WO2019058351A1

WO2019058351A1 - Freeze dried coffee with coffee grounds

Info

Publication number: WO2019058351A1
Application number: PCT/IB2018/057388
Authority: WO
Inventors: Francis Joseph David Bealin-Kelly; Kai WASSERMANN; Hadi ZOHREIE; David BENSAL
Original assignee: Strauss Coffee B.V.
Priority date: 2017-09-25
Filing date: 2018-09-25
Publication date: 2019-03-28
Also published as: IL273367A; RU2679057C2; RU2020110822A; RU2017133265A3; RU2017133265A; EP3672418A1

Abstract

A freeze dried coffee preparation comprising a dry concentrate and ground coffee particles, wherein the ground coffee particles have a median size of not higher than nineteen microns and the said particles were ground in an aqueous environment. Also a preparation where the roast ground coffee particles make up between 3 and 30% of the freeze-dried coffee granule. Also a method and apparatus for making freeze dried coffee with added coffee grounds comprising preparing and concentrating a coffee extract, adding ground coffee particles and wet grinding the concentrate at two successive grinders, each being a different kind of grinder, say a colloid grinder and a ball grinder, then recombining the streams and freeze drying.

Description

FREEZE DRIED COFFEE WITH COFFEE GROUNDS

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to a freeze dried coffee with coffee grounds and, more particularly, but not exclusively, to a way of making a freeze-dried coffee with a body that is as close as possible to that of extracted coffee.

US Patent 3,404,007 filed January 1966 describes the process for freeze drying coffee. The result is an instant coffee that is a considerable improvement in terms of flavor on the earlier powdered instant coffee but still lacks several of the distinguishing characteristics of real coffee prepared directly from the ground roasted coffee beans, in particular fullness or texture of the drink.

Today, freeze-dried coffee is typically made as follows:

Roast & ground coffee is extracted by hot water in a series of percolators. The resulting extract is concentrated further using evaporators.

The concentrated liquid, essentially a coffee extract, is cooled and foamed with C02 or N2 or a combination of both.

The foamed liquid provides a reduced density material, which is poured onto a long (>20m) rotating steel belt cooled to below -50°C in a room cooled to the same low temperature.

The resulting material is an ice-like sheet, and resembles sheets of glass. The ice is broken into small particles, typically using rotating knives or other devices.

The frozen particles are then placed in a vacuum chamber.

Within the vacuum chamber the material made of the small particles is heated and cooled under vacuum and the moisture sublimes.

The resulting material contains less than 5% moisture, and is removed from the vacuum chamber in the form of granules and packed.

US Patent Application No. 2012/027900 discloses a milling or grinding step for roasted coffee beans prior to preparing an extract. Milling of the coffee beans is carried out and is reported to achieve particle sizes below 10 microns, after which an extract is made and then freeze dried or processed in other ways to provide an instant coffee.

European Patent Application 2,676,549 to Starbucks Corporation, priority date July 9, 2008, discusses an instant coffee made from dried coffee extract to which coffee grounds are added. As stated, a dry coffee extract component and a pulverized coffee component are used together, wherein the pulverized coffee component remains in the final coffee, and wherein the pulverized coffee component is added to the dry coffee extract component before and after the dry coffee extract is dried. The idea is to make a coffee with the convenience of freeze dried and yet with the body and flavor of real coffee. The dry coffee extract may be between 70 and 90% of the mixture and the added pulverized coffee component, the roast coffee grounds may be between 10 and 30% of the mixture. The median particle size of the ground coffee component is around 350 microns.

There is no discussion in these documents as to what kinds of grinders are used, and a 350 micron particle size can leave a gritty impression in the mouth as well as fail to impart maximum flavor. Furthermore, with such a particle size, the maximum amount of ground coffee that can be added to the extract is limited to a maximum of 30%. SUMMARY OF THE INVENTION

If wet grinding is carried out then a single pass through a corundum mill provides a particle size of around 100 to 200 microns and the addition of a second corundum mill makes very little difference to the particle size, thus appearing to set up a wet grinding limit. Changing the parameters for the second corundum mill to achieve a finer grind has negligible effect on the smallest particles.

