METHOD FOR ROASTING COFFEE BEANS

Abstract

The invention concerns a method to determine the roasting recipe R.sub.blend for roasting a customised blend of coffee beans C.sub.A, C.sub.B, . . . introduced in a chamber of a roasting apparatus, said recipe R.sub.blend providing the temperature T@t1, T@t2, . . . to be applied at discrete successive times t.sub.1, t.sub.2, . . . , respectively, said method comprising the steps of:—obtaining for each type of coffee beans C.sub.n comprised in said blend at least:. the type C.sub.n of said type of coffee beans, and. the quantity m.sub.n of said type of coffee beans C.sub.n introduced in the chamber, and—based on the obtained type C.sub.n, getting access at least to:. roasting recipes RM.sub.A, RM.sub.B, . . . of the different types of coffee beans C.sub.A, C.sub.B, . . . respectively, and. temperature adaptation factors K.sub.A, K.sub.B, . . . of said different types of coffee beans C.sub.A, C.sub.B, . . . respectively of the customised blend, and—based on the obtained quantities m.sub.n of the different coffee beans C.sub.n and the accessible roasting recipes RM.sub.n and temperature factors K.sub.n, determining the roasting recipe R.sub.blend to be applied to said customised blend of coffee beans introduced inside the chamber.

Claims

1. A method to determine the roasting recipe for roasting a customised blend of coffee beans introduced in a chamber of a roasting apparatus, said recipe providing the temperature to be applied at discrete successive times respectively, said method comprising the steps of: obtaining for each type of coffee beans comprised in said blend at least: the type of said type of coffee beans, and the quantity m.sub.n of said type of coffee beans introduced in the chamber, and based on the obtained type getting access at least to: roasting recipes of the different types of coffee beans respectively, each recipe being adapted to the roasting of one pre-determined quantity of beans of same type and providing the temperatures to be applied at discrete successive times respectively, and temperature adaptation factors of said different types of coffee beans respectively of the customised blend, and based on the obtained quantities mn of the different coffee beans and the accessible roasting recipes and temperature factors, determining the roasting recipe to be applied to said customised blend of coffee beans introduced inside the chamber.

2. A method according to claim 1, wherein the roasting recipe to be applied to the customised blend of coffee beans is determined by at least the following steps: for each type of coffee beans respectively selecting or determining the roasting recipe adapted to the roasting of the obtained quantity of beans of said obtained type said roasting recipe providing the temperature respectively to be applied at time respectively, and from said selected and/or determined roasting recipes and from said accessible temperature adaptation factors and based on the obtained quantities of beans of type introduced inside the chamber, determining the temperature to be applied to the customised blend of beans at each of discrete successive times respectively according to following formula (I): $\begin{array}{cc}{T}_{\mathrm{blend}@t_i}=\underset{n=A}{\overset{N}{.Math.}}{f}_n.Math.K_n.Math.T_{m_n@t_i}& \left(I\right)\end{array}$ wherein n corresponds to all the types of coffee beans C.sub.A to C.sub.N present in the blend and f.sub.n represents the fraction in weight of coffee beans of type C.sub.n in the customised blend of coffee beans.

3. A method according to claim 2, wherein: in at least two of the selected or determined roasting recipes of coffees said recipes providing temperatures to be applied at discrete successive times at least a part of said discrete successive times are set differently, and from the selected or determined roasting recipes for each coffee of the customised blend, interpolated roasting recipes curves are determined by interpolating the curves of the accessible roasting recipes so that all the selected or determined roasting recipes provide the temperatures respectively to be applied at the same discrete successive times.

4. A method according to claim 2, comprising the steps of: selecting or determining: the roasting recipes of the different identified types of coffee beans of different types respectively, each recipe being adapted to the roasting of the quantity of beans of same type and providing the temperatures to be applied at discrete successive times up to a final time tfinal n respectively, and said final time being set differently in at least two of said different roasting recipes, and getting access to: time adaptation factors for each type of coffee beans respectively, and determining the roasting recipe to be applied on the blend of coffee beans by implementing the following steps: based on the obtained roasting recipes, obtaining the final times of all the coffees part of the customised blend, and sorting said obtained final times in an ascending order from the lowest final time up to the highest high for times inferior or equal to the lowest final time low, determining the roasting recipe to be applied to said blend of coffee beans introduced inside the chamber according to formula (I), for times superior to the smallest final time tfinal low, determining the roasting recipe to be applied to said blend of coffee beans introduced inside the chamber by setting temperatures to be applied at calculated times, each of said calculated times t.sub.y being calculated from each corresponding obtained final time tfinal y, from tfinal low+1 up to tfinal high, as follows:
t.sub.y=tfinal y−1+[(tfinal y−tfinal y−1)*Σ(fn′*Sn′)] with n′ corresponding to the coffees presenting a final time superior or equal to tfinal y, up to tfinal high−1, temperature being determined at each of said calculated time ty from the roasting recipes Rm.sub.n′ of all the coffee beans C.sub.n′ presenting a final time superior or equal to tfinal y, according to following formula (II): $\begin{array}{cc}{T}_{\mathrm{blend}@t_y}=\underset{n^{\prime }}{.Math.}{f}_{n^{\prime }}.Math.K_{n^{\prime }}.Math.T_{m_{n^{\prime }}@t_y}& \left(\mathrm{II}\right)\end{array}$ at tfinal high: if only one coffee Cz presents a roasting recipe that presents a final time equal to final high, then the temperature of the blend is the temperature of the roasting recipe of the quantity mz of said coffee Cz part of the blend at said final time: Tblend@final high=Tmz@tfinal z, or if at least two coffees presents roasting recipes that present the same final time equal to tfinal high, then the temperature of the blend is determined according to formula (II).

5. A method according to claim 2, comprising the steps of: selecting or determining the roasting recipes of the different identified types of coffee beans of different types respectively, each recipe being adapted to the roasting of the quantity of beans of same type and providing the temperatures to be applied at discrete successive times up to a final time respectively, and said final time set differently in at least two of said different roasting recipes, and determining the roasting recipe to be applied on the blend of coffee beans by implementing the following steps: based on the selected or determined roasting recipes, obtaining the final times of all the coffees part of the customised blend, and identifying the smallest final time low, limiting the roasting recipe to be applied to said blend of coffee beans introduced inside the chamber to times inferior to the smallest final time low, and determining the roasting recipe to be applied to said blend of coffee beans introduced inside the chamber according to formula (I).

6. A method according to claim 2, comprising the steps of: selecting or determining the roasting recipes of the different identified types of coffee beans of different types respectively, each recipe being adapted to the roasting of the quantity of beans of same type and providing the temperatures to be applied at discrete successive times up to a final time respectively, and said final time set differently in at least two of said different roasting recipes, and determining the roasting recipe to be applied on the blend of coffee beans by implementing the following steps: based on the selected or determined roasting recipes, obtaining the final times of all the coffees part of the customised blend, and identifying the smallest final time low, for times inferior or equal to the lowest final time low, determining the roasting recipe to be applied to said blend of coffee beans introduced inside the chamber according to formula (I), for times superior to the smallest final time low, determining the roasting recipe to be applied to said blend of coffee beans introduced inside the chamber by setting temperatures to be applied at each as follows: up to tfinal high−1, temperature being determined at each of said time tfinal n from the roasting recipes Rm.sub.n′ of all the coffee beans C.sub.n′ presenting a final time superior or equal to tfinal y, according to following formula (II): $\begin{array}{cc}{T}_{\mathrm{blend}@t_{\mathrm{final}n}}=\underset{n^{\prime }}{.Math.}{f}_{n^{\prime }}.Math.K_{n^{\prime }}.Math.T_{m_{n^{\prime }}@t_{\mathrm{final}n}}& \left(\mathrm{II}\right)\end{array}$ at tfinal high: if only one coffee Cz presents a roasting recipe that presents a final time equal to final high, then the temperature of the blend is the temperature of the roasting recipe of the quantity mz of said coffee Cz part of the blend at said final time: Tblend@final high=Tmz@tfinal z, or if at least two coffees presents roasting recipes that present the same final time equal to tfinal high, then the temperature of the blend is determined according to formula (II).

