IE20000694A1 - A Coffee manufacturing process - Google Patents

Abstract

Selected amounts of green coffee beans of a single variety are weighed (15) and delivered to a pre-heated roaster (16). Within the roaster (16), the green coffee beans are slowly roasted in a controlled manner over a period of about twenty-three minutes to produce a batch of roasted coffee beans. Said batch of roasted coffee beans is discharged to a cooler where they are gradually cooled over a period of at least four minutes. After cooling, the roasted coffee beans are immediately packaged. Prior to packaging, the roasted coffee beans may be blended with other varieties of bean. Also, the beans may be ground if desired. <Figure 1>

Description

“A Coffee Manufacturing Process This invention relates to an improved manufacturing process for producing a roasted coffee product Discussion of Prior Art ϊ 1 '5 X ϊ 1 Most commercial roast coffee production involves the blending of roasted coffee beans selected varieties of two commercially cultivated species - namely coffee Arabics and coffee Canephora which is commonly known as Robusta. The highest quality coffee beans are those of the coffee Arabica species and when roasted, these beans ;i typically provide a coffee with smooth flavours which is well balanced and with a perfumed aroma. Robusta beans are of lower quality and tend to provide roast coffee [ with a grassy, astringent taste, with little aroma, a hard after taste and more than twice the caffeine compared to Arabica. Robusta is, however, much cheaper than Arabica to produce and most coffee manufacturers blend Robusta and Arabica beans to produce their coffee.

While it is known in coffee manufacture to roast different varieties of coffee beans separately prior to blending the roasted beans, as described in US 3700462 and US 3725076 for example, commercial production more usually involves the blending of selected quantities of two or more varieties of green coffee beans to form a batch of mixed green coffee beans which is subsequently roasted, typically under intense heat for about four to twelve minutes. An example of such a commercial coffee production process is described in GB 2 282 046. It will be appreciated that different varieties of coffee beans will have different optimal roasting temperatures and conditions. In fact even different crops of the same coffee bean variety will have different densities and moisture content which require different roasting temperatures to bring out the best flavour from the bean variety. Therefore, because a mixture of a number of different green coffee beans is being roasted, at least some of the beans are roasted under less than ideal conditions with a consequent loss in quality. Such a bulk, roasting technique in which alt of the blended green coffee beans are roasted together is IE000694 -2 convenient from a manufacturing point of view having a relatively short roasting time. However, the unique flavour characteristics of each bean variety in the blend cannot survive such a roasting process. This tends to result in a coffee either with a uniform flavour or with one characteristic dominating the blend of flavours. Such a compromise on flavour and quality has heretofore generally been deemed acceptable in view of the processing advantages of this roasting technique for commerdai roast coffee production. Whichever method of blending and roasting is used, the roasting usually involves roasting the green coffee beans at relatively high temperature for a short time period of about four to twelve minutes. While this rapid roasting is attractive from a production point of view, the higher the roasting temperature, the more rapid the loss of volatile oils from the coffee beans which provide the desirable coffee flavours.

Further, after roasting, from a production point of view, it is desirable to provide forced cooling of the roasted coffee beans prior to halt the roasting process. In many cases, this is done by means of a cooling water spray discharged over the hot roasted coffee beans with or without additional air cooling. This provides a relatively rapid cooling of the roasted coffee beans, typically in the order of two to three minutes. Obviously, minimising cooling time is desirable from a production point of view, however, the rapid forced cooling leads to a loss in quality. This water quenching of the hot roasted coffee beans results in a dramatic temperature change, opening the pores of the beans and accelerating loss of flavour. The addition of the water which is absorbed by the beans, which can increase the weight by up to 9% further dilutes the flavour. It also means the whole or ground beans cannot be subsequently packed until they have hardened which may mean that the roasted beans have to be stored for 24 hours prior to packaging. However, coffee will be at its freshest if packaged within 12 to 24 hours of roasting. So this packaging delay leads to a loss in quality.

The above-mentioned limitations have been generally considered acceptable in the interest of convenience and costs in respect of commercial coffee production processes.

