Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
SOLUBL.E COFFEE COMPOSITION
echnical Field
This invention r~lates to a coffee extract or concentrate and
a proc~ss ~or making it and to a soluble coffee composition which
have a flavor similar to that of regular roast and ground coffee
10 and less like the flavor of instant or soluble coffees and to a
brewing articl~ for use Tn conjunction with the soluble coffee
product. The coffee is characteri2ecl by its low furfural content
and high content of pyrazine derivativ@s.
Backgrouncl of the !nv~ntion
Th~ ~tandard of flavor excell~nce among many coffe~
drinkers Is freshly brewed roast and ground coffe~. Thls
beverage provides a balanc~d blend of aroma and flavor notes
contributed by volatile and moderately volatile flavor compouncls,
as w211 as nonvolatil~ coffee solids. Howev~r, for reasons of
20 convenience and economy, many consumers do not prepare freshly
brewed roast and g round coffe~ for each eoffee conslJmpeion
experienc~. Roast and groun~ coffe~ is typically convenient!y
brewed in qlJantities Olf 5 to 10 cups (or more) at a time. For
many consume-~, such as single consumers, it Is uneconomical to
25 brew a large pot of c~fe~ to consum~ a single cup. Brewing a
single cup in most comt7l0n cof1~emakers inYolves th~ s~me
inconvenienc~ as brewing a numb~r of cups. Thu~, many
consumers have turn~d to solubl~ coffe~ products as a substitu~e.
Unfortunat~ly" most solubl~ coffe~ products have serious
30 deficienoies. Many soluble coffee products are lacking in the
volatile and moderately volatile flavor components which are easily
lost during processing. In additiora, the 2conomics of soluble
coffee manufacture forces producers to extraet th~ maximum
possible yield from thelr percolation processes. This typically
35 involYes the use of hlgh temp~rature and pressure extraction
processes to hydrolyz;s otherwisc insolubl~ coffee constituents and
to provld~ a higher solubl~ yield. Thls modifles some of the
existing fl~vor compo~nds pre~n~ in roast and ground cof~ee,
and It also crgat~s or manufactures additional flavor compounds.
q~' ~
~2~ 3'7~
--2--
~ Iso, It i5 both difficult and unoconomical to package, ship
and s~ll sub5tanti~1 quantlties of water in ccffee products. A~ a
r~sult, most commercial extracts are reduced to dryness for
packaglng and sal~, typically by thermal evaporative techniques
5 which furth~r aggravat~ the probl~m of Yolatlle loss and flavor
degradation .
As a result of thts processing, most in~tant coffees are poor
reproduetions of the flavor of freshly brewed roast and ground
cof~ee. Ev~n where low~boiling volatiles have been added by
10 aromatization processes, soluble products are often lacking in
moderat~ly volatile aromatics, and, in additlon, contain off-flavor
aromatic compounds generated by thermal processing and by
hydrolysis during ~x~raction.
For these reasons, it would be desirablg to provide
15 single-serving conv~nience in a roast and grourld 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 coff~e bags is longer than the
time to make an instant coffee, and the extractabllity can be
20 variable depending on the water temperature, ~rew timei volume
of water, etc. Thls has been overcome in some products by the
combination of the roast and ground cof~ee in a packet with
solubl~ coffee, inciudins solubles produc2d by low-temperature
extractlon prDcessing. Th2 use of solubl~s produced by low-
25 tempera~ur~ processing li~e., solubles extraction withouthydrolysls) results in a very acceptable b@verag~. Howev~r, the
low-solids yields of low-temperature extraction processes are such
that it is uneconomical to produce the product except for sale at
a pr~mium prlce. And unfortunately, the combination of roast
30 and ground coffee with conventional instant coffees in a coffee
bag r~sults In a brew that tast~s instant-like and foreign to those
accustomed to drinking fr~sh brewed roast and ground coffee.
Alternatively, it would be deslrable to have a soluble cof~ee
product whose flavor is a cios~ duplicate of freshJy brewed roast
35 and ground coffee solubles and yet economical to produce.
N~lmerous attempts at production olF such a produc~ have b~en
made. Many such proc~sses have involved strenuous efforts to
'7~
--3--
captur~, preserv~ and retain the volatiles pres~nt In freshly
brewed coffe~.
One such attempe is that descrlbe~ In U.S. 4,277,509, Issued
July 7, 19~1 to WolJda and assigned to D. E. J . International
S Researeh Company B.V., relates to a prccess for "primary"
extraction of roast and ground coff~e. The coffee is ~xhau~tively
cxtracte~ at low temperatures with a flrs~ quantity of water. The
coffee is then extracted again wlth a second quantity of water to
remove hydrophobic aroma components, Vlouda then steam strips
10 the second extract and collects the aroma components as a small
volume of stripper condensate, whlch Is then added to the first
extract. This process can be continued throughout the fresh
solubles section of an extraction train.
Another approach is that described in Defensiv~ Publication
T920,012, published March S, 1974 by Pfluger and Bowden,
relates to a method for producing a soluble coffee product. In
this process, the extract drawn offstream from a cof~ee perco-
lation unit is split into two batches, the first containing higher
quality and higher concentration extract, and th~ second
20 containing lower quality and lower concentration extract. The
second batch is evaporatively concentrated within a continuous
evaporator and then added to the first batch. The combined
extracts are dried in conYentional fashlon.
U.S. 3,720,518, issued Mareh 13, 1973 to Ga!do and assigned
25 to General foods, relates to a process for the production of a
high concentration coffee extract containing 30-40% solids by
weight. The key step in this process Ts the use of intercolumn
concentration prior to the fresh stage in a percolator train. The
patent describes intercolumn concentration by a variety of
30 techniques, including flash evaporators and vacuum evaporators,
as well as membrane separators and other techniquesO Like
~Youda, Galdo also describes sSripping aroma from the extract,
then adding the aroma back to the concentrate.
~'o~
Un~or~unately, whsn coupled wlth conventlonal commercial
percolation or extractlon processe~, thes~ aroma retention and/or
aroma add-back process~s hav~ the effeet of also retaTning of~-
flavor volatiles which have b~en generated during the extraction
process. As a result, current instant coffees, both spray dri~d
and free~e dried, have a charaoteristic flavor which is diff~rent
from the flavor of freshly brewed roast and ground coffe~.
Surprisingly, it has been found that an aromatic soluble
coffe~ can be made st about 35~ to 5û~ solids yield which retains
the moderately volatile flavor components characterlstic of roast
and groundl coffee but which does not contain the flavor materials
characterTstlc of soluble or instant cof~ees which have been
hydrolyzed during processing. Th~ process used to create this
new soluble coffee composition involves a conventionai extraction
and hydrolysis of roast and ground coffee followed by multistage
or countercurrent steam stripping of the hydrolysis extract. The
hydrolysis volatiles are discarded.
U . 5 . 4 ,129, 665, issued December 12, 1978 to Clark, and
assigned to Nestle, relates to a process for extracting vegetable
materials in the liquid phase in a group of l'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 rapial
expansion. Then water is added to the partially evaporated
extract In a quantlty at least equal to the quantity of evaporated
ITquici, and preferably greater than the quantity of evaporated
liquid, prior to passage of the extract through the fresh
extraction cells.
Clark used a countercurrent hydrolysis step for vegetable
materials in U.S. 4,129,665. 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 s~eam stripping. Moreover, evapora~ion
involves a heat treatment of the extract which causes thermal
degradation of the aroma and flavor cof~ee solids. Thls heating
and concentratlon also creates or encourag~s the precipitation of
polymeric materials from solution during evaporation.
It is an object of an aspect of this invention to
provide a soluble coffee 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 manufact~red 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 soluble coffee composition comprising volatile
and non-volatile coffee solids, said coffee solids
comprising:
a~ volatile and non-volatile aroma and flavor
compounds, at least two of furfural and
pyrazine derivatives, said pyrazine
,,,,~,i,, 5~
-5a-
~L13a7~7
derivatives having a g.c. count of at least
20,000, and the ratio of furfural to pyrazine
derivatives being less than 1.5:1, wherein
said g.c. counts are measured on a Freon 11
solution of separated volatiles by capillary
gas chromatography on a fused silica column;
and
b) the total composition having an ash analysis
of 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
~29~ 7
chromatography on a fus~d 511i~a column: and (c) whereln the
total ash 1~ less than 12~, on a dly solids basis.
This coffe~ extract is concentrated in a manner which
preserves the coffee volatiles and dried to form a soluble coffee
5 p~oduct with essentially ths same Furfural, pyrazine derivatives
and ash cont~nt.
The process comprises the steps of:
1) forming a hydrolyzed roast and ground cof~ee ext~act;
2) multistage or countercurrently steam-s~ripping the
hydrolysis extract to remove hydrolysis volatiles;
3) discarding said hydrolysis volatiles; and
4~ passing the stripped hy~rolysis extract through roast
and ground coffee at a temperature of from about 138C
(280F) to about 21C (70~) to produce a final
extract.
This extract is concentrated in a manner which preserves
the low and the moderately volatl le compounds . Preferably,
freeze concentraton is useci to produce a concentrated coffee
extract. The concentrated coffee extract can also be dried to
^~. mak~ a solublc coff~o.
