JP7638479B2 - Coffee bean roasting device and method - Google Patents

Description

This disclosure relates to a coffee bean roasting device and method.

As an example of this type of technology, Patent Document 1 discloses a method for producing coffee beans, which includes a step of measuring the amount of carbon monoxide generated from coffee beans during roasting, a step of checking the roast level of the coffee beans when the amount of carbon monoxide is measured during the step of roasting the coffee beans, a step of determining a correspondence relationship between the roast level of the coffee beans and the amount of carbon monoxide based on the results of checking the roast level of the coffee beans, and a step of using the correspondence relationship as an index of the roast level when roasting coffee beans of at least one type or lot different from the coffee beans.

Patent No. 6173395

One of the purposes of roasting coffee beans is to bring out the desired aroma and flavor of the coffee beans. In conventional coffee bean roasting methods, the change in color of the coffee beans during roasting is often used as a criterion for controlling the roasting. For example, in the method disclosed in Patent Document 1, the correspondence between the amount of carbon monoxide generated from the coffee beans during roasting and the roast level of the coffee beans is used as a control index, but since the roast level is based on the change in color of the coffee beans, the change in color of the coffee beans is directly related to the criterion for controlling the roasting (see paragraphs 0063 and 0073 of Patent Document 1).

However, there are many types of flavors that humans can perceive, such as fruity aromas, sweetness, and bitterness. For these reasons, simply using the change in color of coffee beans as a criterion for controlling roasting is not appropriate from the perspective of bringing out the desired flavor and aroma of coffee beans.

This disclosure was made in light of these points, and its purpose is to roast coffee beans to bring out the desired aroma and flavor.

A first aspect of the present disclosure is a coffee bean roasting device that includes a roasting unit that roasts coffee beans, a measuring unit that measures changes in the volatilization amounts of multiple components that constitute flavor and aroma components that volatilize from the coffee beans roasted in the roasting unit to obtain measurement results, and an adjusting unit that adjusts the roasting method performed by the roasting unit based on the measurement results, and the measurement results separately indicate changes in the volatilization amounts of the multiple components.

In this disclosure, the "change in volatilization amount" of each component refers to the time history of the volatilization amount of each component in the air, and "measuring the change in volatilization amount" means being able to measure whether the volatilization amount at a certain elapsed time t has increased or decreased compared to the volatilization amount at elapsed time 0.

In this first disclosure, the measurement unit measures the change in the volatilization amount of multiple components that make up the flavor and aroma components volatilizing from the roasted coffee beans, and the adjustment unit adjusts the roasting method based on the measurement results, so that the coffee can be roasted to bring out the desired flavor and aroma. In addition, the measurement results show the change in the volatilization amount of the flavor and aroma components that contain multiple components separately for each component, so that the coffee can be roasted to adjust the multiple flavor and aroma components of the roasted coffee beans. As described above, the coffee beans can be roasted to bring out the desired flavor and aroma.

A second aspect of the present disclosure is a coffee bean roasting device in which, in the first aspect, the measuring unit has a sensor having an adsorption film on its surface to which molecules constituting the plurality of components can be adsorbed, the measuring unit measures a change in the amount of volatilization of the plurality of components as the molecules contained in the air of the roasting unit are adsorbed by the adsorption film, and a switching means capable of switching the state around the sensor between a first state in which the air of the roasting unit flows around the sensor and a second state in which air outside the roasting device flows around the sensor.

In this second aspect, a specific configuration is obtained in which the change in the volatilization amount of the flavor components is measured by the sensor. In addition, the measurement unit has a switching means that can switch between a first state in which air from the roasting unit flows around the sensor and a second state in which air outside the roasting device flows around the sensor. This not only measures the change in the volatilization amount of the flavor components in the first state, but also allows normal air outside the roasting device to flow in in the second state as necessary, returning the state around the sensor to the state before measurement. Then, even if too many molecules are adsorbed on the adsorption film of the sensor or the moisture content of the adsorption film fluctuates and accurate measurement is no longer possible, the sensor state can be initialized and the volatilization amount of the flavor components can be accurately measured.

A third aspect of the present disclosure is a coffee bean roasting device according to the first or second aspect, in which the plurality of components includes bitter components whose volatilization rate accelerates after the crack when the coffee beans are roasted.

In this third aspect, it is possible to measure the change in the amount of bitter components volatilized, the increase in which occurs accelerates after the roasting process. In other words, coffee can be roasted in a way that suppresses the production of bitter components.

