Coffee machine, and cold brew coffee concentrate and preparation method therefor

Abstract

A coffee machine, and a cold brew coffee concentrate and a preparation method therefor. The coffee machine comprises a heat exchange structure, a temperature adjustment member, a brewing head, a liquid supply pump, and a controller. A heat exchange flow channel for allowing liquid to flow through is formed inside the heat exchange structure; the temperature adjustment member is used for heating and cooling the liquid in the heat exchange flow channel; a brewing cavity is formed inside the brewing head; the brewing cavity is used for accommodating coffee powder; an outlet of the heat exchange flow channel is communicated with the brewing cavity; the liquid supply pump is configured to be capable of pumping at least the liquid in the heat exchange flow channel into the brewing cavity; and the controller is electrically connected to the temperature adjustment member and the liquid supply pump. Also disclosed is a preparation method for the cold brew coffee concentrate. The method comprises: using hot water to perform blooming treatment on coffee powder, and then injecting cold water into the coffee powder subjected to the blooming treatment for drip filtration to obtain the cold brew coffee concentrate.

Description

Coffee machine, cold brew coffee liquid and its preparation method

[0001] Cross-references to related applications

[0002] This disclosure claims priority to Chinese patent applications filed on July 11, 2024, with application number 202410931120.7 entitled "Coffee Machine" and application number 202410931113.7 entitled "A Cold Brew Coffee Liquid and a Method for Preparing the Same", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of coffee making technology, and in particular to a coffee machine, cold brew coffee liquid, and a method for preparing the same. Background Technology

[0004] Cold brew coffee is increasingly popular due to its smooth taste, sweetness, and distinct aroma. The extraction methods for cold brew coffee typically include cold brewing or ice dripping. Cold brewing generally involves steeping ground coffee in cold water for an extended period (usually 10-24 hours) before filtering out the coffee grounds. Ice dripping involves placing ice cubes above a filter cup containing coffee grounds, allowing the melting ice to slowly drip and wet the coffee grounds. Ice dripping typically takes 6-8 hours and requires about 12 hours to steep before drinking.

[0005] In related technologies, because the water temperature for making cold brew coffee is low, the water and coffee grounds need to be in contact for a sufficiently long time in order to produce cold brew coffee with a good taste. Therefore, the process of making cold brew coffee is time-consuming. Summary of the Invention

[0006] The purpose of this disclosure is to provide a coffee machine, cold brew coffee liquid, and a method for preparing the same, in order to solve the technical problems existing in the related art.

[0007] To achieve the above objectives, according to a first aspect of this disclosure, a coffee machine is provided, comprising:

[0008] The heat exchange structure has internal heat exchange channels for the flow of liquid.

[0009] Temperature regulating element, used for heating and cooling the liquid in the heat exchange channel;

[0010] The brewing head has a brewing chamber inside, which is used to hold coffee powder, and the outlet of the heat exchange channel is connected to the brewing chamber.

[0011] The liquid supply pump is configured to at least pump the liquid in the heat exchange channel into the brewing chamber.

[0012] The controller is electrically connected to the temperature regulator and the liquid supply pump;

[0013] The controller is used to control the temperature regulating element to heat the liquid in the heat exchange channel, and pump the heated liquid into the brewing chamber through the liquid supply pump to brew the coffee powder in the brewing chamber. After the brewing is completed, the controller controls the temperature regulating element to cool the liquid in the heat exchange channel, and pump the cooled liquid into the brewing chamber through the liquid supply pump to brew the coffee powder in the brewing chamber.

[0014] Optionally, the coffee machine further includes a liquid outlet pipe, the first end of which is connected to the outlet of the heat exchange channel, and the second end of which is connected to the brewing chamber;

[0015] The liquid supply pump can also pump the liquid in the liquid outlet pipe from the second end of the liquid outlet pipe toward the first end of the liquid outlet pipe.

[0016] The controller is also used to control the liquid supply pump to pump the remaining liquid in the outlet pipe into the heat exchange channel after the heated liquid is pumped into the brewing chamber by the liquid supply pump.

[0017] Optionally, the controller controls the temperature regulating element to heat the liquid in the heat exchange channel, including:

[0018] The liquid in the heat exchange channel is heated to 40℃-60℃;

[0019] The controller controls the cooling of the liquid in the heat exchange channel by the temperature regulating element, including:

[0020] The liquid in the heat exchange channel is cooled to 4℃-10℃.

[0021] Optionally, the temperature regulating element is a thermoelectric cooler, which has a first surface and a second surface facing each other, the first surface being in thermal contact with the heat exchange structure, and the thermoelectric cooler also having a first terminal and a second terminal for connecting to a circuit.

[0022] The first surface is capable of absorbing heat from the liquid in the heat exchange channel when current flows from the first terminal to the second terminal, and releasing heat to the liquid in the heat exchange channel when current flows from the second terminal to the first terminal.

[0023] Optionally, the coffee machine further includes a heat dissipation structure and a pressure cap, the heat dissipation structure being in thermal contact with the second surface, the heat exchange structure and the semiconductor cooling chip being sandwiched between the pressure cap and the heat dissipation structure, and fasteners passing through the pressure cap and the heat dissipation structure to connect the pressure cap and the heat dissipation structure.

[0024] Optionally, the liquid supply pump is a peristaltic pump, and the flow rate of the peristaltic pump is 0.01 ml / s-0.6 ml / s.

[0025] Optionally, the coffee machine further includes a water injection assembly, which includes a drive unit and a water injection pipe. The water injection pipe is located above the brewing chamber and communicates with the outlet of the heat exchange channel. The drive unit is used to drive the water injection pipe to rotate about the central axis of the brewing chamber. The water injection pipe includes a radially extending section that extends radially along the brewing chamber, and a water injection hole is formed on the radially extending section for injecting water into the brewing chamber.

[0026] The water injection holes are multiple and spaced apart along the extension direction of the radial extension section. The diameter of the multiple water injection holes increases sequentially from one end of the radial extension section near the central axis of the brewing chamber to the other end of the radial extension section away from the central axis of the brewing chamber. Alternatively, the water injection holes are located at the end of the radial extension section away from the central axis of the brewing chamber.

[0027] Optionally, the water injection pipe further includes an axial extension section connected to the radial extension section, the central axis of the axial extension section coincides with the central axis of the brewing chamber, and the water injection assembly further includes a transmission assembly, the drive component being drivenly connected to the axial extension section through the transmission assembly;

[0028] The axial extension section has an inlet at one end away from the radial extension section. The water injection assembly also includes a liquid outlet, which has an outlet. The outlet of the heat exchange channel is connected to the outlet. The outlet is located above the inlet and spaced apart from the inlet. The projection of the inlet along the vertical direction covers the projection of the outlet along the vertical direction.

[0029] An overflow hole is provided on the radial extension section, and the overflow hole is located at the end of the radial extension section away from the axial extension section.

[0030] Optionally, the coffee machine includes a body, the body including a main body, a head protruding from the main body, and a neck located between the main body and the head;

[0031] The heat exchange structure, the temperature regulating component, and the liquid supply pump are all installed on the main body of the machine, and the brewing head is connected to the head.