7. A method according to claim 2, comprising the steps of: selecting or determining the roasting recipes of the different identified types of coffee beans of different types respectively, each recipe being adapted to the roasting of the quantity of beans of same type and providing the temperatures to be applied at discrete successive times up to a final time respectively, and said final time set differently in at least two of said different roasting recipes, and getting access to time adaptation factors for each type of coffee beans respectively, and determining the roasting recipe to be applied on the blend of coffee beans by implementing the following steps: based on the selected or determined roasting recipes, obtaining the final times of all the coffees part of the customised blend, and identifying the smallest final time low, for times inferior or equal to the lowest final time low, determining the roasting recipe to be applied to said blend of coffee beans introduced inside the chamber according to formula (I), above the smallest final time tfinal low: calculating one time t.sub.final global from all the final times tfinal n of all the coffees C.sub.n part of the customised blend, as follows:
t.sub.final global=Σ(fn*Sn*t.sub.final n)] limiting the roasting recipe to be applied to said blend of coffee beans introduced inside the chamber to said time tfinal global, and determining the roasting recipe to be applied at said time tfinal global to said blend of coffee beans introduced inside the chamber according to formula (I).

8. A method according to claim 2, comprising the steps of: getting access, for at least one coffee, to one roasting recipe of coffee beans, said recipe being adapted to the roasting of one pre-determined quantity of beans, for said at least one coffee part of the customised blend, determining the roasting recipe adapted to the roasting of the obtained quantity of beans of said identified type from said one accessible recipe adapted to the roasting of one pre-determined quantity of beans of type and providing the temperatures to be applied at discrete successive times t.sub.i respectively, as follows:
if m.sub.n>M.sub.n,then Tm.sub.n@ti=T.sub.Mn@ti+[TM.sub.n@ti.D.(mn−Mn)/Mn]  (IIIa)
if m.sub.n<M.sub.n,then Tm.sub.n@ti=T.sub.Mn@ti−[TM.sub.n@ti.D.(Mn−mn)/Mn]  (IIIb) with D≤1 from said determined roasting recipe, determining the temperature to be applied to the customised blend of beans at each of said discrete successive times according to formula (I) or (II).

9. A method according to claim 2, comprising the steps of: getting access, for at least one type of coffee beans, to at least one series of roasting recipes adapted to the roasting of different successive pre-determined quantities of beans of type respectively and to said pre-determined quantities, and for said at least one coffee part of the customised blend, determining roasting recipe adapted to the roasting of the obtained quantity of beans of said identified type by selecting one of the recipes of the at least one accessible series of roasting recipes, said selection comprising identifying the roasting recipe adapted to the roasting of a pre-determined quantity of beans, said pre-determined quantity of beans presenting the smallest difference of quantity with the obtained quantity. from said determined roasting recipe, determining the temperature to be applied to the customised blend of beans at each of said discrete successive times according to formula (I) or (II).

10. A method according to claim 2, comprising the steps of: getting access, for at least one type of coffee beans to at least one series of roasting recipes adapted to the roasting of different successive pre-determined quantities of beans of type respectively and to said pre-determined quantities, and for said at least one coffee part of the customised blend, determining the roasting recipe adapted to the roasting of the obtained quantity of beans of said identified type by: identifying in said at least one series of roasting recipes the two accessible roasting recipes adapted to the roasting of two successive pre-determined quantities of beans respectively, wherein the quantity is comprised between said two successive pre-determined quantities, from said two identified roasting recipes, said roasting recipes providing the temperatures respectively applied at discrete successive times determining the temperature to be applied to the obtained quantity of beans at each of said discrete successive times as follows:
Tm.sub.n@ti=TM.sub.ny@ti+[(TM.sub.ny+1@ti−TM.sub.ny@ti).E.(m.sub.n−M.sub.ny)/(M.sub.ny+1−M.sub.ny)]  (IV) with E≤1, from said determined roasting recipe determining the temperature to be applied to the customised blend of beans at each of said discrete successive times according to formula (I) or (II).

11. A method according to claim 2, comprising the steps of: getting access, for at least one type of coffee beans to at least one series of roasting recipes adapted to the roasting of different successive pre-determined quantities of beans of type respectively and to said pre-determined quantities, and for said at least one coffee part of the customised blend, determining the roasting recipe adapted to the roasting of the obtained quantity of beans of said identified type by: identifying in said at least one series of roasting recipes the two accessible roasting recipes adapted to the roasting of two successive pre-determined quantities of beans respectively, wherein the quantity mn is comprised between these two successive pre-determined quantities, from said two identified roasting recipes, said roasting recipes providing the temperatures respectively applied at discrete successive times determining the temperature to be applied to the obtained quantity of beans at each of said discrete successive times as follows:
if m.sub.n is closer to M.sub.ny, then Tm.sub.n@ti=TM.sub.ny@ti+[(TM.sub.ny+1@ti−TM.sub.ny@ti).E.(m.sub.n−M.sub.ny)/(M.sub.ny+1−M.sub.ny)]
if m.sub.n is closer to M.sub.ny+1, then Tm.sub.n@ti=TM.sub.ny+1@ti−[(TM.sub.ny+1@ti−TM.sub.ny@ti).E.(M.sub.ny+1−m.sub.n)/(M.sub.ny+1−M.sub.ny)] with E≤1, from said determined roasting recipe determining the temperature to be applied to the customised blend of beans at each of said discrete successive times according to formula (I) or (II).

12. An apparatus for roasting coffee beans comprising: a chamber to contain coffee beans, a heating device to heat coffee beans contained in the chamber, a control system operable to control the heating device and configured to apply a roasting recipe providing the temperature to be applied at discrete successive times respectively, wherein, for a customised blend of coffee beans introduced inside the chamber, the control system is configured to determine the recipe for roasting said blend in the roasting apparatus according to the method to determine the roasting recipe for roasting a customised blend of coffee beans introduced in a chamber of a roasting apparatus, said recipe providing the temperature to be applied at discrete successive times respectively, said method comprising the steps of: obtaining for each type of coffee beans comprised in said blend at least: the type of said type of coffee beans, and the quantity m.sub.n of said type of coffee beans introduced in the chamber, and based on the obtained type getting access at least to: roasting recipes of the different types of coffee beans respectively, each recipe being adapted to the roasting of one pre-determined quantity of beans of same type and providing the temperatures to be applied at discrete successive times respectively, and temperature adaptation factors of said different types of coffee beans respectively of the customised blend, and based on the obtained quantities mn of the different coffee beans and the accessible roasting recipes and temperature factors, determining the roasting recipe to be applied to said customised blend of coffee beans introduced inside the chamber.

13-15. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0221] Specific embodiments of the invention are now described further, by way of example, with reference to the following drawings in which:

[0222] FIG. 1 is a schematic view of a roasting apparatus according to the invention,

[0223] FIG. 2 shows a block diagram of a control system of the apparatus according to FIG. 1,

[0224] FIG. 3 illustrates the calculation of the roasting profile of a blend of coffees derived from the roasting profiles of said coffees,

[0225] FIG. 4 illustrates the process of interpolation of roasting profiles curves,

[0226] FIG. 5 illustrates the calculation of the roasting profile of a blend of coffees derived from the roasting profiles of said coffees presenting different timelines,

[0227] FIG. 6 illustrates the determination of the roasting recipe of a quantity m.sub.A of coffee beans C.sub.A from a roasting recipe adapted for a quantity M.sub.A of coffee beans C.sub.A,

[0228] FIG. 7 illustrates the calculation of the roasting profile of specific quantity of a particular type of coffee derived from roasting profiles of pre-determined quantities of said type of coffee beans,

[0229] FIG. 8 schematically illustrates the use of measuring device to communicate quantities of beans introduced inside the roasting apparatus,

[0230] FIG. 9 shows the block diagram an alternative embodiment of the control system of the apparatus of FIG. 1.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0231] Roasting Apparatus

[0232] FIG. 1 shows an illustrative side view part of a roasting apparatus 10. Functionally, the roasting apparatus 10 is operable to roast coffee beans hold in a chamber 1 by means of a flow of hot air introduced inside this chamber. At a first level, the apparatus comprises: a housing 4, a roasting unit and a control system 80. These components will now be sequentially described.