A fourth aspect of the present disclosure is a method for roasting coffee beans using the roasting device according to the third aspect, the measuring unit having a plurality of sensors capable of measuring different components, the method including a classification step of acquiring the volatilization amount changes of the plurality of components for each component using the plurality of sensors while roasting the coffee beans, a classification step of acquiring the volatilization amount changes of the plurality of components for each component using the plurality of sensors while roasting the coffee beans, and classifying the acquired plurality of volatilization amount changes by flavor type, and from the plurality of volatilization amount changes classified in the classification step, This method for roasting coffee beans includes a step of identifying a bitterness detection sensor capable of measuring the change in the volatilization amount of the bitterness component from among the plurality of sensors by identifying the change in the volatilization amount of the bitterness component, a roasting step of roasting coffee beans after the identifying step, a measurement step of measuring the change in the volatilization amount of the bitterness component volatilized from the coffee beans in the roasting step with the bitterness detection sensor to obtain the measurement result including the change in the volatilization amount of the bitterness component, and an adjustment step of adjusting the roasting method in the roasting step based on the measurement result.

In this fourth aspect, a bitterness detection sensor capable of measuring the change in the amount of volatilization of bitter components is identified from among a plurality of sensors, and then a roasting process is carried out. Then, the change in the amount of volatilization of each bitterness component volatilized from the coffee beans during the roasting process is measured, and the roasting method can be adjusted based on the measurement results. Therefore, it is possible to roast in a way that brings out the desired aroma and flavor while suppressing the generation of bitterness components.

As explained above, according to the present disclosure, coffee beans can be roasted to bring out the desired aroma and flavor.

FIG. 1 is a schematic diagram showing a coffee bean roasting device according to an embodiment. 1 is a graph showing the change in the amount of volatilization of flavor components measured in Reference Example 1. 1 is a graph showing the change in the amount of volatilization of flavor components measured in Reference Example 2. 1 is a graph showing the change in the amount of volatilization of flavor components measured in Reference Example 3.

The following describes embodiments of the present disclosure. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its applications, or its uses.

[Embodiment]
<Coffee bean roasting equipment>
1 shows a coffee bean roasting device D according to an embodiment of the present disclosure. The roasting device D includes a roasting unit 1 that roasts coffee beans, a measuring unit 2 that measures changes in the volatilization amounts of multiple components that constitute flavor and aroma components volatilized from the coffee beans roasted in the roasting unit 1, and an adjusting unit 3 that adjusts the roasting method performed by the roasting unit 1 based on the measurement results of the measuring unit 2.

The configurations of the roasting unit 1, measuring unit 2, and adjustment unit 3 are explained in detail below with reference to Figure 1.

<Roasting Department>
The roasting section 1 has a roasting container 11 for accommodating coffee beans. The roasting container 11 for industrial use is large enough to accommodate, for example, 5 to 80 kg of coffee beans, and for home use is large enough to accommodate, for example, 0.05 to 1 kg of coffee beans. The roasting container 11 is configured to be rotatable in order to mix the coffee beans. The rotation speed of the roasting container 11 is, for example, 30 to 120 rpm.

The roasting section 1 also has a heat source 12 for supplying heat to the coffee beans contained in the roasting container 11. The heat source 12 is, for example, a gas burner. The temperature of the air heated by the heat supplied by the heat source 12 is, for example, 100 to 300°C.

Moreover, roasting unit 1 has an air blowing unit 13 that blows air heated by heat supplied from heat source 12 to the coffee beans contained in roasting container 11. Air blowing unit 13 is, for example, a compressor (blower). The amount of air blown by air blowing unit 13 per 1 kg of coffee beans is, for example, 0.1 to 1 ^m3 per minute.

The roasting section 1 is connected to an exhaust passage 14a through which the air blown from the blowing section 13 passes through the roasting vessel 11 and is discharged outside the roasting device D, and a measurement passage 14b through which the air flows into the measurement section 2 (hereinafter, when describing the positions of the exhaust passage 14a and the measurement passage 14b, the side closer to the roasting vessel 11 is referred to as the "upstream side" and the side farther from the roasting vessel 11 is referred to as the "downstream side"). In the exhaust passage 14a, a temperature measurement section 15 is provided to measure the temperature of the air discharged from the roasting vessel 11 in order to know the atmospheric temperature inside the roasting vessel 11. In addition, a chaff collector 16 is provided in the exhaust passage 14a downstream of the temperature measurement section 15 to collect chaff (so-called silver skin) of coffee beans. The chaff collector 16 is provided with an afterburner 17 to burn and remove the collected chaff.

The roasting unit 1 is also provided with a control unit 18 that adjusts the roasting conditions for the coffee beans to control the roasting. The control unit 18 controls the roasting by, for example, adjusting the roasting conditions or ending the roasting in response to instructions from the adjustment unit 3, as described below.

<Measurement section>
The measurement unit 2 has a filter 21 provided in the middle of the measurement passage 14b. The filter 21 is for removing foreign matter such as chaff from the air that flows into the measurement passage 14b from the roasting container 11. The filter 21 is, for example, a ceramic filter that is resistant to high temperatures.