[0032] The neck includes a knob housing, which is rotatably connected between the main body and the head. A rotary encoder is installed inside the knob housing and is drivenly connected to the knob housing. The controller is electrically connected to the rotary encoder.

[0033] Optionally, a first transmission gear is provided on the inner circumferential surface of the knob housing, and a second transmission gear and a transmission shaft are also provided inside the knob housing. The first transmission gear meshes with the second transmission gear, and the transmission shaft connects the second transmission gear and the rotary encoder.

[0034] Through the above technical solution, since the temperature regulating component in the coffee machine provided by this disclosure can both heat and cool the liquid, when making cold brew coffee, the coffee grounds can first be pre-fermented with heated liquid, and then brewed with cooled liquid. Because the carbon dioxide trapped in the coffee grounds can hinder sufficient contact between water and coffee grounds, pre-fermenting with heated liquid allows the carbon dioxide in the coffee grounds to be released through this process. This ensures more thorough contact between cold water and coffee grounds during the subsequent extraction and brewing with cooled liquid, thus shortening the extraction and preparation time of cold brew coffee. Furthermore, since the carbon dioxide in coffee grounds can contribute to the acidity of the coffee, pre-fermenting with heated liquid removes the carbon dioxide, further reducing the acidity of the brewed coffee and enhancing its flavor.

[0035] When using the coffee machine provided in this disclosure to make cold brew coffee, the preparation time is typically 5 to 8 minutes. Compared with the preparation time of cold brew coffee made using the cold brew method or ice drip method in related technologies, the coffee machine provided in this disclosure can greatly shorten the preparation time of cold brew coffee.

[0036] According to a second aspect of this disclosure, a method for preparing cold brew coffee is provided, wherein the method includes: preheating coffee powder with hot water, and then injecting cold water into the preheated coffee powder for drip filtration to obtain cold brew coffee liquid;

[0037] The temperature of the hot water is 40–70°C; the temperature of the cold water is 2–15°C.

[0038] Optionally, the temperature of the hot water is 45–60°C; the water injection rate is 0.3–1.0 ml / s; and the steaming time is 15–60 s.

[0039] The mass ratio of the coffee powder to the hot water is 1:(1-2.5).

[0040] Optionally, the temperature of the cold water is 3 to 8°C; the injection flow rate of the cold water is 0.05 to 0.6 ml / s.

[0041] Optionally, the total mass of the hot water and the cold water is 5 to 15 g relative to 1 g of the coffee powder.

[0042] Optionally, the steaming process and the drip filtration are carried out in a brewing device, which is equipped with a filter element.

[0043] The brewing device includes a coffee filter cup; the filter components include paper coffee filter paper, metal coffee filter mesh, and coffee filter cloth.

[0044] Optionally, the coffee beans are roasted to one or more of the following degrees: light, medium, medium-dark, and dark.

[0045] Optionally, the coffee beans are sourced from Yunnan, Ethiopia, and Colombia.

[0046] Optionally, the method further includes: grinding and sieving coffee beans to obtain coffee powder; the coffee powder has a particle size of 200-1600 μm.

[0047] Optionally, the hardness of the hot water and the cold water is each 20 to 200 ppm.

[0048] Optionally, the method further includes storing the cold brew coffee liquid at 5°C.

[0049] According to a third aspect of this disclosure, a cold brew coffee prepared using the method described in the second aspect of this disclosure is provided.

[0050] The method disclosed herein uses relatively low-temperature hot water (40-70°C) to bloom the coffee grounds before cold brewing, which promotes the release of carbon dioxide trapped in the coffee grounds, enhances the contact between water and coffee, and effectively improves extraction efficiency. Compared with coffee prepared by conventional cold brew methods, this method can more completely dissolve the aromatic substances and oils in the coffee, resulting in a richer coffee flavor. Compared with conventional pour-over coffee, this method can reduce the dissolution of undesirable flavor components in the coffee, reducing acidity and bitterness, thus producing cold brew coffee that combines the multi-layered flavor of pour-over coffee with the smooth mouthfeel of cold brew coffee. On the other hand, the method provided by this invention, while ensuring that the coffee has both rich flavor and a smooth mouthfeel, effectively shortens the preparation time of cold brew coffee, reduces the difficulty of preparation, has high product stability, high food safety, and can provide a more palatable temperature.

[0051] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0052] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0053] Figure 1 is a perspective view of a coffee machine provided according to an exemplary embodiment of the present disclosure;

[0054] Figure 2 is a perspective view of a coffee machine provided according to an exemplary embodiment of the present disclosure, wherein the side panel of the main body of the machine is not shown;

[0055] Figure 3 is a perspective view of a coffee machine provided in an exemplary embodiment of the present disclosure (different from the perspective of Figure 2);

[0056] Figure 4 is an assembly diagram of the heat exchange structure, temperature regulating component, heat dissipation structure, and pressure cap of a coffee machine provided in an exemplary embodiment of this disclosure.

[0057] Figure 5 is an assembly diagram of the heat exchange structure, temperature regulating component, and pressure cap of a coffee machine provided in an exemplary embodiment of this disclosure.

[0058] Figure 6 is a perspective view of the first heat exchange plate of a coffee machine heat exchange structure provided in an exemplary embodiment of this disclosure;

[0059] Figure 7 is a perspective view of the second heat exchange plate of a coffee machine heat exchange structure provided in an exemplary embodiment of the present disclosure, wherein a flow channel cover plate, a first connector and a second connector are also shown.

[0060] Figure 8 is a perspective view of the second heat exchange plate of a coffee machine heat exchange structure provided in an exemplary embodiment of this disclosure;

[0061] Figure 9 is an assembly diagram of the water injection assembly and mounting bracket of a coffee machine provided in an exemplary embodiment of this disclosure;

[0062] Figure 10 is an assembly diagram of the water injection assembly and mounting bracket of a coffee machine provided in an exemplary embodiment of this disclosure (different from the perspective of Figure 9);

[0063] Figure 11 is a side view of the water injection assembly of a coffee machine provided in an exemplary embodiment of this disclosure;

[0064] Figure 12 is a perspective structural diagram of the water injection assembly of a coffee machine provided in an exemplary embodiment of this disclosure;

[0065] Figure 13 is a schematic diagram of the assembly of the head and neck of a coffee machine according to an exemplary embodiment of the present disclosure, wherein the brewing head is also shown;

[0066] Figure 14 is an assembly diagram of the head and brewing head of a coffee machine provided in an exemplary embodiment of the present disclosure, wherein the outer shell of the head is not shown.

[0067] Figure 15 is an assembly diagram of the head and neck of a coffee machine provided in an exemplary embodiment of this disclosure (different from the perspective of Figure 13);

[0068] Figure 16 is an enlarged schematic diagram of part A in Figure 15;

[0069] Figure 17 is an assembly diagram of the head and neck of a coffee machine provided in an exemplary embodiment of the present disclosure, wherein the knob housing of the neck is not shown.

