CA1240876A - Soluble coffee composition - Google Patents

Abstract

SOLUBLE COFFEE COMPOSITION

Abstract of the Disclosure A coffee extract or concentrate and a soluble coffee which are similar to roast and ground coffee solubles in composition of moderately volatile flavor components are disclosed. The soluble coffee composition also contains less of the off-flavor components normally found in high quantities in conventional instant coffees.
The coffees are characterized by high pyrazines derivative content and low content of furfural. This soluble coffee composition can be aromatized for use as a premium soluble coffee product. Alternatively, it is compatible for mixing with conventional roast and ground coffee in single- and multiple-serving brewing articles, such as coffee bags.

Description

SOLUBLE COFFEE COMPOSITION
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Technical F7~1d This invention relates to a coffee extract or concentrate and a process for making it and to a soluble coffee composition which have a flavor s;milar to that of regular roast and ground coffee lU and less like the flavor of instant or soluble coffees and to a brewing article for use in conjunction with the soluble coffee product. The coffee is characteriled by its low furfural content and high content of pyrazine derivatives.
Background of the Invention The standard of flavor excellence among many coffee drinkers is freshly ~rewed roast and ground coffee. This beverage provides a balanced blend of aroma and flavor notes contributed by volatile and moderately volatile flavor compounds~
as well as nonvolatile eoffee soli~s. However, for reasons of 20 convenience and economy, many consumers do not prepare freshly brewed roast and g round coffee for each coffee consumption experience. Roast and ground coffee Is typically conveniently brewed in quantities of 5 to l O cups (or more) at a time. For many consumers, such as single consumers, it is uneconomical to 25 brew a large pot of coffee to consume a single cup. Brewing a single cup in most common coffeemakers involves the sams inconvenience as brewing a number of cups. Thus, many consumers have turned to soluble coffee products as a substitute.
Unfortunately, most soluble coffee produces have serious 30 deficiencies. Many soluble coffee products are lacking in the volatile and moderately voiatile flavor components which are easily lost during processing. In addi~ion, the economics of soluble coffee manufacture forces producers to extract the maximum possible yield from the;r percolation processes. This typically 35 involves the use of high temperature and pressure extraction processes to hydrolyze otherwise insoluble coffee ~onsti~uents and to provide a higher soluble yield. This modifles some of the existing flavor compounds present in roast and ground coffee, and it also creates or manufactures addi~ional flavor compounds.

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Also, It Is both difficult and uneconomical to package, ship and s~ll substantial quantitles of watel in coffee products, As a result, most commercial extracts are reduced tc dryness for packaglng and sale, typically by thermal evaporative technlques S which further aggravate tha problem of volatile loss and flavor deg radation .
As a resule of this processing, most instant coffees are poor reproductlons of the flavor of freshly brewed roast and ground coffee . Even where low-boi ling volatiies have been added by 10 aromatization processes, soluble products are often lacking in moderately volatile aromatics, and, in addition, contain off-flavor aromatic compounds generated by thermal processing and by hydrolysis during extraction.
For these reasons, it would be desirable to provlde 15 single-serving convenience in a roast and ground coffee product.
As a result, attempts have been made to package roast and ground coffee in single-serving brewing packets, like tea bags.
However, the brewing time of such coffee bags is longer than the time to make an instant coffee, and the extractability can be 20 variable depending on the water temperature, brew time, volume of water, etc. This has been overcome in some products by the combination of the roast and grollnd coffee in a packet with soluble coffe~, including solubles produced by low-temperature extraction processing. The use of solubles produced by low-25 temperature processing (I.e., solubles extraction withouthydrolysis3 results in a very acceptable beverageO However, the low-solids ylelds of low-temperature extraction processes are such that it is uneconomical to produce the product except for sale at a premium price. And unfortunately, the combination of roast 30 and ground coffee with conventional instant coffees in a coffee bag results in a brew that tastes instant-like and foreign to those accust~med to drinking fresh brewed roast and ground coffee.
Alternatively, it would be desirable to have a soluble co~fee product whose flavor is a close duplicate of freshly brewed roast 35 and ground coffec solubles and yet economical to produce.
Numerous attempts at production of such a product have been made. Many such processes have involved strenuous efforts to ~L~
, capture, preserve and retain the volatiles present in freshly brewed coffee.
One such attempt is that described in U.S. 4,277,509, issued July 7, 1981 to Wouda and assigned to D.E.J. International Research Company B.V., relates to a process ~or "primary"
extraction of roast and ground coffee. The coffee is exhaustively extracted at low temperatures with a first quantity of water. The coffee is then extracted again with a second quantity of water to remove hydrophobic aroma components. Y~ouda then steam strips the second extract and collects the aroma components as a small volume of stripper condensate, which is then added to the first extract. This process can be continued throughout the fresh solubles section o~ an extraction train.
Another approach is that described in De~ensive Publication T920,012, published March 5, 1974 by Pfluger and Bowden, relates to a method for producing a soluble coffee product. In this process, the extract drawn offstream from a coffee perco-lation unit is split into two batches. the first containing higher quality and higher concentration extract, and the second containing lower quality and lower concentration extract. The - I
second batch is evaporatively concentrated within a continuous evaporator and then added to the flrst batch. The combined extracts are dried in conventional fashion.
U.S. 3,720~518, issued March 13, 1973 to Galdo and assigned to General Foods, relates to a process for the production of a high concentration coffee extract containing 30-409~ solids by weight. The key step in this process is the use of intercolumn concentration prior to the fresh stage in a percolator train. The patent describes intercolumn concentration by a variety of techniques, including flash evaporators and vacuum evaporator~, as well as membrane separators and other techniques. Like Wouda, Galdo also describes stripping aroma from the extract, then adding the aroma back to the concentrate.

Unfortunat~ly, when coupled with conventional commerclal percolation o~ extractlon processes, these aroma retentlon and/or aroma add~back processes have the effect of also retaining off- -flavor volatiles which have been gen@rated durlng the extraction 5 process. As 3 result, current instant sof~ees, both spray dried and freeze dried, have a characteristic flavor which Ts dTfferent from the flavor of freshly brewecl roast and ground coffee.
Surpris;ngly, it has becn found that an aromatic soluble coffee can be made at about 35% to 50% solids yield which retains 10 the moderately volatlle flavor components characteristic of roast and ground coffee but whlch does not contain the flavor materials characteristic of soluble or instant coffees which have been hydrolyzed during processing. The process used to create this new soluble cof~ee composition involves a conventional extraction 15 and hydrolysis of roast and ground coffee follo~ed by multistage or countercurrent steam stripping of the hydrolysis extract. The hydrolysis volatiles are discarde~.
-~ U.S. 4,129,665, issued December 12, 197~ to Clark, and assigned to Nestle, relates to a process for extracting vegetable materials in the liquid phase in a group of "cells", divided into hydrolysis extraction and fresh extraction cells. Extraction water is run through the cells countercurrently. Extract from the hydrolysis stage is subjected to a vacuum evaporation or rapid expansion. Then water is added to the partially evaporated `ex~ract in a quantity at least equal to the quantity of evaporated Iiquid, and preferably greater than the quantity of evaporated llquid, prior to passage of th~ extract through the fresh extraction cells.
Clark used a countercurrent hydrolysis step for vegetable materials in U.S. ~,129,665. Unfortunately, he evaporated the extract instead of steam stripping. Evaporation is not capable of obtaining the degree of removal, for example, of aqueous furfural as is countercurrent steam stripping. Moreover, evaporation involves a heat treatment of the extract which causes thermal degradation of the aroma and flavor coffee solids. This heating and concentration also creates or encourages the precipitation of polymeric ma~erials from solution during evaporation.

~ 7~3 It is an object of an aspect of this invention to provide a soiuble cofEee which closely approximates the flavor of freshly brewed roast and ground coffee and which is lacking in the off-flavors which are characteristic of hydrolyzed coffee.
It is an object of an aspect of this invention to provide a coffee extract or concentrate which has a flavor and aroma approximating fresh roast and ground coffee extracts.
It is an object of an aspect of this invention to provide a soluble coffee which can be manufactured in high yield for combination with roast and ground coffee to produce a less bitter coffee brew.
It is an object of an aspect of this invention to provide a process for producing a coffee extract and a soluble coffee which closely approximates the flavor of freshly brewed roast and ground coffee.
It is an object of an aspect of this invention to provide a process for making a soluble coffee which can be manufactured in high yield but which does not contain off-flavors associated with hydrolysis extraction.
It is an object of an aspect of this invention to provide a process for making a regular or decaffeinated coffee extract which closely approximates the flavor of freshly brewed coffee.
It is an object of an aspect of this invention to provide an infusion device containing a specially processed soluble coffee in combination with roast and ground coffee.
These and other objects of the invention will be evident from the following disclosure.
Summary of the Invention Various aspects of this invention are as follows:
A coffee brewing article comprising a water-permeable infusion article containing:
a) roast and ground coffee; and b) a soluble coffee composition comprising:
1) volatile and non-volatile aroma and flavor compounds, at least two of said -5a-8~6 .
aroma and flavor compounds being furfural and pyrazine derivatives;
wherein the ratio of furfural to total pyrazine derivatives is less than 1.5:1, and wherein the pyrazine derivatives have a g.c. count of at least 20,000, wherein said g.c. counts, on a dry solids basis, are measured on a Freon 11 solution of separated volatiles by capillary gas chromatography on a fused silica column;
and

2) wherein the total ash is less than 12% on a dry solids basis~
A coffee extract comprising: (a) at least 15~, and preferably at least 35%, coffee solids, said solids comprising non-volatile and volatile aroma and flavor compounds, at least two of said aroma and flavor compounds being furfural and pyrazine derivatives; (b) wherein the ratio of furfural to total pyrazine derivatives is less than 1.5:1 and wherein the total pyrazine derivatives are at least 20,000 corrected g.c.
counts on a dry solids basis, wherein said g.c. counts are measured on a Freon 11 solution of separated volatiles by capillary gas .