The measurement unit 2 also has a cooling device 22 that is provided downstream of the filter 21 and midway through the measurement passage 14b. The cooling device 22 can cool the air passing through the measurement passage 14b, for example, to room temperature.

The measurement unit 2 also has an air valve 23 (switching means) provided in the measurement passage 14b downstream of the cooling device 22. The air valve 23 is configured to be able to switch the air flowing downstream between a first state in which the air in the roasting container 11 flows through the measurement passage 14b to the downstream side of the air valve 23, and a second state in which clean air outside the roasting device D flows downstream of the air valve 23.

The measurement unit 2 also has a gas pump 24 that is provided in the measurement passage 14b downstream of the air valve 23. The gas pump 24 is configured to be able to adjust the amount of air flowing downstream by blowing air downstream as needed.

The measurement unit 2 also has a plurality of sensors 25 downstream of the gas pump 24, which measure the change in the volatilization amount of flavor components in the air flowing in from the roasting unit 1. The plurality of sensors 25 are different from each other in the components that can be measured. The plurality of sensors 25 have an adsorption film on the surface that can adsorb specific molecules that constitute the flavor components. The plurality of sensors 25 are different from each other in the types of specific molecules that can be adsorbed by each adsorption film (hereinafter, in the description of this embodiment, "multiple sensors" will be simply referred to as "sensors"). Since a specific voltage is always applied to the sensor 25, it vibrates at a specific vibration frequency corresponding to the specific voltage. When a molecule is adsorbed to the adsorption film, the sensor 25 changes the vibration frequency in response to the adsorbed molecular weight, and outputs a voltage signal α with an intensity corresponding to the change in the vibration frequency. The "adsorbed molecular weight" here is, strictly speaking, the difference between the weight of the molecule adsorbed to the adsorption film and the weight of the molecule released from the adsorption film, and is correlated with the molecular concentration in the air, i.e., the amount of volatilization. That is, the intensity of the voltage signal α is determined according to the amount of volatilization of adsorbable molecules in the air, and the amount of volatilization of adsorbable molecules can be determined from the intensity of this voltage signal α. In this way, the sensor 25 is configured to measure the amount of volatilization of molecules contained in the air that flows in from the roasting section 1 through the measurement passage 14b. Then, by measuring the change in the voltage signal α of the sensor 25, the change in the amount of volatilization of molecules can be determined. More specific details on the measurement of the change in volatilization amount will be described later as an explanation of the measurement process in the roasting method.

The multiple flavor and aroma components that the sensor 25 can measure include a first component and a second component that has a different composition from the first component (i.e., at least one of the types of constituent molecules and the content rate of the constituent molecules is different). In this embodiment, the first component is a sweet component that starts to increase in volatilization amount prior to other components when the coffee beans are roasted, and the second component is a bitter component whose increase in volatilization amount accelerates after the crack when the coffee beans are roasted. Here, "crack" refers to a cracking sound that occurs during roasting of the coffee beans. Also, "the increase in volatilization amount accelerates" means that the rate of increase in the volatilization amount becomes even faster. In other words, the rate of increase in the volatilization amount of the second component, which is a bitter component, becomes faster after the crack compared to before the crack.

The aforementioned measurement results indicate the time history of the volatilization amount of the flavor component whose change in volatilization amount is measured (volatilization amount at each time point since the start of roasting), and specifically, the time history of the volatilization amount of the first component and the second component separately. In addition, the measurement results may also indicate information at the time of measurement (for example, the temperature inside the roasting container, the air temperature, etc.).

In case the pressure around the sensor 25 increases due to the air blown by the gas pump 24, an exhaust section (not shown) that can exhaust air to the outside may be provided around the sensor 25 so that the pressure around the sensor 25 can be kept constant.

<Adjustment section>
The adjustment unit 3 receives data on the measurement results from the measurement unit 2, and instructs the control unit 18 of the roasting unit 1 to adjust the roasting method as appropriate based on the measurement results. This makes it possible to adjust the roasting method by the roasting unit 1. The specific adjustment method will be described later as an explanation of the adjustment process in the roasting method.

The adjustment unit 3 also has a computer 31 for recording the measurement result data.

<How to roast coffee beans>
The coffee bean roasting method is a method of roasting coffee beans using the above-mentioned roasting device D. That is, the coffee bean roasting method includes a roasting step of roasting coffee beans, a measuring step of measuring the volatilization amounts of a plurality of flavor and aroma components volatilized from the coffee beans roasted in the roasting step to obtain measurement results, and an adjusting step of adjusting the roasting method based on the measurement results of the measuring step. Each step will be described below.