While not wanting to be bound by theory, it is surmised that the wet grinding provides an elasticity to the particles via hydration (the particles swell) which allows them to absorb grinding energy and avoid being ground beyond a certain size.

The present embodiments provide a wet grinding process that overcomes the above wet grinding limit.

The process may involve using two different kinds of grinder in succession. The second grinder may be a ball grinder. In addition a third grinder may be used and that grinder may also be a ball grinder, but with different sizes or settings for finer grinding.

In embodiments a first fraction of a concentrate made from the initial coffee grounds has ground particles added from a coarse grind and is fed to a colloid mill or corundum stone mill. The result is then fed to a ball mill for further grinding. In further embodiments some of the first fraction is passed through a second ball mill, so that the grinding process involves first a corundum mill, then a ball mill and then a second ball mill. The first fraction concentrate is recombined with the second fraction and conventional freeze drying is carried out. The first fraction may be between 10 and 100% of the total and the second fraction is the difference between the first fraction and 100%. Examples could be a first fraction of 45% and a second fraction of 55% or a first fraction of 100% and a second fraction of 0 %.

The result is a coffee preparation that consists of the solids formed by drying a coffee extract, forming a matrix around solid ground coffee particles that make up more than 30% of the first fraction or more than 35% of the first fraction and up to 50% of the first fraction and recombining this first fraction with the second fraction (unless the first fraction is 100%) to produce a total product with more than 5% w/w solids in the finished product and less than 35%w/w R&G particles in the finished product, and have a median size of nineteen microns or less. In embodiments, the preparation may have a certain percentage of the particles with median size of five microns or less.

According to an aspect of some embodiments of the present invention there is provided a solid coffee preparation comprising a freeze dried particle which incorporates ground coffee particles uniformly distributed throughout the particle's 3-D structure, wherein the ground coffee particles have a median size of not higher than fifteen microns and where the particles have been ground under liquid to prevent oxidation pre freeze drying.

In an embodiment, a fraction of the ground coffee particles have a median size of not higher than five microns.

In an embodiment, the fraction is 15 percent or less of the ground coffee particles.

In an embodiment, the fraction is 50 percent or less by weight of the ground coffee particles.

According to a second aspect of the present invention there is provided a freeze dried coffee preparation comprising a dry condensate and incorporated ground coffee particles, wherein the total ground coffee particles comprise between 5% and 25% of the freeze dry preparation by weight.

According to a third aspect of the present invention there is provided a method of making freeze dried coffee granules with added coffee grounds, comprising:

adding coarsely ground roast coffee into a liquid coffee concentrate;

wet grinding the coffee particles in the concentrate using a first grinding method;

further wet grinding the coffee concentrate and particles mixture using a second grinding method different from the first grinding method; and

freeze drying the concentrate to form the freeze dried granules.

In an embodiment, the first grinding method is colloidal / corundum grinding and the second grinding method is ball mill grinding.

The method may comprise dividing the concentrated extract into a first stream and a second stream, adding the ground roast coffee particles to a first of the streams, applying the first grinding method to the first stream, applying the second grinding method to an output of the first grinding of the first stream, and adding the first stream downstream of both the first and second grinding back to the second stream to form a combined stream for the freeze drying. The method may comprise taking a fraction of the first stream after applying the second grinding method, applying a third grinding method to the fraction, adding the fraction back to the first stream and adding the first stream with the fraction, back to the second stream to form a combined stream for the freeze drying.

In an embodiment, the third grinding method is a ball grinding method using a ball mill with relatively fine settings different from settings of the second grinding method.