[0233] Roasting Unit of Roasting Apparatus

[0234] The roasting unit is operable to receive and roast coffee beans.

[0235] The roasting unit typically comprises at a second level of the roasting apparatus 10: a chamber 1 and a heating device 2, which are sequentially described.

[0236] The chamber 1 is configured to receive and hold the coffee beans introduced by the operator. In the preferred embodiment, the chamber 1 is removable from the housing 4. The chamber can be put aside the roasting apparatus: [0237] for the introduction or the removal of coffee beans, or [0238] for cleaning and maintenance of the chamber once it is removed, or [0239] for cleaning of the vertical housing part 43 behind the chamber.

[0240] The bottom opening 11 of the chamber is configured to enable air to pass through, specifically it can comprise a perforated plate on which the beans can lie and through which air can flow upwardly. The chamber 1 comprises a handle in order to enable the user to remove the chamber from the housing and hold it outside the housing.

[0241] A chaff collector (no illustrated) is in flow communication with the chamber 1 to receive chaffs that progressively separate from the beans and due to their light density are blown off to the chaff collector.

[0242] The heating device 2 comprises an air flow driver 21 and a heater 22.

[0243] The air flow driver 21 is operable to generate a flow of air (dotted lines arrows) in direction of the bottom of the chamber. The generated flow is configured to heat the beans and to agitate and lift the beans. As a result the beans are homogenously heated. Specifically, the air flow driver can be a fan powered by a motor. Air inlets 42 can be provided inside the base of the housing in order to feed air inside the housing, the air flow driver blowing this air upwardly though a passage 23 to an air outlet hole 41 in direction of the chamber 1 as illustrated by dotted lines arrows.

[0244] The heater 22 is operable to heat the flow of air generated by the air flow driver 21. In the specific illustrated embodiment, the heater is an electrical resistance positioned between the fan 21 and the bottom opening 11 of the chamber with the result that the flow of air is heated before it enters the chamber 1 to heat and to lift the beans. Other types of heater can be used such as infrared heating, gas burner, . . .

[0245] The heater 22 and/or the air flow driver 21 is/are operable to apply a roasting profile to the beans, this roasting profile being defined as a curve of temperature against time.

[0246] When the chamber is mounted to the housing, the bottom of the chamber is tightly connected to the air outlet hole 41 to avoid that the flow of hot air flow leaks at the connection.

[0247] The top opening 12 of the chamber is connected to a smoke and particulates evacuation device (not illustrated).

[0248] Although the invention is described with a roaster implementing a fluidized bed of hot air, the invention is not limited to this specific type of roasting apparatus. Drum roasters and other kinds of roasters can be used.

[0249] The roasting apparatus 10 usually comprises a user interface 6 enabling the display and the input of information.

[0250] The roasting apparatus can comprise a code reader 7 to read a code associated to a type of coffee beans, for example present on the package of coffee beans. Preferably, this code reader is positioned in the apparatus so that the operator is able to easily position a code in front of it. It is preferably positioned at the front face of the apparatus, for example close to a user interface 6 of the apparatus. Accordingly, information provided by the code can be immediately displayed through the display of the user interface 6 positioned aside.

[0251] Control System of Roasting Apparatus

[0252] With reference to FIGS. 1 and 2A, the control system 80 will now be considered: the control system 80 is operable to control the components of the apparatus to roast coffee beans. The control system 80 typically comprises at a second level of roasting apparatus: the user interface 6, a processing unit 8, temperature probe 5, a power supply 9, a memory unit 13, optionally a database 12, sensors 10, optionally a communication interface 11 for remote connection, optionally a code reader 7, optionally a measuring device 3.

[0253] The user interface 6 comprises hardware to enable a user to interface with the processing unit 8, by means of user interface signal. More particularly, the user interface receives commands from a user, the user interface signal transfers the said commands to the processing unit 8 as an input. The commands may, for example, be an instruction to execute a roasting process and/or to adjust an operational parameter of the roasting apparatus 10 and/or to power on or off the roasting apparatus 10. The processing unit 8 may also output feedback to the user interface 6 as part of the roasting process, e.g. to indicate the roasting process has been initiated or that a parameter associated with the process has been selected or to indicate the evolution of a parameter during the process or to create an alarm.

[0254] In particular, the user interface can be used: [0255] to provide the types C.sub.n of the different coffee beans introduced inside the chamber by the user by manual input such as selection of an identification type in a list of pre-selected coffee beans or by entering a digital reference of the coffee, for example read from a coffee beans package or a user's manual. [0256] to provide the quantities m.sub.n of the different coffee beans forming the customised blend introduced inside the chamber by manual input.

[0257] The hardware of the user interface may comprise any suitable device(s), for example, the hardware comprises one or more of the following: buttons, such as a joystick button, knob or press button, joystick, LEDs, graphic or character LDCs, graphical screen with touch sensing and/or screen edge buttons. The user interface 20 can be formed as one unit or a plurality of discrete units.

[0258] A part of the user interface can also be on a mobile app when the apparatus is provided with a communication interface 11 as described below. In that case at least a part of input and output can be transmitted to the mobile device through the communication interface 11.

[0259] The sensors 10 are operable to provide an input signal to the processing unit 8 for monitoring of the roasting process and/or a status of the roasting apparatus. The input signal can be an analogue or digital signal. The sensors 10 typically comprise at least one temperature sensor 5 and optionally one or more of the following sensors: level sensor associated with the chamber 1, air flow rate sensor, position sensor associated with the chamber and/or the chaff collector.

[0260] If the apparatus or the system comprises a measuring device 3 (for example as illustrated in FIG. 8), this measuring device is operable to provide the input that is the quantity of coffee beans introduced inside the chamber 1. This input can be the weight of the beans measured by a scale or a volume of beans or a level measured by a level sensor associated with the chamber 1.

[0261] A code reader 7 can be provided and operable to read a code, for example on coffee beans package, and automatically provide an input that is the identification of the type Cn coffee beans introduced in the chamber 1 and optionally operation conditions for roasting a specific quantity Mn of said coffee beans.

[0262] The processing unit 8 generally comprise memory, input and output system components arranged as an integrated circuit, typically as a microprocessor or a microcontroller. The processing unit 8 may comprise other suitable integrated circuits, such as: an ASIC, a programmable logic device such as a PAL, CPLD, FPGA, PSoC, a system on a chip (SoC), an analogue integrated circuit, such as a controller. For such devices, where appropriate, the aforementioned program code can be considered programed logic or to additionally comprise programmed logic. The processing unit 8 may also comprise one or more of the aforementioned integrated circuits. An example of the later is several integrated circuits arranged in communication with each other in a modular fashion e.g.: a slave integrated circuit to control the user interface 6 in communication with a master integrated circuit to control the roasting apparatus 10.

[0263] The power supply 9 is operable to supply electrical energy to the said controlled components and the processing unit 8. The power supply 9 may comprise various means, such as a battery or a unit to receive and condition a main electrical supply. The power supply 9 may be operatively linked to part of the user interface 6 for powering on or off the roasting apparatus 10.

[0264] The processing unit 8 generally comprises a memory unit 13 for storage of instructions as program code and optionally data. To this end the memory unit typically comprises: a non-volatile memory e.g. EPROM, EEPROM or Flash for the storage of program code and operating parameters as instructions, volatile memory (RAM) for temporary data storage. The memory unit may comprise separate and/or integrated (e.g. on a die of the semiconductor) memory. For programmable logic devices the instructions can be stored as programmed logic. The instructions stored on the memory unit 13 can be idealised as comprising a coffee beans roasting program.

[0265] The control system 80 is operable to apply this coffee beans roasting program by controlling the heating device 2—that is, in the particular illustrated embodiment of FIG. 1, the air flow driver 21 and/or the heater 22—usually using signal of the temperature probe 5.

[0266] The coffee beans roasting program can effect control of the said components using extraction information encoded on the code and/or other information that may be stored as data on the memory unit 13 or from a remote source through the communication interface 11 and/or input provided via the user interface 6 and/or signal of the sensors 10.