<Roasting process>
Coffee beans are roasted by the roasting unit 1 described above. Specifically, the roasting process is a process in which air heated by a heat source 12 is blown by an air blowing unit 13 to supply heat to the coffee beans in a roasting container 11, so-called a hot air method, in which the coffee beans are roasted. The roasting time is determined according to the capacity of the roasting container and the set values of the types of flavor and aroma components and the amount of volatilization to be measured, and is, for example, 300 to 4800 seconds. The roasting container may be rotated during roasting. Also, the temperature inside the roasting container 11 may be checked during roasting using a temperature measuring unit 15.

The type of coffee beans used is not particularly limited, and may be, for example, any of Arabica, Robusta, Liberica, and Arabusta. The origin of the coffee beans is also not particularly limited, and may be, for example, any of Ethiopia, Kona, Java, Brazil, Ethiopia, Costa Rica, Kilimanjaro, Vietnam, Colombia, Tanzania, Mocha, Blue Mountain, Crystal Mountain, Kenya, Mandheling, and Mexico. The coffee beans may be used alone or in combination of two or more types. The coffee beans may be decaffeinated.

In addition, in the roasting process, in order to remove chaff from the coffee beans while roasting, the chaff generated by roasting may be collected by a chaff collector 16, or the chaff may be burned and removed by an afterburner 17.

<Measurement process>
The volatilization amount of a plurality of flavor components is measured by the measuring unit 2. The measurement of the volatilization amount may be performed continuously without interruption after the start of roasting, or may be performed intermittently with interruptions. When performing the measurement intermittently with interruptions, clean air is allowed to flow into the vicinity of the sensor 25 by the air valve 23 as necessary when no measurement is being performed. Note that, when the adsorption film of the sensor 25 is hydrophilic, it is preferable to make the above-mentioned clean air contain or be saturated with water vapor in order to prevent measurement errors caused by fluctuations in the moisture content in the adsorption film affecting the voltage signal α.

After the start of roasting, the moisture contained in the coffee beans turns into water vapor for a certain time (e.g., 100 seconds), so the measurement of the amount of volatilization of the flavor and aroma components is not stable. In addition, since the moisture turns into water vapor through an endothermic reaction, the temperature inside the roasting vessel 11 remains at about 100°C during the certain time. For this reason, it is preferable to set the start time of the measurement of the flavor and aroma components at the time when the temperature inside the roasting vessel starts to rise after the certain time. In addition, it is preferable to take the average value {α(0)} of each voltage signal of the sensor 25 for a certain time (e.g., 10 seconds) immediately after the start of measurement, and divide the voltage signal α obtained thereafter by the average value {α(0)}, α/{α(0)}, as the reference value for adjusting the roasting method. The reason for this is that the voltage signal immediately after the start of measurement contains information that depends on the initial state of the sensor 25, and such information becomes a bias for adjusting the roasting method, so that such a factor that causes a measurement error must be removed. Hereinafter, α/{α(0)} is set as the reference value β for adjusting the roasting method. This reference value β is considered to be approximately proportional to the amount of volatilization of the flavor components measured by the sensor 25, and indicates the change in the amount of volatilization of the flavor components.

<Adjustment process>
The roasting method in the roasting section 1 is adjusted by the adjustment section 3 described above.

Specifically, the adjustment unit 3 receives data on the measurement results of the measurement unit 2 (i.e., the time history of the aforementioned reference value β), and instructs the control unit 18 of the roasting unit 1 to adjust the roasting method appropriately based on the measurement results. Adjustments to the roasting method include, for example, adjusting the amount of heat from the heat source 12 (e.g., increasing or decreasing the amount of heat supplied, or stopping it), adjusting the amount of air blown by the air blowing unit 13, and adjusting the rotation speed of the roasting container 11.

For example, the adjustment unit 3 sets a threshold value c for the reference value β that represents the change in the amount of volatilization of flavor components measured by the sensor 25, and when the reference value β shown in the measurement result reaches the threshold value c, the adjustment unit 3 instructs the control unit 18 to adjust the roasting method.

<Action and Effects>
In this embodiment, the measurement unit 2 measures the amount of evaporation of multiple flavor and aroma components volatilizing from the coffee beans being roasted, and the adjustment unit 3 adjusts the roasting method based on the measurement results, so that the roasting can be performed to bring out the desired flavor and aroma. Furthermore, the measurement results show the time history of the amount of evaporation of the flavor and aroma components containing multiple components separately for each component, so that the roasting can be controlled to adjust the multiple flavor and aroma components of the coffee beans being roasted. As described above, the coffee beans can be roasted to bring out the desired flavor and aroma.

As shown in Reference Examples 1 to 3 below, the change in color of coffee beans during roasting varies depending on the type of coffee beans, and the amount of each component that makes up the flavor and aroma components that volatilize during roasting also varies depending on the type of coffee beans.