In an embodiment, the settings of the second grinding method comprise a ball diameter of 6mm or less and the settings of the third grinding method comprise a ball diameter of 4mm or less, or of 3mm or less.

In an embodiment, the first stream comprises substantially a third of the coffee extract.

In an embodiment, the fraction is between 2 and 15% of the first stream.

In an embodiment, a fraction of the first stream or the second stream, the fraction comprising from 1 to 100% of the stream, is separated from the stream and particles of a further substance are added and subsequently ground by a grinder using at least one of the first and second grinding methods before being mixed with the first and the second streams prior to the freeze drying.

In an embodiment, the further substance comprises any one of: a food supplement, a food additive, a pharmaceutically active material, a flavor, a green non roasted coffee particle and a combination thereof.

According to a fourth aspect of the present invention there is provided an apparatus for making freeze-dried coffee, comprising:

a source of coarse ground coffee to add to a stream of liquid coffee;

a first grinder placed downstream of the source to grind the added coarse ground coffee in the stream for a first time;

a second grinder, downstream of the first grinder, the second grinder being a kind of mill different from the first kind, to grind the added coarse ground coffee for a second time;

a freezing and a drying unit, respectively for receiving the stream of liquid coffee and freezing and drying.

The apparatus may comprise a third grinder, the third grinder being a third kind of mill, the third grinder being connected to receive a fraction of the stream and configured to carry out fine grinding of ground coffee in the fraction.

In an embodiment, the first kind of mill is a colloid / corundum mill and the second kind of mill is a ball mill. In an embodiment, the settings of the second grinding method comprise a ball diameter of 6mm or less and the settings of the third grinding method comprise a ball diameter of 4mm or less, or of 3mm or less.

In an embodiment, the fraction is between 2 and 15% of the stream.

Embodiments may comprise a foamer located upstream of the freezing unit for foaming with C0₂, N2 or a combination of both, the foamer located to receive a first part of a liquid coffee extract stream directly and a second part of the liquid coffee extract stream via the grinders.

In an embodiment, the first grinder is a corundum stone mill.

Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.

In the drawings:

FIG. 1 is a simplified schematic diagram of a freeze-dried coffee granule according to the present embodiments;

FIG. 2 shows two pie charts of the composition of different constituents in the granule according to the present embodiments;

FIG. 3 is a simplified flow chart illustrating a method of production of freeze-dried coffee according to the present embodiments;

FIG. 4 is a simplified block diagram showing apparatus for producing freeze dried coffee according to the present embodiments; and

FIG. 5 is a simplified schematic diagram of a ball mill as may be used in the present embodiments. DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to a freeze dried coffee with coffee grounds and, more particularly, but not exclusively, to a way of making a freeze-dried coffee with a body that is as close as possible to that of real espresso extracted coffee.

The present embodiments may provide a freeze dried coffee preparation comprising a dry concentrate and ground coffee particles, wherein the ground coffee particles have a median size of not higher than nineteen microns. Embodiments may further include a preparation where the roast ground coffee particles make up between 3 and 30% of the freeze-dried coffee granule, or between 5 and 30% or between 10 and 20% or embodiments exceeding 30%. Embodiments further include a method and apparatus for making freeze dried coffee with added coffee grounds comprising preparing and concentrating a coffee extract, adding ground coffee particles and wet grinding the concentrate at two successive grinders, each being a different kind of grinder, say a corundum grinder and a ball grinder, then recombining the streams and freeze drying. Embodiments may use a third grinder and even third and fourth grinders, which may be ball grinders with finer settings, with each subsequent grinder producing ever finer particulates.

In general, different sized particles behave in different ways. Particles at 100 microns tend to sediment out from a cup of coffee, whereas particles below about 30 microns barely fall and are more subject to Brownian motion. They tend to stay in suspension and impart body to the drink.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.