It is an object of the present invention to provide an improved production process for the commercial production of high quality coffee products. -3IE000694 Summarv ofthe Invention According to the invention, there is provided a manufacturing process for a roasted coffee product which includes the steps: weighing a pre-selected amount of green beans of a single coffee bean variety; pre-heating a coffee bean roaster to a desired temperature; delivering the green coffee beans to the pre-heated roaster slowly roasting the green coffee beans in a controlled manner within the roaster for a period of between twenty minutes and twenty-four minutes at a pre-selected roasting temperature associated with said green coffee variety to produce a batch of roasted coffee beans; discharging the hot roasted coffee beans to a cooler, gradually cooling the hot roasted coffee beans in the cooler preparing in like manner a selected amount or amounts of roasted coffee beans of at least one other coffee bean variety, individually roasting a batch of each of said other coffee bean varieties; mixing desired quantities of two or more of said individually roasted coffee bean varieties to form a batch of blended roasted coffee beans; optionally grinding said batch of blended roasted coffee beans to form ground roast coffee; and packaging said batch of blended roasted coffee beans, or ground roast coffee.

Advantageously according to the invention each different variety of coffee bean used in a blend is individually roasted and can thus be roasted at an optimum temperature -4IE000694 to bring out the fullest flavour in the coffee beans. Only high quality Coffee Arabica beans are used in the process.

Preferably, a slow roasting of the green coffee beans is carried out Typically, the slow roasting is carried out over a period of about twenty to twenty-four minutes, and most preferably about twenty-three minutes. The temperature at which the green beans are roasted will depend on the particular bean being roasted, the optimum roasting temperature for that coffee bean being selected. This slow roasting differs from the more usual commercial roasting which typically takes in the order of eight minutes, and the slow roasting of the invention has been found to enhance the flavour and organoleptic properties generally ofthe roasted coffee beans.

In a particularly preferred embodiment, the process includes roasting the beans in a number of stages at decreasing temperatures in each successive stage. Preferably the process includes roasting the beans in a first stage for a period of about thirteen minutes at a temperature of between 200°C and 240°C, roasting the beans in a second stage for a period of about seven minutes at a temperature of about 150°C, roasting the beans in a third stage for a period of about two minutes at a temperature of about 100°C, and roasting the beans in a fourth stage for a period of about one minute in their own heat without the addition of any further heat In another embodiment the process includes the step of gradually cooling the hot roasted coffee beans in the cooler over a period of at least four minutes, and preferably over a period of between four and a half and six minutes. Conveniently, the cooling can be carried out by directing an ambient air stream over the roasted coffee beans.

In a particularly preferred embodiment, the cooling of the roasted coffee beans is carried out by discharging the roasted coffee beans from the roaster onto a cooling tray having a perforated base and drawing cooling air down through the base over the roasted coffee beans whilst moving the roasted coffee beans about the base by means of a paddle which travels over the base above the base. The paddle turns or rolls the roasted coffee beans over on the tray to ensure an even and thorough cooling of the roasted coffee beans. Preferably, a number of paddles are radially mounted IE000694 -5above the base on an associated centrally mounted rotatable drive shaft which is drivably connected to a prime mover such as an electric motor.

Downstream of the cooler, the roasted coffee beans are preferably delivered through a de-stoner for removing stones and other foreign matter which might be entrained in the batch of roasted coffee beans.

In another embodiment, the process inciudes:delivering selected amounts of two or more roasted coffee bean varieties to a rotatable blending drum, slowly rotating the blending drum for mixing the beans together, the blending drum having internal paddles which project inwardly from an inside face of a side wall of the drum at a shallow angle, each paddle having an outer free end which is spaced-apart from the inside face of the drum side wall, each paddle extending away from the drum wall in a direction opposite to the direction of rotation of the drum, the drum being slowly rotated for delivering the beans outwardly along each paddle in turn away from the drum wall as the drum rotates and gently cascading the beans back onto the drum wall from a free end of the paddle.

In another embodiment, the process includes blending the roasted coffee beans within the rotating drum for a period of between seven and nine minutes.

If desired, the roasted coffee beans can be ground before packaging.

In a preferred embodiment the process includes the step of packing the blended roasted coffee beans, or ground coffee in a sealed pack having a one-way vent valve IE000694 -6for exhausting gas released naturally from the coffee from an interior of the pack.

In another aspect, the invention provides apparatus for the manufacture of roasted coffee products as will be hereinafter described.