In this embodiment, the amount of evaporation of multiple aroma and flavor components evaporating from the roasted coffee beans is measured, and the roasting method is adjusted by the adjustment unit 3 based on the measurement results, so that the coffee beans can be roasted in a way that consistently brings out the desired aroma and flavor, regardless of the type of coffee beans.

Conventionally, when roasting coffee beans, the person roasting the beans (hereinafter referred to as the "operator") often judges when the roasting is finished based on the color of the beans, which changes during the roasting process. When adjusting the roasting method based on the operator's judgment, if the operator's skill is insufficient, there is a risk that the roasting will not be performed accurately.

In this embodiment, the roasting method is adjusted by the adjustment unit 3 based on the above measurement results, so roasting can be performed stably to bring out the desired aroma and flavor regardless of the operator's skill level.

The sensor 25 outputs a voltage signal α corresponding to the amount of volatilization of flavor components from a specific vibration frequency corresponding to the weight of molecules adsorbed to the adsorption film. However, if the adsorption film is hydrophilic, the fluctuation in the amount of moisture in the air may affect the vibration frequency and thus the output voltage signal α. In other words, if the amount of moisture in the air fluctuates, the amount of volatilization of the components that make up the flavor components may not be measured accurately. For example, since the air flowing from the roasting section 1 is generally dry due to roasting, the amount of moisture contained in the adsorption film decreases as the roasting time progresses. Then, the vibration frequency also changes accordingly, but such a change in vibration frequency (and the corresponding change in the voltage signal α) may cause measurement errors in the measurement of the change in the amount of volatilization of flavor components, and therefore accurate measurement may not be possible. In addition, if too many molecules are adsorbed to the adsorption film of the sensor 25, accurate measurement may not be possible.

In this embodiment, the measurement unit 2 has an air valve 23 that can be switched between a first state in which air from the roasting unit 1 flows around the sensor 25 and a second state in which air from outside the roasting device D flows around the sensor 25. If necessary, normal air from outside the roasting device D can be introduced in the second state to initialize the state around the sensor 25, allowing the sensor 25 to intermittently measure the flavor components. Then, even if the amount of vaporization of the flavor components cannot be accurately measured due to fluctuations in the moisture content in the adsorption film or excessive adsorption of molecules to the adsorption film of the sensor 25, the state of the sensor 25 can be initialized to accurately measure the amount of vaporization of the flavor components.

In addition, this embodiment can measure the amount of bitter components that evaporate more rapidly after the roasting process. In other words, coffee can be roasted in a way that suppresses the production of bitter components.

In addition, in this embodiment, the measurement unit 2 has a gas pump 24 upstream of the sensor 25, so that the gas pump 24 can appropriately blow air toward the sensor 25 to stabilize the pressure around the sensor 25, allowing the sensor 25 to stably measure changes in the amount of volatilization of flavor components.

[Modification of the embodiment]
Incidentally, there are many types of flavors that humans can sense, such as fruity aromas, sweetness, bitterness, etc. For this reason, there may be cases where it is desired to understand what types of flavor components humans can sense correspond to components whose volatilization amount can be measured by each of the multiple sensors 25. In other words, there may be cases where it is desired to associate a component whose volatilization amount can be measured by each of the multiple sensors 25 with what flavor a person perceives that component to be.

In consideration of the above-mentioned cases, in the roasting method according to the modified embodiment, the components whose volatilization change can be measured by each of the multiple sensors 25 are associated with the aroma and flavor sensed by a person, and then the roasting method according to the above-mentioned embodiment is performed. Below, the roasting method according to this modified embodiment is explained, but explanations of the parts common to the above embodiment are omitted.

In the roasting method according to this modified example, first, while roasting coffee beans, the volatilization amount changes of multiple components are acquired for each component by multiple sensors 25, and a classification process is performed to classify the acquired multiple volatilization amount changes by flavor type. The method of classifying the multiple volatilization amount changes may be, for example, a method using a learning device that has previously machine-learned the relationship between the pattern of volatilization amount changes and specific flavor components, or it may be statistical analysis including principal component analysis.

Note that the multiple sensors 25 can detect different components, but in this modified example, it may be unclear which specific components can be detected.

Next, from the time histories of each component acquired in the classification process described above, the time histories of the volatilization amounts of the first component (sweet component) and the second component (bitter component) are identified, and an identification process is performed to identify, from among the multiple sensors 25, a first sensor (sweetness detection sensor) and a second sensor (bitterness detection sensor) that can measure the changes in the volatilization amounts of the first component and the second component, respectively.

Then, the roasting process, measuring process, and adjustment process are carried out in the same manner as in the manufacturing method according to the above-mentioned embodiment.