., chromatography on a lFused silica column; and (c) wher~ln the total ash Is less than 12~, on a dry solids basisO
This coffee extract is concentrated in a mann~r which preserves the coffee volatiles and dried to form a soluble coffee 5 product with essentially the same furfural, pyrazine derivatives and ash contentO
The process comprises the steps of:
1) forming a hydrolyzed roast and ground coffee extract;
2) mul~istage or countercurrently steam-stripping the hydrolysis extract to remove hydrolysis volatiles;

3~ discarding said hydrolysis volatiles; and

4) passing the stripped hydrolysis extract through roast and ground coffee at a temperature of from about 138C
~280F) to about 21C 170F) to produce a final extract.
This extract is concentrated in a manner which preserves the low and the mGderately volatile compounds. Preferably, freeze concentraton is used to produce a concentrated coffee extract. The concentrated coffee extract can also be dried to 2~, make a soluble co~fee.
The coffee brewing article comprises a water-permeable infusion article containing:
a) roast and ground coffee; and b) a soluble coffee composition comprising:
1) volatile and non-volatile aroma and flavor com-pounds, at least two o~ said aroma and flavor compounds being furfural and pyrazine deriva-tives;
wherein the ratio of furfural to total pyrazine derivatives is less than 1.5:1, and wherein the pyrazine derivatives have a g.c. count of at least 20,000, wherein said g.c. counts, on a dry solids basis, are measured on a Freon 11 solution of separated volatiles by capillary gas chromatography on a fused silica column; and 2) wherein the total ash is less than 12% on a dry solids basis.

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Brief Descr ption of the Fi~ures Figure 1 is a schematlc of the coffee extract and soluble coffee process.
Figures 2A, 2B, 2C, 3A, 38 and 3C are chromatograms of s various coffee products.
Figures 2A, 2~3 and 2C are chromatograms of organlc compounds in the soluble coffee of this invention.
Figures 3A, 3B and 3C are chromatograms of organic compounds in a commercial spray-dried instant coffee.
Figure 1~ is a drawing of the steam distillation apparatus used to concentrate the coffee volatiles for the analytical gas chromatographio method.
Disclosure of the Invention 1. The Coffee Composition This invention provides an instant or soluble coffiee and a coffee extract or concentrate which are similar to grouncl roast coffee in its composition of moderately volatile flavor components.
At the same time, it is di~erent in composition from other soluble coffees. In particular, the soluble coffee of this invention contains relatively large c;uantities of moderately volatile compounds, having normal boiling points of 88C (190F3 to 205C
(401F), and nolmally found in roast and ground coffees, These quantities are significantly higher than those present in conventional instant coffees. hloreover, the coffee brew made from the extract or soluble cof~ee is less bitter than roast and ground and typical soluble coffees.
All of the specific components of coffee aroma and flavor volatiles have not been identified. It is estimated that over 250 compounds are present or contribute to the aroma and flavor of coffee. While it is not possible to say that the compounds identTfied herein are definitive of ooffee flavor and aroma, it is believed that these compounds represent the retention of good flavors and the removal of off-flavors.
These aroma and flavor compounds importantly include various pyrazines which are ~ormed during coffee roasting and which are considered herein to be key indicators of roast ans~

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ground coffee flavor. Such compounds include, but are not limited to, pyrazlne; methyl ~yraline 2, 5-dimethyl pyra in~;
2,6-dimethyl pyrazine; 2,3-dimethyl pyrazine; 2-ethyl-6-methyl pyrazine; 2-ethyl-5-methyl pyrazine; 2,3,5-trimethyl pyrazine;

5 and 2-ethyl-2,5-dimethyl pyrazine.
These coffee aroma and f3avor compounds also include various other volatiles which are indicators of roast and ground flavor. Such non-pyrazine compounds include, without limitation, isobutyraldehyde, methyl ethyl ketone, 2,3-pentanedione, 10 dihydro-2-methyl-3(2H) furanone, acetoacetate, 5 methyl pyrrole-2-carboxaldehyde, guaiacol, ethyl guaiacol and vinyl guaiacol ~
Additionally, cof~ee volatiles also include various sulfur-bearing coffee volatiles which are formed during coffee 15 roasting, and which are also considered to be key indicators of roast ancl ground flavor. Note that, in general, pyrazines are volatiles which can be formed during the roasting of most grains.
It is the sulfur-bearing volatiles which help to distinctively separate coffee from other roasted grain beverages. These 20 sulfur-bearing compounds, as analyzed by the gas chromato-graphic method described below, are not yet sp~cifically identified. Yet, the analysis demonstrates that the soluble coffee of the process of this invention has (1~ a level of these sulfur volatiles significantly higher than in conventional instant coffee, 25 and (2) a level of these compounds essentially equal to the level in roast and ground coffee.
The composition of this invention contains less of thè
compounds normally found in high quantities in instant cof~ees, and referred to herein as hydrolysis volatiles. Furfural is 30 especially prominent among these compounds and is considered herein as an indicator of the prPsence of hydrolysis volatiles in general. Furfural is a reaction product from the hydrolysis of 5-carbon sugars. It is present in detectable amounts in regular roast and ground coffees, but is present in much larger Q~3'7~ti g qu~ntitles ln in~tant coffees, both spray dried and freeze drled, due to hydroly~ls extraction.
Tho composition of this invention is both a coffee extract and a soluble coffee product comprising non-volatile coffee solTds s and volatile aroma and flavor compsunds. This composition has levels of the key volatiles boiling at atmospheric pressure in the range of from abollt 88C (190F) to about 205C (401F) ("moderately volatile flavor compounds") which are at least substantially equivalent to the levels of those same voiatiles in roast and ground coffee, on a gram for gram basis.
By "at least substantially equivalent to freshly brewed roast and ground coffee" is meant that the key moderately volatile compounds of the composition of this invention, on a gram for g ram basis, average at least 100% or more of the ,ev~ls of the same volatiles in conventional roast and ground coffee.
Preferably, at least 150% of the level of those volatiles present in roast and ground cof~ee are present in the coffee of this invention .
Th~ cof~ee extract and the solubles are further defined by the content of pyrazine derivatives and the ratio of furfural to pyrazines. The aroma and fla~vor compounds are steam distilled and extracted (with Freon 113 from the coffee extract or soluble coffee product. The relative amounts of the aroma and flavor compounds are then measured by capillary gas chromatography on a fused silica column. Each compound can be identifled by its retention time on the column. Gas chromatography giYes the relative proportions of the compounds in composition and can be related to the actuai concentration of the compound in the composition.
The coffee compositions herein are defined by the minimum number of gas chromatographlc counts (g.c. counts) of pyrazine derivativ~s and by the ratio of chromatographic counts of furfural to pyrazine derivatives. Gas chromatographic counts are the electronic output of the ga~ chromatograph.

By pyrazlne derivatives are meant th~ following compounds:
pyrazine, methyl pyrazine, 2 ,5-dimethyl pyrazine, 2 ,6-dllTlethyl pyrazine, 2,3-dimethyl pyrazine, 2-ethyl-6-methyl pyrazine, 2-ethyl-5-methyl pyrazine, 2,3,5-trlmethyl pyrazine, and 5 2-e~hyl-2, S-dimethyl pyrazine. These derivatives are defin~d by their retention times using the capilliary gas chromatographic method as described in the method herein. Figures 2A, 2B, 2C, 3A, 3B and 3C are typical chromatograms. The pyrazine compounds are denoted on each as follows: pyrazine (2); methyl pyrazine (4), 2,5-dimethyl pyrazine (6), 2,6-dimethyl pyrazine (8), 2,3-dimethyl pyrazine (10), 2-ethyl-6-methyl pyrazine (12), 2-ethyl-S-methyl pyrazine (14), 2,3,5-trimethyl pyrazine (16), and 2~ethyl-2,5-dimethyl pyrazine (18). Fur~ural is identified as (20) .
The compositions herein have a gas chromatographic count of at least 20,000 for pyrazine derivatives and pre~rably about 30,000 to about 50,000 counts. Because of the presence of Freon 11 solvent and other impurities associated with the analytical method, the concentration of the volatiles is given in 20 g.c. counts rather than percent volatiles. The ratio of furfural to pyrazine is less than 1.5:1, and preferably from about 0.4:1 to 1 : 1 .
The total sulfur compound le~el is also measured by gas ehromatography as described below. The level of these sulfur 25 compounds approximates those in roast and ground coffee. The total sulfur compounds will be about 4,000 to about 15,000 by the method used herein.
Another characteristic of the coffee extract and cof~ee solubles is their ash content. Ash is the oxidation product 30 minerals of which are present in the green coffee beans. The ash is measured by pyrolysis of the coffee sample. The minerals of the roast and ground coffee are easily extracted. Thus, the ash content of a soluble coff~e or coffee axtract can be used as a me~ure of yield of solids from the roast and ground coffee. The coffee extract and soluble coffee herein has an ash content, on a dry solids basis, of less than 12~, preferably less than 9%, and 5 most preferably from 5% to 7.5%.