Preferably, such apparatus indudes a coffee bean blender comprising:a rotatable drum having associated drive means for slow rotation of the drum, the drum having a cylindrical side wall with internal paddles mounted on an inside face of the side wall, each paddle projecting inwardly from the inside face at a shallow angle having a free end which is spaced-apart from the inside face of the drum side wall, said paddle being swept away from the inside face of the drum in a direction opposite to the normal direction of rotation of the drum.

In a preferred embodiment, two paddles are provided on opposite sides of the drum side wall. Preferably, each paddle is bent into a wave configuration.

In another embodiment, the drum has a central drive shaft mounted at one end of the drum, the drive shaft being supported on a journal bearing, the drive shaft connected through a drive reduction gear box with a drive motor, an opposite end of the drum having a central charging opening with a cylindrical collar mounted about the opening and projecting outwardly therefrom, said collar being supported upon a pair of spacedapart roller bearings.

In another embodiment, the drum has associated charging means comprising a charging duct communicating between a supply hopper and the drum, said duct having an inlet end connected to a supply hopper and an outlet end which projects into the collar on the drum. Conveniently, a feed flap is mounted on the duct adjacent the collar at a discharge chute at a bottom of the duct, the feed flap being movable between a drum charging position closing the discharge chute and a drum discharging position opening the discharge chute for discharge of blended coffee beans from the -7IE000694 drum through the discharge chute.

Brief Description of the Drawings The invention will be more clearly understood by the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawing, in which: Fig. 1 is a schematic illustration of a coffee manufacturing process according to the invention; Fig. 2 is a perspective view of apparatus for manufacturing coffee products according to the invention; Fig. 3 is an enlarged detail perspective view of roasting and cooling portions of the apparatus; Fig. 4 is an enlarged perspective view of a packaging portion of the apparatus; Fig. 5 is a schematic illustration of a blender used in the process; and Fig. 6 is a schematic sectional view of the blender.

Detailed Description of Preferred Embodiments Referring to the drawings, green coffee beans of a selected single variety are delivered into an inlet hopper 10 which has a screen 11 to trap any large pieces of foreign matter, the green coffee beans passing through the screen 11 for collection at a bottom of the hopper 10. A discharge pipe 12 has an inlet 13 at a bottom of the hopper 10 and an outlet 14 which discharges into a weigher 15. A vacuum transfer system is provided for feeding the green coffee beans from the hopper 10 through the pipe 12 to the weigher 15. The vacuum transfer system has a suction pump 40 on the weigher 15 which discharges via duct 41 to a cyclone 42 which separates particulate matter from tine air prior to venting clean air through a vent pipe 43. -8IE000694 A batch of green coffee beans of a desired quantity is collected in the weigher 15 and subsequently discharged into a preheated roaster 16 which is at a charging temperature of about 205°C. Within the roaster 16, the green coffee beans are subjected to an optimum roasting temperature associated with said green coffee bean variety for a preset period of time, at least twenty minutes and preferably about twentythree minutes, to provide a slow roasting of the green coffee beans at a comparatively low heat.

When the green coffee beans are initially delivered into the preheated roaster 16, the temperature within the roaster will drop to about 150°C. The temperature within the roaster is then brought back up to an initial roasting temperature in a first roasting stage which lasts for about thirteen minutes, the roasting temperature being kept between about 200°C and 240eC, depending upon the type of roast required and the bean variety being roasted. Generally speaking, for a light roast, the roasting temperature is about 206°C, for a medium roast, the roasting temperature is about 214°C and for a heavy roast, the roasting temperature is about 225°C. In a second roasting stage which lasts approximately seven minutes, the roasting temperature is dropped to about 150°C. Then in a third roasting stage, which lasts approximately two minutes, the roasting temperature is dropped to about 100°C. Finally, in a fourth roasting stage, lasting about one minute, the heat is turned off and the beans are allowed to continue roasting in their own heat Within the roaster 16, during the roasting process, the green coffee beans will swell and the water inside the green coffee beans begins to steam. The beans audibly crack as woody structures are broken down. After most of the water has left the beans, the bean cells are turned into starches and finally sugars. These sugars then caramelise, adding to the brown colour of the bean and aromatic oils present in the beans volatise to the surface. The expansion of the oils causes a second crack and tine roasting process proceeds much more quickly at this stage. Many of the aromatics present will either vaporise entirely or develop other chemical parts, one giving an oily appearance to the beans.