[0070] Figure 18 is an enlarged schematic diagram of part B in Figure 17;

[0071] Figure 19 is an assembly diagram of the head and neck of a coffee machine provided in an exemplary embodiment of this disclosure (different from the perspective of Figure 15);

[0072] Figure 20 is a schematic diagram showing the relative positional relationship between the brewing head and the water inlet pipe of a coffee machine provided in an exemplary embodiment of this disclosure. Detailed Implementation

[0073] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0074] In this disclosure, unless otherwise stated, directional terms such as "up" and "down" refer to the up and down positions of the coffee machine 100 in its normal operating state. Terms such as "first" and "second" are used only to distinguish one element from another and do not imply any order or importance. Furthermore, the directional terms used above are for the purpose of simplifying the description of this disclosure and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and should not be construed as limiting this disclosure.

[0075] As shown in Figures 1 to 20, according to a first aspect of this disclosure, a coffee machine 100 is provided, including a heat exchange structure 1, a temperature regulating element 2, a brewing head 3, a liquid supply pump 4, and a controller 5. The heat exchange structure 1 has a heat exchange channel 11 for liquid flow, the temperature regulating element 2 is used to heat and cool the liquid in the heat exchange channel 11, the brewing head 3 has a brewing chamber 31 for containing coffee powder, the outlet of the heat exchange channel 11 is connected to the brewing chamber 31, and the liquid supply pump 4 is configured to pump at least the liquid in the heat exchange channel 11 into the brewing chamber 31.

[0076] The controller 5 is electrically connected to the temperature regulator 2 and the liquid supply pump 4. The controller 5 is used to control the temperature regulator 2 to heat the liquid in the heat exchange channel 11 and pump the heated liquid into the brewing chamber 31 through the liquid supply pump 4 to brew the coffee powder in the brewing chamber 31. After the brewing is completed, the controller 5 controls the temperature regulator 2 to cool the liquid in the heat exchange channel 11 and pump the cooled liquid into the brewing chamber 31 through the liquid supply pump 4 to brew the coffee powder in the brewing chamber 31.

[0077] Through the above technical solution, since the temperature regulating element 2 in the coffee machine 100 provided in this disclosure can both heat and cool the liquid, when making cold brew coffee, the coffee powder can be first steamed with heated liquid, and then brewed with cooled liquid. Because the carbon dioxide trapped in the coffee powder can prevent sufficient contact between water and the coffee powder, steaming the coffee powder with heated liquid allows the carbon dioxide in the coffee powder to be released through steaming. This ensures more sufficient contact between cold water and coffee powder during the subsequent extraction and brewing with cooled liquid, thus shortening the extraction and preparation time of cold brew coffee. Furthermore, since the carbon dioxide in the coffee powder can also contribute to the acidity of the coffee, using heated liquid to first wet the coffee powder and then steaming it removes the carbon dioxide, further reducing the acidity of the brewed coffee and enhancing its flavor.

[0078] When using the coffee machine 100 provided in this disclosure to make cold brew coffee, the preparation time is typically 5 to 8 minutes. Compared with the preparation time of cold brew coffee using the cold brew method or ice drip method in related technologies, the coffee machine 100 provided in this disclosure can greatly shorten the preparation time of cold brew coffee.

[0079] To further improve the brewing effect and enhance the taste of the coffee, the coffee machine 100 may optionally include a liquid outlet pipe (not shown), with one end connected to the outlet of the heat exchange channel 11 and the second end connected to the brewing chamber 31. The liquid supply pump 4 can also pump liquid from the second end of the outlet pipe towards the first end. The controller 5 is further configured to control the liquid supply pump 4 to pump any remaining liquid in the outlet pipe into the heat exchange channel 11 after the heated liquid has been pumped into the brewing chamber 31.

[0080] In other words, the liquid supply pump 4 in the coffee machine 100 provided in this disclosure can pump the liquid in the outlet pipe from the first end of the outlet pipe to the second end of the outlet pipe, and also pump the liquid in the outlet pipe from the second end of the outlet pipe to the first end of the outlet pipe. After the heated liquid is injected into the brewing chamber 31, there is still some heated liquid remaining in the outlet pipe. Before the cooled liquid is injected into the brewing chamber 31, the controller 5 controls the liquid supply pump 4 to pump the remaining heated liquid in the outlet pipe back into the heat exchange channel 11, and after being cooled by the temperature regulating element 2, it is then pumped into the brewing chamber 31. In this way, when the liquid cooled by the temperature regulating element 2 is used to extract coffee powder, the liquid entering the brewing chamber 31 is all cooled, low-temperature liquid, which avoids the heated liquid remaining in the outlet pipe affecting the temperature of the low-temperature liquid that needs to enter the brewing chamber 31 later, thereby affecting the flavor and taste of the final extracted coffee liquid.

[0081] The inlet of the aforementioned heat exchange channel 11 can be connected to a water source via a liquid inlet pipe (not shown), such as a water purifier or faucet. In an exemplary embodiment provided in this disclosure, the coffee machine 100 may further include a water tank 14 and a liquid inlet pipe. The first end of the liquid inlet pipe is connected to the outlet of the water tank 14, and the second end of the liquid inlet pipe is connected to the inlet of the heat exchange channel 11, so that the liquid to be heated or cooled can enter the heat exchange channel 11 from the water tank 14 through the liquid inlet pipe.

[0082] Since the inlet pipe, heat exchange channel 11 and outlet pipe are all interconnected, this disclosure does not limit the location of the liquid supply pump 4. The liquid supply pump 4 can be installed on the inlet pipe or on the outlet pipe.

[0083] Optionally, the controller 5 controls the temperature regulating element 2 to heat the liquid in the heat exchange channel 11, including heating the liquid in the heat exchange channel 11 to 40℃-60℃. In this disclosure, using a medium-temperature liquid to bloom the coffee powder can remove the carbon dioxide accumulated in the coffee powder while preventing over-extraction caused by high-temperature blooming, thus reducing the bitterness of the brewed coffee. In other words, compared to using high-temperature hot water (usually 85℃-95℃) to bloom the coffee powder when making hot brew coffee (e.g., pour-over coffee), this disclosure uses medium-temperature water of 40℃-60℃ to bloom the coffee powder. On the one hand, it can remove the carbon dioxide accumulated in the coffee powder, improving the effectiveness of subsequent cold water extraction of the coffee powder. On the other hand, it can avoid over-extraction of the coffee powder, resulting in a bitter and unsmooth taste, such as that of hot brew coffee, while retaining the low-acidity, low-bitterness, and smooth taste of cold brew coffee.

[0084] Optionally, the controller 5 controls the temperature regulating element 2 to cool the liquid in the heat exchange channel 11, including cooling the liquid in the heat exchange channel 11 to 4°C-10°C, so as to cold extract the coffee powder with low-temperature cold water.

[0085] To facilitate brewing coffee powder with cold water at a low flow rate and increase the contact time between the fluid and the coffee powder, the liquid supply pump 4 can optionally be a peristaltic pump. The flow rate of the peristaltic pump can be 0.01 ml / s to 0.6 ml / s. The peristaltic pump can precisely control the flow rate and volume of the liquid, thereby meeting the precise requirements of coffee brewing for the flow rate and volume of the liquid, and ensuring the stability of the quality of the extracted coffee liquid. In addition, the peristaltic pump can meet the need to selectively pump the liquid in the outlet pipe from the first end to the second end of the outlet pipe or from the second end of the outlet pipe to the first end of the outlet pipe.