[0267] In particular, the control system 80 is configured to apply a roasting recipe (R) providing the temperature T.sub.@t1, T.sub.@t2, T.sub.@tfinal to be applied at discrete successive times t.sub.1, t.sub.2, . . . , t.sub.final respectively.

[0268] With that aim, the processing unit 8 is operable to: [0269] receive an input of the temperature probe 5, [0270] process the input according to roasting recipe R, [0271] provide an output, which is the roasting recipe R. More specifically the output comprises the operation of at least the heater 22 and the air flow driver 21.

[0272] The temperature measured by the temperature probe 5 is used to adapt the power of the heater 22 and/or the power of the air driver 21 in a feedback loop in order to apply the roasting recipe R to the beans.

[0273] Depending on the type of control applied in the roaster, the heater 22 can be powered at one pre-determined power, meaning its temperature is constant, and in that case the power of the air driver 21 can be controlled based on the temperature monitored at the probe 5 in order to vary the time of contact of the flow air through the heater during its movement.

[0274] Alternatively, the air driver 21 can be powered at one pre-determined power, meaning the flow rate of air is constant, and in that case the power of the heater 22 can be controlled based on the temperature monitored at the probe 5 in order to heat more or less air during its passage through the heater.

[0275] In a last alternative, both heater 22 and air driver 21 can be controlled based on the monitoring of the temperature by probe 5.

[0276] The control system 80 can comprise a communication interface 11 for data communication of the roasting apparatus 10 with another device and/or system, such as a server system, a mobile device and/or a physically separated measuring apparatus 3. The communication interface 11 can be used to supply and/or receive information related to the coffee beans roasting process, such as roasting process information, type of the beans, quantity of beans. The communication interface 11 may comprise first and second communication interface for data communication with several devices at once or communication via different media.

[0277] The communication interface 11 can be configured for cabled media or wireless media or a combination thereof, e.g.: a wired connection, such as RS-232, USB, 120, Ethernet define by IEEE 802.3, a wireless connection, such as wireless LAN (e.g. IEEE 802.11) or near field communication (NFC) or a cellular system such as GPRS or GSM. The communication interface 11 interfaces with the processing unit 8, by means of a communication interface signal. Generally the communication interface comprises a separate processing unit (examples of which are provided above) to control communication hardware (e.g. an antenna) to interface with the master processing unit 8. However, less complex configurations can be used e.g. a simple wired connection for serial communication directly with the processing unit 8.

[0278] The processing unit 8 enables access to different roasting recipes (RM.sub.A, RM.sub.B, . . . ) adapted to the roasting of pre-determined quantities (M.sub.A, M.sub.B, . . . ) of beans of different natures (C.sub.A, C.sub.B, . . . ).

[0279] These recipes and the pre-determined quantities can be stored in the memory 13 of the processing unit 8. Alternatively, these data can be stored in a remote server and the processing unit 8 can be supplied with access to this remote server through the communication interface 11, directly or indirectly through a mobile device establishing connection between the remote server and the processing unit.

[0280] The control system 80 can comprise a database 12 storing information about coffee beans, in particular about the operation conditions for roasting specific coffee beans as described hereunder. The database 12 can be stored locally in the memory 13 of the control system of the roasting apparatus or remotely in a server accessible through the communication interface 13.

[0281] In one alternative embodiment, the control system can be provided with the roasting recipes Rm.sub.n, and depending on the embodiment with their associated pre-determined quantities M.sub.n, during a code reading operation, these pieces of information being encoded inside the code and decoded by the control system.

[0282] The roasting apparatus 10 and the control system 80 are configured for roasting a customised blend of different coffee beans introduced inside the chamber 1. This customised blend is defined by the types C.sub.n of beans part of the blend and the respective quantities m.sub.n of said types of beans.

[0283] In the present invention, the customised blend can be a mixture created from: [0284] different beans of single origin only,
or [0285] different types of pre-existing blends of beans only. In that case, pre-existing blends of coffee beans can be used and mixed together to create new customised and more complex blends.
or [0286] at least one bean of single origin and at least one pre-existing blend of beans.

[0287] In the description the types C.sub.A, C.sub.B . . . C.sub.n relate indifferently to beans of single origin or pre-existing blends of beans.

[0288] When a customised blend of different types of coffee beans, like for example C.sub.A and C.sub.B in quantities m.sub.A and m.sub.B respectively, is introduced inside the chamber 1 in order to be roasted, the processing unit 8 of the apparatus of the present invention is configured to implement several steps.

[0289] First, the processing unit 8 of the apparatus of the present invention is configured to obtain for each type of coffee beans C.sub.n comprised in said blend: [0290] the type C.sub.n of coffee beans, and [0291] the quantity m.sub.n of said type of coffee beans C.sub.n introduced in the chamber.

[0292] As mentioned earlier, information about identification and quantity can be provided through the user interface 6 of the roasting apparatus, the display of the user interface guiding the user to enter information for each types of coffee.

[0293] Alternatively, for the type of the coffee types, information about the types of coffee introduced inside the chamber can be obtained by means of a code reader 7, the user being able or incited to scan the code of the different beans in front of the code reader 15.

[0294] Alternatively, for the quantity of the beans of each type, the quantity of each type of coffee can be measured and automatically communicated to the control system 80, for example by the use a measuring device 3 either directly connected to the apparatus or indirectly through the communication interface 11, as illustrated in FIG. 8.

[0295] In a particular embodiment, the control system can be configured: [0296] to obtain the input that is the global weight composition of the customised blend, that is the types C.sub.n of coffee beans and the corresponding weight fraction f.sub.n, [0297] to obtain the total weight of said customised blend to roasted, for example 500 g, [0298] to calculate the weight of each type of coffee C.sub.n corresponding to the fraction f.sub.n for said global weight, [0299] as an output, to request the operator to introduce each calculated weight m.sub.n of coffee C.sub.n in the chamber.

[0300] Then, in a further step, the control system of the roasting apparatus is configured to get access to information related to the roasting of these specific types of coffee beans C.sub.n, for example C.sub.A and C.sub.B, part of the customised blend, and in particular to: [0301] the roasting recipes R.sub.A, R.sub.B of the different identified types of coffee beans C.sub.A, C.sub.B respectively.
Each of said recipes R.sub.n is usually adapted to the roasting of one pre-determined quantity m.sub.n of beans of same type C.sub.n and provides the temperatures Tm.sub.n@t.sub.i to be applied to this quantity of beans C.sub.n at discrete successive times t respectively.
and [0302] temperature adaptation factors K.sub.A, K.sub.B of the different identified types of coffee beans C.sub.A, C.sub.B respectively,
and optionally: [0303] time adaptation factors S.sub.A, S.sub.B of different identified types of coffee beans C.sub.A, C.sub.B respectively.

[0304] In one embodiment, the control system comprises a memory or database 12 storing these roasting recipes R.sub.A, R.sub.B, the temperature adaptation factors K.sub.A, K.sub.B of said different types of coffee beans C.sub.A, C.sub.B and optionally the time adaptation factors S.sub.A, S.sub.B of said different types of coffee beans C.sub.A, C.sub.B and the processing unit 8 of the control system is configured to get access to said database.

[0305] This database 12 can be stored locally in the memory unit 13 of the processing unit or in a remote server accessible through the communication interface 11 of the control system. This remote database can be accessible through remote connection with a mobile device or through connection with a modem.

[0306] Based on the first step where identification and quantities of each of the different coffee beans part of the customised blend are obtained, the control system 80 is configured to get aces to the above roasting recipes and factors in the database 12.

[0307] In one alternative embodiment, the control system 80 can be provided with the roasting recipes, the temperature adaptation factors and the time adaptation factors during the code reading operation, these pieces of information being encoded inside the code and decoded by the control system 80.

[0308] Then, in a further step, the control system is configured to calculate the roasting recipe R.sub.blend to be applied to the customised blend of coffee beans introduced inside the chamber based on at least: [0309] the quantities m.sub.A and m.sub.B of each type of beans C.sub.A and C.sub.B respectively that are part of the blend, [0310] the accessible roasting recipes R.sub.A, R.sub.B of these beans part of the blend, and [0311] the accessible temperature factors K.sub.A, K.sub.B of these beans part of the blend.