I l . The Process A. Green Bean Blendin~
The solùble eoffee product of this invention is made by extraction of conventional roast and ground coffee. Because the 10 product of this invention is designed to duplicate closely the flavor of freshly brewed roast and ground coffee, it will be evident that the starting blend of green beans and the roasting and grinding conditions will contribute importantly to the final product characteristics. While these parameters are more 15 important than is usual in making soluble coffee, they are not critical .
Three major types of green coffee beans are blended to formulate a coffee blend for subsequent roasting. These three types of coffee are milds, Brazilians, and Robustas. Botanically, 20 the milds and Brazilians are traditionally thought of as Arabicas.
The miids give coffee brews which are fragran~ and acidic.
The Brazilian beans result in coffee brews which are relatively neutral flavored. The Robusta beans produce brews with strong distinctive flavors that possess varying degrees of dirty or 25 rubbery notes.
Traditionally, the milds are the most expensive of the three types of beans, with Brazilians being of intermediate expense, and Robustas being least expensive.
Since the fiavor of the c~ffee blend is more prominent in the 30 soluble product of this invention than in conventional soluble products, more care must be taken in formulation of the blend.
For example, conventional instant coffees are often made using high levels of Robustas, which are less expensive and yield more solubles but have poorer flavor characteristics. The blend of 35 coffees used in the process of this invention preferably contains lower levels of Robusta coffees. If it i~ desired to use a major ~,.2~t~

-lla-proportion of Robustas, th~n at least a portion of the Robustas should be "upgraded" by techniques known to the art, such as those described 5n U. S. 3,640,726, i~sued February 3, 1972 to Bolt et al., and U.S. ~,234,613, issued November 18, 1980 to 5 Lewis. However, some persons prefer a heavier, more robust coffee flavor and could use a higher level of Robusta~.
~ )ecaffeina~ed beans can be used to make a decaffeinated soluble coffee or decaffeinated coffee ex~ract. Blends of decaf-feinated beans with undeeaffeinated or partially decaffeinated 10 beans will provide a low caffeine coffee extract or soluble coffee.
B, Roasting and GrindTn~
A variety of roasting techniques known to the art can be used to roast the green coffee in the process of this invention.
In the normal operation of preparing conventionai roasted and 15 ground coffee, coffee beans are roasted in a hot gas medium whereby the coffee bean temperature is raised to a temperature of from about 176.6C ~350~F) to about 218C (425F) with the time of roasting being dependent on the flavor characteristics desired in the coffee beverage when brewed. Where coffee beans are ~ roasted in a batch process, the batch roasting time at the hereinbefore given temperatures is from about ~ minutes to about~
20 minutes, preferably about 6 minutes. Where coffee beans are roasted in a continuous process, the residence time of the coffee beans in the roaster are from about 30 seconds to about 9 25 minutes, preferably about S minutes. The roasting procedure can involve static bed roasting as well as fluidized bed roasting.
In roasting green coffee for conventional instant coffee extraction, darker roasts are commonly used. This is done t develop strong but somewhat harsh flavors which can survive 30 conventional instant coffee processing. Because the process of this invention provides much better carry-through of roast flavor, this process does not require darker roasts. Lighter roasts can preferably be used to provide a flavor that is not burnt-tasting, yet strong. The lighter roasts also produce 35 clearer, reddish cup colors. Additionally, the lighter roasts do not develop as much of the dirty, rubbery note in th~ Robusta coffees as wou!d a darker roast. Thus, the blended beans are roasted to a Hunter "L" color of from about 18 to about 27, but preferably about 22 to about 26. The Hunter Color "L" scale values utilized herein to deflne the color of coffee beans and the degree to which they have been roasted are units of color measurement in the Hunter Color system. That system ts a well-known means of defining the color of a given material. A
complete technical description of the system can be found in an article by R. S. Hunter, "Photoelectrlc Coior Difference Meter", J. of the Optical Soc. of Amer., 48, 985-95 (1958). Devices -specifically designed for the measurement of color on the Hunter Color scales are described in U.S. Patent No. 3,003,388 to Hunter et al., issued October 10, 1961. In g~neral, it is noted that Hunter Color "L" scale values are units of light reflectance measurement, and the higher the value is, the lighter the color is since a lighter colored material reflects more light. In particular, in the Hunter Color system the "L" scale contains 100 equal units of division; absolute black is at the bottom of the scale lL = 0) and absolute white is at the top (L - 100). Thus, in measuring degrees of roast, the lower the "L" scale value the greater the degree of roast~ since the greater the degree of roast, ~he darker the color of the roasted bean is. The use of the Hunter Color "L" scale value provides an accurate and reproducible means for measurement of degree of roast. The Hunter Color "L"
scale values herein are measured utili~ing ground beans, the grind size being through 12-mesh U.5. Standard Sieve Series and more than 75 weight percent on 30-mesh U . S~ Standard Sieve Series. With roasted beans, the level of moisture in the beans is adjllsted to below 7 weight percent if not already at that level, before color measurement.
Grinding of the whole roasted coffee can be done in any of the ways known to ~hose skilled in the art. In the process of this invention, finer coffee grinds are preferred to allow the most efficient fresh extraction possible. Efficient fresh extraction is impor~ant in this invention to minimize as much as possible the carryover of low-temperature extractable solubles into the hydroiysis section of the train. If they are carried into the 3'76 - ~ 3 hydrolysis 5eetion, they will be thermally degraded and produce inseant coffee off-flavors.
C. Extraction The roast and ground coffee is extracted with water to form S a fresh coffee extract. The extracted coffee is hydrolyzed and extracted to produce an hydrolyzed extract. Any conventional coffee extraction and coffee hydrolysi5 process can be used herein. Most commercial extraction processes use a coffee extraction train and, therefore, this type of process will be used 10 to illustrate the invention.
Water is passed countercurrently through a coffee extraction train consisting of a series of extraction columns filled with roast and ground cof~ee. The operation of such a system is well understood and many modifications and variations will be apparent 15 to those skilled in the art from the description and examples that fol low .
A plurality of extraction columns filled with roast and ground coffee are connected in series by piping between the individual columns. Typicaily, six columns are found In the 20 countercurrent extraction system, and therefore this description is given with reference to a six-column system. The las~ three columns, i.e., those containing the most nearly spent coffee grounds, are referred to collectively as the hydrolysis columns, while the next two columns which contain coffee grounds of an 2s intermedi~te degree of spentness, together with the first column which contains the freshest coffee grounds, are referred to as the fresh extraction columns. As above noted, the extraction columns are intended to be used with roast and ground coffee;
however, it should be realized that they can be adapted to the 30 extraction of whole coffee beans.
Water enters the column containing the most nearly spent coffee grounds at the lower extremity of the column and is discharged at the top of the column. The outlet line from one column is connected to the inlet line of the next column. The 35 extracting fluid progresses from column to column in the series entering each column at the bottom and being discharged from the top. Heat exchangers can be fitted in the lines between the 38~3~3 columns Immediately prior to the extraction liquld inlet to th~
columns. The heat exchangers can be used when required to achiev~ or to maintain the hydrolysis temperature, i.e., about 30ûF to 380F in the hydrolysis columns of the extraction 5 system. They can also be used in the extraction columns to cool or to heat the extraction liqlJid to any desired extracting temperature, i.e., usually within the range of from 37.8C (100F
to 137.8C (280F). Each column is filtted with a means for charging the column with roast and ground coffee, for 10 discharging the coffee from the co3umn, and for keeping the coffee in the column during the overall extraction cycle. The column which the extract liquor enters just prior to being withdrawn from the system contains the freshest coffee, In most systems, at least one extra column is provided in 15 each series so that the extraction operation is not interrupted while the most nearly spent coffee column is being emptied and refilled~ The extra column is a standby column which is cut into the system either slightly before or simultaneousiy with the removal of the most nearly spent coffee column. Additional extra 20 columns are usually avai!able to allow operation of an extraction train of more than six columns, if desired, In the operation of a cof~ee extraction system, aqueous extract is drawn off at a draw-off ratio of about 1 to 3. As is well known to those skilled in the art, the clraw-off ratio is the 25 amount of extract withdrawn fron3 the fresh extraction column compared to the average weight of coffee in the individual columns. Preferably, a draw-off ratio of 1 . 5 to 2 . S is employed in the process of this invention.
After extract draw~off from the fresh extraction column is 30 complete, a new column containing fresh roast and ground coffee is cut into the system with the original fresh extraction column becoming the next succeeding stage, and so on to the point where the column that originally contained the most nearly spent cof~ee is removed from the system. The cotumn removed from the 35 system is cleared of the spent coffee grounds and charged with fresh roast and ground coffee to become the standby fresh extraction column. The cycle tim~ is defined as the time interv~l between successive draw-off~ of final extract. The cycle time of this process can vary from about 15 minutes to about 1 hour. In the practlc~ of this invention, a cycle time of about 30 minutes Is preferred. The cycle time al50 corresponds to the interval 5 between other operating steps besides draw-off; for example, i~
also corresponds to the tirne interval between the exposure of coffee in one coffee column to hydrolysis, and the exposure of coffee in the next freshPr column, to hydrolysis temperature.
The fresh extraction temperature profile is preferably 10 relatively steep, i.e., the extraction temperatures should range from about 50C 1122F) to about 99C (210F), to allow for efficient fresh extraction. This is generally achieved by starting extraction at a relatively low temperature and increasing the extraction temperature to near that of boiling water. The relatively rnild fresh column temperature 50C (122F) is preferred to extract heat sensitive components early in th~ extraction process, to avoid thermal degradation. The steep profile, up to 9â.9C ~210F), in only four columns, is preferred to extract as much as possible of the fresh solubles. As described in the case of the use of flner coffee grinds, efficient fresh extraction is important in this invention to minimize as much as possibl~ the carry-over of low temperature extractable solubles into the hydrolysis section of the train.
The hydrolysis extraction temperature profile is preferably relatiYely mild. That is, the temperatures should be high enough to effect hydrolysis, generally in the range of from about 154C
(310F) to about 166C (about 330F), but low enough to avoid excessive thermal degradation of the coffee, which can occur at hTgher temperatures.
D. Removal of Hydrolysis Volatiles In the practice o~ this invention, the coffee extract issuing from the last hydrolysis column of the extraetion train ti.e., immediately preceding the fresh extraction columns~ is referred to as a hydrolysis extract. In making the coffee product of this invention, the hydrolysis extract is multistage or countercurrently steam-stripped to thoroughly remove volatiles created during the hydrolysis stage of the extraction process. The resulting 8~3 strlpped hydrolysis extract is then passed through the fresh extractlon columr;s, preferably in a countercurrent manner.
The steam stripping process of this invention can be practiced in a varlety of ways known to the art. Typically, the S stripping is accomplished at temperatures of from 38.9C (102F) to 108.9C (228F) and pressures of 1 to 20 psia. The mass ratio of steam to extract is from 0.3 to 10, and most preferably from 0.5 to 1.5. Evaporation, which involves boiling the extract, does not efficiently or effectively remove the volatiles which multistage 10 or countercurrent steam stripping removes. Importantly, this steam stripping removes furfural very effectivelyO Furfural is representative of the hydrolysis volatiles. Removal of furfural indicates that the off-flavors are also being removed.
In a preferred method, hydrolysis extract leaves the 15 hydrolysis section of the extraction train and is sprayed into the top of a vacuum chamber. The feed temperature of the extract must be at or above the boiling point of water at the pressure of the stripping chamber. Otherwise, steam in the chamber will condense onto the extract droplets and reduce the efficiency of 20 the stripper. As the extract falls through the chamber, it is met with an upflow of steam introduced into the bottom of the chamber. The extract is rernoved from the bottom of the chamber, and the steam, along with the hydrolysis volatiles stripped from the extract, is drawn from the top of the chamber 25 and collected in a condenser for appropriat~ disposal. It will be appreciated that in the process described, the steam flows countercurrent to the extract. This results in highly efficient and effective removal of hydrolysis Yolatiles from the extract.
In another method, the extract is successively sprayed into 30 and collected from a series of stripping chambers, with fresh steam introduced into each chamber. In such a process it is not critical that the steam flow countercurren~ to the extract, because the gradient for removal of hydrolysis volatiles is re-established in each successive chamber. This method o~ers certain 35 advantages and is thus also preferred although it is less energy efficient than a strict countercurrent stripping process. The stripping process can be conducted at any desired pressure.