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 of said aroma and flavor
compounds being furfural and pyrazine deriva-
tives;
wherein the ratio of ~urfural to total pyrazine
derivatives is less than 1 .5: 1, and wherein the
pyrazine derivatives have a g . c. count of at least
20,QOo, 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 ~han 12~ on a dry
solids basis.
~Z~ 77
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Brief Description of th~ Figures
Figure 1 is a sohematic of the coffee extract and soluble
coffee process.
Figur~s 2A, 2B, 2C, 3A, 3B and 3C are chromatograms of
5various coffee products.
Figures 2A, 2B and 2C are chromatograms of organic
compounds in the ~olu~le coffee of this invention.
Figures 3A, 3B and 3C are chromatograms of organic
compounds in a commercial spray-dried instant coffee.
10Figure 4 is a drawing of the steam distillation apparatus
used to concentrate the coffee volatiles for the analytical gas
chromatographic method.
Disclosure of the InYentlon
.
1. The Coffee~Pe!
.
This invention provides an instant or soluble coffee and a
coffee extract or concentrate which are similar to ground roast
coffee in its compositlon of moderately volatile flavor componen~s.
At the same time, it is dTfferent in composltion from other soluble
coffees. In particular, the soluble coffee of this invention
contains relatively large quantities of moJerately volatile
compounds, having normal boiling points of 88C ~1~0F) to 205C
(401F), and normally found in roast and ground coffees. These
quantities are signlncantly higher than those present in
oonventional instant coffees. Moreover, the coffe~ brew made
from the extrac~ or solubl~ cof~ee is less bltter than ro~t and
ground and typical sol~ble coffees.
~11 of the speciflc components of coffee afoma and flavor
volatlles have not be~n identified. It Is estimated that over 250
compounds are present or contribut~ to the aroma ant flavor of
coffee. Whlle it is not possible to say that the compounds
identified herein are definitive of coffee flavor and aroma, it is
believed that thess compounds rep-esent the retention of good
flavors and the removal of off-Zflavors.
These aroma and flavor fompounds importantly includ~
various pyrazines which are formed during coffee roasting and
which are considered hereln to b~ Icey indicators of roast anci
7~7
ground coffee flavor. Such compounds includ~, but ar@ no~
llmi~ed to, pyrazine rnethyl ~yra~ine; 2,5-dimethyi pyra;!ine;
2,6-dimethyl pyrazine; 2,3-dimethyl pyra~ine; 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 flavor compounds also include
various other volatiles which are indicators of roast and ground
flavor. Such rlon-pyrazine compounds include, without iimitation,
isobutyraldehyde, methyl ethyl ketone, 2,3-pentanedione,
10 dihydro-2-methyl-3(2H~ furanone, ac~toacetate, 5-methyl
pyrrole-2-earboxaldehyde, guaiacol, ~thyl guaiacol and vinyl
guaiacol.
Additionally, coffee volatiles also include variouç
sulfur-bearing coffee volatiles wl-ich are f~rmed during coffee
15 roastlng, and which are also considered to be key incllcatoYs of
roast anà ground flavor. Note that, in general, pyrazines are
volatTles which can be forrned 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 specifically
identified. Yet, the analysis demonstrates that the soluble coffee
of thla process of this invention has (1) a level of ~hese sulfur
volatiles significantly higher than in conventional instarot coffee,
25 and (2) a lev~l of these compounds ess~ntlally equal to the level
in roast and ground cof~ee.
The composition of ehis invention contains less of the
compounds normally found in high quantities in instant coffees,
and referred to herein as hydrolysis volatiles. Furfural is
30 especially prominent among these compounds and is considered
herein as an indica~or of th~ presence of hydrolysis volatiles in
general. Furfural is a reaction product from the hydrolysi~ of
5-carbon sugars. I~ is pres~nt in detectable amounts in regular
roas~ and ground cof~ees, but is present in mwch larger
7~7
g
quantities in instant coffees, both spray drled and freeze dried,
du~ t~ hydrolysls extraction.
The composition o~ this inventlon is both a coffee extrart
and a soluble coffee product comprising non-volatil2 coffe~ solids
and volatile aroma and flavor compounds. This composition has
levels of the key volatiles boiling at atmospheric pressure in the
range of from about 88C (190F) to about 205C (401F)
("moderately volatile flavor compounds"3 which are at least
substantially equivalent to the levels of those sam~ volatil~s 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
gram basis, average at least 100% or more of the levels of the
same volatiles in conventional roast and ground coffee.
Preferably, at least 150~ of the level of those volatiles present in
roas~ and ground coffee are present in the coffee of this
invention.
The coffee extract and the solubles are further defined by
the content of pyrazine derivatives and the ratio of fur~ral to
pyra~ines. The aroma and flavor compounds are steam distilled
and extracted (with Freon 11) from the coffee extract or soluble
cof~ee product. The relative amounts of the arorna and flavor
compounds are then measured by capillary gas chromatography on
a fused silica column. Each compound can be iden~ified by its
retention time on the column. Gas chromatography gives th~
relative proportions of the compounds in composition and can be
related to the actual concentration of the compound in the
compositlon .
3^ The coffee compositions herein are defined by ~he minimum
number of gas chromatographic counts (g.c. co~nts~ of pyrazine
derivatives and by the ratio of chromatographic counts oF furfural
to pyrazine derivatives. Gas chromatographic eounts are the
electronic output of the gas chromatograph.
,
- 10
By pyra~ine derivatlves ar3 m~ant tl~ followin5~ compounds:
pyrazine, methyl pyrazine, 2,5-dimethyl pyrazine, 2,6-dimethyl
pyrazine, 2,3-dimethyl pyrazine, 2-ethyl-6-methyl pyraieine,
2-e~hyl-5-methyl pyra~ine, 2,3,5-~rlme~hyl pyrazine, and
5 2-ethyl 2,5-dimethyl pyrazine. These d~rivatlves ar~ deflnorl by
ehelr 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-dirnethyl pyrazine
(8), 2,3-dimethyl pyrazine (10), 2-ethyl-6-methyl pyrazlne 112),
2-ethyl-5 methyl pyrazine (14), 2,3,5-trimethyl pyrazine (16),
and 2-ethyl-2,5-dimethyl pyrazine (18). Furfural i5 identified as
(20) .
The compositions herein have a ga~ chromatographlc count of
at least 20,000 ~or pyrazine derivaUves and preferably about
30,000 to about 50,000 counts. E~ecause of the presence of
Freon 11 solvent and other impurities associated with th~
analytical method, the concentration of the volatiles is given in
20 g.c. counts rather than percent volatiles. The ra~lo of furfural
to pyrazine is less than 1.5:1, and preferably from about 0.1~:1 to
1:1.
The total suifur compound level is alco measured by gas
chromatography as described below, The level of these sulfur
25 compounds approximates those in roast and ground coffee. The
total sulfur oompounds will be about 4,0ûO ~o about tS,000 by the
meth¢d used herein.
Another characteristic of the cof~e extrac~ and coffee
solubles is their ash con~en~. Ash is the oxidation product
30 minerals of which are present in the green eoffee beans. The
ash is measured by pyrolysls of the coffee sample. The minerals
of the roast and ground coffee are easily extracted. Thus, the
3'7~7
ash cont¢nt of a solubl~ cofh~ or coff~ ~xtract can b~ ~Is~d ~s ~
m~asure ~f yield ~f sol3ds from the ro~st and groulnd coffeo, The
coffee extract and soluble coffee h~rein has an ash content, on a
dry solids basis, of less than 12~, preferably less than 9%, and
most preferably from 5~ to 7.S%.
I l . Th~ Process
. _
A. Green Bean Blendln~
The soluble coffee product of this invention is made by
extraction of conventional roast and ground coffee. 8ecause the
10 product of this tnvention is designed to duplicate closely the
flavor of freshly brewed roas- and ground coffee, it will be
evident that t51e starting blend of green beans and the roastinS3
and grinding conditions will contribute importantly to the flnal
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 i~lended 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 milds give coffee brews which are fragrant and acidicO
The Brazilian beans result in coffee brews which are relatively
neutral flavored. The Robusta beans produce brews with strong
distinctlve flavors that possess varying degrees of dirty or
25 rubbery notes.
Traditionally, the milds are the most expenslve of the thr@e
types of beans, with Brazilians being of intermedia~e expense,
and Robustas being least expensive.
Since the flavor of the coffee blend is more prominent Tn the
30 soluble product of this invention than in conventional soluble
products, more care must be taken in formulation of the bJend.
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
3S coffees used in the process of this invention preferably contains
lower levels of Kobusta coffees. If it is desired ~o use a major
~2~77
proportlon o~ Robusta$, then at least ~ portion of the Robustas
should b~ ~upgraded~ by t~chnlques known to the art, such as
those described in U.S. 3,61~0,726, Issu~d February 3, 1972 to
Bolt et al., and U.S. ~,234,613, issu~d N~vember 18, 198û to
5 Lewis. Howover, som~ person~ prefer a h~avier, more robust
coffee flavor and could use a high~r level of Robustas.