[0312] This roasting recipe can be used to roast the customised blend of coffees introduced in the chamber. This recipe takes into account the properties of each types of coffees and, when applied, provides a roasting of the blend that prevents over-roasting of the more fragile beans and yet sufficient roasting of the denser beans.

[0313] This roasting recipe can be calculated for any customised blend of beans in an automatic manner and guarantees a safe roasting of the blend meaning no spill of the blend.

[0314] The only condition is that the control system is able to get access to roasting recipes R.sub.A, R.sub.B, . . . of the different types of coffee beans C.sub.A, C.sub.B, . . . respectively, and to the temperature adaptation factors K.sub.A, K.sub.B, . . . of said coffee beans C.sub.A, C.sub.B, . . . respectively. In case that a new type of coffee beans is used in the customised blend, it is sufficient that at least one roasting recipe of said new type of beans to be applied for one pre-determined quantity is uploaded in the memory or database of the control system or provided through a readable code.

[0315] At each time t.sub.i the calculation is generally based on a average of the temperatures Tm.sub.A@t.sub.i and Tm.sub.B@t.sub.i, said average being weighted with the quantity fractions (f.sub.A=m.sub.A/m.sub.A+m.sub.B, f.sub.B=m.sub.B/m.sub.A+m.sub.B) of coffees C.sub.A and C.sub.B respectively and modulated with the temperature factors K.sub.A and K.sub.B respectively.

[0316] More precisely, the roasting profile to be applied to the blend of coffee beans can be determined by the following formula (I):

[00005]$T_{\mathrm{blend}@t_i}=\underset{n=A}{\overset{C}{.Math.}}{f}_n.Math.K_n.Math.T_{m_n@t_i}$

[0317] Although one type of beans may be present inside the blend with a small quantity fraction, the sensitivity of this type of beans to temperature may be high; in particular in terms of profile aroma, colour and/or generation of acrylamides. For example, final properties of one type of beans may easily deviate from usual expected properties with a roasting profile differing too much from its own optimal roasting profile. Accordingly, in order to avoid such deviation in the roasted blend, the temperature adaption factor for this type of sensitive coffee beans is set relatively high to keep the profile of this specific type of beans in the blend close to the optimal roasting profile of this type of beans when roasted alone and in order compensate a low fraction quantity in the roasting profile formula (I) of the blend.

[0318] As an example, FIG. 3 illustrates the calculation of the roasting profile of a blend of three coffees A, B and C derived from the roasting profiles of each of said coffee A, B and C.

[0319] For a blend comprising: [0320] 50% in weight of coffee A, said coffee presenting a temperature factor K.sub.A of 1 and a roasting temperature at time ti of 220° C., and [0321] 30% in weight of coffee B, said coffee presenting a temperature factor K.sub.B of 0.9 and a roasting temperature at time ti of 205° C., and [0322] 20% in weight of coffee C, said coffee presenting a temperature factor K.sub.C of 1 and a roasting temperature at time ti of 185° C.,
the roasting temperature to be applied to the blend at time ti is:

[00006]$\begin{array}{c}{T}_{\mathrm{blend}@\mathrm{ti}}=\left(0,5⨯1⨯220\right)+\left(0,3⨯0,9⨯205\right)+\left(0,2⨯1⨯185\right)\\ =110+55,35+37\\ =202,35\mathrm{°C}\end{array}$

[0323] Curves Interpolation

[0324] Often the roasting recipes Rn of the coffee beans are defined by discrete sets of points (ti, T.sub.@ti) rather than with a complete continuous curve.

[0325] In a customised blend of different coffees, it can happen that the roasting recipes of the different coffee beans are not defined by discrete sets of points set at the same abscissas ti.

[0326] In that case, the calculation of the roasting profile of the blend preferably comprises an intermediate additional step to interpolate the different accessible curves of the roasting recipes R.sub.n so that all the accessible roasting recipes Rn provide the temperatures Tm.sub.n@t.sub.1, Tm.sub.n@t.sub.2, Tmn@t.sub.final to be applied at the same discrete successive abscissa times t.sub.1, t.sub.2, . . . t.sub.final and to be able to calculate the roasting profile of the blend by means of the formula (I) applied at each of said discrete successive abscissa times t.sub.1, t.sub.2, . . . t.sub.final.

[0327] FIG. 4 illustrates the process of interpolation of two roasting profiles curves of one coffee C.sub.A and one coffee C.sub.B. The first diagram shows the roasting profile curves of C.sub.A and C.sub.B such as provided to the control system, through database, memory or code. It appears that the curves do not present points at common abscissa. The second diagram shows the roasting profile curves of C.sub.A and C.sub.B after a process step of interpolation: both roasting profile curves provide temperatures Tm.sub.A@ti and Tm.sub.B@ti at the same abscissas ti.

[0328] Interpolation is a process that can be automatically implemented by an algorithm applied by the control system. The choice of the new abscissa ti at which interpolation is executed can be defined at regular times, for example at every 10 seconds or 20 seconds, or at particular periods in the timeline, for example every 10 seconds during the period covering the first crack periods of all the coffee beans part of the blend, and then every 10 seconds until and during the second crack periods of all the coffee beans part of the blend.

[0329] Determination of the Roasting Recipe Rm.sub.n from Pre-Determined Roasting Recipes RM.sub.n with Different Final Times

[0330] It can happen that the different roasting recipes R.sub.n of the different coffee beans are defined by curves or discrete sets of points wherein the last abscissa t.sub.final different from one type of is coffee to another for at least two of the coffees part of the blend as illustrated in FIG. 5A. In that case, the processing unit can be configured to implement additional steps to determine the roasting recipe R.sub.blend of the blend.

[0331] In particular, the control system can be configured to obtain additional information about the coffee beans of the blend that is time adaptation factors S.sub.A, S.sub.B, S.sub.n for each identified type of coffee beans C.sub.A, C.sub.B, . . . C.sub.n respectively.

[0332] In addition, the processing unit is configured to obtain the final times t t.sub.final n of all the coffees C.sub.n part of the customised blend (for example through the different roasting recipes R.sub.n of the identified coffees or alternatively by direct access to that piece of information) and to sort said obtained final times in a series of time t.sub.final y in an ascending order from the smallest final time t.sub.final low, t.sub.final low+1 up to the highest t.sub.final high.

[0333] Then, the processing unit is configured to determine the roasting recipe R.sub.blend of the blend as follows: [0334] for times inferior or equal to the smallest final time t.sub.final low, the processing unit determines the roasting recipe (R.sub.blend) to be applied to said blend of coffee beans introduced inside the chamber according to above defined formula (I), [0335] for times superior to the smallest final time t.sub.final low, the processing unit determines the roasting recipe R.sub.blend to be applied to said blend of coffee beans introduced inside the chamber by setting temperatures to be applied at new calculated times t.sub.y, as follows: [0336] each of said new calculated times t.sub.y is calculated from each corresponding obtained final time t.sub.final y, from t.sub.final low+1 up to t.sub.final high, as follows:

t.sub.y=t.sub.final y−1+[(t.sub.final y−t.sub.final y−1)*Σ(f.sub.n′.S.sub.n′)]with n′ corresponding to the coffees presenting a final time superior or equal to t.sub.final y, [0337] up to t.sub.final high−1, temperature is determined at each of said calculated time t.sub.y from all the roasting recipes Rm.sub.n′ of the coffee beans C.sub.n′ presenting a final time superior or equal to t.sub.final y according to following formula (II):

[00007]$T_{\mathrm{blend}@t_y}=\underset{n^{\prime }}{.Math.}{f}_{n^{\prime }}.Math.K_{n^{\prime }}.Math.T_{m_{n^{\prime }}@t_y}$

[0338] Preferably the values of the temperatures Tm.sub.n′@ty are interpolated values extracted from the recipes Rm.sub.n′ at the new calculated times ty. [0339] at t.sub.final high: [0340] if only one coffee C.sub.z presents a roasting recipe that presents a final time equal to f.sub.inal high, then the temperature of the blend is the temperature of the roasting recipe of the quantity m.sub.z of said coffee C.sub.z part of the blend at said final time: T.sub.blend@tfinal high=Tm.sub.z@t.sub.final z, [0341] or [0342] if at least two coffees present roasting recipes that present the same final time equal to t.sub.final high, then the temperature of the blend is determined according to formula II.

