GB2282046A

GB2282046A - A coffee production process

Info

Publication number: GB2282046A
Application number: GB9319673A
Authority: GB
Inventors: Patrick Bewley; Patrick Campbell; Thomas Brennan
Original assignee: VALMAS MANUFACTURING Ltd
Current assignee: VALMAS MANUFACTURING Ltd
Priority date: 1993-09-23
Filing date: 1993-09-23
Publication date: 1995-03-29
Anticipated expiration: 2013-09-23
Also published as: GB2282046B; BE1005666A6; GB9319673D0

Abstract

Between two and five types of green coffee beans are discharged from respective hoppers 12 into a cumulative weigher 14 to produce a mixed batch. The batch is blown along a supply pipe 16 to a rotating drum gas-fired roaster 20. After roasting, the beans are cooled on a perforated support plate 25 and then delivered to a weigher 30. After testing for colour and taste, the sorted beans are ground 50, de-gassed 60 and then packed. <IMAGE>

Description

"A coffee production process" The invention relates to a coffee production process.

According to the invention, there is provided a coffee production process comprising the steps: (a) sampling supply batches of green coffee beans and delivering acceptable batches of green coffee beans to associated storage hoppers, (b) selectively discharging pre-desired quantities of between two and five different types of green coffee beans from the hoppers into a cumulative weigher, weighing each quantity of green coffee beans delivered to the weigher in turn to produce a pre-desired batch of mixed green coffee beans, (c) blowing the batch of mixed green coffee beans along a supply pipe from the weigher to a rotating drum gas-fired roaster, (d) roasting the batch of mixed green coffee beans for a pre-desired time at a preset temperature, (e) discharging hot roasted coffee beans into a cooler, circulating the hot roasted coffee beans on a substantially horizontal perforated support plate in the cooler by means of rotating paddles, blowing air upwardly through the plate to cool the hot roasted coffee beans for a preset period, (f) delivering the cooled roasted coffee beans to a weigher to weigh the batch of roasted coffee beans, (g) delivering the batch of roasted coffee beans from the weigher to an associated storage hopper, (h) testing the batch of roasted coffee beans for colour and taste and, if acceptable, delivering the batch of roasted coffee beans to a roller grinder, passing the beans through a magnetic metal detector at an inlet of the grinder for removal.of any entrained metal pieces, (i) grinding the coffee beans and delivering ground coffee by auger conveyors to a de-gassing bin, holding the ground coffee in the de-gassing bin for a preset period to allow expiration of carbon dioxide gas from the coffee and (j) delivering the ground coffee from the de-gassing bin to a packing machine by means of auger conveyors and packing the coffee into sealed packages of a pre desired size.

In one embodiment of the invention the process includes the step of conveying whole coffee beans upstream of the grinder along a number of coffee bean transfer pipe sections, each transfer pipe section having a pipe inlet and a pipe outlet, generating a pressurised air supply, passing a stream of pressurised air delivered from the pressurised air supply to an inlet of each pipe section, delivering the pressurised air supply through the pipe section in a controlled manner between the inlet and outlet of the pipe section, delivering the coffee beans to the inlet and carrying the coffee beans in the air stream between the pipe inlet and the pipe outlet.

In a preferred embodiment the process includes the step of evacuating air in a controlled manner from each package during packaging of the ground coffee.

Conveniently the air may be evacuated by applying a vacuum to each package to extract air from the package prior to sealing the package.

Alternatively, the air may be evacuated from each package by delivering nitrogen gas to the package and flushing out air from the package with excess nitrogen gas prior to delivering ground coffee into the package and sealing the package.

In a particularly preferred embodiment the green coffee beans are roasted by: preheating the roaster to a charging temperature in the range 230-240"C, preferably 235"C; opening an inlet to the roaster and delivering a batch of green coffee beans into the roaster; continuously turning the beans within the roaster; maintaining the temperature within the roaster in the range 140"C-250"C during roasting of the green coffee beans; roasting the coffee beans for a period of 8 minutes; and then opening an outlet of the roaster and discharging the roasted coffee beans for delivery to the cooler.

In a further embodiment the process includes the step of spraying water onto hot roasted coffee beans downstream of the roaster outlet prior to delivering the roasted coffee beans to the cooler.

Preferably the roasted coffee beans are cooled in the cooler by blowing ambient air over the coffee beans for a period of three minutes.

In another aspect the invention provides apparatus for carrying out the process as will hereinafter be described.