Decaffeinated beans can b~ used ~o make a decaffeinated
soluble coff ~ or decaffeinated coff~e extract. Blends o~ decaf-
feinated beans with lund~caffeinated or partially decaffeinated
lQ beans will provid~ a low eaffeine coffee extract or solubls coffee.
B. Roasting ?nd Grindi~a
A variety of roasting technique~ known to the art ean be
used to roast the green coffee irs the process of this inven~ion.
In the normal operation of preparing conventional roasted and
15 ground coffee, coffee beans ~re roa5teldl in a ho~ gas rredil3m
whereby the cof~ee bean temperature Is raised to a temperature of
from about 176~6C (350F~1 to about 218C (425F) with the time
of roasting being dependent on the flavor characte~istics desired
in the coffee ~everage when brewed. Where cof~ee beans are
20 roasted in a batch process, the batch roasting time at the
hereinbefo~e given temperattJres is from about 2 minutes to about
20 n~inutes, preferably about 6 minutes. Where cof~ee beans ar~
roasted in a continuous process, the residence time of the ooffee
beans in t5 e roaster are from abotlt 30 s~conds to abou~ 9
2s minu~es, pr2~erably abo~lt 5 min~tes. The roasting procedur~ can
involve statlc b~d roasting as well as fluidized bgd roasting.
In roasting gr~en coffee for conventiQnal instant coffee
extraction, darker roasts are commonly used. This is done to
develop strong but somewhat harsh flavors which can survive
30 conventional instant coffee p~ocessing. Becaus~ the process of
this invention provides much bett~r carry-through of roast
flavor, this process do~s not requ~rq darker roast~. Llghter
roasts can preferably b~ us~d to provide a Flavor that is not
burnt-tasting, yet strong. The light~r roasts also produce
35 clearer, r~ddish oup colors. hdditlonally, the light~r roasts do
not de~elop as much of th~ dirty, rubbery rote in th~ Robusta
coffees as would a dark~r roast~, Thu~, th~ blended beans are
8~7 12_
roast~d to a Hunter UL" color of f-om about 1~ to about 27, b~Jt
preforably about 22 to abolJt 26. The Hunter Color " L" scale
values utliized her~in to define the color of coffee beans and the
degree to which they have been roasted are units of . color
measurement in the Hunter Coîor system. That systgm is a
well-known means of defining the color of a given material. A
compl~te technical description of the system can be found in an
article by R. S. Hunter, "Photoelec~ric Color Difference Meter",
J. of the Optical Soc. of Amer., 48, 985-95 (1958). Devices
specifically designed for the measurement of color on the llunter
l::olor scales are described in U.5. Pa~ent No. 3,003,3B8 to Hunter
et al., issued October 10, 1961. In gen~ral, it is noted that
Hunter Color "L" scale values are units of light reflectanc~
measurement, and the hlgher the value is, th~ lighter ~he color is
since a lighter colored material reflects more light. In particulaF,
in the Hunter Color system the "L" sca1e contains 100 equal units
of division; absolute black is at the bottom of the scale (L ~ 0~
and absolute white is at the top lL - 100). Thus, in measuring
degrees of roast, the lower the "L" scale value the greater ~h~
degree of roast, since the greater the degree of roast, ~h~
darker the color of the roasted bean is. The use of the H~Jnter
Color "L" sca,~ value provides an accurate and reproducibie
means for measurement of degree of roast. The Hunter Col3r "L"
scale values herein are measured utili~ing ground beans, the
2S grind si2e being through 12-mesh U.S. Standard Sieve Series and
mor~ than 75 weight percent on 30-mesh U. S. Standard Sieve
Series. With roasted beans~ the level of moisture in the beans is
adjusted 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
thTs invention, finer coffee grinds are pre~erred to allow the most
efficient fresh extractlon possible. Efficient fresh extraction is
important in ~his invention to minimize as much as possible the
carryover of low-temperature extractable solubles into the
hydrolysis section of the train. If they are carried into the
77
--13--
hydrolysl~ section, they wlll be thermally degraded and produce
Instant coffee o~f-flavors.
C. Extractlon
The ro~st and grour.d cof~ee is ~xtracted wtth water to ~orm
5 a fresh coff~e extract. The ~xtractQd coffe~ Is hydrolyzed and
extracted to produce an hydrolyzed extract. Any conventTon31
coffee extractlon and coffee hydrolysis process ca~ b0 used
herein. Most comm~rcial extraction processes use a coffe~
extraction traln and, therefor~, this type of process will be used
lo to illustrate the inven~ion.
Water is passed countercurrently through a coffee extraction
train consJsting of a series of extractlon columns filled with roast
and ground coffee. The operation of such a system is well
understood and many modiflcations and variations will be apparent
15 to those skilled in the art from the descriptlon and examples that
fol low .
A plurality of extraction columns filled with roast and
ground cof~ee are connected in series by piping between the
individual columns. Typioally, slx columns are found in th~
20 countercurrent extraction system, and therefore this description
is given with reference to a six-column system. The last thre~
columns, T.~., thos~ containing the most neariy spent coffee
gro~lnds, are referred to collectively as the hydrolysis columns,
while the next two columns which contain coffee grounds of an
2S intermediate degree of spentness, together with the first column
which contalns the freshest coffe~ grounds, are re~err~d to as
the fresh extraction columns. As abovc noted, the extraction
- columns ar~ intended to be used with roast and ground coffee;
however, i~ should be reaiized that they can be adapted to the
30 extraction of whole coffee beans.
Water enters the col~lmn containing the mos~ nearly spen~
coffee grounds a~ the lower extremity of the colwmn and is
discharged at the top of the column. The outlet line from on~
column is connected to the inle~ line of the next column. The
3s extracting fluid progresses from column to column in ~he series
entering each column at the bottom and being discharged from the
top. Heat exchangers can b~ fitted in the lines between the
~Ll OIS 7~
, 1,
columns Immediately p~ior to th~ extractlon liquid inlet to the
columns. The heat exchanger5 can be used when requlred to
achieve or to malntain the hydroly5is temperatur~, i.e., about
300F to 38QF in the hydrolysis columns of the extraction
5 system. They can also be used in the extraction columns to cool
or to heat the extractlon liquid to any desired ex~racting
temperature, i.e., usually within th~ range of from 37.8C (10ûF
to 137.~C (280F). Each column Is fitted wlth a means for
charging the column with roast and ground coffee, for
10 discharging the coffee from the ~olumn, and for keeplng ~h~
coffee in the column during the overall extraction cycle. The
column which the extract liqlJor enters just prior to being
withdrawn from the system contains the freshest soffee.
In most systems, a~ least one extra column is provided in
15 each seri0s so that the extraction operation is no~ interrupted
while the most nearly spent coffee column is being emptied and
refillecl. The extra eolumn is a standby column which is cut int3
the system either slightly before or simultaneously with t51~
removal of the most nearly spent coffee column. Additional xtra
20 columns are usually avai!able to allow operation of an extrac~on
train of more than six columns, if desired.
I n the operation of a coffee extraction system, aqueous
extract i5 drawn off at a draw-off ratio of about 1 to 3. As is
well known to those skilled in the art, the draw off ratio is the
25 amount of ~xtract withdrawn from the fresh extraction column
compared to the a~erage weigh~ of coffee in the individual
columns. Preferably, a draw-off ratio of 1.5 to 2.5 is employecl
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 coffe~
is cut into the system with the original fresh extractlon colurnn
becoming the n~xt succeeding stage, and so on to the point where
the column that originally contained the rnosS nearly spent coffee
is removed from the system. Th2 column removed from the
35 system is cleared of the sp~nt coffee grounds and charged wi~
fresh roast and g rownd coffee to becom~ the ~tandby fre~h
extraction column. The cycl~ time is defined as ~he time interval
-15-
between successlve draw-offs of final extract. l he cycle time of
this proc~ss can vary from about 15 minutes to abo~Jt 1 hour, In
th~ practice of this invention, a cycle tlme of about 30 minute~ 15
preferred. The cycle time also corresponds to the interval
S be~ween other operating steps besides draw-off; ~or exampl~, it
also corresponds to the tirne interval between the exposure of
cof~ee in one co~ee column to hydrolys~s, and th~ exposur~ of
coffee in the next fresher column, to hydrolysis temperature.
The fresh extraction temperature profile is pre~erably
10 relatively steep, i.e., the extraction temperatures should range
from about 50C (122F) to about 99C (210F), to allow for
efficient fresh extraction. This is generally achieved by star~ing
extraction at a relatively low temperature and Increasing th~
extraction temperature to near that of boiling water. The
relatively mild fresh column temperature 50C 1122F) is preferred
to extract heat sensitive components early in th~ extractlon
process, to avoid thermal degradation. The steep profile, up to
98.9C (210F), in only four columns, is preferred to extract as
much as possible of the fresh solubles. As described in the cas~
of the use of flner coffee grinds, efficient fresh extraction Is
important in this invention to minimize as much as possible the
carry-over of low terrperature extractable solubles into the
hydrolysis section of the train.