[0343] This determination of the roasting recipe for a blend comprising coffees with different final times is illustrated in FIG. 5A. In the case related to this figure, the blend comprises three coffees C.sub.A, C.sub.B and C.sub.C with respective quantities m.sub.A, m.sub.B and m.sub.C and the figure represents the roasting curves Rm.sub.A, Rm.sub.B, Rm.sub.C. It can be noticed that these roasting curves present different final time abscissa. Coffee C presents the smallest t.sub.final low and coffee A the highest t.sub.final high, whereas coffee B presents an intermediate t.sub.final 2.

[0344] The roasting curve of the blend can be determined as follows.

[0345] First up to t.sub.final low, the temperature to be applied to the blend is determined by the above mentioned formula (I) calculated at different times ti. For example, at the time t.sub.final low the temperature to be applied to the blend is:

T.sub.blend@t.sub.final low=f.sub.A.K.sub.A.T.sub.A@t.sub.final low+f.sub.B.K.sub.B.T.sub.B@t.sub.final low+f.sub.C.K.sub.C.T.sub.C@t.sub.final low

[0346] Then, for times between t.sub.final low and t.sub.final high, new abscissa times are calculated from the final times of the different recipes: [0347] a new abscissa time t.sub.2 is calculated from t.sub.final 2 as follows: t.sub.2=t.sub.final 1+[(t.sub.final 2−t.sub.final 1)*(f.sub.BS.sub.B+f.sub.AS.sub.A)] that is t.sub.final low+[(t.sub.final 2−t.sub.final low)*(f.sub.BS.sub.B+f.sub.AS.sub.A)] [0348] a new abscissa time t.sub.3 is calculated from t.sub.final high as follows: t.sub.3=t.sub.final 2+[(t.sub.final 3−t.sub.final 2)*(f.sub.AS.sub.A)] that is t.sub.2=t.sub.final 2+[(t.sub.final high−t.sub.final 2)*(f.sub.AS.sub.A)]

[0349] Then at these new calculated times t.sub.2 and t.sub.3, the temperature of the blend is determined as follows.

[0350] At the new calculated time t.sub.2, the temperature to be applied to the blend is determined by the above mentioned formula (II) calculated at time t.sub.2 and only for the coffee beans presenting a final time abscissa superior or equal to t.sub.final2 that is to say in the present case for coffees A and B only, as follows:

T.sub.blend@t2=f.sub.A.K.sub.A.Tm.sub.A@t2+f.sub.B.K.sub.B.Tm.sub.B@t2

[0351] At the new calculated time t.sub.3, the temperature to be applied to the blend corresponds to Tm.sub.A@t.sub.3 since only coffee A presents a roasting recipe with a final time abscissa superior or equal to t.sub.final 3.

[0352] FIG. 5A makes clear that, up to the time t final low, the roasting recipe of the blend of coffees A, B and C can be calculated at whatever abscissa ti common to the three curves interpolated or not. But, for time abscissa greater than t.sub.final low, the roasting curve of the blend is determined by calculating new time abscissas t2 and t3 from t.sub.final 1, t.sub.final 2 and t.sub.final 3 and then by calculating the temperatures of the blend at these new time abscissas respectively.

[0353] Based on the same blend of coffees C.sub.A, C.sub.B and C.sub.C, FIG. 5B illustrates an alternative method to determine the roasting recipe of the blend.

[0354] In that embodiment, the smallest final time t.sub.final low is identified that is here t.sub.final1 of coffee C. Then the temperature to be applied to the blend is determined by limiting the recipe to times inferior or equal to this smallest final time t.sub.final low and for times ti inferior or equal to this smallest final time Sinai low determining the roasting recipe (R.sub.blend) to be applied to said blend of coffee beans introduced inside the chamber according to formula (I), that is:

T.sub.blend@t.sub.i=f.sub.A.K.sub.A.Tm.sub.A@t.sub.i+f.sub.B.K.sub.B.Tm.sub.B@t.sub.i+f.sub.C.K.sub.C.Tm.sub.C@t.sub.i

[0355] Whatever the embodiment, he control system such as described above is based on the access of the pre-determined roasting recipes R.sub.A, R.sub.B, . . . of the different types of coffee beans C.sub.A, C.sub.B, . . . , or eventually pre-determined roasting recipes R.sub.Blendα, R.sub.Blendβ, . . . (R.sub.Blendx) of pre-determined blends Blendα, Blendβ, and the use of at least said pre-determined roasting recipes to define the roasting recipe of the new customised blend.

[0356] The roasting recipes R.sub.A, R.sub.B, . . . or R.sub.Blendα, R.sub.Blendβ, . . . can be provided more or less precisely as explained below.

[0357] Determination of the Roasting Recipe Rm.sub.n from One Pre-Determined Roasting Recipe RM.sub.n

[0358] In one first mode, the accessible roasting recipe R.sub.n of coffee beans of types C.sub.n can correspond to the roasting recipe of one single pre-determined quantity M.sub.n of beans of type C.sub.n. This roasting recipe is usually defined by experimentation by defining the optimal profile for a pre-determined quantity of beans C.sub.n. It is generally linked to the roasting in a type of roaster too. If the quantity m.sub.n of beans C.sub.n introduced in the customised blend is different from this quantity M.sub.n corresponding to the accessible roasting recipe, the control system can be configured to adapt this roasting profile for the quantity m.sub.n of the beans of type C.sub.n used in the customised blend before determining the roasting profile of the blend as illustrated in FIG. 6.

[0359] Accordingly, based on the access to the recipe RM.sub.A for the pre-determined quantity M.sub.A, for a quantity m.sub.A of coffee C.sub.A part of the customised blend, the control system is configured to determine the roasting recipe Rm.sub.A providing the temperatures Tm.sub.A@ti to be applied at time t.sub.i respectively as follows:

if m.sub.A>M.sub.A, then Tm.sub.A@ti=TM.sub.A@ti+[TM.sub.A@ti.D.(m.sub.A−M.sub.A)/M.sub.A]  (IIIa)

if m.sub.A<M.sub.A, then Tm.sub.A@ti=TM.sub.A@ti−[TM.sub.A@ti.D.(M.sub.A−m.sub.A)/M.sub.A]  (IIIa)

with C≤1.

[0360] For example, if for coffee C.sub.A, the pre-determined quantity M.sub.A of the roasting recipe R.sub.MA accessible by the control system is set to 150 g and if the quantity m.sub.A of coffee beans C.sub.A in the customised blend is 160 g, then, at time t.sub.1, the temperature to be applied Tm.sub.A@t1 is:

Tm.sub.A@t1+[TM.sub.A@t1×D×(160−150)/150]

[0361] Alternatively, if the pre-determined quantity M.sub.A is set to 150 g and if the quantity M.sub.A of coffee beans A in the customised blend is 135 g, then, at time t.sub.1, the temperature to be applied T.sub.mA@t1 is:

Tm.sub.A@t1+[TM.sub.A@t1×D×(150−135)/150]

[0362] The calculation is reproduced for the different time abscissas of the roasting recipe R.sub.MA in order to determine the roasting recipe Rm.sub.A for the quantity m.sub.A of beans as illustrated in FIG. 6 corresponding to the situation where M.sub.A is greater than M.sub.A.

[0363] These discrete successive times of the pre-determined recipe RM.sub.n can be pre-defined to provide a final roasting recipe with enough points to be implemented by the roasting apparatus. For example, successive time may differ by about 20 to 40 seconds.

[0364] In the above formula, the coefficient D is usually fixed experimentally and can vary depending on the roaster specifications (power, chamber size, type of heater, . . . ) and/or the type of the beans.