After roasting, hot roasted coffee beans are discharged from the roaster 16 to a cooler IE000694 -918. The cooler 18 has a perforated tray 19 mounted within a casing 20 having a base 21 and an upstanding peripheral side wall 22. The tray 19 is mounted spaced below an upper rim of the side wall 22 to retain the roasted coffee beans on the tray 19. Rotatable paddles 25 are radially mounted on a central drive shaft 26 which projects up through the tray 19, and may be driven by any suitable drive means such as an electric motor (not shown), to sweep the paddles 25 over the surface of the tray 19 to turn the hot roasted coffee beans for cooling on the tray 19. An extraction fan 28 sucks ambient air down through the perforated tray 19 for cooling the hot roasted coffee beans. The cooling of the hot roasted coffee beans takes about four and a half to six minutes, slowly cooling the hot roasted coffee beans in a controlled manner. Hot air extracted by the fan 28 is delivered through a duct 45 to a cyclone separator 46 with clean air from the cyclone 46 being discharged through a vent 47.

The cooled roasted coffee beans are conveyed from the tray 19 through a vacuum transfer duct 30 to a de-stoner 32 within which any entrained stones or other foreign matter is removed from the roasted coffee beans.

Downstream of the de-stoner 32, the roasted coffee beans may be delivered direct to a packaging station 35 for immediate packaging or alternatively delivered through a grinder 36 prior to packaging 35. More usually, however, the roasted coffee beans will be delivered to a blender 37 within which two or more varieties of roasted coffee beans are blended prior to packaging 35. The blend created in the mixer 37 may be delivered through the grinder 36 prior to packaging 35 in an alternative arrangement.

Referring to Figs. 5 and 6, the blender 37 is shown in more detail. The blender 37 has a cylindrical drum 50 having a side wall 51 with an inner end wall 52 and an outer end wall 53. A central drive shaft 54 projects outwardly of the end wall 52 and is supported on a journal bearing 55. This drive shaft 54 is connected through a drive reduction gear box 56 with a drive motor 57 which is operable to slowly rotate the drum 50. At an opposite end of the drum 50, a central charging opening 60 is provided in the outer end wall 53. A cylindrical collar 61 is mounted about the opening 60 and projects outwardly therefrom. The collar 61 is supported upon a pair of spaced-apart roller bearings 62. Within the drum 50, two paddles 65 are provided on opposite sides of the drum side wall 51. Each paddle 65 projects inwardly from an inside face of the IE000694 -10side wail 51 at a shallow angle having a free end 66 which is spaced-apart from the inside face of the drum side wall 51. It will be noted that each paddle 65 is swept away from the inside face of the drum 50 in a direction opposite to the normal direction of rotation X of the drum 50. It will be noted also that each paddle is bent into a wave configuration.

A charging hopper 70 is mounted above the drum 50 and receives roasted coffee beans through a vacuum delivery line 71 which lifts roasted coffee beans from a collecting tray 72 beneath a discharge outlet 73 of the de-stoner 32. A slide valve 75 is mounted at an outlet of the hopper 70. Extending downwardly from the hopper 70 is a charging duct Ti communicating between the supply hopper 70 and the drum 50. An outlet end 78 of the duct 77 projects inwardly through the collar 61 on the drum 50 for delivery of beans from the hopper 70 into the drum 50. A feed control flap 80 is mounted on the duct 77 adjacent the collar 61 at a discharge chute 82 which is provided at a bottom of the duct 77. This feed flap 80 is pivoted at 84 being movable between a drum charging position, as shown, closing the discharge chute 82 and a drum 50 discharging position, as shown in broken outline, opening the discharge chute 82 for discharge of blended beans from the drum 50 through the discharge chute 82.

In use, selected quantities of different varieties of roasted beans are delivered into the drum 50 which is then slowly rotated by the motor 57 for a period of between seven and nine minutes to blend the coffee beans within the drum 50. It will be noted that as the drum rotates, the beans will move downwardly along each paddle 65 in turn moving away from the drum side wall 51 and upon reaching the end of the paddle 65, the beans gently cascade back onto the drum side wall 51 from the free end 66 of the paddle 65. Thus conveniently, the beans are gently turned and mixed within the drum 50 without damaging the beans. A very good mixing of the beans is achieved which is particularly advantageous. After mixing, the flap 80 is moved to the discharge position and the beans are discharged through the chute 82 into a container for delivery to the packing station 35.

Examples of different blends of coffee beans are given on the blend table below.