[0086] In one specific implementation, the coffee powder in the brewing chamber can weigh 16g. The controller 5 controls the temperature regulator 2 to heat the liquid in the heat exchange channel 11 to 50°C, and the liquid supply pump 4 injects heated water into the brewing chamber 31 at a flow rate of 0.5ml / s for 48s. The water weight for steeping is 24g. After steeping for 20s, the controller 5 controls the temperature regulator 2 to cool the liquid in the heat exchange channel 11 to 5°C, and the liquid supply pump 4 injects cooled water into the brewing chamber 31 at a flow rate of 0.3ml / s for 507s. The water weight for steeping is 176g. Thus, cold brew coffee with a TDS (Total Dissolved Solids) of 1.8%-2.2% can be obtained within 10 minutes.

[0087] Furthermore, to achieve heating and cooling of the liquid, optionally, as shown in Figure 5, the temperature regulating element 2 can be a thermoelectric cooler 21. The thermoelectric cooler 21 has a first surface and a second surface facing each other. The first surface is in thermal contact with the heat exchange structure 1. The thermoelectric cooler 21 also has a first terminal and a second terminal for connecting to a circuit. The first surface is capable of absorbing heat from the liquid in the heat exchange channel 11 when current flows from the first terminal to the second terminal, and releasing heat to the liquid in the heat exchange channel 11 when current flows from the second terminal to the first terminal.

[0088] According to the Peltier effect, the state of the first surface is different when the direction of current flow is different. By making the first surface in thermal contact with the heat exchange structure 1, the direction of current flow in the semiconductor cooling chip 21 can be controlled by the controller 5, thereby switching the first surface of the semiconductor cooling chip 21 between the states of heat absorption and heat release to heat or cool the liquid located in the heat exchange channel 11.

[0089] In other embodiments, the temperature regulating element 2 may also include a heating element and a cooling element, which are used to heat or cool the liquid in the heat exchange channel 11, respectively.

[0090] To facilitate heat dissipation from the second surface of the thermoelectric cooler 21 when cooling the liquid in the heat exchange channel 11 on the first surface, as shown in Figures 2, 3, and 4, the coffee machine 100 further includes a heat dissipation structure 7, which is in thermal contact with the second surface. This thermal contact between the second surface of the thermoelectric cooler 21 and the heat dissipation structure 7 allows for faster heat dissipation when the second surface of the thermoelectric cooler 21 releases heat, ensuring the normal operation of the thermoelectric cooler 21.

[0091] As one specific embodiment, as shown in Figures 2 and 3, the heat dissipation structure 7 may include a heat-conducting plate 72, a heat dissipation pipe 71, heat dissipation fins 73, and a fan 74. One side of the heat-conducting plate 72 is in thermal contact with the second surface of the thermoelectric cooler 21, and a groove 721 is formed on the side of the heat-conducting plate 72 away from the thermoelectric cooler 21. One end of the heat dissipation pipe 71 is disposed in the groove 721 and in thermal contact with the heat-conducting plate 72, and the other end of the heat dissipation pipe 71 is inserted into the heat dissipation fins 73 and in thermal contact with the heat dissipation fins 73. The heat dissipation fins 73 are disposed below the thermoelectric cooler 21 and the heat exchange structure 1. The fan 74 is arranged side by side with the heat dissipation fins 73 and is used to blow air onto the heat dissipation fins 73 to accelerate the cooling speed of the heat dissipation fins 73, thereby further improving the cooling effect of the heat dissipation structure 7.

[0092] Optionally, as shown in Figure 4, there are multiple heat dissipation pipes 71 and multiple grooves 721 on the heat-conducting plate 72, with the multiple heat dissipation pipes 71 corresponding to the multiple grooves 721. Multiple heat dissipation pipes 71 can increase heat dissipation efficiency and improve the heat dissipation speed of the second surface of the semiconductor cooling chip 21.

[0093] Optionally, the coffee machine 100 may further include a pressure cap 8, a heat exchange structure 1, and a thermoelectric cooler 21 sandwiched between the pressure cap 8 and the heat dissipation structure 7. Fasteners pass through the pressure cap 8 and the heat dissipation structure 7 to connect the pressure cap 8 and the heat dissipation structure 7. This connection method, where the pressure cap 8 and the heat dissipation structure 7 are connected by fasteners, and the heat exchange structure 1 and the thermoelectric cooler 21 are sandwiched between the pressure cap 8 and the heat dissipation structure 7, avoids contact between the fasteners and the thermoelectric cooler 21, preventing heat transfer from the thermoelectric cooler 21 to the fasteners and thus reducing the heating or cooling efficiency of the thermoelectric cooler 21 for the liquid within the heat exchange structure 1.

[0094] As one specific embodiment, as shown in FIG5, a receiving groove 81 is formed on one side of the pressure cover 8. The semiconductor cooling chip 21 and the heat exchange structure 1 are both disposed in the receiving groove 81. The receiving groove 81 also has an opening, and the heat conduction plate 72 of the heat dissipation structure 7 covers the opening.

[0095] Furthermore, the heat exchange structure 1 can have any suitable structure and shape. For example, the heat exchange structure 1 can be a heat exchange block with a serpentine heat exchange channel 11 inside.

[0096] As an exemplary embodiment provided in this disclosure, as shown in Figures 6, 7, and 8, the heat exchange structure 1 includes a first heat exchange plate 12 and a second heat exchange plate 13, which are arranged opposite to each other and connected to each other. A flow channel cover plate 121 is provided on the side of the first heat exchange plate 12 near the second heat exchange plate 13, and a sensor 6 is provided on the side of the first heat exchange plate 12 away from the second heat exchange plate 13. The sensor 6 is used to detect the temperature of the first heat exchange plate 12 to indirectly obtain the temperature of the liquid in the heat exchange flow channel 11. A liquid injection tank 131 is formed on the side of the second heat exchange plate 13 near the first heat exchange plate 12. A plurality of spaced heat exchange plates 132 are provided in the liquid injection tank 131 to divide the liquid injection tank 131 into a plurality of sub-liquid injection tanks. The plurality of heat exchange plates 132 and the flow channel cover plate 121 together enclose the heat exchange flow channel 11. The structure of multiple heat exchange plates 132 spaced apart can increase the contact area between the heat exchange structure 1 and the liquid, thereby improving the heat exchange efficiency and enabling the liquid to be heated or cooled more quickly.

[0097] The side of the first heat exchange plate 12 away from the second heat exchange plate 13 is abutted against the pressure cap 8, and the side of the second heat exchange plate 13 away from the first heat exchange plate 12 is in thermal contact with the first surface of the semiconductor cooling chip 21. A first connector 15 and a second connector 16 are formed on the side of the pressure cap 8 away from the first heat exchange plate 12. The first connector 15 communicates with the inlet of the heat exchange channel 11, and the second connector 16 communicates with the outlet of the heat exchange channel 11. The first connector 15 is used to connect to the liquid inlet pipe, and the second connector 16 is used to connect to the liquid outlet pipe.