Referring now to the drawings, FIG. 1 schematically shows two views of a solid granule from a freeze dried coffee preparation according to the present embodiments. Freeze dried coffee granules such as granule 10 are of generally irregular shape and are formed by obtaining a coffee concentrate, freezing the concentrate, breaking the frozen concentrate and then placing the resulting pieces in a vacuum chamber. In the vacuum chamber, as discussed in the background, the coffee is warmed and the frozen ice sublimes to leave behind coffee solids in the form of granules. The effect on the coffee flavor of the above processes has an adverse effect on the flavor content of the reconstituted coffee, reducing the levels of many of the aroma compounds that give coffee its flavor and aroma.

Looking at freeze dried solid granule 10 under the microscope, the solid is seen as a matrix 12 of coffee condensate with pieces of much smaller roast ground coffee particles 14 distributed within and protected by the matrix. The freeze dried coffee preparation of the present embodiments may be characterized in that the roast ground coffee particles have a median size of not higher than 19 microns and more likely a median size of <15 microns. The roast & ground particles contribute fresh roast flavors and aromas that may have been lost during the concentration processes and may impart to the coffee a body that is usually absent in instant coffee.

Reference is now made to FIG. 2 which illustrates 2 pie charts showing the distribution of solids in the freeze-dried coffee granules. The first pie chart, 20 shows the freeze dried coffee as a whole. The segment 22 indicates the proportion that is made up of ground roast coffee particles (up to around 30%). The segment 24 indicates the proportion made up of ultra small ground roast coffee particles (up to around 25%). The fraction of the ground coffee particles indicated by line 24 may have a median size of 15 to 20 microns, and in some cases, for example with multiple ball mills, may be as small as five microns, which is a size that is less felt as grit and more sensed as body.

The fraction of finely ground particles may be 15 percent or less of the ground roast coffee particles present overall.

The overall concentration of roast ground coffee particles (weight / weight), indicated by line 22 may be between 3% and 30% of ground coffee particles, or between 5 and 30% or between 10 and 20% or may even exceed 30%, and this is possible where the median size of the coffee particles is below 15 microns. In prior art systems where coffee particles are 300 or so microns, such a concentration of ground particles would lead to exceeding the back pressure on the grinder, eventually cause the process to come to a halt. In addition a high percentage of large particles would precipitate quickly, not provide benefits to the coffee taste or body and leave a very large deposit in the bottom of the cup.

Reference is now made to FIG. 3, which is a simplified flow chart illustrating how the process of making freeze-dried coffee is modified according to embodiments of the present invention. Box 30 indicates the initial stages, common to methods of making instant coffee, in which a coffee extract is made 32 by extracting from ground coffee with hot water. The extract is then concentrated 34. In box 36 the concentrate is divided into two streams. The division may be a third and two thirds or half and half.

Then, using just one of the streams, typically the smaller, ground coffee is added in box 38, and in box 40 the stream with the added ground coffee is milled in a first grinder to carry out wet grinding. The wet grinding may typically reduce the particle size of the added ground coffee to between 200 and 70 microns. A colloid mill is a typical kind of mill used for wet grinding, particularly for grinding particles in suspension in a liquid as the coffee grinds are here in suspension in the coffee concentrate. A Corundum mill is a specific version of a colloid mill where the grinding surfaces are made from corundum stone. While not wanting to be bound by theory, the inventors postulate that the broad scale use of Colloid mills in liquid based grinding is due to the relatively high throughput for a low cost and small physical size. Colloid / corundum mills may work on a rotor- stator principle where the rotor turns at relatively high speeds, say 2000 to 18000 rpm. While not wishing to be bound by theory as a result, high levels of hydraulic shear disrupt structures in the fluid.

While not wishing to be bound by theory, a particle size at or above 70 microns however feels gritty, and rather than imparting the full body feel to the coffee and also imparting flavor larger particles sediment out and lie on the bottom of the cup. However it was noted that carrying out a second grinding process using the same or a similar grinder had very little additional effect on the smaller particle size distribution. Even substantially changing the grinder settings and setup in order to grind more closely had little additional effect on the particle size, and while not wanting to be bound by theory the inventors surmise that this is due to the hydration of the particles in the presence of the liquid which has increased the elasticity of the particles.