The invention will be more clearly understood from the following description of an embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which; Fig. 1 is a schematic illustration of a coffee production process according to the invention; Fig. 2 is a perspective view of storage hoppers and weighing apparatus used in the process; Fig. 3 is a detailed perspective view of portion of the weighing apparatus; Fig. 4 is a perspective view of a roaster and a cooler forming portion of the apparatus for carrying out the process; Fig. 5 is an elevational view showing the cooler and a weigher of the apparatus for carrying out the process; Fig. 6 is a perspective view of a diverter valve forming portion of the apparatus for carrying out the process; Fig. 7 is a plan view of the diverter valve of Fig. 6;; Fig. 8 is a perspective view showing a grinder and degassing bins forming portion of the apparatus for carrying out the process; and Fig. 9 is a perspective view showing packing machines forming portion of the apparatus for carrying out the process.

Referring to the drawings, the coffee production process according to the invention will be described. Supply batches 10 of green coffee beans are sampled and tested and, if acceptable, the supply batch 10 is delivered to one of a number of storage hoppers 12. Outlets of the storage hoppers 12 discharge to a weigher 14. Depending on which blend of coffee is desired, preselected quantities of between two and five different types of green coffee bean are discharged from the hoppers 12 into the weigher 14. Each quantity of green coffee beans is delivered to the weigher 14 in turn to produce a predesired batch of mixed green coffee beans.

The batch of mixed green coffee beans is blown from the weigher 14 along a supply pipe 16 to a rotating drum gasfired roaster 20. The roaster 20 is preheated to a charging temperature of 235"C. Within the roaster 20, the batch of mixed green coffee beans is roasted for a predesired time, typically eight minutes, at a preset temperature in the range 140"C-250"C.

Roasted coffee beans are discharged from the roaster 20 into a cooler 25. Within the cooler 25, the hot roasted coffee beans are circulated on a substantially horizontal perforated support plate 26 by means of rotating paddles (not shown), ambient air being blown upwardly through the plate 26 to cool the hot roasted coffee beans for a preset period, typically three minutes.

Then the cooled roasted coffee beans are delivered to a weigher 30 to weigh the batch of roasted coffee beans.

The roasted coffee beans are delivered from the weigher 30 via a diverter valve assembly 35 to a storage hopper 40, a number of different hoppers 40 being provided for different coffee blends.

The roasted coffee is then tested for colour and taste and, if acceptable, the batch is delivered through a roller grinder 50. A magnetic metal detector is provided at an inlet of the grinder 50 to detect and remove any loose metal pieces which may be entrained with the coffee beans.

The coffee beans are ground in the grinder 50 and then ground coffee is delivered by auger conveyors 55 to a degassing bin 60, a number of which are provided for holding different batches of ground coffee. The ground coffee is held in the de-gassing bin 60 for a preset period, typically about three hours, to allow expiration of carbon dioxide gas from the ground coffee.

From the de-gassing bin 60, the ground coffee is delivered by means of auger conveyors 65 to packing machines 70 for packing the coffee into sealed packages of a pre-desired size. During packaging of the ground coffee air is evacuated from each package prior to sealing the package.

This air evacuation may be carried out by applying a vacuum to each package to extract the air prior to sealing the package. Alternatively, the air may be evacuated from each package by delivering nitrogen gas to the package and flushing out air from the package prior to filling the package with ground coffee and subsequently sealing the package.

Downstream of the packaging machines the packages are then boxed for delivery to customers.

It will be noted that upstream of the grinder 50 whole coffee beans are conveyed between apparatus at different processing stations by means of a number of coffee bean transfer pipe sections 80 which are generally similar to the supply pipe 16, each pipe 16, 80 having a pipe inlet and a pipe outlet. Means is provided for generating a pressurised air supply. Said means is connected to each pipe 16, 80 for delivery of pressurised air to an inlet of the pipe 16, 80 for passing a stream of pressurised air through the pipe 16, 80 between the inlet and outlet of the pipe 16, 80. Coffee beans delivered to an inlet of each pipe 16, 80 are carried in the air stream between the pipe inlet and the pipe outlet for delivery between pieces of apparatus linked by each pipe 16, 80.

Referring now to Fig. 2, the storage hoppers 12 include a number of main storage hoppers 85 arranged in a hexagonal configuration, each storage hopper 85 being of generally triangular cross section. Each storage hopper 85 has a lower discharge section 86 which tapers inwardly having a lower end 87 closed by a pneumatically operated valve (not shown). It will be noted that the lower ends 87 of the storage hoppers 85 are all positioned directly above a weighing pan 88 of the weigher 14. The weighing pan 88 is supported on a number of spaced-apart load cells 89 for accurate weighing of the green coffee beans. An outlet of the weighing pan 88 can be operated to discharge beans from the weighing pan 88 into a transfer bin 90 located directly below the weighing pan 88.

From the transfer bin 90 the green coffee beans are carried in an air stream through the supply pipe 16 for delivery to a feed hopper 92 for the roaster 20. When the roasting chamber within the roaster 20 has been brought to a desired charging temperature - preferably 235"C, a valve at an outlet of the hopper 92 is opened for delivery of green coffee beans into the roasting chamber. Within the roaster 20 the beans are continuously turned to ensure an even roasting of the beans.

