IE830561L - Freeze-dried coffee - Google Patents

Freeze-dried coffee

Info

Publication number
IE830561L
IE830561L IE830561A IE56183A IE830561L IE 830561 L IE830561 L IE 830561L IE 830561 A IE830561 A IE 830561A IE 56183 A IE56183 A IE 56183A IE 830561 L IE830561 L IE 830561L
Authority
IE
Ireland
Prior art keywords
coffee
frozen
freeze
coffee extract
extract
Prior art date
Application number
IE830561A
Other versions
IE53999B1 (en
Original Assignee
Gen Foods Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gen Foods Corp filed Critical Gen Foods Corp
Publication of IE830561L publication Critical patent/IE830561L/en
Publication of IE53999B1 publication Critical patent/IE53999B1/en

Links

Classifications

    • AHUMAN NECESSITIES
    • A23FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23FCOFFEE; TEA; THEIR SUBSTITUTES; MANUFACTURE, PREPARATION, OR INFUSION THEREOF
    • A23F5/00Coffee; Coffee substitutes; Preparations thereof
    • A23F5/24Extraction of coffee; Coffee extracts; Making instant coffee
    • A23F5/28Drying or concentrating coffee extract
    • A23F5/32Drying or concentrating coffee extract by lyophilisation

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Polymers & Plastics (AREA)
  • Tea And Coffee (AREA)
  • Freezing, Cooling And Drying Of Foods (AREA)

Abstract

The coffee is produced by (a) slowly freezing the lower portion of a layer of aqueous coffee extract while leaving the upper portion not completely frozen; (b) instantly freezing the upper portion by spraying a cryogenic fluid, preferably liquefied nitrogen, on to it; and (c) freeze-drying and grinding (in either order) the frozen coffee extract. The combination of slow and fast freezing gives a frozen coffee extract comprising dark and light layers, giving on grinding, particles of different colours, which when mixed, simulate the appearance of roast and ground coffee. [GB2119625A]

