1~3i554 This invention relates to coffee and more particularly to a process for preparing a natural coffee flavor/aroma and an aromatized soluble coffee product.
The prior art has long been confronted with the problem of preparing soluble coffee products which resemble home-brewed roasted and ground coffee's flavor and aroma characteristics.
Commercial soluble coffee preparation involving extracting ~`~
soluble solids from coffee and then drying the resultant extract to a powder normally involve processing techniques which tend to ;
degrade the flavorful coffee principals which characterize fresh brewed roasted and ground coffee. Processes such as dilute extraction (U.S. Patent 3,089,772 to Bowden), low temperature spray-drying, freeze-drying and the like, designed to retain a large number of volatiles from the coffee have met with varying ~;
degrees of success. Such processes, however, also generally involve increased costs.
A substantial effort has been made in capturing coffee : . . -principals prior to possible loss or degradation during process-ing to soluble powder. Roaster gases, grinder gases, volatiles ~-stripped from extract after percolation, and the like, have ail been suggested as means for enhancing soluble coffee products.
One general area of investigation has been aromas obtained by ^
steaming a bed of roasted and ground coffee. Examples of such processes may be found in U.S. Patent 2,853,387 to Nutting; ~
3,132,947 to Mahlmann; and 3,421,901 to Mahlman~ et al. ~, Not surprisingly, art workers in the steamed volatile flavor/aroma area have generated such aromas from a bed of frPshly ground roasted coffee, i.e., coffee which has yet to be :.
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extracted in the percolation process. Not onl~ does the une~trac~ed coffee contain the fullest complement of aromatics, but such processing involves less cumbersome percolation processing.
The art, however, has recognized that coffee extract obtained from previously steamed coffee beds is somehow dis-advantageously altered, most notably in the perceptible presence of a highly sour character. Processes have been studied to obviate this problem. See, for example, U.S. Patents 3,420,674 to McCartney; 3,656,964 to Mansky et al.; 3,653,910 to Pitchon;
and 3,644,1~3 to Pitchon. Of particular interest is U.S. Patent 3,164,474 to Gianturco et al. patented January 5, 1965. Therein is set out a process involving extracting roasted and ground coffee wlth cold water, then steaming to obtain volatiles, then further extracting with hot water to obtain coffee solids. While ~ -Gianturco's process represents an improvement in the art, it is found that the sour character of the base extract obtained after ~ -steaming remains to some extent. Further, and more importantly, ;-~
the above process involves extremel~ cumbersome processing techniques if applied to commercial percolation processes. Still further, the overall extraction process, involving cold atmos-pheric extraction prior to steaming, greatly increases processing times.
It has been discovered that a good quality natural coffee aroma can be obtained by steaming roasted coffee which has been exhaustively extracted in a percolation process, including extraction under hydrolysis conditions. The quality of this -aroma is surprisingly close to a steam aroma generated from freshly ground, unextracted roasted coffee.
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The advantages of this invention are readily apparent.
The ability to generat.e a quality aroma/flavor principal from fully extracted coffee obviates the need for the treatment of unextracted or partially extracted coffee which has shown to degrade these coffees. Since the coffee steamed.in accordance with this invention, by definition,. will not be subject to ~, further extraction, there will be no degradation of the coffee `
extract normally experienced in prior art methods. Moreover, the overall process is extremely simple and.will not interfere with the operation of the percolation process itself.
According to this invention, roasted coffee is meant to ~
include both a single variety and a blend of coffee varieties and ~ ~.
both decaffeinated or.undecaffeinated coffees in.either sub-divided (e.g. ground) or whole bean form. ~
This invention is.broadly applicable to any aroma/ - :
flavor process whereby volatile principals are generated from a bed of roasted coffee by passing steam through the coffee bed Various techniques and parameters such as.pre-wetting, internal reflux, temperatures and pressures are equally appli¢able to the process of this invention and may be.practiced in accordance with ~ ~
the numerous teachings thereof as found in the.. patents referred ~ : .
to above.