In this modified example, a first sensor (sweetness detection sensor) and a second sensor (bitterness detection sensor) capable of measuring the change in the volatilization amount of a first component (sweetness component) and a second component (bitterness component), respectively, are identified from among a plurality of sensors 25, and then a roasting process is carried out. Then, the change in the volatilization amount of the first component and the second component volatilized from the coffee beans during the roasting process is measured, and the roasting method can be adjusted based on the measurement results. Therefore, it is possible to roast in a way that brings out the desired aroma and flavor while suppressing the bitterness components.

In addition, in this modified example, the sensors 25 capable of measuring the first and second components are identified, so that even if it is unknown which components can measure the change in volatilization amount with each of the multiple sensors 25, coffee can be roasted to bring out the desired aroma and flavor.

[Other embodiments]
In the roasting device D according to the above embodiment, the roasting unit 1 only needs to be able to roast coffee beans. For example, direct-fire roasting may be performed in which the coffee beans are directly heated, in which case the blower unit 13 is not necessary. The measuring unit 2 only needs to be able to measure the amount of volatilization of flavor and aroma components, and only needs to have at least the sensor 25. The measuring unit 2 is configured independently of the roasting unit 1 via the measurement passage 14b, but the measuring unit 2 may be configured integrally with the roasting unit 1, for example, may be incorporated inside the roasting unit 1. With this configuration, if the distance between the coffee beans to be roasted and the sensor 25 of the measuring unit 2 is reduced, the time difference between roasting and the measurement of the amount of volatilization of flavor and aroma components is reduced, enabling more accurate control of roasting.

In addition, in the above embodiment, the measurement results by the measuring unit 2 separately show the change in the volatilization amount of the first component as a sweet component and the second component as a bitter component, but the measurement results are not limited to this and may be any that separately show the time history of the volatilization amount of multiple components.

In addition, although there are multiple sensors 25 in the above embodiment, a single sensor may be used. In addition, the sensor 25 changes its vibration frequency when molecules are adsorbed to an adsorption film, but is not limited to this and may be any sensor capable of measuring the change in the amount of volatilization of flavor components.

In addition, in the above embodiment, the change in the amount of volatilization of flavor and aroma components is used as a criterion for controlling roasting, but the color of the coffee beans may also be added as a criterion.

In the above embodiment, the adjustment unit 3 instructs the control unit 18 to adjust the roasting method when the reference value β shown in the measurement result reaches a preset threshold value c. Alternatively, or in addition, the adjustment unit 3 may do the following. That is, after the start of measurement, at the point of time t that has elapsed, the adjustment unit 3 predicts the reference value β(t+Δt) at the time t+Δt has elapsed based on the change in the reference value (β(0)-β(t)) from the time 0 to t, and issues an instruction to adjust the roasting method. For example, if the reference value β is for a flavor component whose volatilization amount increases or decreases monotonically after the start of measurement, the reference value β(t+Δt) at the time t+Δt can be easily predicted at the time t that has elapsed.

Below, we will explain Reference Examples 1 to 3 in which coffee beans were actually roasted and evaluated to demonstrate the usefulness of the coffee roasting device D and roasting method according to the present disclosure. As described above, the roasting device D and roasting method according to the present disclosure are based on the change in the volatilization amount of the first and second components in order to adjust the way the roast is done, but Reference Examples 1 to 3 are based on the change in the volatilization amount of only the second component. Furthermore, Reference Examples 1 to 3 use the same roasting device and roasting method, except that the roasted coffee beans are produced in different places.

<Preparing the roasting equipment>
The configuration of the roasting device used was the same as that described in the above embodiment, except for the adjustment unit. Specific product names, etc. are as follows.

The filter used was Isofil (registered trademark) IV manufactured by Isolite Industries Co., Ltd. The roasting section used an industrial roasting furnace (model number R60ROA) manufactured by Gotthot Co., Ltd. The heat source used was a gas burner, and the blower was used as the air blowing section.

As sensors, 180 nose@MEMS (registered trademark) manufactured by I-PEX Corporation were used. In other words, the 180 sensors used were able to measure the change in the volatilization amount of a total of 180 types of molecules. As a gas pump, an accessory to the nose@MEMS (registered trademark) was used. The capacity of the gas pump was stable at 100 mL/min.

<Classification process and identification process>
Since the molecules capable of measuring the change in volatilization amount were unknown for the 180 sensors described above, the classification process and identification process described in the description of the modified example described above were carried out. That is, the patterns of change in the voltage signals of the 180 sensors during roasting were classified, and six types (patterns 1 to 6) that are particularly related to the aroma and flavor component x of coffee beans (hereinafter, the aroma and flavor component of coffee beans will be referred to as x) were identified from the classified patterns, and sensors A to F whose obtained time changes in the reference value βx are similar to these patterns 1 to 6 were identified. An explanation of these patterns 1 to 6 is shown in Table 1.