Description

2 The present invention relates to a method of producing a freeze-dried coffee having the appearance of roast and ground coffee. Specifically, this invention involves a process of instantly freezing a portion of substantially frozen coffee extract by spraying a cryogenic fluid thereon. The aqueous coffee extract frozen in this manner is ground and freeze-dried according to a method well known in the art.
Methods of producing the desired color freeze-dried coffee, either light or dark-colored, are known in the art. It is recognized that rapid freezing of a water-bearing substance promotes the distribution of a great number of small ice crystals and slow freezing produces a lesser number of larger ice crystals. With respect to freeze-dried coffee, it is established that a rapidly frozen coffee extract containing smaller ice crystals yields a light-colored soluble coffee whereas a slowly frozen extract containing larger ice crystals provides a darker coffee. 3 05 A dark-colored freeze-dried coffee has generally been preferred and much effort has been directed towards producing such a coffee, usually by controlling the manner of freezing the coffee extract. For example, U.S. Patent No. 3,253,420 to DeGeorge discloses a method of freezing coffee extract on a chilled metal belt over an approximately 15 minute period. A method of freezing whereby coffee extract is agitated while being chilled from its ice point to a temperature below its eutectic point over a period of between 15 minutes and 30 minutes is disclosed in U.S. Patent No. 3,399,061 to Lutz.
More rapid methods of freezing coffee extracts which also darken product color are known, such as the 15 disclosure of U.S. Patent No. 3,443,963 to Simon et al. wherein coffee extract is first chilled to about minus 5°C and held at that temperature for nearly 20 minutes prior to rapid freezing. Another disclosure, U.S. Patent No. 3,966,979 to Katz et al., describes 2q a layered freezing process wherein the upper portion of a fast frozen extract layer is melted by having a layer of warm coffee extract placed on top and both layers are then frozen prior to the addition of the next layer.
Although the dark-colored freeze-dried coffee is generally considered as more nearly resembling the appearance of roast and ground coffee in comparison to a light-colored freeze-dried coffee, inspection of roast and ground coffee reveals that it is actually composed of particles of many different shades, ranging from light to dark coffee color. A freeze-dried coffee of only one color, even though it is dark, cannot resemble the appearance of roast and ground coffee as nearly as a freeze-dried coffee 4 comprised of light- and dark-colored freeze-dried coffee particles.
It is an object of the present invention to provide a method of producing a freeze-dried coffee ^ having the appearance of roast and ground coffee which freeze-dried coffee is comprised of light- and dark-colored freeze-dried coffee particles.
A method of producing a freeze-dried coffee having the appearance of roast and ground coffee has now been discovered. The method generally involves instantly freezing a portion of substantially frozen coffee extract by applying a cryogenic fluid thereto. The coffee extract so frozen is ground and subsequently freeze-dried or vice versa.
According to the present invention there is provided in one errbodiment a method of producing a freeze dried coffee having light and dark coloured particles to give the appearance of roast 20 and ground coffee which cottprises: (a) slowly freezing the lower portion of a layer of aqeuous coffee extract while leaving the upper portion substantially but not conpletely frozen solid; (b) instantly freezing the upper portion of the coffee extract 25 layer by applying a cryogenic fluid onto the surface thereof; (c) grinding the frozen coffee extract of step (b); (d) freeze drying the ground, frozen coffee extract of step (c).
Tn another embodiment there is provided a method of producing a freeze dried coffee having light and dark coloured particles to give the appearance of roast and ground coffee which conprises: (a) slowly freezing the lower portion of a layer of aqueous coffee extract while leaving the upper portion substantially but not conpletely frozen solid; (b) instantly freezing the upper portion of the coffee extract layer by applying a cryogenic fluid onto the surface thereof; (c) freeze drying the frozen coffee extract of step (b); (d) grinding the freeze dried coffee of step (c).
Preferably the cryogenic fluid is sprayed onto the surface.
The initial step in the method of the present invention is freezing a portion of an aqueous coffee extract layer while leaving the remaining portion substantially but not completely frozen solid. The term "substantially frozen" is intended to mean that state of the coffee extract wherein there is virtually no free water present but said extract is not yet frozen solid to the point of being brittle. Said freezing may conveniently be carried out by placing the coffee extract layer in a pan and chilling the underside of the pan. In this way, the lower portion of the extract layer is frozen solid before the upper portion of the extract layer is completely frozen solid. Most preferably, the freezing is carried out on a continuous, moving metal belt as described in U.S. Patent No. 3,253,420 to DeGeorge. The continuous metal belt is chilled underneath by a series of brine pans maintained at progressively lower temperatures along the length of said belt.
Here again, the lower portion of the coffee extract ri->liw»w«gya a o layer may be frozen while the upper portion of the layer is substantially but not completely frozen solid. The cryogenic fluid is conveniently sprayed or poured on the surface of the coffee extract at 5 that point along the length of the belt where the preferred extent of freezing is attained.
What is meant by "cryogenic fluid" is a fluid which results from the condensation of the typically inert gases, which gases liquify at extremely low 10 temperatures. For instance, liquid nitrogen which condenses at minus 196°C, is particularly well suited for use in the present invention. Cryogenic fluids are useful because of the extremely low temperature at which they evaporate, which in effect 15 instantly freezes the substantially frozen coffee extract when sprayed thereon. Said fluids rapidly evaporate from the surface of the instantly frozen coffee extract, leaving no residual trace in either the frozen or finished coffee product. Even if 20 residual traces of the cryogenic fluid were to remain in the frozen coffee extract (though, as noted, no such traces do in fact remain), the preferred use of liquified inert gases prevents any possible contamination of the freeze-dried coffee 25 product.
The cryogenic fluid is applied to the substantially frozen portion of the coffee extract surface preferably in the form of a spray. Such a spray is effective in instantly freezing only the upper 30 portion of the extract layer, which upper portion is substantially yet not completely frozen solid prior to application of the fluid. The net effect of spraying the cryogenic fluid on the surface is to create a light-colored instantly frozen coffee 35 extract layer on top of the darker colored conventionally o t) j j 3 7 frozen coffee extract layer- A spray of cryogenic fluid is convenient for controlling the quantity of said fluid applied, as well as providing for the even distribution of the fluid to the surface of the 5 coffee extract layer. Proper control of the amount of cryogenic fluid applied is important in conserving the valuable cryogenic fluid.
After the cryogenic fluid has been applied to the coffee extract, the completely frozen coffee 10 extract layers are removed or discharged from the apparatus in which it is frozen and subsequently ground. The purpose of grinding the frozen extract is to both facilitate the freeze drying operation and provide a homogenous mixture of instantly frozen 15 and more slowly frozen coffee extract particles. An object of the invention is to provide a method of producing a freeze-dried coffee comprised of light and dark-colored freeze-dried coffee particles.
Grinding of the frozen extract provides for the 2o random disperson of the light-colored and dark-colored particles by the mixing action that takes place during the size reduction of said frozen coffee extract. The actual method of grinding is not particularly important; a hammer mill such as is 25 known in the art is particularly convenient for grinding the frozen extract.
The ground, frozen coffee extract is then freeze-dried according to methods well-known in the art. Freeze drying is basically the removal of 30 water from a frozen article by subliming the water directly from the frozen into the vapor state. Such drying is typically carried out in a vessel maintained at a sufficiently low pressure as to permit sublimation.
'J J « ^ 8 The method is disclosed, for example, in U.S. Patent No. 3,365,806 to Pfluger et al. After drying, the product is removed from the freeze drying vessel and the freeze-dried coffee having the appearance of 5 roast and ground coffee is obtained.
As an alternative, the frozen coffee extract layer may be freeze-dried in whole form and subsequently ground. Such an embodiment is not preferred because of the relative inefficiency of freeze 10 drying a whole frozen slab. The grinding operation is not particularly efficient after freeze drying, with the resulting generation of a considerable amount of coffee fines. It is, however, possible to operate the process according to this embodiment if 15 sufficient control of the coffee fines is provided.
Freeze-dried coffee particles of at least three different colorations are seen to result from the method of the present invention. As hereinabove described, the frozen coffee extract is comprised of 20 two layers, a light and a dark-colored layer, after the application of the cryogenic fluid. So, on grinding, particles are formed at least from the dark-colored layer and the light-colored layer, giving two distinct particle colorations. A third 25 coloration is provided from that portion of the frozen extract comprising the boundary of the light and dark colored layers. Particles produced therefrom will be dark-colored on certain faces and light-colored on others. The particles of three colorations are 30 mixed homogeneously during grinding so that upon drying, a freeze-dried coffee having the appearance roast and ground coffee is produced. 9 The following example is meant to demonstrate certain aspects of the present invention. The example is not intended to limit this invention beyond what is claimed below.
EXAMPLE 1. A 19mm deep layer of aqueous coffee extract (25% by weight soluble solids) was placed in a stainless steel tray maintained at minus 30°C. The extract was maintained at minus 30°C until the bottom of the layer was frozen solid but the upper portion was still tacky. 2. Liquified nitrogen was poured on top of the extract layer so as to cover the whole surface of said layer, instantly freezing the tacky upper portion. The liquified nitrogen was subsequently allowed to evaporate. 3. The frozen coffee extract was reduced in size by forcing the slab through an 8 mesh (U.S. Standard Sieve Screen). The frozen particles were 2o shaken so as to distribute the different colored particles uniformly throughout. 4. The frozen coffee particles were then freeze-dried in a laboratory freeze dryer maintained at a pressure of about 250 microns and a platen temperature of 42°C for a period of 16 hours.
The resulting freeze-dried coffee had different colored particles and was characterized as having the appearance of roast and ground coffee.
U u o ^ J ID