The hydrolysis extraction temperature profile is pre~erably
relatively mild. That is, th2 temperatures should be high enough
~o effect hydrolysis, generally in the range of from about 15~C
(310F) to about 166C (about 330F), but low enough to avoid
excessive thermal degradation of the coffee, which can occur at
higher temperatures.
D. Removal of Hydro!ysis V latiles
In the practice of this invention, th~ co~fee extract issuing
from the last hydrolysis column of the extraction train (i.e.,
immediately precedlng the fresh extraction columns) is referred ~o
as a hydrolysis extract. In making th~ coffee product of this
invention, the hydrolysis extract is multistage or countercurr@ntly
steam-stripped to thoroughly remov~ volatiles created during the
hydrolysis stage of the extraction process. Th~ resulting
371~-
strlpped hydrolysis ex~r~ce is thon pas~ed through the fresh
extractlon columns, pr~ferably In ~ counterclJrrent mann~r.
The steam strlpping proces~ of this invention can be
practiced in a varlety of ways known to th@ art. Typically~ the
stripping is accomplished at temp~ratures of from 38.9C 11û2F)
to 108.9C (228F) and pressur~ of 1 to 20 psia. The mass ratlo
of steam to extract is from 0.3 to 10, and mos~ preferably from
0.5 to 1.5. Evaporationl, which Involves boiling th~ extract, doe~
not ef~ciently or ~f~ectively remove the volatiles which multistag~
0 or countercurren~ steam strippir,y removes. Importantly, ehis
steam stripping removes furfural very effectively. Furfural is
representative of the hydrolysis volatiles. RemoYal of fur~ral
indicates that the off-flavors are also being removed.
In a pr~ferred method, hydrolysis ex~ract leaves th~
hydrolysis section of the extraction train and is sprayed into the
top of a vacuum chamber. The feed temperature of the exîrac~
must be at or above the !boiling point of water at the pressure Gf
the stripping chamber. Otherwise, steam in the chamber YVili
condense onto the extract droplets and reduce the efficiency ~f
the stripper. As the extract falls through the chamber, it is me~
with an upflow of steam introduced into the bottom of th~
chamber. Ths extract is removed lFrorn the bottom of the
chamber, and the steam, along with the 7eydrolysis volatiles
stripped from the extract, is drawn from the top of the chamber
and collected in a condenser for appropriate disposal. It wiil be
appreGiat~d that Tn the process described, the stean flows
countercurrent to the extract. This results in highly efficierllt
and effective removal of hydrolysis volatiles from the extract.
In ano~her method, the extract is successively sprayed into
and collected from a series of stripping chambers, with fresh
steam introduced into each chamber. In such a proces~ it is not
critical tha~ the steam flow countercurrent to the extract, because
ths gradien~ for removal of hydrolysis volatiles is re-establishecl
in each suceessive chamber. This method offers certain
advantages and is thlJs also preferred although it is less energy
emcient than a s~rict countercurrent stripplng process. The
stripplng process can b~ conducted at any desired pressure~.
'77
--17--
Atmosph~ic pres~iurl! is preferred for simplicity of equipment
des39n and oper;~ion, but sub- or superatmospherle pressures
can b~ ~Jsed.
In another ~thod, somewhat les~ preferred, th~ extract is
S drawn off not bet~een the fresh and hydrolysls sections of ~he
train, b~t in pOSitt~on further forward in th~ train. For example,
an extra~ion trair~ with the Following profile is being used:
~ olysis Fresh
Column ~o. 1 2 3 4 5 5 7
lo Temp., ~F 330 320 310 210 180 150 120
The extr21ct stean~ stripping column would bo used to strip th~
extract le:aving c~mn 4 and entering coîumn 5. Alternativeiy, i~
would be used to ~strip the extract leaving column 5 and entering
column ~.. This rrplocation of the stripper ha~ th~ ~ollowins~
15 advanta~s: (1 ) It allows tar-like materials, which emerge from
the hydr~lysis se~tion along with the hydrolysis extract, to be
filtered Q~t in the~ colder, ~resh columns of partially spent ro~st
and grown~ coffeee, before the materials enter the stripping
column and (2) Itt allows any volatile off-flavors produced in the
zo hotter, firesh coluRmns to be stripped away.
The number ~f countercurrent contacting stages will have a
marked ~a~fect on ~ffectiveness of off-flavor removal in the
str5pper~ A mulS~stage stripping system is highly preferred.
O~her 1~ efficie~r~t steam stripping methods can be used, but are
25 not pref~rred, ~Sfter steam stripping, the stripped hydrolysis
extract i~; ~ed cQountercurrently through the fresh extraction
columns a,s descri~ed above, and ~he final extract is drawn oflF
the fres~est columnn. The distillate or condensate which results
from the ~;team strripping operation is discarded. E~y "discarded"
30 is simpl~ meant t~at the stripper condensate is not used ~or
coffee i~cessing-
E- oncentrcation of the Extract
~ he fresh s~s~luble flavor of the soluble coffee of this
inventio~, is mo~ :s~nsitive to chang~ and variation than typical
~2~ t,~7
-lB-
lnstant flavor. Thcrefore, after leavlng th~ ~xtraction traln~ tho
coffe~ extract of this inventlon Is processed In a manner which
preserv~s th~ volatile compounds, particularly the low and
moderately volatlle compounds, and avoids substantlal thermal
5 degradatlon of those volatiles. In this contcxt it is also important
to note She interdependence of the stripping ope~atlon and the
post extraction processing. In particular, if the stripping i5 not
p~rformed to remove hydrolysis-generated off-flavor volatiles, the
careful post-extraction processing will actually produce an in~rior
10 coffee by concentrating off-flavor materlals in the producl~.
Conversely, if the stripped extract is processed by conv~ntOonal
post-extraction techniqu~s, such as thermal evaporative
concentration, the resulting cof~ee product will be remarkably
flat, since most of the flavor of conventlonal instant coffee~ i5
15 provided by the hydrolysis volati1es, due to the absence ~f
authentic moderately volatile compounds which are lost during
conventional processing.
After the extract issues from the extrac~ion train, it is
preferably concentrated to a solids concentration of at least 3S~.
20 For the concentration step, a concentration ~echnique which does
not involve substantial loss of aroma and flavor volatiles is
essential. Freeze conc~ntratior: is a highly preferred process.
Freeze concentration is accomplished in a manner in which the
water is removed a~ substantially or essentially pure ice crys~.als.
25 Adhering or occluded comp~unds must no~ be present in the ice
and must not be rern~ved with the ice.
A pre~erred embodiment of a concentration process involvcs a
freeze concentrator which has a scraped-wall heat e%changer
connected to an adiabatic recrystallizer tank. The recrystalliz~r
30 tank allows water to recrystallize and ice crys~als to grow in 5i2e
under conditions which form pure ice. A filter at the exit of the
tank retains all crystals of more than 100 microns in size. This
insures that most ice nuclei are retained for recrystallization.
The recrystallized ic~ is separated from the concentra~ed ex~rac~
35 by the use of a wash column. The wash column rinses any
adhering concentrate from the ice crystals, and 0xpedi~s removal
of essentially pure ice flom the freeze concentrate. A preferr~d
1~9L08~7
app~ratus for ~Jse In~ ~ncer~ration 3s th~ Grenco freez~
concentration unit. This unlt i5 described in U,S, 3,777,892,
issued to Thijssen In 1973: U.S. 3,872,009, issued to Thijssen in
1975; and U.S. 4,00~,896, issued to Thijssen et al. in 1977,
Other free~e concentration approaches that can be used
herein are those which havs been develope~ by CMC Soncentra-
tion Specialists, Inc., and Chicago Bridge and Iron Works,
Other concentration methods whish minimize loss of volatiles,
such as other freeze consentraticn processes, membl ane concen-
tration, reverse osmosis or sublimation concentration involving
slow freezing and slow water removal, can ~e used but are less
preferred. Combinations of any of the foregoing concentration
methods can also be used.
As mentloned, concentration of the extract is carried out
until the extract has a "solids" content of at least 20%, pre~erably
at least 35% and most pre~erably 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
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, 6096 solids, water
is actually a minority species in the concentrate. Because of ~he
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 during
subsequent processing,
The extract car. be decaffeinated either before or after the
extract concentration. Liquid/liquid decaffeination of coffee
extract processes are well known~ See, for example, Morrison,
Elder ~ Phillips, U.S. Patent 4,409,253.
The cof~ee extract or concentrated coffee extract can be
pasteurized, frozen or aseptically packaged. The extract or
concentrate can be aromatized or flavored with natural or artificial
sweeteners, cream or artificiai creamers, natural or artificial
flavors, such as herbs and spices. Preservatives such as
.. , ~/q~
~2~0~7~7
-20-
antloxldants or mold Inhibitors can be added to th~ extract, as
can be aneifoaming agents.
F. ~_
The extract produoed In this Inventlon can b~ dried tc a
moisture content of from abo~ut 1~ to about ~ by weight, and
preferably from abo-l~ 3% to about S~ by weight. Thls is a dry
soluble coffee powder. The ~xtract can be dried In any known
manner to provide a dry soluble coffee product. The drylng
method should be designed to retain volatlles. Fr~eze drying or
other known moistur~-removal processes which preserv~ volatile
compounds can be used.