Atmosph~r;c pres~ure Is preferred for simplicity of cquipm~nt design ~nd op~ra~k~n, but sub- or superatmospherlc pressures can be used.
In another ~hod, somewha~ less preferred, the extract is S drawn o~ not be~een the fresh and hydrolysis sections of the train, but in pOs~ on further ~orwardl in the traln. For example, an extr~ction trainl with the following profile is being used:

~ydrolysis Fresh Column P~b. 1 2 3 4 5 6 7 Temp., ~F 330 320 310 210 180 150 12û

The extract steant stripping column would be used to strip the extract l~aaving CO~mn 4 and entering column 5. AlternativelyJ it would b~ used to ~strip the extract leaving col~amn 5 and entering column ~ This rr~location of the stripper has the following 15 advanta~s~ It allows tar-like materials, which emerge from the hydr~lysis se~::tion along with the hydrolysis extract, to be filtered ~ut in the~ colder, fresh columns of partially spent roast and gro~Jmd coffe~, before the materials enter the stripping column; and (2) Itt allows any volatile off-~lavors produced in the 20 hotter, fir~sh colu~mns to be stripped away.
Th~ number a~ countercurrent contacting stages will have a marked ~ffect on ~effectiveness of off-flaYor removal in the stripper~ A mult~stage stripping system is highly preferred.
Other le~ efFlcienst steam stripping methods can be used, but are 25 not pref~rred. ~fter steam stripping, the stripped hydrolysis extract i~ ~ed cl~u-Jntercurren~ly through the fresh extraction columns as descri~ed above, and the final extract is drawn off the fre~best colu~7mn. The distillate or condensate which results from the steam strripping operation is discarded. By "discarded"
30 is simply~, meant t~at the stripper condensate is not used for coffee P~cessing.
E- ~oncentrcation of the Extract -The fresh 5ssDluble flavor of the soluble coffee of ~his invention~ is more sensTtive to change and variation than typical '7~

-lB-Instant flavol. Therefore, after l~avlng the extraction tralf1, the coffe~ extract of this inventlon Is processed in a manner which preserves the volatile compounds, particularly the low and moderately volatile compounds, and avoids substantial thermal 5 degradation 9f those volatiles. In this context it Is also important to note the interdependence of the stripping operation and the post extraction processing. In particular, if the stripping is not performed to remove hydrolysis-generated off-flavor volatiles, the careful post-extraction processing will actually produce an inferior 10 coffee by concentrating off-flavor materials in the product.
Conversely, if the stripped extract is processed by conventional post-extraction techniques, such as thermal evaporative concentration, the resulting coffee product will be remarkably flat, since most of the flavor of conventional instant coffees is 15 provided by the hydrolysis volatiles, due to the absence of authentic moderately volatile compounds which are lost during conventional processing.
After the extract issues from the extraction train, it is preferably concentrated to a solids concentration of at least 35~.
20 For the concen~ration step, a concentration techniclue which does not involve substantial loss of aroma and flavor volatiles is essential. Freeze concentration is a highly preferred process.
Freeze concentration is accomplished in a manner in which the water is removed as substantially or essentially pure ice crystals.
25 Adhering or occluded compounds must not be present in the ice and must not be removed with the ice.
A preferred embodiment of a concentration process involves a freeze concentrator which has a scraped-wall heat exchanger connected to an adiabatic recrystallizer tank. The recrystallizer 30 tank allows water to recrystallize and ice crystals to grow in size under conditions which form pure ice. A filter at the exit of the tank retains alt crystals of more than 100 microns in size. This insures that most ice nuclei are retained for recrystallization.
Ths recrystallized Ice is separated from the concentrated extract 35 by the use of a wash column. The wash column rinses any adhering concentrate from the ice crystals, and expedites removal of essentially pure jCQ from ths freeze concentra~e. A preferred - 1 g-apparatus for use In free~e concentratlon 5s the Grenco freeze concentration unit. This unit is described in U,S, 3,777,892, Issued to Thijssen In 1973; U.S. 3,872,009, issued to Thijssen in 1975; and lJ.S. 4,004,896, issued to Thijssen et al. in 1977.
Other freeze concentration approaches that can be used herein are those which have been developed by CMC Concentra-tlon Specialists, Inc., and Chicago Bridg~ and Iron Works, Other concentration methods which Iminimize IOS of volatiles, such as other free~e concentration processes, membrane concen-l0 tration, reverse osmosis or sublimation concentration involving slow freezing and slow water removal, can be used but are less preferred. Combinations of any of the foregoing concentration methods can also be used.
As mentioned, concentration of the extract is carried out lS until the extract has a "solids" content of at least 20~, preferably at least 35% and most preferably at least 40% by weight. For the purposes of this invention, the term "solids" is defined to encompass any and all materials in the extract or concentrate other than water. It thus includes a number of organic 20 compounds which are volatile liquids under normal conditions of temperature and pressure. It is important to note that when the extract has been concentrated to, for example, 6û% solids, water is actually a minority speeies in the concentrate, Because of the organic nature of most of the solids, these high solids concentrates behave more like organic solutions than aqueous solutions, and this effect enhances volatile retention durin subsequent processing.
The extract can be decaffeinated either before or after the extract concentration. Liquidlliquid decaffeination of coffee extract processes are well known. See, for example, Morrison, Elder ~ Phillips, U.SO Patent 4,409,~53.
The coffee extract or concentrated cof~ee extract can be pasteurized, frozen or aseptically packaged. The extract or concentrate can be aromatized or flavored with natural or arti~lcial sweeteners, cream or artificial creamers, natural or artificial flavors, such as herbs and spices. Preservatives such as ~20-anSioxidants or mold Inhibitors can be added to the extract, as can be antifoaming agentsr F~ Preparation of Solubl~ Coffec Product The extract produced in this Invention can be dried to a moisture content of from about 1~ to abou~ 8~ by weight, and preferably from about 3% to about 5% by weight. This is a dry soluble coffee powder. The extract can be drled in any known rnanner to provide a dry soluble coffee product. The drying method should be designed to retain volatlles. Freeze drying or other known moisture-removal processes whîch preserve volatile compounds can be used.
If the resultant dry product is not in the form of particles, it can be broken up by a number of methods to form instant coffee particles. A preferred economical method for drying the aqueous extract is spray drying wherein the liquid extract is sprayed into a tower and simultaneously contacted with a flow of heated air. Vi~ater is removed from the droplets of the aqueous coffee extract as they fall through the spray tower and they emerge from the bottom as porous, spherical particles of instant coffee containing, for example, from about 1.596 to about 5.0% by weight moisture. lTypical disclosures of spray drying processes which can be used to prepare instant coffee particles can be founJ, for example, in Sivetz ~ Desrosier, " Coffee Technology", Avi Publishing Co., ~estport, Conn., 1979, pp. 373-~3, and in U.S. Patents Nos. 2,771,343 to Chase et al., issued on Nov. 20, 1956; 2,750,998 to Moore, issued on June 19, 1956; and 2,~69,553 to Hall, issued on A~ay 10, 1949.) Preferably, the spray drying Is conduc~ed under conditions which maximize volatile retention and minimize thermal degradation or oxidation of the soluble coffee, The extract ~eed temperature to the drier is preferably in the range of from about 15C (60F) to about 38C (100F). Air flows and air temperatures which produce inlet and outlet temperatures of from about 121C (250F) to about 204C (400F) and from about 82C (180F) to 121C
(250F), respectively, are preferred. An inert gas atmosphere can be used to minimize possible oxldatlve effects.