Claims (8)

CLAIMS :
1. A method of producing a freeze-dried coffee having light and dark coloured particles to give the appearance of roast and ground coffee which ccrrprises : 05 (a) slowly freezing the lower portion of a layer of aqueous coffee extract while leaving the upper portion substantially but not conpletely frozen solid; (b) instantly freezing the upper portion of the coffee extract layer by applying a cryogenic fluid onto the surface thereof; 10 (c) grinding the frozen coffee extract of step (b); (d) freeze drying the ground, frozen coffee extract of step (c).
2. A method of producing a freeze dried coffee having light and dark coloured particles to give the appearance of roast and 15 ground coffee which comprises ; (a) slowly freezing the lower portion of a layer of aqueous coffee extract while leaving the upper portion substantially but not conpletely frozen solid; (b) instantly freezing the upper portion of the coffee extract 20 layer by applying a cryogenic fluid onto the surface thereof; (c) freeze drying the frozen coffee extract of step (b); (d) grinding the freeze dried coffee of step (c).
3. A method according to either of claims 1 and 2 wherein 25 the cryogenic fluid is sprayed onto the surface.
4. A method according to claim 3 wherein the cryogenic fluid is sprayed as a mist. 30 5.
A method according to any one of claims to 1 to 4 wherein the cryogenic fluid is liquified nitrogen. f>.
A method according to any one of claims 1 to 5 wherein the aqueous coffee extract is frozen on a continuous, chilled rowing metal Ixilt,. 11
7. A method of producing a freeze dried coffee substantially as hereinbefore specifically described in the Exanple.
8. A freeze dried coffee when produced by a method as claimed in each of claims 1 to 6. F.R. KELLY & CO. AGENTS FOR THE APPLICANTS
IE561/83A 1982-03-30 1983-03-15 Freeze-dried coffee with a roast and ground appearance and a method therefor IE53999B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US36371882A 1982-03-30 1982-03-30