Thus after use of a heat exchanger -box 42 - the stream is passed on to a different kind of grinder that uses a different grinding method. In the present embodiments, it was discovered that a ball grinder unexpectedly is not affected by this elasticity phenomenon. The inventors postulate that this unexpected discovery is due to the nature of the forces exerted repeatedly by the balls over the length of the path taken by the particles within the mill. Ball mills used in grinding foods in liquids tend to almost exclusively use non-aqueous oil based solvents so there is limited if any experience of water based hydratable particle grinding processes where the particles can hydrate and swell.

The ball grinder - box 44 - is used, where continued grinding, specifically continued wet grinding, obtains a median particle size of at or below fifteen microns. While not wishing to be bound by theory, a fifteen micron median size ensures that a large percentage of the particles are smaller than this size and these particles, especially those particles below 5 microns, provide for a fuller body and / or perception of body and impart more flavor.

Optionally, a third kind of grinding is used. A further grinding operation is added, shown by box 46, in which a second ball grinder, with finer settings, is fed with a fraction of the stream, and which grinds the particles down to a median size at or below five microns. While not wishing to be bound by theory, between five and fifteen microns and also below 5 micrometers size may provide particles that are not sensed at all as grit when consuming the product but still contribute to the body and or perception of the body of the coffee. The fraction that is fed to the second ball mill may be between 2 and 100% of the first concentrate stream output of the first ball mill.

The two streams are then recombined as shown in box 48, for example using static mixing. In box 50 the standard stages of freeze drying of the concentrate are carried out. Specifically the combined streams are poured into a tray or the like and frozen, following which the resulting coffee ice is smashed - box 52, typically using rotating knives as discussed in the background. The pieces are placed in a vacuum chamber and warmed until the ice sublimes - box 54, and the remaining solid is then packaged as freeze-dried coffee granules.

More particularly, using a corundum mill and a ball mill, desired particle size distributions may be achieved to obtain a suitable body and flavor for the coffee. However it is still desirable to produce a higher fraction of very small particles to further improve the body of the coffee.

Normal wisdom of one skilled in the art is to use a bigger capacity mill or recirculate the liquid. However, the inventors found that even leaving the second mill grinding for long periods on a recirculation loop failed to significantly change the smaller particle sizes further. Replacing the second grinder with a differently configured ball mill grinder to achieve smaller particles managed to reduce the sizes of the smaller particles but unexpectedly not the larger ones from the first corundum mill, and hence was not acceptable.

The present embodiments instead take the output of the second grinder and pass a fraction (2 - 100%) of the material through a second ball mill grinder with a finer bead / ball to produce a relatively high percentage of ultrafine particles that do not sediment over short periods of time, and instead provide body in terms of consumer perceived viscosity to the resulting cup of coffee while keeping the bulk of the particles, some 50 to 60% unchanged.

The stream with the added ground coffee is then mixed back into the overall liquid, say via static mixing.

Despite the unexpected finding that a ball mill can overcome the elasticity phenomenon, ball mills are not economically optimal for an end to end process. Colloid / corundum mills are smaller, consumer less energy and are significantly less expensive on a like for like throughput compared to ball mills. In some instances the size and energy requirements are an order of magnitude different. The present inventors have unexpectedly found that an optimal economical process can be achieved using a relatively small colloid / corundum grinder as the first grinder and a significantly larger ball mill as the second grinder to overcome the elasticity phenomenon. If subsequent sub fractions of ultra small particles are required to give the finished product different attributes then a 3^rd grinder should be a ball mill again to overcome the elasticity phenomenon. This second ball mill needs to use smaller beads / balls.