If the resultant dry product is not in th~ form of particl@s,
it can be broken up by a number of methods to form instant
coffee particles. A preferred economical method for drying th
aqueous extract is spray drying wherein th~ llquid extract i5
sprayed into a tower and simultaneously contacted with a flow of
heated air. Y~ater is removed from the droplets ~f the aqueous
ccffee extract as they fall through the spray tower and th~y
emerge from the bottom as porous, spherlcal particles of instant
coffee containing, for example, from about 1.5~ ~o about S.0~ by
weight moisture. (Typical disclosures of spray drying processes
which can be used to prepare instant coffee partlcles can be
found, for example, in Sivetz ~ Desrosier, "Coffee Technology",
AYj Publlshing Co., Westport, Conn., 1979, pp. 373-433, and In
U.S. PatentS NOS. 2,771,343 tO ChaSe et al., ;SSUed On NOV. 20,
1956; 2,750,998 to Moore, issued on June 19, 1956 and 2,41j9,553
to Hall, issued on May 10, 194g.)
Preferably, the spray drying is conducted under conditions
which maxirnize volatile retention and minimize ~hermal degrada~ion
or oxidat~on of the soluble coffee. The extract feed temperature
to the drier is preferably in the range of from about 15C t60F)
to about 38C l1oooF~. Air flows and air temperatures which
produce inlet and outlet temperatures of from about 121C (2S0F)
to abou~ 20~C t400F) and from about 82S: (180F) to 121C
(250F), respectlvely, are preferred. An inert gas atmosph~re
can be ~sed to minimlze possibie oxidative effects.
-21--
Free2e drylng can produGe superlor volatiles retentlon,
compared to spray drylng, but is also more expenslve. Typical
disclosur~s of freeze drylng processes which can be used can be
found in Sivetz and Desrosier, c;ted above, at pp. ~8~-52~.
S After drying, the ~oluble coffee of thls Inventlon ean b~
pelleti~ed or agglomerated to improve its handling and dlssolution
characterlsttcs. It can also be aromatized to supply additional
high volatiles, i.ee, those boillng at temperatures below about
88~C. These volatil~s can be supplied by practic~ of any of ~he
many aromatization techniques known to the art. Pr~ferr~d
arornatlzation techniques include those ~escribed in U . SO
4, 335 ,149, issued June 15, 19~2 to Stipp, and Reissue Pat~nt
31,427, reissued October 25, 1983 to Lubsen et al. Other
aromatization techniques are describ~d at pp. 43~ to ~83 of the
Sivet~ and ûesrosier text cited hereinabove.
This soluble product can also be milled into flalces or
agglomerated. U.S. 3,652,293, issued to Lombana et al. (1~72)
descri~es such products. The dried soluble coffee of this
invention can be packaged, with or without agglomeration and
with or without arcmatization, for use as an instant coffe~
product.
111. of~ee Brewing Mixtures
However, a preferrad 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 abou~ 1 to
abcut 2.5 grams of soluble coffee and from about 1.5 to about 5
grams of roast an~ ground coffee. Combined in these ratios in
such a product, each component contributes to a positive overall
product perception. Th~ roast and ground portion provides
practically all of the coffeg aroma during opening of the package
and be~ore brewing. I~ also contributes noticeably to the brewin~
aroma during preparatTon and cup aroma. The soluble portion
provides most of the unique navor of th~ solubles of thTs
-2a-
inv~ntlon, and 75% or moro of the produce brew sollds and titrat-
able acids.
In general, finer gr~nds of roast and ground coffee will
provide better extractior~, although a tradeoff wlth pluggin~ of
S bag pores must be made when extremcly fine grinds are used. If
deslred, the roast and groalnd coffee component can be flak~d or
milled to Increas~ its extractabillty. Exampl~s of this can be
found Tn U.S. 3,615,667, issued in 1971 to Jof~, U,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 989,246, issued in 1976 to Bergeron and Schlichter;
U.S. 4,110,485, isslled in 1978 to Grubbs et al.; U.S. q,267~200,
issued in 1981 to Klien and Gleseker: and U.S. 4,331,6Y6, issued
in 1982 to ~ruce.
Th~ roast and ground coffee componerlt can al50 b~ fast
roasted to provide an expanded cellular structure and improv~d
extractability. U . S. 3, 088, 825, issued in 1983 to Topalian and
Luddington and U.S. 3,122,439, issued in 1964 to MoAllister and
Spothaltz, disclose processes ~or the fast roastlng of coffe~. Th~
~439 pat~nt aiso dlscloses that fast roast~d coffee can be flak¢d~
Ths cof~eo art3cle of thi3 Invention can be mad~ of any
water-permeable In~uslon material. A m~tal contalner with small
holes, such as a l'tea ball", can b~ used for brewln~ th0 solu~l~
cof~ee, roast and ground coff~e combination. Other articles
include plastlc, metal or wood~n spoons covered with a wa~er-
permeabl~ infuslon mat~rlal. For eas~ of masnufacture and
econom3cal dellvery, the pr~ferred article is a water-p~rmeabie
Infusion b~g.
Also, particularly pre~erred is a brewing article containing
roast and ground coffee and the soluble coffee of thEs inveneion
in which the soluble coffee, the roast and ground coffee, or
both, are milled into flakes. Flaking of th~ coffee squee~es ou~
air and o~her gases and makes the coffee more dense. The result
is that a coffee brewing bag using this mixture will be
sTgnificantly less buoyant than a coffee bag not containing flaked
~ 77 23-
coffee. A less buoyant bag results in faster brewing
and more convenience during coffee preparation. An
added benefit is that a mixture of soluble flaked coffee
and roast and ground coffee flows easily when filling
bags on a packing line.
The coffee can be milled by any means, but a
preferred method is by passing it through a two roll
pressurized flake mill using about 400-500 psig pressure
and about 20 to 30 rpm at zero gap between the rolls.
U.Su 4,267,~00, issued to Klien and Gieseker, describes
milling. The soluble flaking operation may include an
addition of coffee 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 30-45 seconds, delivering
about 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 produGt
composition, the coffee extraction is non-linear, with
very high extraction rates during the initial lS seconds
or so of extraction, slower rates for about the next 30
seconds, but then only slight concentration changes
during the next several minutes if brewing is continued.
The preferred coffee article of this invention can
be formed from both nonwoven and woven fabxics.
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,
! ~
-23a-
1'7~
polypropylene, and hemp and mixtures thereof. It is
immaterial for the purposes of this invention the type
of fiber used as the
~L~c~ t7
- 24 -
water-perm~abl~ material for forming ~he pouch so long as it is
chemically inert, essentially tasee-free and sufficlently strong to
remain an integral unit throughout norrnal handling, packagin~,
shipping of the coffee bag, brewing of the coffee ~everag~, and
s disposing of the l~se~ packet.
It is ~ssentlal ~hat the fabric used for preparing th~ coffe~
bag be pe~meable to water. Yet the pores in the ~abric allowing
water perm~ability should be of such a nature and siz0 that the
roast and ground coffee particles present in the bag do not pass
through with ehe brewing water. The fabric must act as a
fllt~rlng means to accomplish the objectives of pfev~n~ing the
formation of sedirnent In the brewed coff~e. The fabric thickness
used can vary but will generally range from about 0.002 InO to
about 0. 012 in ., preferably from about 0 . 003 in . to about
0.009 in.
l he slze of the pores in the pouchin~ material used in
making the coffee article of the present invention can vary in si~e
from about S microns to about 1000 microns, preferably from
about 20 microns to about 200 mlcrons. If a substantial portlon
of the pores are smaller than approximately S microns, it m~y be
impossible, irrespective of time, to extract all of the desired
flavor components and constituents from the cof~e in the article
into the brewed bev~rage since smaller pore si~es tend to clog
during brewing of the coffee beverage~ Where the pore sJzg Is
extremely flne inordlnately long b~ewing eimes are neededO ~ore
openings larger than about 1000 microns are to be avoided since
th~y permit passage of coffee fines into the beverage resulting in
a high IQV~I Of sediment. In 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 coffee packet
having an undesirable appearance can resule.
At least a portion of the coffe~ article can be an apertured
or formed fllm, rather than a ~abric. Such matcrials, affl
methods for making them, are described in U . S. Patents
~,151,240, issued April 2~, 1979 to Lucas and VanConey, and
77
4,3~2,314, Issued Au~ust 3, 1982 to Radel and Thompson. In
general, th~ crlt@rla for selectlon of materlals and aperture sizes
for formed ftlms are the same as those described above as
applicab3e to fabrics.