[0098] Optionally, a heat insulation element 82 is also provided inside the receiving tank 81. The heat insulation element 82 is disposed between the inner wall of the receiving tank 81 and the heat exchange structure 1 and the semiconductor cooling chip 21. Providing the heat insulation element 82 on the inner wall of the receiving tank 81 can reduce the heat exchange between the heat exchange structure 1 and the pressure cap 8, thereby reducing the heat loss when heating / cooling the liquid.

[0099] It should be noted that this disclosure does not limit the specific material of the insulation component 82. In one embodiment provided in this disclosure, the insulation component 82 can be a heat-insulating sponge.

[0100] To facilitate the injection of liquid into the brewing chamber 31 of the brewing head 3 and to ensure that the liquid can evenly wet the coffee powder, as shown in Figures 9 to 12 and 20, the coffee machine 100 also includes a water injection assembly 9. The water injection assembly 9 includes a drive member 91 and a water injection pipe 92. The water injection pipe 92 is located above the brewing chamber 31 and communicates with the outlet of the heat exchange channel 11. The drive member 91 drives the water injection pipe 92 to rotate around the central axis of the brewing chamber 31. The water injection pipe 92 includes a radially extending section 921 extending radially along the brewing chamber 31, and a water injection hole 923 is formed on the radially extending section 921 for injecting water into the brewing chamber 31. The drive member 91 drives the water injection pipe 92 to rotate around the central axis of the brewing chamber 31, thereby causing the radially extending section 921 of the water injection pipe 92 to rotate. This allows the liquid heated / cooled by the heat exchange structure 1 to be sprayed evenly onto the coffee powder in the brewing chamber 31 through the water injection hole 923 during the rotation of the radially extending section 921. Due to the rotation of the radial extension 921, the liquid sprayed from the water inlet 923 can cover the entire brewing chamber 31, so that the coffee powder in the brewing chamber 31 can be wetted and soaked by the liquid at the same time, making the brewing and extraction of coffee flavor more complete.

[0101] In one implementation, there are multiple water injection holes 923, which are spaced apart along the extension direction of the radial extension section 921. The diameter of the multiple water injection holes 923 increases sequentially from one end of the radial extension section 921 near the central axis of the brewing chamber 31 to the end of the radial extension section 921 away from the central axis of the brewing chamber 31. The multiple water injection holes 923 spaced apart along the extension direction of the radial extension section 921 can spray liquid at different positions away from the central axis of the brewing chamber 31, thereby improving the uniformity of coverage of the coffee powder, improving extraction efficiency, and enhancing the quality of the extracted coffee liquid.

[0102] In addition, since centrifugal force is generated during the rotation of the water injection pipe 92, the liquid will move away from the central axis of the brewing chamber 31 under the action of centrifugal force. The diameter of the multiple water injection holes 923 increases sequentially along the direction away from the central axis of the brewing chamber 31, which can meet the need for more liquid to be discharged through the position away from the central axis of the brewing chamber 31, and further improve the efficiency of spraying liquid.

[0103] In another embodiment, the water inlet 923 is located at one end of the radial extension 921 away from the central axis of the brewing chamber 31. Injecting water from the end away from the central axis of the brewing chamber 31 allows the water flow to fully wet the coffee grounds.

[0104] Optionally, as shown in Figures 11 and 12, the water injection pipe 92 further includes an axial extension section 922 connected to the radial extension section 921. The central axis of the axial extension section 922 coincides with the central axis of the brewing chamber 31. The water injection assembly 9 also includes a transmission assembly 93, and the drive member 91 is connected to the axial extension section 922 via the transmission assembly 93. An inlet 9221 is formed at the end of the axial extension section 922 away from the radial extension section 921. The water injection assembly 9 also includes a liquid outlet 94, on which an outlet 941 is formed. The outlet of the heat exchange channel 11 communicates with the outlet 941. The outlet 941 is located above and spaced apart from the inlet 9221, and the projection of the inlet 9221 in the vertical direction covers the projection of the outlet 941 in the vertical direction. An overflow hole 9211 is provided on the radial extension section 921, located at the end of the radial extension section 921 away from the axial extension section 922.

[0105] Since the axial extension 922 of the water injection pipe 92 can rotate around the central axis of the brewing chamber 31 under the drive of the driving member 91, and the outlet of the heat exchange channel 11 is connected to the outlet 941 of the liquid outlet member 94 through the liquid outlet pipe, the spaced-apart outlet 941 and inlet 9221 ensure that the outlet 941 will not rotate when the inlet 9221 rotates. Simultaneously, the vertical projection of the inlet 9221 covers the vertical projection of the outlet 941, ensuring that the liquid flowing from the outlet 941 can drip into the inlet 9221, thus ensuring that the liquid delivery is not affected even though the outlet 941 is spaced apart from the inlet 9221.

[0106] An overflow hole 9211 is provided on the radial extension section 921, which allows the liquid entering the water injection pipe 92 to be discharged from the overflow hole 9211 if it is not discharged through the water injection hole 923 in time. This prevents the liquid from overflowing from the water inlet 9221 when the liquid flow rate is large, and ensures the uniformity of liquid spraying.

[0107] Optionally, as shown in Figures 9 to 14, the coffee machine may include a mounting bracket 1022 located above the brewing head 3, with a drive unit 91, a transmission assembly 93, a liquid dispensing component 94, and a water inlet pipe 92 mounted on the mounting bracket 1022. The drive unit 91 may be a motor 911, and the transmission assembly 93 may include a meshing drive gear 931 and a driven gear 932. The drive gear 931 is connected to the output end of the motor 911, and the driven gear 932 is sleeved on the axial extension 922 of the water inlet pipe 92 to drive the water inlet pipe 92 to rotate.

[0108] Optionally, as shown in Figures 1, 13, and 14, the coffee machine 100 also includes a body 10, which includes a main body 101, a head 102 protruding from the main body 101, and a neck 103 located between the main body 101 and the head 102. The heat exchange structure 1, the temperature regulating component 2, and the liquid supply pump 4 are all installed on the main body 101, and the brewing head 3 is connected to the head 102.

[0109] Optionally, as shown in Figures 13 and 14, the head 102 includes a housing 1021 and a mounting bracket 1022. The housing 1021 has an internal cavity, within which the mounting bracket 1022, a screen 1024, and a PCB board 1023 are disposed. The PCB board 1023 divides the cavity into upper and lower cavities. The screen 1024 is disposed in the upper cavity and electrically connected to the PCB board 1023. The mounting bracket 1022 is located in the lower cavity, and the water injection assembly 9 is mounted on the mounting bracket 1022. The lower cavity can communicate with the brewing chamber 31 when the brewing head 3 is connected to the housing 1021.