[0365] In one embodiment, the coefficient D can be set according to the roaster specifications only. In another embodiment, the coefficient D can be set according to the type of beans. In that case, coefficient D can be set: [0366] generally at a high level of definition of the beans such as the big common botanical varieties of the beans, e.g. Arabica or Robusta providing a coefficient D.sub.A when Arabica beans are roasted and a coefficient D.sub.R when Robusta beans are roasted, or the usual origins, e.g. Colombia, Ethiopia, . . . [0367] or more precisely for each type of beans Cn by defining the corresponding coefficient D.sub.n specifically adapted to this type of beans with more precise criteria than the two general origins.

[0368] Based on the obtained type of beans (Arabica, Robusta or C.sub.n) introduced in the chamber, the control system is configured to get access to the coefficient D.sub.n corresponding to that type of beans.

[0369] Preferably, the coefficient D is set according to the roaster specifications and the type of beans.

[0370] In absence of information about the roaster or the type of beans or the further use, by default, the coefficient D equals 1.

[0371] In a further step, this new determined roasting recipe Rm.sub.n adapted to the quantity m.sub.n of coffee C.sub.n part of the blend can be used to determine the roasting recipe of the customised blend according to above mentioned formulas (I) or (II).

[0372] Selection of the Roasting Recipe Rm.sub.n from a Series of Pre-Determined Roasting Recipes RM.sub.n

[0373] In other modes, the control system can get access to a series of roasting recipes Rm.sub.ny, RM.sub.nyi+1, . . . of coffee beans Cn adapted to the roasting of different successive pre-determined quantities M.sub.ny, M.sub.nyi+1, respectively of beans of type C.sub.n. These temperature profiles are usually defined by experimentation by defining the optimal profile for a pre-determined quantity of beans. It is usually linked to the type of roaster too.

[0374] FIG. 7 schematically illustrates the series of roasting recipes RM.sub.n0, RM.sub.n1, RM.sub.n2, RM.sub.n3, RM.sub.n4 of coffee beans C.sub.n adapted to the roasting of different successive pre-determined quantities M.sub.n0, M.sub.n1, M.sub.n2, M.sub.n3, M.sub.n4. Each of the illustrated roasting recipes provides the temperature profile to be applied to a corresponding dedicated quantity of beans respectively in function of time. For example, the different pre-determined quantity of beans that are M.sub.n0, M.sub.n1, M.sub.n2, M.sub.n3, M.sub.n4 can be discrete weights such as: 50 g, 100 g, 150 g, 200 g and 250 g of the same type of beans C.sub.n.

[0375] If the quantity m.sub.n of beans C.sub.n introduced in the customised blend is identical to one of these pre-determined quantities M.sub.ny, M.sub.nyi+1, . . . then the roasting recipe can be directly used in the determination of the roasting recipe of the blend.

[0376] If the quantity m.sub.n of beans C.sub.n introduced in the customised blend is different from these pre-determined quantities M.sub.ny the control system can be configured to adapt this roasting profile for the quantity m.sub.n of the beans of type C.sub.n used in the customised blend before determining the roasting profile of the blend, in particular according to one of the below modes.

[0377] In one second mode, based on the quantity m.sub.n of coffee beans introduced inside the chamber, the control system is configured to determine the roasting recipe Rm.sub.n adapted to the roasting of the obtained quantity m.sub.n of beans of said identified type C.sub.n, by selecting in the series the roasting recipe RM.sub.ny corresponding to the pre-determined quantity of beans C.sub.n presenting the smallest difference of quantity M.sub.ny with the obtained quantity m.sub.n used in the blend.

[0378] Then this roasting recipe RM.sub.ny adapted to the quantity m.sub.n of coffee C.sub.n part of the blend can be used to determine the roasting recipe of the customised blend according to above formula (I) or (II).

[0379] For illustration of the second mode, based on the series of recipes of FIG. 7 to be applied to different pre-determined weights of beans such as: 50 g, 100 g, 150 g, 200 g and 250 g, if the input for the quantity m.sub.n of beans is 210 g, then the processing unit 8 is operable to select the roasting recipe corresponding to the pre-determined quantity of beans 200 g because the smallest difference between 210 and the five pre-determined quantities 50 g, 100 g, 150 g, 200 g, 250 g is the difference between 210 g and 200 g.

[0380] In another third mode, based on the quantity m.sub.n of coffee beans introduced inside the chamber, the control system is configured to determine the roasting recipe Rm.sub.n adapted to the roasting of the obtained quantity m.sub.n of beans of said identified type C.sub.n, by: [0381] identifying in the series of roasting recipes the two roasting recipes RM.sub.ny and Rm.sub.ny+1 adapted to the roasting of two successive pre-determined quantities M.sub.ny and M.sub.ny+1 of beans respectively, wherein the quantity m.sub.n is comprised between said two successive pre-determined quantities M.sub.ny and M.sub.ny+1, [0382] from said two identified roasting recipes RM.sub.ny and Rm.sub.ny+1, determining the temperature Tm.sub.n@t1, Tm.sub.n@t2 . . . to be applied to the obtained quantity m.sub.n of beans C.sub.n at each of said discrete successive times t.sub.1, t.sub.2, . . . as follows:

Tm.sub.n@ti=TM.sub.ny.sub.@ti+[(TM.sub.ny+1@ti−TM.sub.ny@ti).E.(m.sub.n−M.sub.ny)/(M.sub.ny+1−M.sub.ny)]

with E≤1.

[0383] Then the temperatures Tm.sub.n@t1, Tm.sub.n@t2 . . . adapted to the quantity m.sub.n of coffee C.sub.n part of the blend can be used to determine the roasting recipe of the customised blend according to above formula (I) or (II).

[0384] For example, based on FIG. 7, if the obtained quantity m.sub.n is 160 g, then roasting recipes R.sub.150 and R.sub.200 corresponding respectively to 150 g and 200 g of coffee beans of type C.sub.n are identified.

[0385] In a second step, at discrete successive times t.sub.1, t.sub.2, . . . , t.sub.6, the temperature Tm.sub.n to be applied to the obtained quantity m.sub.n of beans C.sub.n at each of said discrete successive times t.sub.1, t.sub.2, . . . t.sub.6 is calculated from the roasting recipes R.sub.150 and R.sub.200 as follows:

Tm.sub.n@ti=T.sub.150.sub.@ti+[(T.sub.200.sub.@ti−T.sub.150.sub.@ti)*E*(160−150)/(200−150)]

with E≤1.

[0386] The calculation is reproduced at each time t.sub.1 to t.sub.6 determining the full roasting recipe Rm.sub.n for the quantity m.sub.n of beans.

[0387] These discrete successive times of the pre-determined recipe RM.sub.n can be pre-defined to provide a final roasting recipe with enough points to be implemented by the roasting apparatus. For example, successive time may differ by about 20 to 40 seconds.

[0388] In the above formula, the coefficient E is usually fixed experimentally and can vary depending on the roaster specifications (power, chamber size, type of heater, . . . ) and/or the type of the beans.

[0389] In one embodiment, the coefficient E can be set according to the roaster specifications only. In another embodiment, the coefficient E can be set according to the type of beans. In that case, coefficient E can be set: [0390] generally at a high level of definition of the beans such as the big common botanical varieties of the beans, e.g. Arabica or Robusta providing a coefficient E.sub.A when Arabica beans are roasted and a coefficient E.sub.R when Robusta beans are roasted, or the usual origins, e.g. Colombia (coefficient E.sub.C), Ethiopia (coefficient E.sub.E), [0391] or more precisely for each type of beans C.sub.n by defining the corresponding coefficient E.sub.n specifically adapted to this type of beans with more precise criteria than the two general origins.

[0392] Based on the obtained type of beans (Arabica, Robusta or C.sub.n) introduced in the chamber, the control system is configured to get access to the coefficient En corresponding to that type of beans.

[0393] Preferably, the coefficient E is set according to the roaster specifications and the type of beans.

[0394] In absence of information about the roaster or the type of beans or the further use, by default, the coefficient E equals 1.

[0395] In a further step, this new determined roasting recipe Rm.sub.n adapted to the quantity mn of coffee Cn part of the blend can be used to determine the roasting recipe of the customised blend according to above mentioned formulas (I) or (II).