Use of the terms aroma and flavor to describe the steam ~ . :
generated material obtained from the.fully extracted.coffee will be made throughout the description of this invention. The steam .
generated.material when added to a soluble coffee product may impart a flavor or aroma contribution depending in part on the ~ -mode of addition. Thus,.addition to a coffee extract which is then dried may generally result in a flavor improvement in the : .
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;4 reconstituted cup, although some aroma enhancement will be perceived upon reconstitution. Conversely, addition to soluble cof~ee powder will generally result in an improved aroma in the package itself, although these components will also be percepti-ble as flavorants upon reconstitution. More typically, and as skilled art workers readily appreciate, flavor and aroma are combined effects. As such, it is to be understood that the process of this invention is not to be limited to any such characterization of the steam generated material. "Enhanced 10 soluble coffee" is the general term used herein for a soluble ~ ;
product to which the steamed component is added.
Skilled art workers will recognize the roasted and ground coffee being steamed as what is commonly referred to as "spent" coffee. While this is now a generally recognized term of art, some earlier art workers have broadly used it to describe coffee which is not to be subjected to any further extraction according to their particular process. As used herein and as now generally understood in the art, spent coffee is meant to describe roasted coffee which has been subjected to solubles extraction in any extraction process which includes the genera-tion of hydrolysis or autoclave products therefrom. Typical extraction processes include conventional semi-continuous counter~
current multi-stage extraction, continuous countercurrent extraction, single stage extraction, and countercurrent multi- ~ ;
stage, or single stage slurry extraction.
Commercial percolation processes involve the semi-continuous, countercurrent extraction of coffee solubles from roasted and ground coffee contained in a series of extraction columns generally referred to as a percolator set. At steady-state operation, the extraction column will contain coffee of ~;~.. ,.~..... .
~36~;4 varying degrees of extraction or solubles depletion. An extrac-tion li~uid, generally water, is heated to 300 to 350F. and fed to the extraction column containing the most extracted coffee in the set, referred to as the spent stage extraction column. The extraction liquid then flows through the columns contacting coffee of progressively less extraction and i5 drawn o~f as coffee extract from the extraction column containing the least extracted coffee in ~he set, typically fresh, unextracted roasted and ground coffee. This column is referred to as the fresh stage extraction column. Extract concentrations are typically in the 20% to 40% solids by weight range.
To begin the next cycle ta cycle is the period from successive draw-offs of extract from the fresh stage), the spent stage is taken off-stream and the extraction liquid is fed to the ~-new spent stage for this cycle, the coffee in the column having beer. the next most extracted coffee in the previous cycle. The liquid is drawn off as coffee extract from the fresh stage for this cycle, this column having been put on stream after draw-off from the fresh stage of the previo~s cycle.
A given batch of coffee, then, becomes progressively more extracted in successive~cycles. In a typical six column set, the first four cycles will generally remove soluble coffee solids while the final cycles are designed to generate (solu~
bilize) and remove hydrolyzed or autoclaved material. ;~
In accordance with the process of this invention, the roasted and ground coffee base which is steamed to remove enhancing material is spent coffee, i.e., the coffee remaining .. .
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in the spent stage extraction column a~ter extraction li~uid has been passed through it~ ~he coffee, therefore, has been subjected to extraction designed to remove soluble coffee solids therefrom and has had removed therefrom at least some hydrolyzed material. The generation of this material is typically and preferably achieved through high water temperatures. Utiliza-tion of hydrolysis aids, however, e.g. acids, may also be practiced.
The steaming of the spent grounds may be practiced in any of the variety of methods taught in the previously referred to patents. It will be appreciated by art workers that where some of these patents require pre-wetting the roasted and ground coffee prior to steaming to generate volatiles, such a step may be unnecessary in the pxocess of this invention, since the spent coffee will have been adequately pre-wet during percolation. However, according to one mode of practicing this invention, the spent grounds are removed from the spent stage extraction column, separated from any associated extraction liquid, dried and then steamed according to prior art processes including those involving a pre-wetting step. Since the above-enumerated steps prior to steaming would in any event have beenperformed before burning or shipping away spent grounds, no economic disadvantages are occasioned thereby.