The change in voltage signal corresponding to the change in the volatilization amount of the flavor component (first component) that increases before the other components is pattern 2 and 4, and the first sensors that can measure the change in the volatilization amount of this first component are sensors B and D. The change in voltage signal corresponding to the change in the volatilization amount of the flavor component (second component) that increases after the break is pattern 3, and the second sensor that can measure the change in the volatilization amount of this second component is sensor C.

<Roasting process and measurement process>
Arabica coffee beans were roasted in amounts of 60 kg each from Colombia (Reference Example 1), Brazil (Reference Example 2), and Ethiopia (Reference Example 3). The point at which the temperature in the roasting container started to rise after the start of roasting was set as the start point of measurement of the flavor and aroma components. Data on the voltage signal αx for flavor and aroma component x was received from sensors A to F. The average value {αx(0)} of the voltage signal for 10 seconds immediately after the start of measurement was calculated, and then the obtained voltage signal αx was divided by {αx(0)} to obtain αx/{αx(0)}, which was set as the reference value βx of flavor and aroma component x.

The changes in the reference value βx (corresponding to the change in the volatilization amount of the second component) measured in Reference Examples 1 to 3, obtained from sensor C capable of measuring the change in the volatilization amount of the second component (bitter component), are shown in Figure 2 (Reference Example 1), Figure 3 (Reference Example 2), and Figure 4 (Reference Example 3), respectively. In the graphs of Figures 2 to 4, the vertical axis indicates the reference value βx of the second component x, and the horizontal axis indicates the measurement time of the flavor component x, with the measurement start time being set to 0.

<Adjustment process>
The adjustment unit 3 is configured to stop the supply of heat to the coffee beans by the roasting unit 1, terminate the roasting, and stop the gas pump when the reference value βx obtained from the sensor C exceeds a preset threshold value cx for three seconds or more.

(Comparison of roasting results and sensory test)
A sensory test was conducted using the sense of smell of five people, and the roasting results were compared with those of Reference Examples 1 to 3.

In the aforementioned measurement process, when the standard value βx of the flavor and aroma components measured by sensor C reached 1.1, 1.2, and 1.3, 100 g samples of the coffee beans being roasted were taken from the roasting furnace and used as samples for evaluation. Hereinafter, the samples of Reference Example 1 (produced in Colombia) will be referred to as C1, C2, and C3 in the order in which they were taken. Similarly, the samples of Reference Example 2 (produced in Brazil) and Reference Example 3 (produced in Ethiopia) will be referred to as B1, B2, and B3, and E1, E2, and E3, respectively, in the order in which they were taken. Note that Figures 2 to 4 show the time points at which these samples were taken.

The sampled coffee beans were each crushed into powder, and a sensory test was conducted in which five people smelled the compressed coffee beans. The results of the sensory test are shown in Table 2 below. Note that the sensory test results shown in Table 2 are the results of the most consistent evaluations among the opinions of the five people who participated in the sensory test.

Although the results of the sensory test differed depending on the type of coffee beans (place of origin) and the degree of roasting (the magnitude of the reference value βx), in all of Reference Examples 1 to 3, when the reference value βx (indicating the change in the amount of volatilization of the second component) measured by sensor C reached 1.3, a burnt odor was sensed (see C3, B3, and E3 in Table 2). This shows that, regardless of the type of coffee beans, the generation of a burnt odor can be suppressed by ending the roasting before the reference value βx reaches 1.3.

(Checking the color of coffee beans)
The colors of the coffee beans roasted in Reference Examples 1 to 3 were confirmed as follows.

As mentioned above, the coffee beans collected as samples were each crushed into powder and compressed, and their color was measured using a Lightells kit (model number CM-100), which was used as a standard. The color of the coffee beans crushed into powder and compressed was compared with the color sample of the Specialty Coffee Association of America (SCAA) standard measurement scale shown in Table 3 below.

The color evaluation results for the coffee bean samples are shown in Table 4 below. Note that the values in the "SCAA value of sample" section in Table 4 are the results of comparing with the SCAA standard color samples in Table 3.

According to Table 4, when comparing the roasting times of samples roasted in Reference Example 1 and Reference Example 2 with the same reference value βx, there are differences in that C1 is 70 seconds shorter than B1, C2 is 90 seconds shorter than B2, and C3 is 120 seconds shorter than B3. Despite these differences in roasting times, the color matching results show that C1 (74) and B1 (75), C2 (55) and B2 (56), and C3 (35) and B3 (35) all show almost the same values, meaning that there is no significant difference in color between Reference Example 1 and Reference Example 2.