Freeze drying can produce superior volatlles retention, compared to spray drylng, but Is also more expen51v~. Typical disciosures of freeze drylng processes which can be used can be found in Sivetz and Desrosier, cited above, at pp. 484-524.
After drying, the soluble coffee of thls invention can be pelletized or agglomerated to improve its handllng and dissolution characteristics. It can also be aromatized to supply additi~nal high volatiles, i . e., those boiling at temperatures below about 88C. These volatiles can be supplied by practice of any of the many aromatl~ation techniques known to the art. Preferred aromatization techniques include those ~escribed in U.S.
4, 335 ,149, issued June 15, 1982 to Stipp, and Reissue Patent 31,1127, reissued October 25, 1933 to Lubsen et al. Other arornatization techniques are described at pp. 434 to 483 of the Sivetz and Desrosier text cited hereinabove.
This soluble product can also be milled into flakes or agglomerated. U.S. 3,652,293, issued to Lombana et al. (1972) describes such products. The dried soluble coffee of this invention can be packaged, with or withou~ agglomeration ancl with or without aromatization, for use as an instant coffee product.
111. Coffee Brewing Mixtures However, a preferred use of the soluble coffee of this invention is in combination with roast and ground coffee. A
particularly preferred product provides the soluble coffee of this invention and roast and ground coffee in a soluble: roast and ground ratio of from 1: 4 to 1:1 by weight. A particularly preferred product is a permeable bag containing from about 1 to about 2.5 grams of soluble coffee and from about 1.5 to about 5 grams of roast and ground coffee. Combined in these ratios in such a product, each component contributes to a positive overall product perception. The roast and ground portion provides practically all of the coffee aroma during opening of the package and before brewing. It also contributes noticeably to the brewing aroma during preparation and cup aroma. The soluble portion pro~ldes most of the unique flavor of the solubles of this 2~8~

Inventlon, and 75% or mors of the product brew sollds and titrat-able aclds.
In general, finer grlnds of roast and ground coffee will provide better extraction, although a tradeoff with plugging of S bag pores must be made whan extremely fine grinds are used. If desired, the roast and ground coffee component can be flaked or milled ts increase its extractability. Examples of this can be found in U.S. 3,615,667, issued in 1971 to Joffe, lJl.S. 3,640,727, issued in 1972 to Heusinkveld; U.S~ 3,660,106, issued in 1972 to McSwiggin; U.S. 3,769,031, Issued in 1973 to McSwiggin;
Canadian 939, 246, issued in 1976 to Bergeron and Schlichter;
U.S. 4,110,485, issued in 1978 to Grubbs et al.; U.S. 4,267,200, issued in 1981 to Klien and Gieseker; and U.S. 4,331,696, issued in 1982 to Bruce.
The roast and ground coffee component can also be fast roasted to provide an expanded cellular structure and improved extractability. U.S. 3,0û8,825, issued in 1963 to Topalian and Luddington: and U.S~ 3,122,439, issued in 1964 to McAllister an~
Spothaltz, disclose processes for the fast roasting of coffee. The ~439 patent also dlscloses that fast roasted coffee can be flaked.
The coffee articlo of this Invention can bo mad~ of any water-permeable Infuslon material. A metal eonta~ner with small holes, such as a "tsa ball", can be used for brewing the soluble coffee, roast and ground coffee colrbination. Other articles Include plastic, metal or woodan spoons covered with a water-permeable infusion material. For ease of manufacture and economlcal dellvery, the preferred article is a water-permeable infusion bag.
Also, particularly pra~erred is a brewing article containing roast and ground coffee and the soluble coffee of this invention in which the soluble coffee, the roast and ground coffee, or both, are milled into flakes. Flaking of the coffee squeezes out air and other gases and makes the coffee more dense. The result is that a coffee brewing bag using this n-ixtura will be significantly less buoyant than a coffee bag not containing flaked coff~. A lese buoyant bag results in faster brewing ~nd mor~
convenlence during coffe~ preparation. An added benefit i5 that a mixture of soluble flaked coffee and roast and ground coffee flows easily when fllling bags on a packing line.
The coff~e can be milled by any means, but a preferred method is by passing it through a two roll pressurized flake mill uslng about 400-500 psig pressure and about 20 to 30 rpm at zero gap between th~ rolls. IJ . S. 4, 267, 200, issued to Klien and Gieseker, describes milling. The milling method is Incorporated 1( by reference herein. Th~a soluble flaking operation may include an addition of cof~ee oil to the powder to aid in roll lubrication and flake strength. Alternately, the soluble coffee and the roast and ground coffee can be milled together, with the oil coming from the roast and ground coffee.
When the coffee article is used, most of the fresh solubles are dissolved after 30-~5 seconds, delivering abol~t 1.0~ solids concentration in 200 ml of water. Extraction of the roast and ground coffee continues until a concentration of about 1.15% to 1.30% is reached after about 3 minutes of brewing. With this product composition, the coffee extraction is non-linear, with very high extraction rates during the initial 15 seconds or so of extraction, slower rates for about the next 30 seconds, but then only sli~ht concentration changes during the ne)~t several minutes if brewing is continued.
The preferred coffee article of ~his invention can be ~ormed from both nonwoven and woven fabrics. Included within the class of nonwoven and woven fabrics are synthetic fabrics made of rayon, nylon, polyesters, polyacrylic and polypropylene fibers and natural fibers made of hemp and cotton fibers. In addition, it will be appreciated that combinations of fibers can be used to prepare the fabrics suitable for use as the pouch material of the coffee bag of this invention, e.g., where greater fabric strength or increased fabric porosity is desired. Particularly preferred are the nonwoven fabrics comprising fibers of rayon, nylon, polypropylene, and hemp and mixtures thereof. It is immaterial for the purposes of this invention the type of fiber used as the water-permeable material for forming the pouch so long as it is chemically inert, essentially taste-fre~ and sufficiently strong to remain an integral unit throughout normal handling, packaging, shipping of the coffee bag, brewing of the coffee beverage, and disposing of the used packet.
It iS essential that the fabric used for preparing the coffee bag be permeable to water. Yet the pores in the fabric allowing water permeabTlity should be of such a nature and size that the roast and ground coffee particles present in the bag do not pass thr~ugh with the brewing water. The fabric must act as a filter5ng means to accomplish the objectives of preventing the formation of sediment in the brewed coffee. The fabric thickness used can vary but will generally range from about 0.002 in. to abo-~t 0. 012 in ., preferably from about 0. 003 in . to about 0. 009 in .
The size of the pores in the pouching material used in makin!3 the coffee article of the present invention can vary in size from about 5 microns to about 1û00 microns, prefer3bly from about 20 microns to about 200 microns. If a substantial portion of the pores are smaller than approximately 5 microns, it may be impossible, irrespective of time, to extr~ct all of the desired flavor components and constituents from the coffee in the article into the brewed beYerage since smaller pore si~es ~end to clog during brewing of the coffee beverage. Where the pore size is extremely fine inordinately long brewing times are needed. Pore openings larger than about 1000 mierons are to be avoided since they permit passage of coffee fines into the bevera~7e resulting in a high level of sediment. în addition, pore sizes larger than about 1000 microns will allow the smaller particles to sift out on agitation, as for example on shipping, and a dusty cof~ee packet having an undesirable appearance can result.
A~ least a portion of the coffee article can be an apertured or formed fllm, rather than a fabric. Such materials, and methods for making them, are described in U . S. Patents 4,151,240, issued April 24, 1979 to Lucas and VanConey, and ~,3q2,31q, Jssuad August 3, 1982 to Radei and Thompson. In general, the crltella ~or selectlon of materlals and aperture sizes for formed ~ilms are th~ same as those described above as applicable to fabrics.
The preferred article of this invention is simply and easily made. All that is necessary is to form a pouch out of the water-permeable materials hereinbefore described to contain the coffee.
This can be done by "drawstring" means whereby the bag is gathered at one end or by stitching the material together to form the bag. A preferred embodiment of this invention involves heat sealing the water-permeable material to form a bag. In this preferred embodirnent the heat sealing is accomplished through the use of a heat-sealing binder. Binders which are acceptable f~r heat sealing are those binders having a rnelting polnt lower than l' the softening or charring point of the bag material but a meltTng point higher than the temperature of boiling water. In addition, the binder, similar to the bag material, must be chemically inert and essentially taste-free. It i5 important that the binder be sufficiently inert and insoluble in hot water so that no adverse physiological effect from consumption o~ the coffe0 beverage can result. Examples of suitable binders for heat sealing of the bag materials described above are the polymeric binders, as for example, the polymeric binder described in U. S. Patent No.
3,183,096, issued to Hiscock (196S).
The coffee article of this invention can be of any shape that will contain the roast and ground and soluble coffees. The shape to be used may be determined to a certain extent by the brewing method employed. The coffee article of this invention can be brewed in any type of vessel. After brewing, the coffee article containing the spent roast and ground coffee particles may be easily disposed of as a unit.
In addition to packaging the roast and ground coffee and soluble coffee of this invention in a coffee article, the mlxture of the two coffees can be pelleted or tableted for convenient handling. The pellets or tablets are preferably used in a brewing device with a filter to retain the extracted roast and ground coffee.