[0396] In another fourth mode, based on the quantity m.sub.n of coffee beans introduced inside the chamber, the control system is configured to determine the roasting recipe Rm.sub.n adapted to the roasting of the obtained quantity m.sub.n of beans of said identified type C.sub.n, by: [0397] identifying in the series of roasting recipes the two roasting recipes RM.sub.ny and Rm.sub.ny+1 adapted to the roasting of two successive pre-determined quantities M.sub.ny and M.sub.ny+1 of beans respectively, wherein the quantity mn is comprised between said two successive pre-determined quantities M.sub.ny and M.sub.ny+1, [0398] from said two identified roasting recipes RM.sub.ny and Rm.sub.ny+1, determining the temperature Tm.sub.n@t1, Tm.sub.n@t2 . . . to be applied to the obtained quantity mn of beans at each of said discrete successive times t.sub.1, t.sub.2, . . . as follows:

if m.sub.n is closer to M.sub.ny, then Tm.sub.n@ti=TM.sub.ny@ti+[(TM.sub.ny+1@ti−TM.sub.ny@ti).E.(m.sub.n−M.sub.ny)/(M.sub.ny+1−M.sub.ny)]

if m.sub.n is closer to M.sub.ny+1, thenTm.sub.n@ti=TM.sub.ny+1@ti−[(TM.sub.ny+1@ti−TM.sub.ny@ti).E.(M.sub.ny+1−m.sub.n)/(M.sub.ny+1−M.sub.ny)]

with E≤1,

[0399] Then the temperatures Tm.sub.n@t1, Tm.sub.n@t2 . . . adapted to the quantity m.sub.n of coffee C.sub.n part of the blend can be used to determine the roasting recipe of the customised blend according to above formula (I) or (II).

[0400] For example, based on FIG. 7, if the obtained quantity m.sub.n is 160 g, then then roasting recipes R.sub.150 and R.sub.200 corresponding respectively to 150 g and 200 g of coffee beans of type C.sub.n are identified. Then, since 160 g is closer to 150 g, the temperature Tm.sub.n to be applied to said 160 g of beans C.sub.n at each of discrete successive times t.sub.1, t.sub.2, . . . t.sub.6 is calculated from these roasting recipes R.sub.150 and R.sub.200 as follows:

T.sub.160.sub.@ti=T.sub.150.sub.@ti+[(T.sub.200.sub.@ti−T.sub.150.sub.@ti)*E*(160−150)/(200−150)]

with E≤1.

[0401] But, if the obtained quantity m.sub.n had been 180 g, m.sub.n would be closer to 200 g and the temperature to be applied at ti would have been T.sub.200.sub.@ti−[(T.sub.200.sub.@ti−T.sub.150.sub.@ti)*E*(200−180)/(200−150)].

[0402] The coefficient E is defined in the same manner as in the third mode.

[0403] Generally, in the step of determining the recipe R.sub.blend to be applied to a customised blend of different coffee beans introduced inside the chamber from the quantities m.sub.A, m.sub.B, . . . and roasting recipes RM.sub.A, RM.sub.B, . . . of said different types of coffee beans C.sub.A, C.sub.B, . . . any of the different above described modes enabling the determination of roasting recipes Rm.sub.A, Rm.sub.B, can be used. In particular, different modes can be used for different coffees.

[0404] FIG. 8 illustrates the use of a measuring device 3 to communicate quantities of beans introduced inside the roasting apparatus to the processing unit of the control system.

[0405] The measuring device 3 is connected to the processing unit 8 of the roasting apparatus 10. When a blend of coffees is customised, different coffees are introduced inside the chamber 1 positioned in relation to the measuring device 3. For example if the measuring device is a scale, the chamber 1 can be positioned on the scale.

[0406] In a step 1, a first quantity of coffee C.sub.A is introduced inside the chamber. The scale detects the introduction of beans and provides the information to the control system 80 of the apparatus. The control system can be configured to display a message through the user interface 6 to require the operator enters the identification of the beans C.sub.A. In the operation of identification, the operator can input the type of the beans like a SKU reference, a trademark or a more general level description like Arabica green beans or Robusta pre-roasted beans.

[0407] Then or simultaneously, in step 2, the measuring device provides the quantity m.sub.A of beans C.sub.A present in the chamber. A further step, not illustrated, can happen where the control system asks the operator to confirm the introducing of beans C.sub.A in the chamber is finished.

[0408] In step 3, the scale detects the introduction of beans again and provides the information to the control system 80 of the apparatus, which implements the steps 4 and 5 identical the previous steps 1 and 2 of requiring identification of the beans being introduced, here C.sub.B, and getting access to the measured quantity m.sub.B of said beans C.sub.B in the chamber.

[0409] In step 6, the chamber 1 is positioned inside the apparatus 10 finishing the steps of obtaining the identification and quantities of the different coffee beans part of the customised blend. Alternative implementations can be used: the measuring device can be part of the chamber which does not require the withdrawal of the chamber form the apparatus.

[0410] Usually the measured quantity is the weight of the beans. Alternatively, it can be the volume. If the quantity provided by the measuring device is a volume and not a weight, the weight can be deduced indirectly from an average density of coffee beans or more preferably, the identification of the nature of the beans provides access to the exact density of said beans enabling the calculation of the weight of beans introduced in the chamber.

[0411] FIG. 9 illustrates the block diagram of an alternative embodiment of the control system 80 of a roasting apparatus 1.

[0412] In this embodiment, the control system is implemented through two processing units, one processing unit 8 being part of the roasting apparatus 1 and the other processing unit 81 being part of an external command device like a tablet or a smartphone.

[0413] The processing unit 8 of the roasting apparatus can provide less functions than the processing unit illustrated in FIG. 2 and is limited essentially to the core functions of the roasting apparatus that is applying a determined recipe by control of the air flow driver and the heater. The presence of a user interface can even be optional.

[0414] The determined roasting recipe for the new customized blend can be provided through the communication interface 11 establishing communication with the communication interface 111 of the processing unit 81 of the external device. The processing unit 81 is configured to receive input about the types and quantities of the beans introduced inside the chamber of the roasting apparatus through the user interface 61 of the external device and/or through a measuring device 3 and/or through a code reader 71.

[0415] The processing unit 81 of the external device is configured to execute the program enabling the determination of the roasting recipe of the blend, this program being stored in the memory unit 131 of the processing unit or accessible in a remote server 15 through the communication interface 111. Once the roasting recipe of the blend is determined, it can be communicated to the processing unit 8 of the roasting apparatus 1 for execution of the roasting operation.

[0416] The present invention provides the advantage of enabling the rapid and easy determination of the roasting recipe of a customized blend from the at least one existing recipe of each of the coffee beans part of the blend. Once at least one roasting recipe of a type of beans is accessible, it becomes possible to use this existing roasting recipe to determine the roasting recipe of a blend comprising said type of beans.

[0417] Another advantage is that, when the roasting recipes of existing commercialized blends of coffee beans are defined by this method and the sourcing of one type of the beans of the blend is no more possible for various reasons, it becomes possible to replace this type of beans by another one and to define rapidly and automatically the new roasting recipe of the blend based on the recipe of this new type of coffee beans and the recipes of the other types of beans already present in the blend.

[0418] Although the invention has been described with reference to the above illustrated embodiments, it will be appreciated that the invention as claimed is not limited in any way by these illustrated embodiments.

[0419] Variations and modifications may be made without departing from the scope of the invention as defined in the claims. Furthermore, where known equivalents exist to specific features, such equivalents are incorporated as if specifically referred in this specification.

[0420] As used in this specification, the words “comprises”, “comprising”, and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean “including, but not limited to”.

LIST OF REFERENCES IN THE DRAWINGS

[0421]

TABLE-US-00001 roasting apparatus 10 chamber  1 bottom opening 11 top opening 12 heating device  2 air flow driver 21 heater 22 passage 23 measuring device  3 housing  4 air outlet hole 41 air inlets 42 temperature probe  5 user interface  6, 61 code reader  7, 71 processing unit  8, 81 control system 80 power supply  9, 91 sensor 10 communication interface 11, 111 database 12 memory unit 13, 131 coffee beans 14 server 15