The preferred article of this inventlon is simply and easily
made. Rll that is neces~ary is to form a pouch out of the water-
permeable rnaterials hereinbefore described to contain the colFfe~O
~his can be done by "drawstrlng" means whereby the bag is
gathered at one end or by stitching the m3terial together to form
the bag. A preferred embodiment of this invention involves heat
sealing the wa~er-permeable material to form a bag In this
preferred embodlment the heat sealing is accomplished through the
us~ of a heat-sealing blnderO Binders which are acceptabl~ for
heat sealing ara those blnders havlng ~ meltin~ polnt lower ~han
1~ the softening or charrZng point of the bag material but a me~tDng
point higher than the temperature of boiling water. In addition,
the bind~r, similar to the bag material, must be chemically in~rg
and essentially taste-free. It is important that the binder be
sufficiently inert and insoluble in hot water so that no advaf~e
physiological effect from consumption of the coffee beverage can
result. Examples of suitable binders for heat sealing of the bag
materials described abov0 are the polymeric binders, as for
example, the polymeric binder described in IJ. S. Patent No.
3 1~3,096, issued to Hiscock (19CS).
The coffee article of this invention can be of any shape that
will contain th~ roast and ground and soluble cof~es. The shape
to be used may be determined to a certain extent by the brewjn
method employ~d. 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 disposeci of as a unit.
In addition to packaging the roast and ground cof~ee and
soluble coffee of this invention in a coffee article, the mixture of
the two coffiees can be pelleted or tableted for convenient
handling. The pellets or tablets are preferably used in a
brewing device wlth a ~ilt~r tc retain the extracted r oast and
ground coff~e.
2~7
The methods ~or brewlng cof~ee with the coffeo bag of thi~
invention ar~ numerous. A coffee beverags can be brewed by
placing the eoffee bay in a cup or pot of water which has ~een
brought to a boil and allowed to cool just slis~htly (to about 160F
5 to about 210F) and the soffee bag steeped in the hot wat~r for
from about 0. 3 minutes with agitatTon of the bag to about 6
minutes with little or no agitation of the bag. The bag can ther,
be removed and disposed of. A coffee beverage can also be
prepared using a suitably shaped cof~ee bag of ~his invention and
methods and eguipment in gener31 use for brewing ~ coff~o
bev@rage.
Capillary Gas Chromatographk Analysis of Volatilo
Coffee Components Separated and Concentrated by
15 Simultaneous Distilla~30n and Extraction (SDE-CG~
. . _ .
A. Princip!e
The steam distillation/extraction method of Schultz et al,,
J. Agr;c. Food Chem., _, 446-449 (1977) has been applied to the
analysis of volatile components of coffees. The first step i~
20 simultaneous distillation and extraction (SDE). Figur~ 4 i~ a
drawing of the apparatus used for this process. The vola~lle
components are steam distilled from a coffee sample. These
volatiles are co-condensed with Freon 11. The volatll~
- oon~ponents are extract~d by the Freon 11. The co-condensed
25 water and Freon 11 are allowed to separate and returned to their
respective flasks. Th~ls, the volatile compon~nts are extracted
and concentrated in the Freon 11. After ninety minutes the
volume 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 analyz~d by capillary gas
chromatography lCGC) using a Hewlett-Packard 5880A Gas
Chromatograph ancl fused siliea columns. A ~:)BS column is used
35 with a flame ionization detec~or (FID) to detect the carbon and
hydrogen in volatile compounds in the SDE extract. A CP-57-CIB
3'7~7
27 - -
col~mn is used wlth a flan~ photometric detector lFPD) to detect
sulfur-bearlng volatll~ compounds. The injected sample is split
between the two columns. Two Hewlett-Packard level ~our data
terminals are usecl to process the data, giving retention times,
peak areas and area percents. The methylene chloride (solventl
peak is excluded from the data. Additionally, a total of six other
peaks which are considered to be "artifacts of the method" are
excluded from the numerical data. However, they do appear on
the chromatograms. They are detectable on a blank a~alysl~. These
ln peaks repre~ent lmpuritie~ in the methylene chloride and Freon 11
and ~onstituents ~f the antlfoam.
So far, 27 compounds In tho separated coffee volatiles hav~
been identified by the SDE-CGC method: Isobutyraldehyde"
methyl ethyl ketone, diacetyl, 2,3-pgntanedion~, pyrazine,
pyridine, pyrrole, dihydro-2-methyl-3(2H)-furanone, methyl
pyrazine, furfural, furfural alcohol, aceto acetate, 2,5-disn~thyl
pyrazine, 2,6-dimethyl pyra~lne, 2,3-dimethyl py~azine, 5-met5~yl
furfural, furfural acetat~, 2-ethyl-6~methyl pyrazine,
2-ethyl-S-methyl pyrazine, 2,3,5-trimethyl pyrazine, S-methyl
pyrrolQ-2-carboxaldehyde, 2-ethyl-2, S-dimethyl pyrazine,
guaiacol, 2-(2-furan methyl)-5-methyl pyrrole, ethyl guaiac~l,
vinyl guaiacol.
The data obtained by the SDE-CGC method are sufficisntly
accurate and precis~ to be valid for a comparison of dlfferenc0s
in composltion of coffe~ samples.
B. Sam~!e Preparation
Cof~ee weighing 1C.0~0 ~ 0.005 grams is placed into a S00
ml. flask. Two hundred ml. of distllled water is added. Then
3 ml. of internal standard solution and 3 bolling stones are
added. (With instant coffee, 3 drops of Antifoam ~ are also
added. )
C. Internal Standard_Preparation
First, 0.0100 ~ .00005 g-ams of 2-acetyl pyra~ine are
weighed and placed into a clean, dry 100 ml. volumetric flaskO
Then sufficient methylene chlorlde is added So fill the flask to
1 0~
'77
28
D. SDE Prr ~dur~:
1. Th~ apparatus Is s~t up as shown in Figur~ 4.
The apparatus Includes a sample flask 214 and ~ solvent
flask 218. The sampl~ flask 214 is heat~d by a stirrer-hot plat~
222 while flask 218 Is heated by hot plate 224. Positioned on top
of flask 21~ and 218 Is a steam dTstillatlon/extraction (SDE~
coiumn 226 whlch Includes a sample vapoP column 22~ which
receives vapors from the cof~e~ sannple and a solvent vapor
column 232 which receives vapors from ~lask 218. The top
sections of th~ vapor columns ~28 and 232 are JoineJ to cond~nser
column 244. Mounted on top of condens~r column 24~ is ~ Dewar
condens~r 2~8 provided with a core 250 for rec~iYing coolant.
Cond~ns~r column 2~ is provid~d with a wat~r Inlet 252 and
a water outlet 254 for the circulatlon of water through ~ flrs~
cooling system 256 which cools core 258 of column 24q. Column
244 is also fitted with a second water inlet 260 and a second
water outlet 262 for circulation of water through a second co3ils~a
system indlcated by 26~ which cools the periphery 266 of column
24Z.
Vapors which conden~ in core 258 and along periphery 266
are collected in U-tub~ 268 connected to ~he bottom end o~
condenser 244. Tubing section 272 connects trap 268 to sample
eolumn 228 for passag2 of condensed vapors to flask 214. Tublng
section 276 connects trap 268 to solven~ column 232 for passage of
condensed vapors to fiask 218. The cooling water Is circulated
through systems 256 and 284 and the Dewar condenser core 250 i5
fi31ed with dry ice.
2. The Freon 11 is redistilled before using it. Abou~ 150
ml. of Freon is collected in a 250 ml. flask 218 to be used as the
extracting solvent.
3. Th~ Freor~ 11 is drained from th~ U-tube 268 wh~n th~
liquid level reaches the "Y" part 272 of the U-tub~.
~, The cof~ee sample is prepared while the Fr~on 11 is
being redistilled.
5. After the Freon redistillation is complete, ~he Freon is
drained unUI the liquld level is in the mlddle of the 'Y" Junction.
3'7
-- 29 --
6. Dlstlll~d wate~ 15 add~d through th0 conn~ction 27~
wh~r0 th~ D~war conden~or 250 flts onto the top cf ~hs water
condens~r 256, untll the wat~r liq~uid lev~l reaches the bottom of
th~ large out~r wat~r condens~r 260.
7. Three boillng stones are ~dded ~o flask 218 containing
the redistllled Freon.
8. The 500 ml. lFlask 214 containing the coffee solution is
conne~l:ted .
9. Ice Is added to a plastic res~rvoir which Is then used to
imm~rse U-tube 268.
10. Distillation is c~ried out for 1-1/2 hours a~er wil~er
vapor and Freon 11 begin condensing and collecting In U-tu~e
268.
11. The heat to the coffe~ solutlon in flask 21~ and th~
Freon 11 in flask 218 is turned off at the end of th~ dlstilla~lon
perlod. After the coffee solution stops boiling, the dlstill~lon
apparatus is disassembled.
12. The Freon 11 is drained out of U-tube 268 until ~he
liquid level Is at the Y-junction of th~ U~tube 268 and tubo 27
It is then poured into a flask 218 with the rest of th~ Freon 1~
13. Th~ Freon 11 is evaporated down to about S ml. ~nd@r
nitrogen on a steam bath set at 60~C (140F) to 71C (160F3,
~ 4. Eight ml. of dichloromethan~ is added to the flask
containing the Freon 11 and swirl~d.
2s 15. The contents of the flask containing ~he Freon i1 and
dichlorom~thane are evaporated down to about 3 ml.
