatiles of the aroma~flavor concentrate produced by the process of the invention is gas chromatography. ihe flame ionization gas chromatograph analytical measurement herein measures groups of organic compounds in a gas headspace or 15 void-space sample from a septum bottle containing a solution of the soluble coffee. The scale is graduated in microvolt-seconds (referred to herein as "counts") which is a measure of the area under each intensity curve. The results are reported as an integration of the total area 20 under the curve of the compounds which have a retention time of less than 11 minutes, those ~vhich elute first, and also for the total area under the curve of the entire curve.
A. PRINCIPLE O' OPERATION
The chromatograph comprises a 6-foot"Por2sil D"80~100 mesh column of 1/4 inch diameter and is housed in an oven section for temperature programming. "Porasil-D"is a porous silica bed substrate. The column is packed with a uniform sized solid called the solid support but is not 30 coated with a non-volatile liquid (called the substrate).
A hydrogen flame detector is used at the outlet port. An electrometer receives the output signal from the flame detector and amplifies it into a working input signal for an integration. The integrator both sends a display 35 signal to a recorder to print out the response curve and electronically integrates the area under the curves.

* Trademark '~

.

The gas sample is injected into a heated injection port, and is immediat21y s~wept into the packed col~mn by a carrier gas flo~. The gas mixture is then separated into a number of peaks while proceeding through the col~mn and into the detector. The detector t~en ionizes the sample and generates an electrical signal proportional to the concentration of the materials in the carrier gas. The ionized gases and carrier gas are then vented from the unit.
B. SPECI~IC E~UIP~l~NT ~ND CONDITIûNS
A"Hewlett Packard'gas chr matogra?h (~lodel 583nA), and printing integrator (Model 1885ûA~, were used. Nitrogen pressure in the cclumn is approximately 50 psig with a flow rate of 55 ml/min. Air pressure of 4~ psig is used to flush out the detector and support combustion. An initial oven temperature of lOQC is used and temperature programmed up to 220C at 8C/min. The hydrogen is supplied from a gas c~,~linder regulated at 20 lbs. psig.
C. ANALYTICAL PRûCEOURE
Each peak is measured in counts, the counts being first measured by the flame detector and then both integrated and recorded. The peaks are identified by the retention time on the column.
The recorder was synchronized with the integrator as 2j follo~lS:
1. Calibration A standard methane gas is used to precisely set the flame ionization response. Prior to analyzing the samples, a 1 cc. sample of gas is obtained from a gas cylinder (0.5% by weight of CH4). The gas sample is at a pressure of 4.û psig. The gas sample is syringed into the inlet port of the gas chromatograph. The attenuation of the recorder is set at 2~(5). The total counts when the procedure is repeated three times average between 35 2,675,000 to 2,725~000 total counts. If the average is not within the specified range, the H2 flow rate is adjusted.

; Trademark ~1 2. Sample Analysis A one percent solution of the soluble coffee is made up in a 125 ml. septum bottle. The solution is prepared using 34 g. sodium sulfate, 8û ml. distilled water, and û.8 gm of the soluble coffee or aroma/flavor concentrate.
The solution is sealed in the bottle using a rubber septum. The bottle containing the solution is heated in boiling water for 15 to 30 minutes. It is magnetically stirred during the heating.
A 1 cc. sannple of the aromatic atmosphere of the septum bottle headspace/voidspace is taken using the same type of syringe used for the methane stan~ard sample. The gas sample is then injected into the inlet port of the gas chrom3tograph. The recorder automatically integrates the area under the curve in counts (microvolt-seconds).

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Claims (11)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for producing a coffee volatiles concentrate from roast and ground coffee comprising the steps of:
(1) wetting roast and ground coffee having a particle size of from 1000 microns to 3200 microns with from 0.1 to 0.9 parts of water per part of coffee;
(2) desorbing the wetted roast and ground coffee with from 0.05 to about 0.5 parts of steam in a fluidized bed, said wetted coffee being at a moisture level of about 15% to 65%, at a temperature of from 10°F to 125°F
and a pressure of 5mm to 100mm Hg;
(3) condensing the volatiles in two fractions, one at temperatures of from 32°F to 125°F at a pressure of from about 5 to 100mm of mercury, and one at temperatures below -100°F at an absolute pressure of from about 5 to about 100mm of mercury; and (4) combining the two condensates with soluble coffee to form a coffee volatiles concentrate having a solids concentration of from about 20% to 65%.

2. The process of Claim 1 which comprises the additional step of extracting the desorbed roast and ground coffee to form a coffee solubles solution having from 13% to about 26% solids concentration.

3. The process according to Claim 1 wherein the moisture level of the wetted coffee during the desorbing step (2) is between 20% and 55%.

4. The process of Claim 3 wherein the moisture level is between about 30% and 50%.

5. The process of Claims 1, 3 or 4 wherein the temperature of the wetted fluidized bed of the wetted coffee is maintained at a temperature of between 70°F and 125°F and the pressure is maintained at from about 20 mm to about 100 mm mercury.

6. The process of Claims 1, 3 or 4 wherein the condensation of the first fraction of the volatiles is at a temperature of from 32°F to 70°F.

7. The process of Claim 1, 3 or 4 wherein the condensation of the first fraction of the volatiles is at a temperature of 32°F to 45°F.

8. A process for producing a coffee volatiles concentrate from roast and ground coffee comprising the steps of:
(1) wetting roast and ground coffee having a particle size of from 1000 microns to 3500 microns with from 0.1 to 0.9 parts of water per part of coffee;
(2) desorbing the wetted roast and ground coffee in a fluidized bed, said wetted coffee being at a moisture level of about 15% to to 65%, at a temperature of from 10°F to 125°F, and a pressure of 5 mm to 100 mm Hg;
(3) condensing the volatiles in two fractions, one at a temperature of from 32°F to 125°F and at a pressure of from 0 to 100 mm of mercury, and the second at temperatures between 0°F and -320°F at an absolute pressure of from about 100 mm to 8000 mm of mercury; and (4) combining said condensates with soluble coffee to form a coffee volatiles concentrate having a solids concentration of from about 20% to about 65%.

9. The process of Claim 8 which comprises the additional step of extracting the desorbed roast and ground coffee to form a coffee solubles solution having from about 13% to to about 26% solids concentration.

10. The process of Claims 1 or 8 which comprises the additional step of equilibrating the coffee volatiles concentrate to remove the carbon dioxide.

11. The process of Claims 1 or 8 which comprises the additional steps of:
(1) equilibrating the coffee volatiles concentrate to remove the carbon dioxide; and (2) freeze drying the coffee volatiles concentrate to a moisture level of from about 1% to about 7%.