1~4~6 The methods for brewlng coffee wlth the coffee bag of thi~
inventlon are numerous. A coffee beverage can be brewed by placlng the coffee bag in a cup or pot of wat~r which has been brought to a boil and allowed to cool just slightly (to about 160F
5 to about 210F) and the cof~ee bag steeped in the hot water for from about 0. 3 minutes with agitation of the bag to about 6 minutes with little or no agitation of the bag. The bag can then be removed and disposed of. A coffee beverage can also be prepared using a suitably shaped coffee bag of thls invention and ~, methods and equipment in ger~eral us~ for ~rewlng a coff~
beverage.
Gas C:hromatographic Method Capillary Gas Chromatographic Analysis of Volatil~
Coffee Components Separa~ed and Concantrated by 15 Simultaneous Distillation and Extraction ~SDE-CGC) A. Princip!e The steam distillationlextraction method of Schultz et al., J. Agric. Food Chem., 25, 446-449 (1977) has been applied to the analysis of volatile components of coffees. The first step i~
20 simultaneous distillation and extraction ~SDE). Figure 4 is a drawing of the apparatus used for this proc~ss. The volatile components are steam distilled from a coffee sample. These votatiles ar~ co-condensed with Freon 11. The volatile connponents are extracted by th~ Freon l l . The co-condensed 25 water and Freon 11 are aJlowed to separate and returned to their respective flasks. Thus, the volatile components are extracted and concentratcd in the Freon 11. After ninety minutes the voiume of Freon is reduced by evaporation and methylene chloride (dichloromethane) is added to reduce the loss of extracted 30 volatiles prior to evaporation to a specific volume. The extract is not allowed to evaporate to dryness.
The extract obtained by SDE is analyzed by capillary gas chromatography ((~GC) using a I lewlett-Packard 5880A Gas Chromatograph and fused silica columns. A DB5 column is used 35 with a fiame ionization detector (FID) to detect the carbon and hydrogen in volatile compounds in the SDE ex~ract. A CP-57-CB

87 ~

column Is used with a flame photometric detector (FPD) to det~ct sulfur-bearlng volatlle compounds. The injected sample Is spllt between ~he two columns. Two Hewlett-Packard level four data ~erminals are used to process the data, giving retention times, peak areas and area percents. The methylene chloride (solvent) peak is excluded from the data. Additionally, a total of sTx other peaks which are considered to be "artifacts of the method" are excluded from the numerical data. However, ~hey do appear on the chromatogr~ms. Th~y are detectable on a blank analysis. These 1~ peaks represent impurieles in the methyl~ne chloride and Freon 11, and constltuents of the antifoam.
So far, 27 compounds In th~ separated coffee volatlles have been identified by the SDE-CC;t: method: isobutyraldehyde, methyl ethyl ketone, diacetyl, 2, 3-pentanedione, pyrazine, pyridine, pyrrole, dihydro-2-methyl-3(2H)-furanone, methyl pyrazine, furfural, furfural alcohol, aceto acetate, 2,5-dimethyl pyrazine, 2,6-dimethyl pyrazine, 2,3-dimethyl py~azine, 5-methyl furfurai, furfural acetate, 2-ethyl-6-methyl pyrazine, 2-ethyl-S-methyl pyrazine, 2,3,5-trimethyl pyrazine, 5-methyl pyrro!e-2-carboxaldehyde, 2-ethyl-2,5-dimethyl pyrazine, guaia~ol, 2-t2-furan methyl)-5-methyl pyrrole, ethyl guaiacol, vinyl gualacol.
The data obtained by the SDE-CGC method are sufficiently accurate and preclse to be valid for a comparison of differences in composition of coffee samples.
B. mple Preparation Cof~ee weighing 10.000 + O.OOS grams is placed into a S00 ml. flask~ Two hundred ml. of distilled water is added. Then 3 ml. of in~ernal standard solution and 3 boiling stones are added. (With instant cof~ee, 3 drops of Antifoam B are also added. ) C Internal S ndard Preparation First, 9.0100 ~ .00005 grams of 2-acetyl pyrazine are weighed and placed Tnto a clean, dry 100 ml. volumetric flask.
Then sufflcient methylene chlorlde is added to fill the flask to 100 ml.

3'7~

D. SDE Procedure:
1. The apparatus Is set up as shown In Figure 4 .
The apparatus Includes a sample flask 214 and a solvent flask 218. The sample flask 214 is hsated by a stirrer-hot plate 222 while flask ~18 is heated by hot plate 224. P~sitloned on top of flask 21~ and 218 is a steam distillation/extraction (SDE) column 226 which includes a sample vapor column 228 which receives vapors from the cof~ee sample and a solvene vapor column 232 which receives vapors from flask 218. The top sections of the vapor columns 228 and 232 are joined to condenser column 244. Mountad on top of condenser column 24~ is a Dewar condenser 2~8 provided with a cor~ 250 for receiving coolant.
Condenser column 244 Is provided with a w~ter Inlet 252 and a water outlet 254 for the circulation of water throlJgh a first cooling system ~56 whlch cools core 258 of column 244. Column 244 is also fitted with a second water inlet 260 and a second water outlet 262 for circulation of water through a second cooling system indicated by 264 which cools the periphery 266 of column 244.
Vapors which condense in core 258 and along periphery 266 are c~llected in U-tube 268 connected to the bottom end o~
condenser 24q. Tubing section 272 connects trap 268 to sample column 228 for passage of condensed vapors to flask 214. Tubing section 276 connects trap 268 to solvent column 232 for passage of condensed vapors to flask 218. The cooling water is circulated through systems 256 and 264 and the Dewar condenser core 250 is filled with dry ice.
2, The Freon 11 is redistilled before using it. About 150 rnl. of Freon is collected in a 250 ml. fiask 218 to be used as the extracting solvent.
3. The Freon 11 is draine~ from the U-tube 2~8 when the liquid level reaches the "~"' part 272 of the U-tube.
4. The coffee sample is prepared while the Freon 11 is being redistilled.
5. After the Freon redistillation is cornplete, the Freon is drained until the Jiquid level is in the middle of the "Y" juncticn.

8~76

6. Dlstlll~d water Is add~d through the connectlon 278 wh~r~ thl~ Dewar condenser 25û flts onto the top of the water condensar 256, untll the water liquid level reaches the bottom of the large outer water condenser 260.

7, Three boiling stones are added to flask 218 containing the redistilled Freon.

8. The 500 ml. flask 214 containing the cof~ee solution is cnnnected .

9. Ice Is added to a plastic reservoir which is then used to immerse U-tube 268.

10. Distillation is carried out for 1-1/2 hours a~er water vapor and Freon 11 begin condensing and collecting In U-tube ~68 O

11. The heat to th~ coffee solutlon in flask 214 and tho Freon 11 in flask 218 is turned off at the end of the distlllatlon period. After the coffee solution stops boiling, the distlllation apparatus is disassembled.

12. The Freon 11 is drained out of U-tube 268 until the liquid level is at the Y-junction of the U-tube 268 and tube 272.
It is then poured into a flask 218 with the rest of the Freon 11.