The two-machine of the present embodiments, where one grinder is a colloid / corundum grinder and one is a ball mill can be replicated with two in- series ball mills. However the result is a far more costly process both in terms of capital outlay and running costs to deliver the same output. The present embodiments unexpectedly discovered an optimal process using a combination of technologies.

Reference is now made to FIG. 4, which illustrates apparatus 60 for making freeze-dried coffee according to the present embodiments by enhancing the concentrate with roast ground coffee and wet grinding within the concentrate prior to freeze drying. The apparatus applies concentrate 62 and roast ground coffee 64 from a relatively coarse grind to a first grinder 66. The grinder may be a colloid grinder or a corundum stone mill or the like and is placed downstream of the source of the coffee concentrate so that the grinder receives the coffee concentrate with the added roast ground coffee solids to carry out wet grinding on the stream.

A second grinder 68, is located downstream of the first grinder. The second grinder may be a ball mill, and may provide a second grinding of the extract, namely the stream of concentrate with the added coarse ground coffee.

Optionally, a third grinder 70, being a second ball grinder with finer settings, is placed downstream of the second grinder 68. A fraction of the stream is passed to the third grinder. As mentioned above the fraction may be between 2 and 100%, and optionally between 2 and 15%.

The two or three streams of concentrate are then recombined. Carbon dioxide or nitrogen or a combination of both may be added to the result at foamer 72, and then the result is added to a freezing belt 74 or tray or the like where the combined foamed concentrate is frozen into ice. The ice is smashed into small pieces, say using rotating knives as discussed above, and then added to vacuum chamber 76, where it is warmed in vacuum to cause the water to sublime. The result is granules of freeze dried coffee 78.

Thus the third grinder 70, is a second ball mill, which is connected to receive a fraction of the stream and carries out fine grinding of ground coffee in the fraction. As discussed, the fraction is between 2 and 15% of the stream. The foamer 72 is located upstream of the freezing unit 74, the belt or tray or the like, for foaming with C0₂ or N2 or a combination of these.

The foamer 72 obtains a first part of a liquid coffee extract stream directly and the second part of the liquid coffee extract stream via the two or three grinders.

As mentioned, the colloidal mill providing the first grinder may be a corundum stone mill. In an embodiment, further substances are added. These may include a food supplement, a food additive, a pharmaceutically active material, a flavor, a green non roasted coffee particle or any combination of the same.

One way of doing this is to take off a fraction from one of the streams. The fraction can be anywhere between 1 and 100% of the stream. The fraction is separated from the stream and particles of the substance or substances are added and subsequently ground by a grinder using the colloid or ball grinding method or even both, before being mixed back into the streams prior to freeze drying.

Reference is now made to FIG. 5 which is a side view of a ball mill. The mill 90 comprises a cylindrical chamber 92 with a drive shaft 94 located typically along a central axis. The grinding medium is typically made up of steel balls 96 of a given size within a liquid. The ball size is a property of the specific grinder and is varied for the specific circumstances.

Propeller discs 98 are turned by the shaft to move the balls within the liquid. The substance to be ground comes in via inflow pipe 100 and exits after grinding via outflow 102, where a filter system ensures that only the ground substance and not the balls exist via the outlet pipe.

In general, a generic ball mill, is a type of grinder, is a cylindrical device used in grinding (or mixing) materials such as ores, chemicals, ceramic raw materials and paints, and typically use in the food industry is in grinding oil or fat based food stuffs such as cacao and chocolate. Ball mills have internal baffles which rotate around a horizontal axis, when the cylinder is partially filled with the material to be ground plus the grinding medium. Different materials are used as the grinding medium including ceramic balls, flint pebbles and stainless steel balls of different sizes and densities as known to someone skilled in the art.

An internal cascading effect reduces the material to a fine powder. Industrial ball mills can operate continuously, fed at one end and discharged at the other end. Large to medium-sized ball mills are mechanically rotated on their axis, but small ones normally consist of a cylindrical capped container that sits on two drive shafts. High-quality ball mills are potentially expensive and can grind mixture particles to as small as 5 nm, although the present embodiments only require 5μιη.