Publications (2)

Publication Number Publication Date
IE830561L true IE830561L (en) 1983-09-30
IE53999B1 IE53999B1 (en) 1989-05-10

Family

ID=23431414

Family Applications (1)

Application Number Title Priority Date Filing Date
IE561/83A IE53999B1 (en) 1982-03-30 1983-03-15 Freeze-dried coffee with a roast and ground appearance and a method therefor

Country Status (10)

Country Link
JP (1) JPS58187138A (en)
AT (1) AT380628B (en)
CA (1) CA1204327A (en)
CH (1) CH658571A5 (en)
DK (1) DK163330C (en)
ES (1) ES8406851A1 (en)
FR (1) FR2524267B1 (en)
GB (1) GB2119625B (en)
IE (1) IE53999B1 (en)
IT (1) IT1167090B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK168418B1 (en) * 1992-02-26 1994-03-28 Taarup As Maskinfab Mowers with mechanical simultaneous adjustment of river rotor angle and height
US8549768B2 (en) * 2011-03-11 2013-10-08 Linde Aktiengesellschaft Methods for freeze drying
GB2496177B (en) * 2011-11-04 2016-06-08 Kraft Foods R&D Inc Processes for forming soluble coffee products
CN113271786B (en) * 2019-02-05 2024-04-05 雀巢产品有限公司 Soluble coffee powder
FR3098090B1 (en) 2019-07-05 2021-06-04 Genialis SUPERIOR LYOPHILISE COFFEE AND ITS PREPARATION PROCESS
KR20220151654A (en) * 2020-03-10 2022-11-15 소시에떼 데 프로듀이 네슬레 소시에떼아노님 Soluble Coffee Powder
CN113712224B (en) * 2021-08-24 2023-12-22 昆明弘承食品科技有限公司 Coffee bean baking system capable of controlling caffeine content and baking method thereof

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1137461A (en) * 1966-01-14 1968-12-18 Atlas As Method for freeze-drying liquids and plant for carrying the method into effect
FR1482105A (en) * 1966-04-01 1967-05-26 Nestle Sa Process for the preparation of powdered extracts of plant materials
US3493388A (en) * 1966-11-30 1970-02-03 Procter & Gamble Process for preparing instant coffee
DE1927801B2 (en) * 1969-05-31 1976-02-05 Dr. Otto Suwelack Nachf., 4425 Billerbeck PROCESS FOR THE PRODUCTION OF GRANULES BY FREEZE-DRYING
GB1286288A (en) * 1969-10-23 1972-08-23 Hag Ag Process for the preparation of freeze-dried products from liquids
US3809766A (en) * 1972-05-12 1974-05-07 Gen Foods Corp Method for producing an enhanced freeze dried coffee
CA1182326A (en) * 1980-04-09 1985-02-12 Fouad Z. Saleeb Edible carriers for volatile components
US4313265A (en) * 1980-04-10 1982-02-02 General Foods Corporation Process for preparing microporous structured soluble coffee product
CA1151940A (en) * 1980-04-10 1983-08-16 William J. Einstman Soluble coffee product
DE3132563A1 (en) * 1980-08-30 1982-10-07 Werner Georg 7981 Vogt Munk Process for producing freeze-dried products, in particular foods

Also Published As

Publication number Publication date
GB8307526D0 (en) 1983-04-27
ES521084A0 (en) 1984-09-01
DK122783A (en) 1983-10-01
GB2119625B (en) 1985-10-30
DK163330C (en) 1992-07-20
CA1204327A (en) 1986-05-13
IE53999B1 (en) 1989-05-10
IT8347991A0 (en) 1983-03-25
JPH0379974B2 (en) 1991-12-20
CH658571A5 (en) 1986-11-28
AT380628B (en) 1986-06-25
FR2524267A1 (en) 1983-10-07
FR2524267B1 (en) 1988-07-22
GB2119625A (en) 1983-11-23
ATA111383A (en) 1985-11-15
JPS58187138A (en) 1983-11-01
IT1167090B (en) 1987-05-06
DK163330B (en) 1992-02-24
DK122783D0 (en) 1983-03-17
ES8406851A1 (en) 1984-09-01

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