[0110] Optionally, the brewing head 3 is detachably connected to the head 102, for example, detachably connected to the housing 1021. A first magnet is provided on the end of the brewing head 3 that contacts the head 102, and a second magnet is correspondingly provided on the end of the head 102 that contacts the brewing head 3, thus magnetically connecting the brewing head 3 and the head 102. This magnetic connection between the brewing head 3 and the head 102 improves the convenience for users to install and remove the brewing head 3, facilitating the addition of coffee grounds before brewing and the pouring of coffee grounds after brewing.

[0111] Optionally, the neck 103 may include a knob housing 1021, which is rotatably connected between the main body 101 and the head 102. A rotary encoder 104 is provided inside the knob housing 1021, and the rotary encoder 104 is connected to the knob housing 1021 in a transmission manner. The controller 5 is electrically connected to the PCB board 1023 and the rotary encoder 104.

[0112] Users can rotate the housing 1021 of the knob, thereby rotating the shaft of the rotary encoder 104. The rotating rotary encoder 104 transmits the user's operation signal to the PCB board 1023 and the controller 5, allowing the user to select parameters such as water temperature, water volume, and brewing time on the display interface 1024 by operating the knob. Furthermore, positioning the knob between the head 102 and the main body 101 effectively utilizes the space at the connection between the head 102 and the main body 101, reducing the overall size of the coffee machine occupied by the knob. This also increases the integration of the knob and the main body 101, enhancing the aesthetic appeal of the coffee machine 100.

[0113] To drive the knob housing 1031 to the rotary encoder 104, as shown in Figures 15 to 18, optionally, a first transmission gear 1032 is provided on the inner circumferential surface of the knob housing 1021, and a second transmission gear 1033 and a transmission shaft 1034 are also provided inside the knob housing 1021. The first transmission gear 1032 meshes with the second transmission gear 1033, and the transmission shaft 1034 connects the second transmission gear 1033 to the rotary encoder 104.

[0114] The neck 103 of the body 10 may also include a connecting bracket 1035. The two ends of the connecting bracket 1035 extend into the outer shell 1021 of the head 102 and the body 101, respectively. The rotary encoder 104 and the second transmission gear 1033 are both mounted on the connecting bracket 1035, and the rotary housing 1031 is fitted over the connecting bracket 1035.

[0115] As shown in Figures 16 and 19, a wiring channel 1036 is formed within the connecting bracket 1035 for the passage of the liquid supply pipe and control circuit. The control circuit is used to connect the PCB board 1023 and / or the controller 5. The second transmission gear 1033 and the rotary encoder 104 are both disposed on the upper surface of the connecting bracket 1035, and the wiring channel 1036 is located below the connecting bracket 1035.

[0116] By utilizing the space on the upper and lower sides of the connecting bracket 1035 to simultaneously install the rotary encoder 104, the second transmission gear 1033, the liquid outlet pipe, and the control circuit, the space of the coffee machine body 10 of the coffee machine 100 can be fully utilized, thereby improving the compactness of the structure and the integration between the various components of the coffee machine 100.

[0117] According to a second aspect of this disclosure, a method for preparing cold brew coffee is provided, wherein the method includes: preheating coffee powder with hot water, and then injecting cold water into the preheated coffee powder for drip filtration to obtain cold brew coffee liquid;

[0118] The temperature of the hot water is 40–70°C; the temperature of the cold water is 2–15°C.

[0119] The method disclosed herein uses relatively low-temperature hot water (40-70°C) to bloom the coffee grounds before cold brewing, which promotes the release of carbon dioxide trapped in the coffee grounds, enhances the contact between water and coffee, and effectively improves extraction efficiency. Compared with coffee prepared by conventional cold brew methods, this method can more completely dissolve the aromatic substances and oils in the coffee, resulting in a richer coffee flavor. Compared with conventional pour-over coffee, this method can reduce the dissolution of undesirable flavor components in the coffee, reducing acidity and bitterness, thus producing cold brew coffee that combines the multi-layered flavor of pour-over coffee with the smooth mouthfeel of cold brew coffee. On the other hand, the method provided by this disclosure, while ensuring that the coffee has both rich flavor and a smooth mouthfeel, effectively shortens the preparation time of cold brew coffee, reduces the difficulty of preparation, has high output stability, high food safety, and can provide a more palatable temperature.

[0120] In a preferred embodiment, the temperature of the hot water is 45–60°C, more preferably 45–55°C. In the above embodiments, controlling the hot water temperature within the preferred range allows for the further release of carbon dioxide accumulated in the coffee, further improving extraction efficiency, further reducing the dissolution of undesirable flavor components in the coffee, and the release of carbon dioxide promotes the contact between water and coffee, enabling the more complete dissolution of aromatic substances and oils in the coffee. This results in a cold brew coffee that combines the multi-layered flavor of pour-over coffee with the smooth texture of cold brew coffee.

[0121] In one specific embodiment, the hot water injection flow rate is 0.3–1.0 ml / s, preferably 0.4–0.6 ml / s; the blooming time is 15–60 s, preferably 25–40 s. In the above embodiment, by controlling the hot water injection flow rate and blooming time within the preferred ranges, the dissolution of undesirable flavor components in the coffee is further reduced, thereby further improving the taste and flavor of the prepared cold brew coffee.

[0122] In one specific embodiment, the mass ratio of coffee powder to hot water is 1:(1-2.5), preferably 1:(1.2-2.0). Within the above-mentioned preferred amount of hot water, the brewing effect of coffee powder is better, further improving the efficiency of carbon dioxide removal and promoting the dissolution of flavor substances in coffee powder, and is also more conducive to maintaining the smooth taste of the subsequent cold water drip-filtered coffee liquid.

[0123] In one specific embodiment, the total mass of the hot water and the cold water relative to 1g of coffee powder is 5-15g, preferably 9-12g. Within the above-mentioned preferred water volume range, the extraction degree of the coffee powder is more suitable, the concentration, flavor, and taste of the prepared coffee liquid are more suitable and balanced, and the drinking experience is better.

[0124] In a preferred embodiment, the temperature of the cold water is 3–8°C. In a specific embodiment, the flow rate of the injected cold water is 0.05–0.6 ml / s, preferably 0.25–0.45 ml / s. By controlling the cold water temperature and the flow rate within the preferred range in the above embodiments, the prepared cold brew coffee can have a smoother texture and a richer flavor and aroma.

[0125] In the method disclosed herein, the water injection flow rate and water temperature can be controlled by conventional methods or devices, such as controlling the water injection flow rate by a drip funnel, a peristaltic pump, etc., and controlling the water temperature by a liquid storage device with temperature control function, which will not be elaborated here.

[0126] In one specific embodiment, the steaming process and the drip filtration are carried out in a brewing device, which is equipped with a filter element.

[0127] In one embodiment, the brewing device includes a coffee filter cup, an automated water dispensing system, a manual stop valve, and a heating / cooling module; the filter element includes paper coffee filter paper, a metal coffee filter mesh, and a coffee filter cloth. In a further embodiment, the brewing device includes a filter cup and filter paper placed in the filter cup, the filter paper being an inverted cone shape.

[0128] The method disclosed herein does not impose any particular limitation on the amount of coffee powder used, and can be appropriately selected based on the type, size, and consumption amount of brewing equipment that is conventional in the art.