The grinding works on the principle of critical speed. Critical speed can be understood as that speed after which the steel balls, which are responsible for the grinding of particles, start rotating along the direction of the cylindrical device; thus they continue to rotate and do not fall down to the bottom of the vessel under gravity.

The ball mill is a key piece of equipment for grinding crushed materials, and may grind materials either wet or dry, although in the present embodiments the material is wet. There are two kinds of ball mill, grate type and overfall type due to different ways of discharging material. Many types of grinding media are suitable for use in a ball mill, each material having its own specific properties and advantages. Key properties of grinding media are size, density, hardness, and composition.

• Size: The smaller the media particles, the smaller the particle size of the final product. At the same time, the grinding media particles should be substantially larger than the largest pieces of material to be ground.

• Density: The media should be denser than the material being ground. It becomes a problem if the grinding media floats on top of the material to be ground.

• Hardness: The grinding media needs to be durable enough to grind the material, but where possible should not be so tough that it also wears down the tumbler at a fast pace.

• Composition: With respect to the food industry, it is desirable to ensure that as little as possible of the grinding media ends up in the finished product.

Ball mills are predominantly used for industrial chemical production, and ball mill usage in foods tends to be for non-aqueous food materials e.g. fat based milling of cacao beans.

Ball mill usage in foods tends to use medium sized balls, say from 3 to 5mm, whereas ball mill usage in pharmaceuticals and industrial chemicals can use balls from 200 micrometers up to 3mm.

As is noted above, multiple passes through a well setup ball mill does not dramatically change the particle size distribution of ground coffee and to make significant changes a secondary process with smaller sized balls is needed to significantly change the particle size distribution. In the present embodiments, the first pass ball mill has 4 -7 mm steel balls or 4 -7mm ceramic balls, and a second ball mill (3rd wet grinding) uses 2-4mm or smaller balls either made of steel or ceramic material.

Thus in embodiments, three forms of milling may be used on the coffee concentrate, colloid milling, ball milling and fine ball milling. These are considered herein as three different and distinct kinds of milling.

It is expected that during the life of a patent maturing from this application many relevant freeze drying and instant coffee preparation techniques will be developed or existing techniques improved, and the scopes of the corresponding terms are intended to include all such new technologies a priori.

As used herein the term "about" refers to ± 10 %

The terms "comprises", "comprising", "includes", "including", "having" and their conjugates mean "including but not limited to".

The term "consisting of means "including and limited to". The term "consisting essentially of" means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure.

As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 2 to 15% shall be considered to have specifically disclosed subranges such as from 2 to 3, from 2 to 4, from 2 to 5, from 3 to 4, from 3 to 5, from 3 to 6 etc., as well as individual numbers within that range, for example, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases "ranging/ranges between" a first indicate number and a second indicate number and "ranging/ranges from" a first indicate number "to" a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals there between.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.

Claims

WHAT IS CLAIMED IS:

1. A solid coffee preparation comprising a freeze dried particle which incorporates ground coffee particles uniformly distributed throughout the said particle's 3-D structure, wherein the ground coffee particles have a median size of not higher than fifteen microns and where the particles have been ground under liquid to prevent oxidation pre freeze drying.

2. The freeze dried coffee preparation of claim 1, wherein a fraction of said ground coffee particles have a median size of not higher than five microns.

3. The freeze dried coffee preparation of claim 2, wherein said fraction is 15 percent or less of said ground coffee particles.

4. The freeze dried coffee preparation of claim 2, wherein said fraction is 50 percent or less by weight of said ground coffee particles.

5. A freeze dried coffee preparation comprising a dry condensate and incorporated ground coffee particles, wherein the total ground coffee particles comprise between 5% and 25% of the freeze dry preparation by weight.