13. The Freon 11 is evaporated down to about 5 ml. under nitrogen on a steam bath set at 60C (140F) to 71C (ï60F).

14. ETght ml. of dichloromethane is added to the flask containing the Freon 11 and swirled.

15. The contents of the flask containing the Freon 11 and dichlorornethane are evaporated down to about 3 ml.

16. A portion of the extract is transferred into a 2 ml.
reaction vial.

17. The extract in the reaction vial is evaporated down to 1 ml. and portions of extract from the fiask are added to the vial and partially evaporated to 0.5 ml. until the flask is empty. Two ml. of dichloromethane are added to the flask and swirled. The solvent wash from the flask is added to the reaction vTal and partially evaporated to 0.5 ml. The extract in the reaction vial is evaporated to 0. 3 ml. if it is to be injected into the gas ~Q~'7~

cht~matograph; otherwls~, It is evaporated to 0.5 ml. and put inSo a frl~ezer untll prlor to g.c. InJectlon, at whlch tlm~ It Is evaporated to the 0.3 ml. Ievel, The extract is not evaporated to dryness.
S E. Gas Chromatographic Analysis;
Conditions for the HP 5880A Q.C.
Septum purge flow :1 ml.lmin.
Inlet pressure : 26 psTg Vent flow :30 ml./min, Make-up carrier flow :30 ml./min.
FID:
Hydrogen flow rate :30 ml./min.
Air nOw rate :400 ml.lmin.
Column flow :3 ml.Jmin.
Spllt ratlo : 1011 FPD:
Hydrogen flow rata :75 ml. Imtn.
Air flow rate :50 ml.lmin.
Oxygen flow rate :40 ml.lmin.
Detector temperature : 200C
Temperature Pro~ram Oven temperature 25C, limit of 405C. The oven is heated at 25C ~or 2.6 minutes.
The oven is then programmed to rise 20. ûClmin. to a 2s temperature of 45C. Then the oven rises at 3.0C/min. to a temperature of 65C. Then the oven rises a~ 2. 0Clmin. to a temperature of 125C. Finally the oven rises at 3.0C to a temperature of 220C. The oven is then heated to 230C and held there for 15 minutes.
The DB5 gas chromatography column used to detec~ and separate the organic compounds are 60 meter columns of 0. 322 mrn. inner diameter. A film of crosslinked polyethylene glycols 1 micron thick is used. The DB5 column is available from J~-W
Scientifc, Inc., Cardova, CA.
The CP-57-CB column used to separate the organic sulfur compounds is 25 micron in length and has an inner diameter of 0.33 mn~. The CP-57-CB column is available from Chrompak ~L2~3'7~ - 31 -Incor~ora~ed, N.J., Cat. No. 7763. ~ fllm of CP~TM-~ax S7, WSCC)T fused sillca column ~t 1.12 mlcron thlckne~ U51~d.
Th~ chromatograms ar~ analyzed by determinlng area percent o~ each peak from the ga~ chromat~3raphic counts (electrical s impulses recorded).
The total gas chromat~raphis counts of the sample as obtained from the chromatogram are corrected to mak~ all of the samples on the same basis for compaJison.
The internal standard (2-acetyl pyrazine1 Is assumed to be 3000 counts based on the concentratlon added and the resp~nse factor. A sample calculation is as follows:
Internal Standard as measured 2737 Pyrazines to~al 21~785 21,785 ~c 3050 = 23,87 Corrected pyrazine count is 23,878.

The furfural count is co~rec~ed in the same mann~r~
The furfural to pyra~ine ratio is obtained by dividlng the total furfural corrected g.c. counts by the total corrected 20 pyrazlne counts.
The total sulfur-bearing volatiles count is also correcsed to make all samples on the same basis for comparison.
Ash Measurement A sample of coffee extract or soluble coffee is weighed into a 25 crucible, The sample is then heated as follows: heated from 20C (68F) to 400C (752F) in one hour; cooled to 200C
(392F) then heated to 1000C (1832F) and kept at that temperature overnight (about 16-18 hours). The percent ash is then determTned by taking the weight o~ the final sample ~imes 30 100 and dividing by the weight of the original sample.

., 3'7~

Ex?mple 1 Th~ ~ollowing @xampl~ Illustrates the process of this invention. Unless otherwise stated, all p~rcentages are given on a weight basi~.
A blend of 25% primes, 25~ Bra2ils, 20% natural Arabicas, and 30~ Robustas was roasted on a Thermalo roaste~ model 23R5.
The roast slze was 3013 Ib5. green cof~ee, and le was repeated three times. The results oF the roasts are listed below:

Roast time, minutes 6.50 6.25 6.33 Final temperature of 442 438 440 roast, F
Water quench le~el, 13.9 13.9 13.9 % of green weigh~
llunter L color 21.1 22.1 21.9 The roasts were blended together to form a single whole roast lot. The whole roast was held at room temperature for about 8 hours belFore the start of grinding and extraction.
An 8-eolumn extraction train and extract steam-stripping 20 column, with assoclated pumps, hea~ers, coolers, and piplng, was utllized. Once begun, the process was operated long enough to tnsure that a truly countercurrent progression of grounds and extract liquor exit~d be~ore taking data and test extract draw-off. This was accomplished by sequentially adding columns 25 to the process until the to~al was seven operating extraction columns plu~ the extract steam-stripping column. As ~he fresh column was put on-line into the system, the most spent column was taken out of the process, emptied, cooled, washed, and refilled to be ussd again. This procedure is known in the art as 30 "startup".
The extraction col~mns are 0.5 ft. in internal diameter and 4.0 ft. high. As known to those skllled in the art, appropriate piping for feedwater and extracts is also used. The columns are also Jacketed w3th a heating oil to prevent heat loss from the 35 columns during operation. The temperature of the oil was adjusted per column approximately to match the inlet fluid . ~ .

~LZ41D876 temp~rature, In a temperature proflle as describ~d later in thls example.
The appropriate piping from and returning to the extraetlon allowed the us~ of an ex~ract steam-stripping column (6 inches 5 internal diameter, 20 ft. hlgh, steam.inl~t at the bottom, extract Tnlet at the top, no internal packing, extract enters through a spray nozzle poTntlng down the column) to strip the hydrolysls volatiles from the hydrolysis extract. Thus, the stripping column stripped the extract leaving column 3 and the stripper bottoms 10 became the extract whTch entered column 4. About 130 Ibs. per hour of steam was fed to the stripping colurnn which operated at atmospheric pressure. A l~eed temperature o~ about 230F was used .
Grinding was done on a Gump model 33 coffe~ granuli~er.
15 The following is a typical particle size dis~ributlon:

U.S. Sieve Screen +~ 8.q -~+8 41 . 4 -~+1 2 25 .
20-12~16 12.~
-16~20 6.0 -20 6.0 After startup, th~ temperatures in the extraction train starting with the column containing the most spent coffee grouncls 25 and progressing to the fresh column, as measured at the inlet and outle~ to each column, were as follows:

2 3 4 5 6 7_ _ _ _ 30 Inlet, F 334 319 310 246 1~1 150 119 Outlet, CF 316 307 261 1~5 151 127 131 The average column load of roast and ground was 20.3 Ibs.
The pressure of columns 1, 2 and 3 was 150 psig. The 35 pressure o~ columns 4, 5, 6 and 7 was near at~nospheric. The ~, -3~ -draw-of~ ratlo was 2.1 and the average cycle time was 30 mlnutes.
The vap~drs and th~ extract ~rom the fresh column were condensed and/or cooled to aboue 10C (50F). The fresh extraction column was exhausted through a chill~d wat~r heat exchanger to an open weigh tank. The percentage yield of solubles based on the roast and ground cof~ee was 39. 0%. The resultant extract of this example contained 1~1. 6~ solubles. ~ sample of the extract was analyzed by SDE-fllD and the results are contained in Table 1.
The corrected g.c. area for ~he pyrazine derivatives is 12,037 the corrected g.c. area for furfural is 8,251; and the ratio of furfural to pyrazine derlvatives is 0.64:1.
The extract was then filtered through a spiral wound cartridge filter rated at 15 micron openings. The fiîtered extract was chilled to about 2C (35F) and pîaced into a refrigerated storage tank.
A Grenco model W8 freeze concentration unit was fed from the refrigerated supply tank. The Grenco system is a closed system.
The refrigerator unit and recircu3ation pump circulating the extract from the recrystalllzer through the scraped-wall heat exchanger were started and the extract was cooled down to about -1C (30F) and formatlon of recrystalli2ed ice was achleved after about 2 hours. Removal of Ice via the wash column started about 3 hours later. A concentration of about 40% dissolved solids was achiev~d after about 20 hours of operation. The unit was then drained of extract. The drained extract was then immediately spray drîcd, as described below. The Grenco was then recharge~ with fresh extract and the process was repeated.
The average age of the extract tfrom draw off to drying) for the first freeze concentration run was about 36 hours. The age for the second run was about 2~ hours, The concentrated ex~ract was dried on a co-current spray drier. The inlet extract temperature was about 16C (61F).
The inlet air temperature was about 171C 1340F). The outlet air temperature was about 93C (200F). The dried solids were collected at a rate of about 40 Ibs. per hourd at a moisture of 3~-about 4. 5~. This powder would have an ash cont~nt of abou~
7.0%.
A sample of the spray-dried powder was anal3~zed with both SDE FID (for furfural and pyra~ines3 and SDE-FPD (for sulfur) 5 to yieid the data in Table 1 and Figure 2A, 2B, & 2C. The corrected g.c. area for the pyrazine deriYatives Is 36,343; the corrected g.c. area for furfural is 27,gO8; and the ratio of furfurai to pyrazine derivatives is 0.77:1. The total corrected sulfur compounds is 10,994.

Example 2 A sample of a commercial freeze-dried premium-priced instant coffee was analyzed by SDE-FID and SDE-FPD, and the results are detailed in Table 1. The corrected g.c.
area for the pyrazine derivatives is 12,474; the corrected g.c.
l5 area for furfural is 28,426; and the ratio of furfural to pyrazine derivatives is 2.28:1. The total corrected sulfur g.c. counts is 2 ,994.

Example 3 A sample of a commercial spray-dried instant coffee was 20 analyzed by SDE-FID and SDE-FPD, and the results are detailed in Table 1 and Figures 3A, 3B, ~ 3C. The corrected g.c. area for the pyra~ine derivatives is 12,386; the correcteJ g.c. area for furfural is 64,428; and the ratio of furfural to pyrazine derivatives is 5.2:1. The total corrected sul~ur g.c. counts is 4, IJ211 .