IE000694 -11 BLEND TABLE Blend No.

Costa Rican Tarazu Columbian Supremo Ethiopian Sidamo Brazilian Santos Sumatra Lingtong 1 20% 40% 40% 2 50% 50% 3 20% 40% 40% 4 50% 50% 5 70% 30% 6 30% 70% 7 25% 10% 40% 25% 8 10% 30% 25% 25% 10% It will be noted that instead of providing the mixer 37, mixing of two or more varieties of roasted coffee beans could be earned out in the cooler 18, using the paddles 25 to mix the different roasted coffee beans together on the tray 19, however, this is not as effective as the blender 37.

At the packaging station 35, whole roasted coffee beans, or ground coffee as the case may be, are delivered into a packaging machine which forms and fills a predetermined sachet size with a measured quantity of the coffee product The sachet incorporates a one-way gas vent valve in a sidewall of the sachet This allows gases released naturally from the coffee to vent from the sachet whilst preventing air from entering the sachet Thus, coffee can be packaged shortly after roasting for optimum freshness.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail within the scope of the appended claims.

Claims (11)

1. A manufacturing process for a roasted coffee product which includes the steps: weighing a pre-selected amount of green beans of a single coffee bean variety; pre-heating a coffee bean roaster to a desired temperature; delivering tine green coffee beans to the pre-heated roaster; slowly roasting the green coffee beans in a controlled manner within the roaster for a period of between twenty minutes and twenty-four minutes at a pre-selected roasting temperature associated with said green coffee variety to produce a batch of roasted coffee beans; discharging the hot roasted coffee beans to a cooler; gradually cooling the hot roasted coffee beans in the cooler; preparing in like manner a selected amount or amounts of roasted coffee beans of at least one other coffee bean variety, individually roasting a batch of each of said other coffee bean varieties; mixing desired quantities of two or more of said individually roasted coffee bean varieties to form a batch of blended roasted coffee beans; optionally grinding said batch of blended roasted coffee beans to form ground roast coffee; and packaging said batch of blended roasted coffee beans, or ground roast coffee.

2. A process as claimed in claim 1 wherein the process includes the step of slowly IE000694 -13roasting each batch of green coffee beans in the roaster over a period of about twenty-three minutes.

3. A process as claimed in claim 1 or 2, including roasting the beans in a number of 5 stages at decreasing temperatures in each successive stage.

4. A process as claimed in claim 3, including:roasting the beans in a first stage for a period of about thirteen minutes at a 10 temperature of between 200°C and 240°C, roasting the beans in a second stage for a period of about seven minutes at a temperature of about 150°C, 15 roasting the beans in a third stage for a period of about two minutes at a temperature of about 100°C, and roasting the beans in a fourth stage for a period of about one minute in their own heat without the addition of any further heat

5. A process as claimed in any preceding claim, including the steps:delivering selected amounts of two or more roasted coffee beans to a rotatable blending drum, slowly rotating the blending drum for mixing the beans together, the blending drum having internal paddles which project inwardly from an inside face of a side wall of the drum at a shallow angle, each paddle having 30 an outer free end which is spaced-apart from the inside face of the drum side wall, each paddle extending away from the drum wall in a direction opposite to the direction of rotation of the drum, the drum being rotated for delivering the beans outwardly along each paddle IE000694 -14in turn away from the drum wall as the drum rotates and gently cascading the beans back onto the drum wall from a free end of the paddle.

6. A process as claimed in claim 5 which includes blending the beans within the 5 rotating drum for a period of between seven and nine minutes.

7. A process as claimed in any preceding claim including the step of gradually cooling the hot roasted coffee beans in the cooler over a period of at least four minutes by directing an ambient air stream over the roasted coffee beans.

8. A process as claimed in claim 7 wherein the cooler has a perforated tray for reception of the hot roasted coffee beans, and a cooling air stream of ambient air is drawn down through the tray over the roasted coffee beans, whilst turning the coffee beans over on the tray by means of a paddle which travels over the tray.

9. A process as claimed in any preceding claim including the step of immediately packing the blended roasted coffee beans or ground coffee in a sealed pack having a one-way vent valve for exhausting gas from an interior of the pack. 20

10. A process for manufacturing a roasted coffee product substantially as hereinbefore described with reference to the accompanying drawings.

11. A roasted coffee product whenever produced by the process as claimed in any preceding claim.