In Table 4, on the other hand, when comparing the roasting times of the samples roasted in Reference Example 1 and Reference Example 3 with those showing the same βx, there were only slight differences: C1 was the same as E1, C2 was 10 seconds shorter than E2, and C3 was 10 seconds shorter than E3. However, the color matching results were C1 (74) and E1 (80), C2 (55) and E2 (61), and C3 (35) and E3 (38), and overall Reference Example 1 had a smaller SCAA value and a darker color than Reference Example 3. Furthermore, the difference in the respective SCAA values is greater when comparing Reference Example 1 and Reference Example 3 than when comparing Reference Example 1 and Reference Example 2.

The results shown in Table 4 described above reveal the following. First, in a comparison between Reference Example 1 and Reference Example 2, the roasting time is significantly different between the same βx, but the difference in color is relatively small. In contrast, in a comparison between Reference Example 1 and Reference Example 3, the difference in roasting time is small between the same βx, but the difference in color is relatively large. In other words, the roasting level determined from the reference value βx may differ from the change in color of the coffee beans, and may also differ from the roasting level determined from the roasting time. For this reason, it can be seen that even if the roasting method is adjusted using either the change in color of the coffee beans or the roasting time as the criterion for determining the roasting level, the desired flavor and aroma components may not be extracted. In contrast, the manufacturing apparatus and manufacturing method disclosed herein, which adjust the roasting method using the change in the volatilization amount of the flavor and aroma components as a reference value, are excellent in that they directly measure the volatilization amount of the flavor and aroma components, and therefore can extract the desired flavor and aroma components.

(Measurement of changes in volatilization of multiple flavor components)
The changes in each reference value β obtained by sensors A to F during roasting in Reference Examples 1 to 3 are shown in Tables 5 to 7. Table 5 shows the results of each reference value βx obtained by sensors A to F during roasting in Reference Example 1 (Colombian).

Table 6 shows the results of the reference values βx obtained by sensors A to F during roasting of Reference Example 2 (Brazilian).

Table 7 shows the results of the reference values βx obtained by sensors A to F during roasting of Reference Example 3 (produced in Ethiopia).

As shown in Tables 5 to 7, the standard value βx of the flavor components volatilized from coffee beans by roasting has different patterns depending on the type of coffee beans. In other words, the roasting device and roasting method disclosed herein, which measures the change in the volatilization amount of multiple flavor components and adjusts the roasting method using multiple corresponding standard values as judgment criteria, is particularly useful when you want to bring out subtle flavors in the roasting of coffee beans.

D Roasting device 1 Roasting section
2. Measurement section
3 Adjustment section
11. Roasting container
12. Heat source
13 Blower section
14a Exhaust passage
14b Measurement passage
15 Temperature measurement unit
16 Chaff Collector
17. Afterburner
18 Control unit
21 Filter
22 Cooling device
23 Air valve (switching means)
24 Gas pump 25 Sensor (sensors)
31 Computer

Claims (4)

A roasting section for roasting coffee beans;
a measurement unit that measures changes in volatilization amounts of a plurality of components that constitute flavor and aroma components volatilized from the coffee beans roasted in the roasting unit and acquires measurement results;
and an adjustment unit that adjusts the roasting method by the roasting unit based on the measurement results.
The measurement unit has a plurality of sensors,
The plurality of sensors have an adsorption film on a surface thereof on which molecules constituting the plurality of components can be adsorbed, and the molecules contained in the air in the roasting section are adsorbed onto the adsorption film to measure a change in the amount of volatilization of the plurality of components;
the adsorption films of the plurality of sensors are different from one another in the types of specific molecules that they can adsorb;
The measurement results show the volatilization changes of the multiple components separately.
Coffee bean roasting equipment. In the roasting apparatus according to claim 1,
The coffee bean roasting device , wherein the measurement unit has a switching means capable of switching a state around the sensor, between a first state in which air from the roasting unit flows around the sensor and a second state in which air outside the roasting device flows around the sensor. A method for roasting coffee beans using the roasting device according to claim 1 or 2,
The method for roasting coffee beans, wherein the plurality of components include bitter components whose volatilization amount increases accelerated after the crack when the coffee beans are roasted. 4. The method for roasting coffee beans according to claim 3 ,
a classification step of acquiring a change in the volatilization amount of each of the plurality of components by the plurality of sensors while roasting the coffee beans, and classifying the acquired changes in the volatilization amount by flavor type;
a step of identifying a bitterness detection sensor capable of measuring the change in the volatilization amount of the bitterness component from among the plurality of the volatilization amount changes classified in the classification step, from among the plurality of sensors;
a roasting step of roasting the coffee beans after the identifying step;
a measuring step of measuring a change in the amount of volatilization of a bitter component volatilized from coffee beans in the roasting step with the bitterness detection sensor to obtain the measurement result including the change in the amount of volatilization of the bitter component;
and an adjusting step of adjusting the roasting method in the roasting step based on the measurement results.

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