6. A method of making freeze dried coffee granules with added coffee grounds, comprising:

adding coarsely ground roast coffee into a liquid coffee concentrate;

wet grinding the said coffee particles in the concentrate using a first grinding method; further wet grinding the coffee concentrate and particles mixture using a second grinding method different from said first grinding method; and

freeze drying said concentrate to form said freeze dried granules.

7. The method of making freeze dried coffee granules of claim 6, wherein said first grinding method is colloidal grinding and said second grinding method is ball mill grinding.

8. The method of making freeze dried coffee granules of claim 6 or claim 7, comprising:

dividing said concentrated extract into a first stream and a second stream; adding said ground roast coffee particles to a first of said streams;

applying said first grinding method to said first stream;

applying said second grinding method to an output of the first grinding of the first stream; and

adding said first stream downstream of both the first and second grinding back to said second stream to form a combined stream for said freeze drying.

9. The method of claim 8, further comprising:

taking a fraction of said first stream after applying said second grinding method;

applying a third grinding method to said fraction;

adding said fraction back to said first stream and

adding said first stream with said fraction, back to said second stream to form a combined stream for said freeze drying.

10. The method of claim 9, wherein said third grinding method is a ball grinding method using a ball mill with relatively fine settings different from settings of said second grinding method.

11. The method of claim 10, wherein said settings of said second grinding method comprise a ball diameter of 6mm or less and said settings of said third grinding method comprise a ball diameter of 4mm or less, or of 3mm or less.

12. The method of any one of claims 7 to 9, wherein said first stream comprises substantially a third of said coffee extract.

13. The method of claim 9, wherein said fraction is between 2 and 15% of said first stream.

14. The method of any one of claims 6 to 8, wherein a fraction of said first stream or said second stream, the fraction comprising from 1 to 100% of said respective stream, is separated from said respective stream and particles of a further substance are added and subsequently ground by a grinder using at least one of said first and second grinding methods before being mixed with said first and said second streams prior to said freeze drying.

15. The method according to claim 14 where said further substance comprises one member of the group consisting of: a food supplement, a food additive, a pharmaceutically active material, a flavor, a green non roasted coffee particle and a combination thereof.

16. Apparatus for making freeze-dried coffee, comprising:

a source of coarse ground coffee to add to a stream of liquid coffee;

a first grinder placed downstream of said source to grind said added coarse ground coffee in said stream for a first time;

a second grinder, downstream of said first grinder, said second grinder being a kind of mill different from said first kind, to grind said added coarse ground coffee for a second time;

a freezing and a drying unit, respectively for receiving said stream of liquid coffee and freezing and drying.

17. The apparatus of claim 16, further comprising a third grinder, said third grinder being a third kind of mill, said third grinder being connected to receive a fraction of said stream and configured to carry out fine grinding of ground coffee in said fraction.

18. The apparatus of claim 16 or claim 17, wherein said first kind of mill is a colloid mill and said second kind of mill is a ball mill.

19. The apparatus of claim 18, wherein said third kind of mill is a ball mill having relatively fine settings being different from said second mill.

20. The apparatus of claim 19, wherein said settings of said second grinding method comprise a ball diameter of 6mm or less and said settings of said third grinding method comprise a ball diameter of 4mm or less, or of 3mm or less.

21. The apparatus of claim 17, wherein said fraction is between 2 and 15% of said stream.

22. The apparatus of any one of claims 16 to 21, further comprising a foamer located upstream of said freezing unit for foaming with C0₂, N2 or a combination of both, the foamer located to receive a first part of a liquid coffee extract stream directly and a second part of said liquid coffee extract stream via said grinders.

23. The apparatus of any one of claims 16 to 22, wherein said first grinder is a corundum stone mill.

24. The apparatus of any one of claims 18 to 20, wherein said respective ball mills comprise balls made from any one of steel, stainless steel and ceramic material.