Example 4 A sample of roast and ground co~fee was analyzed by SDE-FID and SDE-FPD, and the results are detailed in Table 1.
The corrected g.c. area for the pyra~ine 30 derivatives is 23,89g; the corrected g.c. area for furfural i~
12,876; and the ratio of furfural to pyrazine derlvatives is 0.54:1. The total corrected sulfur g.c. counts is 12,953.

3'7 ~36-C~ .
Examplo ~ shows th~ nor~ral ratios of furfural to py~azines in roast and ground coffe~ whlch is consldered to b~ the targ~t standard of composition for an instant coff~. Thes~ levels of S furfural and pyrazines in roast and ground coffee have also been indep~ndently established by outside researchers, ~Nakamichi, L., "Coffee Flavor", New Food Industry 25, No. 11, pp. 54 59, 1983. ) Example 1 ~hows that an extraet and a powder with a furfural to pyrazines ratio sllghtly higher than roast and ground coffee is obtained with the process of this Inventlon. Example 2 shows how a commercial premium freeze-drTed coffee has a much higher furfural to pyrazines ratio, and l~xample 3 shows an e~en higher ratlo, Regarding sulfur volatile Intensities, it is apparent that the soluble coffee of this inventlon has a significantly higher level of sulfur volatiles than in conventional instant coffees, and the level is about equal to that of roast and ground~

Exampl~ 5 A eoffee bag was made by formlng a single chamber bag of Dextel 25B8 paper of the following specificasions:

1. Heat sealing bTnder on one side of th~ paper.
2. {;rammage: 24.6 g./m.3 3. Alr permeability:
460 Llmin./100 cm2 Q 12.7 mm. 112O P
4. Tensile strength:
dry machine directlon 5300 9./25 mm.
dry cross directlon 1990 9.~25 mm.
wet cross direction ~25 g./25 mm.
5. pH: 5.2 Th2 bags were manufactured on a Hayssen vert5Oal form filled seal machine~ The dimensions of the bag were 2 inches wide by 2.75 inches long with a 114 inch heat seal on the bottom . of the bag. The coff~e las desclibed below) was placed into the -~ ` bag. A 1/4 inch heat seal was made along the top of ~he bag. A

1/8 Inch wide by 4~1/8 inch Mylar strip (with paper tag attached) was attached uslng a heat sealer to the top of th~ bag.
The roast and ground eoffe~ was mad~ from a blend of green coffee consisting of 55~ milds, 25~ Brazils and 20~ Rcbustas. The 5 cof~ee was roasted on a Probat~Model UG22N batch roaster in a 59 Ib. batch. The coffee was roasted to a Hunter L color readTng of 21. 6 In 8-1/2 minutes at a f3nal roast temperature of 465F. It was quenched at the end of the roast with water 3t a level of 11.7~ of the initial load of green coffee. The whole roast was 10 aged about 6 hour5 and the ground on a Gump cof~ee granulizer Model 66. The ~ollowlng is a typical partiele size distributlon:

U. S. Screen Ran~e, Weigh~

on 12 0-2 through 12, on 16 12-20 through 16, on 20 35-ll9 through 20, on 30 18-30 through 30 12-30 The coffee was then screened through a U . S . 1~ mesh screen ~to remove coarse particles) and on a U.S. 40 mesh screen 20 (to removo flne particles). The coarse and ~n~ fractions were discarded .
The soluble coffee was prepared much in the sam~ way as in Exampl~ 1. The soluble coffee was then milled on a Lehman mill Model 4X8, to form flakes. The ftakes were sized through a U.S.
25 7 mesh screen tto ren ove large flakes) and on a U . S. 30 mesh screen (to remove fines). The coarse and fines were recycled through the mill. The flaked and sized solubles were mixed with the sized roast and ground coffee in a ratio of ~.0 parts solubles and 3.5 parts roast and ground. The coffea bag was paeked with 30 5 . 5 grams of th~s mixture. The mixture of roast and ground coffee and drled powder coffee was analyzed by SDE FID and SDE-FPD, and the results are detailed in Table 1. The corrected g . c . area for the p~yrazlne derivatives is 27, 857 the correc~ed . .

37~
-3~-g.c. area for furfural ts 22,992; and the ratio of ~ur~ural to pyrazine derlvatives is 0.83:1.
A brew test of the bag was run. The bag was placed in 200 milllliters of 88C (190F) water in a cup for 1 minute. During 5 this period the bag was occasionally dunked, uslng the mylar strip-tag to raise and lower the bag, The resulting brew contained 1.3196 solubles. Organoleptic evaluatlon of the brew by an expert panel showed that, in the absolute, the brew tasted smooth and flavorful like fresh brew~d coffee.

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Example 6 Two samples of hydrolysis extract and a hydrolysis extract stripper condensate, which were obtained in runs conducted in a manner similar to that detailed in Example 1, were analy ed by 5 SDE-FI D, and the results are detailed in Table 2, Column A is the feed extract to the stripping column. Column B is the stripper extract leaving the bottom of the column. Column ~, a hydrolysis extract stripper condensate, is a sample w~¢h typifies the composition of the strippate which Is disclosed.
Table 2 Yolatiles Analysis Results of Hydrolysis Extracts and Hyd~rsis Condensate .
Example 6 StripperStripper Stripper Feed Bottoms Condensate A B C
FurfiJral 30,205 1,491 30,451 Pyrazines 581 67 638 % furfural 52.0 6.7 57,3 % pyrazines 1.0 0.3 1.2 Total corrected 58,086 22,252 53,143 9 . c. counts The reslJles in Table 2 show that the hydroly is extract steam-stripping column removes virtually all of the fur~ral 25 present in the hydrolysis extract. The furfural is contained in the condensate from the stripping process and discarded. Few valuable volatiles are present in the feed to the stripping column, as evidenced by the low pyrazines levels, and thus little besides furfural is lost. The calculat1On be1Ow estimates the actual degree 30 of removal of furfural:

Feed ~urfural 58,086 x .52 = 30,205 Bottoms furfural 22,25,2 x .067- 1491 100 x ll - (1491/30,205)] = 95.1% remo~al ~,~?t~3'76 This degree of removal car: obviously, to those skllled in the art, be improved signifieantly by the use of additional stages in the countercurrent multiple staga stripperr or by a higher steam to extract ratio. In Example 1, a tall column spray stripper was 5 used. A taller column wou5d add extra contacting stages, for example. A 99. 0% or better removal could be achieved. Thus, the stripping column allows almost total furfural removal from the hydrolysis extract.

Claims (19)

WHAT IS CLAIMED IS:

1. A coffee brewing article comprising a water-permeable infusion article containing:
a) roast and ground coffee; and b) a soluble coffee composition comprising:
1) volatile and non-volatile aroma and flavor compounds, at least two of said aroma and flavor compounds being furfural and pyrazine derivatives;
wherein the ratio of furfural to total pyrazine derivatives is less than 1.5:1, and wherein the pyrazine derivatives have a g.c. count of at least 20,000, wherein said g.c. counts, on a dry solids basis, are measured on a Freon 11 solution of separated volatiles by capillary gas chromatography on a fused silica column; and 2) wherein the total ash is less than 12% on a dry solids basis.

2. An article according to Claim 1 wherein the soluble coffee and roast and ground coffee are present in a soluble:roast and ground ratio of from about 1:4 to about 1:1 by weight.

3, A single-serving article according to Claim 2 containing from about 1 to about 2.5 grams of soluble coffee and from about 1.5 to about 5 grams of roast and ground coffee.

4. An article according to Claim 2 wherein the roast and ground coffee is a flaked roast and ground coffee.

5. An article according to Claim 2 wherein the roast and ground coffee is a fast-roasted coffee.

6. An article according to Claim 2 wherein the soluble coffee composition is milled.

7. An article according to Claim 6 wherein the soluble coffee composition is milled by roll milling under about 400 to 600 psig at about 20 to 30 rpm at zero gap.

8. An article according to Claim 7 wherein coffee oil is added to the soluble coffee composition before milling.

9. An article according to Claim 7 wherein roast and ground coffee is added to the soluble coffee composition before milling.

10. An article according to Claim 2 wherein the roast and ground coffee is fast-roasted and flaked, and wherein the soluble coffee is flaked.

11. An article according to Claim 1 wherein the article is a nonwoven fabric bag made from chemically inert, essentially taste-free fiber.

12. An article according to Claim 11 wherein the fiber is rayon, nylon, polyester, polyacrylic, polypropylene, hemp, cotton, or a mixture thereof.

13. An article according to Claim 11 wherein at least a portion of the bag is a chemically inert, essentially taste-free apertured film.

14. An article according to Claim 12 wherein the bag is a heat-sealed pouch of the nonwoven fabric.

15. A coffee brewing article according to Claim 1 wherein the soluble coffee composition is decaffeinated.

16. A coffee brewing article according to Claim 1 wherein the roast and ground coffee is decaffeinated.

17. A coffee brewing article according to Claim 1 wherein both the soluble coffee and the roast and ground coffee are decaffeinated.

18. A coffee brewing article according to Claim 17 wherein the soluble coffee is in the form of pellets or tablets.

19. A coffee brewing article according to Claim 2 wherein the soluble coffee is in the form of pellets or tablets.