Referring to Fig. 5, the cooled roasted coffee beans are delivered into a weighing pan 100 of the weigher 30. The weighing pan 100 is mounted on a number of spaced-apart load cells 102 on a support frame 103. After weighing, the roasted beans are delivered by means of an air stream through the transfer pipe 80 to one of the roasted beans storage hoppers 40. The diverter valve assembly 35 is operable to channel delivery of roasted beans to selected storage hoppers 40. The diverter valve 35 is shown in more detail in Figs. 6 and 7. A flexible inlet pipe 110 communicating with the outlet of the weigher 30 has an outlet end attached to a movable carrier plate 111. The movable carrier plate 111 is pivotable on a support frame 112 by means of a ram 113. The movable carrier plate 111 is mounted against a fixed carrier plate 115 to which a pair of pipes 116, 117 are connected, the pipes 116, 117 leading to different hoppers 40. Upon swivelling the carrier plate 111 an outlet of the pipe 110 can be matched with an inlet of one of the pipes 116, 117 for direction of coffee beans to the desired hopper 40.

The invention is not limited to the embodiment hereinbefore described which may be varied in both construction and detail.

Claims

1. A coffee production process comprising the steps; (a) sampling supply batches of green coffee beans and delivering acceptable batches of green coffee beans to associated storage hoppers, (b) selectively discharging pre-desired quantities of between two and five different types of green coffee beans from the hoppers into a cumulative weigher, weighing each quantity of green coffee beans delivered to the weigher in turn to produce a pre-desired batch of mixed green coffee beans, (c) blowing the batch of mixed green coffee beans along a supply pipe from the weigher to a rotating drum gas-fired roaster, (d) roasting the batch of mixed green coffee beans for a pre-desired time at a preset temperature, (e) discharging hot roasted coffee beans into a cooler, circulating the hot roasted coffee beans on a substantially horizontal perforated support plate in the cooler by means of rotating paddles, blowing air upwardly through the plate to cool the hot roasted coffee beans for a preset period, (f) delivering the cooled roasted coffee beans to a weigher to weigh the batch of roasted coffee beans, (g) delivering the batch of roasted coffee beans from the weigher to an associated storage hopper, (h) testing the batch of roasted coffee beans for colour and taste and, if acceptable, delivering the batch of roasted coffee beans to a roller grinder, passing the beans through a magnetic metal detector at an inlet of. the grinder for removal of any entrained metal pieces, (i) grinding the coffee beans and delivering ground coffee by auger-conveyors to a de-gassing bin, holding the ground coffee in the de-gassing bin for a preset period to allow expiration of carbon dioxide gas from the coffee and (j) delivering the ground coffee from the de gassing bin to a packing machine by means of auger conveyors and packing the coffee into sealed packages of a pre-desired size.

2. A process as claimed in claim 1 including the step of conveying whole coffee beans upstream of the grinder along a number of coffee bean transfer pipe sections, each transfer pipe section having a pipe inlet and a pipe outlet, generating a pressurised air supply, passing a stream of pressurised air delivered from the pressurised air supply to an inlet of each pipe section, delivering the pressurised air supply through the pipe section in a controlled manner between the inlet and outlet of the pipe section, delivering the coffee beans to the inlet and carrying the coffee beans in the air stream between the pipe inlet and the pipe outlet.

3. A process as claimed in claim 1 or claim 2 including the step of evacuating air in a controlled manner from each package during packaging of the ground coffee.

4. A process as claimed in claim 3 wherein the air is evacuated by applying a vacuum to each package to extract air from the package prior to sealing the package.

5. A process as claimed in claim 3 wherein the air is evacuated from each package by delivering nitrogen gas to the package and flushing out air from the package with excess nitrogen gas prior to delivering ground coffee into the package and sealing the package.

6. A process as claimed in any preceding claim wherein the green coffee beans are roasted by: preheating the roaster to a charging temperature in the range 230-240"C, preferably 235 ; opening an inlet to the roaster and delivering a batch of green coffee beans into the roaster; continuously turning the beans within the roaster; maintaining the temperature within the roaster in the range 140"C-250"C during roasting of the green coffee beans; roasting the coffee beans for a period of 8 minutes; and then opening an outlet of the roaster and discharging the roasted coffee beans for delivery to the cooler.

7. A process as claimed in any preceding claim wherein the process includes the step of spraying water onto hot roasted coffee beans downstream of the roaster outlet prior to delivering the roasted coffee beans to the cooler.

8. A process as claimed in any preceding claim wherein the roasted coffee beans are cooled in the cooler by blowing ambient air over the coffee beans for a period of three minutes.

9. A coffee production process substantially as hereinbefore described with reference to the accompanying drawings.

10. Roasted coffee produced by the process as claimed in any preceding claim.