[0129] The method disclosed herein does not impose any particular restrictions on the type of coffee beans used, and can be any common type. In one specific embodiment, the coffee beans are roasted to one or more of the following degrees: light, medium, medium-dark, and dark; the coffee beans are sourced from Yunnan, Ethiopia, and Colombia; in a preferred embodiment, the coffee beans are selected from Arabica beans to provide a richer flavor and aroma and a smoother mouthfeel.

[0130] In one specific embodiment, the method further includes: grinding and sieving coffee beans to obtain the coffee powder; the particle size of the coffee powder is 200–1600 μm. The particle size of the coffee powder refers to the median particle size, which can be tested using conventional methods in the art.

[0131] In a further embodiment, the coffee beans are Arabica, and the coffee powder particle size is 400–600 μm. In another further embodiment, the coffee beans are Robusta, and the coffee powder particle size is 600–800 μm. Controlling the preferred coffee powder particle size in the above embodiments is more conducive to bringing out the aroma and flavor characteristics of the coffee beans themselves.

[0132] In one embodiment, the hardness of the hot water and the cold water are each between 10 and 200 ppm. In another embodiment, the hardness of the hot water and the cold water are the same.

[0133] In one specific embodiment, the method further includes: storing the cold brew coffee at 5°C to maintain a suitable drinking temperature and flavor of the coffee liquid.

[0134] According to a third aspect of this disclosure, a cold brew coffee prepared using the method described in the first aspect of this disclosure is provided.

[0135] The present disclosure is further illustrated by the following examples, but the disclosure is not limited thereto. The coffee beans used in the following examples are commercially available, and the water used is softened water.

[0136] Example 1

[0137] a. Place coffee beans in a grinder, grind them, and sift them to remove fine powder, obtaining coffee powder; the coffee beans are dark roasted, originate from Yunnan, and are Arabica; the particle size of the coffee powder is 500μm.

[0138] b. Place 16g of coffee powder on the filter paper inside the filter cup, pour in hot water for blooming, then pour in cold water for drip filtration to obtain cold brew coffee; wherein, the temperature of the hot water is 50℃, the water flow rate of the hot water is 0.5ml / s, the blooming time is 30s; the temperature of the cold water is 5℃, the water flow rate of the cold water is 0.3ml / s; the mass ratio of coffee powder to hot water is 1:1.5; the total mass of hot and cold water is 176g.

[0139] Example 2

[0140] The method and raw materials of Example 1 are used, except that in step a, the coffee beans are roasted to a medium degree, the coffee beans are from Yunnan, and the coffee bean type is Arabica.

[0141] Example 3

[0142] The method of Example 1 is used, except that in step b, the temperature of the hot water is 40°C.

[0143] Example 4

[0144] The method of Example 1 is used, except that in step b, the injection flow rate of hot water is 0.75 ml / s.

[0145] Example 5

[0146] The method of Example 1 is used, except that in step b, the injection flow rate of cold water is 0.5 ml / s.

[0147] Example 6

[0148] The method of Example 1 is used, except that in step b, the steaming time is 60 seconds.

[0149] Comparative Example 1

[0150] Using the method and raw materials of Example 1, the only difference is that in step b, 16g of coffee powder is placed in a cold brew coffee pot, 176ml of room temperature water (25℃) is added, and after stirring and mixing, it is placed in a refrigerator under sealed condition and refrigerated at 5℃ for 12 hours. After the soaking is completed, the fine coffee grounds are removed by filtering with filter paper to obtain cold brew coffee.

[0151] Comparative Example 2

[0152] a. Place coffee beans in a grinder, grind them, and sift them to remove fine powder, obtaining coffee powder; the coffee beans are dark roasted, originate from Yunnan, and are Arabica; the particle size of the coffee powder is 500μm.

[0153] b. Place 16g of coffee powder into a filter paper that has been rinsed with hot water (90-96℃). Place the filter paper in a pour-over coffee maker, pour in 32ml of hot water, let it wet evenly, and let it stand for 30 seconds for pre-brewing. The temperature of the hot water should be 90-96℃.

[0154] c. Slowly and evenly pour hot water into the preheated coffee grounds in a spiral motion, ensuring that the water flows outward from the center and covers all the coffee grounds, until the water volume reaches 256mL.

[0155] d. Once the coffee liquid has almost completely dripped into the container below, cut off the last stream to obtain pour-over coffee.

[0156] Comparative Example 3

[0157] a. Place coffee beans in a grinder, grind them, and sift them to remove fine powder, obtaining coffee powder; the coffee beans are dark roasted, originate from Yunnan, and are Arabica; the particle size of the coffee powder is 500μm.

[0158] b. Place 16g of coffee powder into a filter paper that has been rinsed with ice water (2-5℃). Place the filter paper in a cylindrical pour-over coffee maker and pour in 32ml of ice water (2-5℃) to wet it evenly.

[0159] c. Slowly and evenly add ice water (2-5℃) to the moistened coffee powder. The pouring speed of the ice water is 0.05ml / s, ensuring that the water droplets drip into the coffee powder from the center, until the total amount of water poured reaches 176mL (including the amount of room temperature moistening water).

[0160] d. Once the coffee liquid has almost completely dripped into the container below, intercept the final tail stream to obtain iced drip coffee.

[0161] Test case

[0162] The coffee concentrations of Examples 1-6 and Comparative Examples 1-3 were tested using a PAL-COFFEE TDS (Total dissolved solids) coffee concentration tester.

[0163] The flavor and mouthfeel evaluation test method included: selecting 20 testers (10 men and 10 women, aged 25-50 years), all of whom had more than 2 years of coffee drinking experience and drank coffee beverages an average frequency of more than 3 times per week. Each tester tasted the coffee of Examples 1-6 and Comparative Examples 1-3 in random order, and rinsed their mouths with water between adjacent tastings to avoid the influence of aftertaste. Then, each flavor profile is rated on a scale of 0 to 5. For aroma, 0 indicates no caramel / nut / fruit aroma, 1 indicates a slight caramel / nut / fruit aroma, 2 indicates a caramel / nut / fruit aroma, 3 indicates a relatively strong caramel / nut / fruit aroma, 4 indicates a rich caramel / nut / fruit aroma, and 5 indicates a very strong caramel / nut / fruit aroma. For acidity and bitterness, 0 indicates a large amount of acidity or bitterness, 1 indicates a noticeable acidity or bitterness, 2 indicates a relatively strong acidity or bitterness, 3 indicates an acidity or bitterness, 4 indicates a slight acidity or bitterness, and 5 indicates no acidity or bitterness. The total score is the average of the scores for aroma, flavor, sweetness, acidity, bitterness, and smoothness. Overall preference is rated out of 100. The average scores from the 20 testers are listed in the table below.