16. A portTon 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 portlons of extract from the flask are added to the vial
and partlally evaporated to 0.5 ml. until th~ flask is empty. Two
ml. of dichl~romethane are added to the flask and swirled. The
solvent wash from the flask is added to the reaction vlal and
partially evaporated to 0.5 ml. The extract in the reaction vial is
evaporated to 0. 3 ml. if it is to be inj~cted Into the gas
chrom~tograph; otherwl~-, it is ~vaporat~d to 0.5 ml. ~nd put
into ~ fro~2~r untll prlor to g.c. InJ~ction, at wh!ch tln~ it is
evaporatod to the 0.3 ml~ lev~l. The extla~ Is not evaporated to
dryness.
5 E. Gas Chromatographic Analysis;
Cond5t!ons for the HP 5880A g.c.
Septum purge flow :1 ml./mln.
InlDt pressure : 26 psig
Vent flow :30 ml./mln.
Make-up carrier flow :30 ml.lmin.
FID:
Hydrogen flow ratc :30 ml.lmln.
Air flow rate :400 ml./min.
Column flow :3 ml./snln.
l Spllt ratlo : 1011
FPD .
Hydrogen fhw rat~ :75 ml./mlnO
Air flow rate :50 ml./min.
Oxygen flow rate :4û ml./min.
Detector ~emp~rature : 200C:
Temperature Pr~ram
O~n temperatlJr~ 25C, llmlt of 405C. The oven is heat~d
at 25C for 2.~ minutes.
Th~ oven is then programm~d to rise 20. 0~e/mln. to a
2s temperatur~ of 45C. Then the ov~n rises at 3. 0C/min . to a
temperatl~r~ of 65C. Then the oven rlses at 2.0ClmTn. to a
temp*rature of 125C. Finally the oven rise~ at 3.0C to a
temperature of 220C. The oven is then heated to 230C and
held there for 15 minutes.
Ths DB5 gas chromatography column used to detect and
separate the organic compounds are 60 meter columns of 0. 322
mm. inner diameter. A film of crosslinked polyethylene glycols
1 micron thick is used. The DB5 column is available from J~W
Scientlfic, Inc., Cardova, ~:A.
The CP-~7-C~ column used to separate the organic sulfiur
cornpounds is 25 micron in length and ha~ an inner dlameter of
0.33 mm. The C:P-57 CB column Is available from Chrompak
Q~'7~7
~ 31 --
Incorporated, N.J., ~t. No, 7763. A fllm of CP-TM-~/ax 57,
WSCOT fus~d sillca column ~It 1.12 micron thickness i~ ed.
The chromatograms are analyzed by determining ar~a percent
of each peak from the gas chromatographic eoun~s (electrical
s impulses record~d).
The to~al gas chromatographic counts of the sample as
obtained from the chromatogram are corrected to make all of the
samples on the same basis for comparison.
The internal standard (2-acetyl pyra~ine) is assumed to be
lû 3000 col~nts based on the concentration added and the response
factor. A sample calculation is as follows:
Internal Standard as measured 2737
Pyrazines total 21,785
21,785 x 3000 = 23,878
2737
Corrected pyra~ine count Is 23,878.
The furfural count is corrected In the same manner,
The furfural to pyrazine ~atlo is obtained by dividing the
total furfural corrected g.c. counts by the total corrected
20 pyrazTne counts.
The to~al sulfur-bearing volatiles colJnt Ts also correoted to
make all samples on the same basis for oomparison.
Ash Measurement
.
A sample of coffee extract or soluble coffee Is weighed into a
25 crucible. The sample is then heated as follows: heated frorn
20C (68F) to 400(: (752F) in one hour; cooled to 200C
(392F); then heated to 1000C (1~32F) and kept at tha~
temperature overnight (about 16-18 hours). The percent ash is
then determined by taking the weight of the final sample times
30 100 and dividing by the weight of the original sample.
~2~'7~
-32-
~e~
The following exampl~ Illustrates th~ ps ocess of ~his
invention. Unless otherwlse stated, all peroentages are giv~n on
a weight basis.
S A blend of 259~ primes, 25% Brazils, 2û9~ natural Arabic~s,
and 309~ Robustas was roasted on a Thermalo roaster model 231RS.
The roast Si;~Q was 3û0 Ibs. green coffee, and it was repeated
three times. The results of the roasts are listed below:
2 3
Roast time, minutes 6.S0 6.2S 6.33
Final temperature of 4~2 438 44û
roast, F
Water quench level, 13.9 13.9 13.9
% of green weight
Hunter 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 before the start of grinding and extraction.
An 8-column extraction train and extract steam-stripping
20 column, wi~h associated pumps, heaters, coolers, and piplng, was
utilized. Once begun, the proce~s was operated long enough to
insure that a truly counterGurrent progression of grounds and
extract llquor exited before taking data and test extract
draw-off. This was accomplished by sequentially adding oolumns
25 to the process until the total was seven operating extrac~ion
columns plus the extract steam-stripping column. As the fresh
column was put on-line into the systern, the most spent column
was taken out of the process, emptied, cooled, washed, and
refilled to be used again. This procedure is known in the art as
30 "startup".
The extraction columns are 0.5 fe. in internal diameter and
4.0 ft. high. As known to those skllled in the art, appropriate
piping for feedwater and extracts i~ also used. The columns are
also jacketed with a heating oil to prevent heat loss from ~he
35 columns during operation. The temperature of the oil was
adjusted per column approximately ~o match the inle~ fluid
,, ;
-33-
temperatur~, In a temperatur2 proflle as descrlbed later In thls
exampi~
The appropriate piping from and returning to the ~xtractlon
allowed the use of an extract steam-stripping col~Jmn (6 inch~s
5 internal diameter, 20 ft. hlgh, steam inlet at the bottom, esctracs
inlet at the top, no internal packing, ~xtract entars through a
spray noz~le pvintlng down She column) to strip th~ hydrolysl~
volatiles from the hydrolysis extract. Th~5, the strlpping column
stripped the extract leaving column 3 and the stripper bottorns
10 became the extract which entered column 4. About 130 Ibs. p~r
hour of ~team was fed to the stripping column which operat~d at
atmospheric pressure. A feed temperature of about 230F was
used.
~,rinding was done on a Cump model 33 coffee granullzelO
15 The following is a typ;cal particle size dis~ribution:
U.S. Sieve Screen
~6 8.4
-6+8
-8~1 2 25. 6-
20-12~16 12.6
-16~20 6.0
-20 6.~
After startup, the tempera~ures in the extraction train
starting with the column containTng the most sp~nt coffee ground~
25 and progressing to the fresh column, as measured at th~ inl~t
and outlet to each column, were as follows:
2 3 4 5 6 7
Inlet, F 334 319 310 246 181 150 119
Outlet, F 316 307 261 195 151 127 131
The average column load of roast and ground was 20.3 Ibs.
The pressure of columns 1, 2 and 3 was 150 psig. Th~
pressure of columns 4, S, 6 and 7 was near atmosph~ric. The
,, .
--34--
draw-off ratio was 2.1 and the averag~ cycle time was 3Q mlnut~s.
The vapors and the ex~ract from th@ Fresh column were condans~d
andlor cooJed to about 10C (50F). Th~ fresh extraction column
was exha-~sted through a chill~d water heat exchang~r to an open
S weigh tank. The percentage yield of solubl~s based on tlh~ r~st
and ground coff~ wa~ 39 . 0%. Th~ rosultant extract of thls
exampl~ contalned 1~.6~ solubles. ~ sampl~ o~ the ~xtract was
analyzed by SDE-FID and the results aro contain~d In Table 1.
The corrected g.c. area for the pyrazine derlvatives is 12,037;
the ~orrected g.c. area ~or fur~ural is 8,251; and the ratio of
furfural to pyrazine derivatives is 0.6~
The extract was then flltered through a spiral wound
cartrldge filter rated at 15 micron openlngs. lho flltered ex~raet
was chilled to about 2C (35F~ and placed into a refrigerated
s~orage tank.
A Grenco model Y~8 free~e concentratlon unit was fed frosn
the refrigerated supply tank. The Grenco system is a elos~d
system.
The refrlgerator unit and recirculation pump sircula~ing th~
extrac$ from the recrystallizet through the scraped wail h~at
exchanger were started and the extract was cool~d down ~o albout
-1C ~30F) and formation of recrystallized ice was achi~ved after
about 2 hours. Removal of Ice v~a the wash column started albout
3 hours lat~r. A conc~ntration of about ~0% dlssolved solids was
2~ achieved after aboue 20 hours of operation. The unit was then
drained of extract. The drained extract was then Immedlat@ly
spray dried, as described b~low. The Grenco was then
recharged with fresh extract and the process was repeated.
lhe averag~ aga of the extract (from draw-off to drying)
for the firs~ freeze concentration run was about 36 hours. Th~
age for the second run was about 24 hours.
The concentrat~d extract was dried on a co-current spray
drier. The inlet extract temperatur~ was about 16C (61F~.