Typical flavor/aroma generation processes useful in the process of this invention include steaming at atmospheric !~
pressure followed by condensation (U.S. 2,562,206 to Nutting);
steaming followed by removal of water from a condensed extract of the steam-distilled volatiles (U.S. 2,853,387 to Nutting);
steaming under in'cernal reflux conditions followed by , . . . .
;i5~a fractionation (U.S. 3,132,947); steaming an agitated bed of roasted and ground coffee (U.S. 3,244,532 to Mahlmann); pre-wetting with water according to U.S. 3,532,507 to Cascione;
confined volume steaming (U.S. 3,615,665); steaming with subsequent heat treatment of the distillate (U.S. 3,615,666);
downflow steaming (U.S. 3,653,910). The common ingredient of these teachings in general and the basic technique to which this invention is applicable may be termed simply as obtaining volatile materials via contact of the spent coffee with steam or more simply stated, steam stripping of volatiles from spent coffee.
Preferred steaming techniques comprise passing steam at 1 to 10 psig through a bed or column of the spent grounds for 10 to 70 minutes. Where the volatiles generated thereby are to be condensed, condenser temperatures are generally from 40 to 50F.
The material obtained by steam stripping the spent coffee may be processed in any number of art-recognized ways to obtain a condensate or volatile extract suitable for use in enhancing solukle coffee products. Thus the condensed volatile material can be added to a liquid extract; added to coffee oil ~ -and then added to extract or spray-plated onto soluble coffee powder, injected into a jar of soluble coffee, etc. The con-densed volatile material may also be used to impart a coffee flavor to non-coffee foodstuffs or to enhance the flavor of coffee-flavored foodstuffs. In another embodiment, the volatiles may be directly passed to a coffee product, e.g., coffee extract without a condensation step; similarly, vapors can be s~
contacted directly with cofee powder which is preferably chilled and oil-plated prior to contact with the steam aroma.
A surprising feature of this invention is the un-expectedness of being able to obtain any useful enhancing material from spent material which, by definition, has under-gone exhaustive extraction under stringent conditions including ~ the generation of hydrolyzed solids. By virtue of this dis- ~.
covery, the base extract degradation problem is removed since extraction is not performed after steaming. Further, since the percolation process is not interrupted, the technique is simple .~ and economical.
~ A specific manner of practicing the present invention : is as follows.
`~ Roasted and ground coffee is placed in the six : columns of a percolator set. At.steady-state conditions, water at 350F is fed to the spent stage extraction column and . .:
. thereafter flowed through the remaining columns.. in a conven-tional manner. After the extraction liquid has passed through the spent stage, the contents thereof are blown..down and 13.5 pounds of the spent grounds (at.50% moisture.) are placed in a 4 inch I.D., 36 inch high, glass column. Steam at.2-5 psig is continuously admitted to the bottom of the glass.column. Total steaming time of 61 minutes occurs after.which 14.cc of con-:..
densed material (condensed.at 48F.) has been collected.
Addition of 1% by weight of this condensed material ~- to an unaromatized coffee extract was.then effected and com- :
. ~ parisons were made between such.~n unaromatized extract and also extract to which an.equivalent level of:condensate , ~ obtained from unextracted roasted and ground coffee was added.
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The spent grounds flavor sample was preferred to unaromatized extract, especially in its "more like regular coffee" charac-teristic. Thou~h "weaker" than the aroma/flavor.generated from fresh coffee, the spent ground steam condensate was found to possess the same desirable.enhancement attributes of fresh coffee steam condensates, most notably.in imparting.a "woody,"
brew-like character to soluble coffee.
In a similar embodiment, the spent grounds were first dried in a.laboratory size air dryer operating at below 200F.
to a moisture content of below 10% prior to steaming. Similar results were obtained in comparative testing.
While specific examples and embodiments have been utilized herein to describe the preferred methods of practice, .:
skilled art workers will appreciate that such details are not intended in a limiting sense.. Various modifications in steaming methods, methods of addition and the like, are believed ascertainable without departing from the scope of this . :~
invention as defined in the appended claims. .
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