The inlet air ~emperatlJre was about 171C (340~F~. Th~ outlet
air temp~rature was about 93C 1200F). The dried solids were
collected at a rat~ of about 40 Ibs. p~r hour, at a moisture o~
-3S--
about ~.5~. This powd~r would have an ash content olF al~out
.0~.
A sampl~ of th~ spray-dried powder was analyzed with boah
SDE-FID (fo~ furfural and pyra2ines) and SDE~FPD (f~r ~ul~ur~
5 to yield th- data in Table 1 and Flgure 2A, 2B, & 2C. The corrected
g.c. area for the pyra21ne derivatives i~ 36,343; tho corrected
g.c. area for fur~ural Is 27,908 and tho ra~io of ~urfural to
pyrazine derivatlves is 0 . 77 :1. Th~ tOeal corrected sulfur
compounds is 10,994.
Exampl~ 2
A sample of a commerclal freeze-drled premlllm-pricsd lhstarit
coffee was analyzed by SDE-FID and S~DE-FPDo and th~ r~sults
are detailed in Table 1. The corrected g.c.
area for the pyrazin~ derivatives is 12,47~ tho corrected ~.c.
area for fur~ural is 28,426; and the ratio of furfural to pyra2in~
derivatives is 2.28:1. The total corrected sulfur g.c. coun~ 15
2 ,994.
A sample of a commercial spray-drled instas~t coff~ wa~
20 analyzed by 5DE-FID and SDE-FPD~ and th~ results are detall~d
in Table 1 and Figur~s 3A, 3B, & 3C. The corrected g.c. ar2a for the
pyra2in~ derlvatlYes Is 12,386; the corrected g.c. area ~or
furfural is 64,~28~ and th~ ratio of furfiwal to pyrazine
d~rivatiYes is 5.2:1. The total corrected sulfur g.c~ counts is
~5 4,424.
Example 4
A sample of roast and ground coffee was analyzed by
5DE-FID and SDE-FPD, and the results are detalled in Ta~le 1.
The corrected g.c. area for the pyra~ine
30 derivatives is ~3,899; the corrected y.C. area ~or furfural Is
12,876; and the ratlo of fur~rai to pyra2ine derlvatives is
0.54:1. Th~ totai corrected sul~r g.c. counts is 12~9i3.
--36--
Example 4 shows the normal ratlos of fur~ural ~o pyrazines in
roast and ground coff~e which is consldered to bs th~ targst
standard of composition for an instant coffe~. These levels of
S fu~fural and pyrazines in roast and 9round coffee hav~ also been
independ~ntly establishgd by outside researchefs. [Nakamich5,
L., "Coffee Flavor", New Food Industry 25, No. 11, pp. 54-59,
1983. ) Example 1 shows that an extract ~nd a powder with a
furfural to pyrazines ratTo sl3ghtly hTgher than roast and ground
10 coffee is obtained with the process of this invention, Example 2
shows how a comm~rcial premlum freeze-dried coffee has a much
higher furfural to pyrazines ratio, and Example 3 shows an eYen
higher ratio.
Regarding sulfur volatile interlsltie~, it is appar~nt that ~he
15 soluble coffee of this invention has a significantly hTgher level Qf
sulfur volatiles than in conventional instant coffees, and the levei
is about equal to that of roast and ground.
~e~
A~coffee bag was made by formlng a single chamber bag of
20 Dexter 2588 paper of the following specifications:
1. Heat seallng bincler on on~ side of the paper.
2. Grammag~: 24.6 9. Im.3
3. Alr permeability:
480 L/min./1û0 cm2 ~ 12.7 mm. H;10 P
4. Tensi1e strength:
dry machlne d~rection 5300 9./25 mm.
dry cross dlrection 1990 9./25 mm.
wet cross direction 525 9./25 mm.
s. pH: 5.2
The bags were manufactured on a Hayssen ver~ical form
filled seal machine. l he dimensions of the bag were 2 inches
wide by 2.75 inches lon~ with a 1/4 inch heat seal on the bottom
of the bag. The coffee (as described below) was placed into the
bag. A 114 inch heat seal was made along the ~op of the bag~ A
18'~7
1/8 Inch wid~ by ~ Inch Mylar strip twith paper Sag attached)
was attached using ~ h~at sealor to the top of the bag.
The roast and ground coffe~ was made from a blend of green
coffee con~isting of 55% milds, 25~ Bra2ils and 20~ P~obustas. The
5 cof~ee was roasted on a Probat Model UG~2N batch roastor in a 50
Ib. batch. The coffee was roasted to 2 tiunter L color reading of
21.S In 8-1/2 minutes at a finaJ roast temperature of ~65F. It
was quenched at the end of the roast with water at a level of
11.7% of the initial load of green coffe~. The whol~ roast was
lo ag~d about 6 hours and th~ ground on a Gump coffe~ granuli2er
Model 66. Th~ following is a typical particle ske distrlbution:
U. S. Screen Range, Weight %
on 12 0-2
through 12, on 16 12-20
through 16, on 20 35-4~
through 20, on 30 18-30
through 30 12-30
The coffce wa~ then screened through a U.S~ 12 mesh
screen tto remove coarse particles) and on a U.S. 40 mesh screen
20 (to remov~ flne particl~s). ~he coarse and fine fractions were
discard~d.
The solubl~ coffee was prepared much in the same way as in
Exampl~ 1. The soluble coffee was then milled on a Lehman mili
Mod~l 4X8, to form flakes. The flakes were sized through a U.S.
25 7 mesh screen (to remove large flakes) and on a U . S. 30 mesh
screen (to removs~ fines). The. coarse and flnes were recycled
through the mill1 The flaked and sized solubles were mixed wi~h
the sized roast and ground coffee in a ratio of 2.0 parts solubles
and 3.5 parts roast and ground. The coffee bag was pack~d with
30 5.5 grams of this mixture. The mlxture of roast and ground
coffee and dried powder coffee was analyzed by SDE-FID and
SDE-FPD, and the results are deta31~d in Table 1. The corrected
. g.c. area for the pyrazine derivatlves is ~7,857; the correc~ed
37
-38~
g.c. area for fur~ral is 22,992: and the ratlo of furfural to
pyrazine derlvatives is 4.~3:1.
A brew test of the bag was run. The bag was placed in 200
millllfters of 88C tl90F) wat~r In a cup for 1 mlnuto.. Durir3g
this perlod the bag was occasionally dunked! uslng the mylar
strip-tag to rafs~ and lower th~ bag. The resultTn~3 brew
contained 1.31% solubles. Organoleptk evaluatlon of th~ br~w by
an expert panel showed that, In th~ absolu~te, thc br~w tasted
smooth and flavorful llke fresh brewed coff~e.
7~7
-39
~x'~
r~ ~ o
-
E ~ o r ~ ~
X O CL.C~ ~ a~r ~ . 5
W ~ V~ ~ ~
~ ,~
$ ~
a7
o ~ o
O ~
o
C~ e
. ~ . 2 ,, 8,
2 2 ~ ~
~2~ 7~7
-- 4~ --
Example 6
Two samples of hydrolysis extract and a hydrolysis ex~rast
stripper condensate, which were obtained in runs conduct~d in a
manner similar to that detailed in Example 1, were analyzad by
SDE-FID, and the results are detailed in Table 2, Column A is
the feed ex~ract to the stripping column. Column B is th~
stripper extract leaving the bottom of the column. Column Ç, a
hydrolysis extract stripper condensate, Ts a sample w~¢h
typlfies the composition of the strippa~e which i5 dlsclosed,
Tæbl2 2
Volatiles Analysis Results of Hydrolysis
Extracts and HvdrolYsis Condensate
,
Example 6
Stripper Strippar Stripper
Feed Bottoms Condensate
A B C
__ _
Furfural 30,205 1,~91 30,451
Pyrazines 581 67 638
~ fur~ural 52.0 6.7 57.3
% pyra~ines 1.0 0.3 1.2
Total corrected58,08622,252 53,143
g.c. counts
Th~ results in ~abl~ 2 show` that the hydrolysis extract
steam-stripplng column removes virtual3y all of the fur~ural
25 present in the hydrolysis extract. The furfural is contained in
the condensate from the stripping process ancl discarded. Few
valuable ~rolatlles are present in the feed to the stripping column,
as evidenoed by the low pyrazlnes lev~ls, and ~hus little besides
furfur~l is lost. The ealculation below estimates the actual degree
30 of l~emoval of furfural:
Feed furfural 58,086 x .52 = 30,2~5
Bottoms furfuraJ 22,252 x .967 = 14~1
100 x 11 - (14gl/30,205)1 = 95.1~ removal
~2~8'7~
-41-
Thls degre~ of removal can obvlously, to thoso skllled in tho art,
be improved signiflcantly by the us~ of additlonal stages in th~:
countercurrent multipl~ sta~e strippor" o~ by a hlgher steam to
extrac~ ratlo. In Examplo 1, a tall column spray stripp~r was
5 used. ~ taller column would add extra contacting stages, ~or
example. A 99.0% or bett~r r~moval could be achieved. Thus,
th~ stripping column al10ws almost total furlFural removal from the
hydrolysis extract.