[0164] Table 1

[0165] Table 2

[0166] The test results in Tables 1 and 2 show that the method provided in this paper, which involves low-temperature blooming of coffee powder, promotes the release of carbon dioxide trapped in the coffee, effectively improving extraction efficiency and reducing the dissolution of undesirable flavor components. Furthermore, the release of carbon dioxide promotes contact between water and coffee, allowing for the more complete dissolution of aromatic substances and oils. This results in a cold brew coffee that combines the multi-layered flavors of pour-over coffee with the smooth texture of cold brew. Compared to the comparative example, the cold brew coffee provided in this disclosure, while possessing both rich flavor and a smooth texture, effectively shortens the preparation time, reduces preparation difficulty, ensures high product stability and food safety, and provides a more palatable drinking temperature.

[0167] The test results of Comparative Examples 1-3 show that Comparative Example 1, prepared using the conventional cold brew method, suffers from a relatively simple flavor profile due to prolonged low-temperature extraction. It lacks the rich layers and complexity of hot or pour-over coffee, has lower sweetness, and higher acidity and bitterness than Examples 1-6 of this disclosure. The long preparation time, temperature changes, and oxidation during the process easily affect the flavor of the coffee. Furthermore, cold brew coffee typically requires more coffee powder to produce the same amount of liquid, resulting in waste. Comparative Example 2, prepared using the conventional pour-over method, is easily affected by factors such as water temperature, pouring speed, and pouring method. Even slight changes in any of these factors can lead to uneven extraction, affecting the flavor, quality, and mouthfeel of the coffee, resulting in poor consistency. The pour-over coffee also exhibits significantly higher acidity and bitterness than the examples of this disclosure, and has a less smooth mouthfeel. Similarly, the iced drip coffee prepared in Comparative Example 3 suffers from a long preparation time, and the low-temperature extraction process makes it difficult to fully release the subtle aromas and flavor characteristics of the coffee, resulting in a relatively simple mouthfeel and a lack of complex flavor layers.

[0168] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0169] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0170] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A coffee machine (100), characterized in that, include: The heat exchange structure (1) has a heat exchange channel (11) formed inside for the liquid to flow through; Temperature regulating element (2) is used to heat and cool the liquid in the heat exchange channel (11); The brewing head (3) has a brewing chamber (31) inside, which is used to hold coffee powder, and the outlet of the heat exchange channel (11) is connected to the brewing chamber (31). The liquid supply pump (4) is configured to pump liquid from the heat exchange channel (11) into the brewing chamber (31); The controller (5) is electrically connected to the temperature regulator (2) and the liquid supply pump (4); The controller (5) controls the temperature regulating element (2) to heat the liquid in the heat exchange channel (11) and pumps the heated liquid into the brewing chamber (31) through the liquid supply pump (4) to steam the coffee powder in the brewing chamber (31). After steaming, the controller controls the temperature regulating element (2) to cool the liquid in the heat exchange channel (11) and pumps the cooled liquid into the brewing chamber (31) through the liquid supply pump (4) to brew the coffee powder in the brewing chamber (31).

2. The coffee machine (100) according to claim 1, characterized in that, The coffee machine (100) also includes a liquid outlet pipe, the first end of which is connected to the outlet of the heat exchange channel (11), and the second end of which is connected to the brewing chamber (31). The liquid supply pump (4) can also pump the liquid in the liquid outlet pipe from the second end of the liquid outlet pipe toward the first end of the liquid outlet pipe. The controller (5) is also used to control the liquid supply pump (4) to pump the remaining liquid in the liquid outlet pipe into the heat exchange channel (11) after the heated liquid is pumped into the brewing chamber (31) by the liquid supply pump (4).

3. The coffee machine (100) according to claim 1, characterized in that, The controller (5) controls the temperature regulating element (2) to heat the liquid in the heat exchange channel (11) including: The liquid in the heat exchange channel (11) is heated to 40°C-60°C; The controller (5) controls the temperature regulating element (2) to cool the liquid in the heat exchange channel (11) by including: The liquid in the heat exchange channel (11) is cooled to 4℃-10℃.

4. The coffee machine (100) according to claim 1, characterized in that, The temperature regulating element (2) is a semiconductor cooling chip (21), which has a first surface and a second surface opposite to each other. The first surface is in thermal contact with the heat exchange structure (1). The semiconductor cooling chip (21) also has a first terminal and a second terminal for connecting to a circuit. The first surface is capable of absorbing heat from the liquid in the heat exchange channel (11) when current flows from the first terminal to the second terminal, and releasing heat to the liquid in the heat exchange channel (11) when current flows from the second terminal to the first terminal.

5. The coffee machine (100) according to claim 4, characterized in that, The coffee machine (100) further includes a heat dissipation structure (7) and a pressure cap (8). The heat dissipation structure (7) is in thermal contact with the second surface. The heat exchange structure (1) and the semiconductor cooling chip (21) are sandwiched between the pressure cap (8) and the heat dissipation structure (7). Fasteners pass through the pressure cap (8) and the heat dissipation structure (7) to connect the pressure cap (8) and the heat dissipation structure (7).

6. The coffee machine (100) according to any one of claims 1-5, characterized in that, The liquid supply pump (4) is a peristaltic pump, and the flow rate of the peristaltic pump is 0.01 ml / s-0.6 ml / s.

7. The coffee machine (100) according to any one of claims 1-5, characterized in that, The coffee machine (100) also includes a water injection assembly (9), which includes a drive (91) and a water injection pipe (92). The water injection pipe (92) is located above the brewing chamber (31) and communicates with the outlet of the heat exchange channel (11). The drive (91) is used to drive the water injection pipe (92) to rotate around the central axis of the brewing chamber (31). The water injection pipe (92) includes a radial extension section (921) extending radially along the brewing chamber (31). A water injection hole (923) for injecting water into the brewing chamber (31) is formed on the radial extension section (921). The water injection holes (923) are multiple, and the multiple water injection holes (923) are spaced apart along the extension direction of the radial extension section (921). The diameter of the multiple water injection holes (923) increases sequentially along the direction from one end of the radial extension section (921) near the central axis of the brewing chamber (31) to the other end of the radial extension section (921) away from the central axis of the brewing chamber (31); or, the water injection holes (923) are located at the end of the radial extension section (921) away from the central axis of the brewing chamber (31).

8. The coffee machine (100) according to claim 7, characterized in that, The water injection pipe (92) also includes an axial extension section (922) connected to the radial extension section (921), the central axis of the axial extension section (922) coincides with the central axis of the brewing chamber (31), the water injection assembly (9) also includes a transmission assembly (93), and the drive member (91) is connected to the axial extension section (922) through the transmission assembly (93); The axial extension section (922) has an inlet (9221) at one end away from the radial extension section (921). The water injection assembly (9) also includes a liquid outlet (94), on which an outlet (941) is formed. The outlet of the heat exchange channel (11) is connected to the outlet (941). The outlet (941) is located above the inlet (9221) and spaced apart from the inlet (9221). The projection of the inlet (9221) in the vertical direction covers the projection of the outlet (941) in the vertical direction. An overflow hole (9211) is provided on the radial extension section (921), and the overflow hole (9211) is located at the end of the radial extension section (921) away from the axial extension section (922).

9. The coffee machine (100) according to any one of claims 1-5, characterized in that, The coffee machine (100) includes a body (10), the body (10) including a main body (101), a head (102) protruding from the main body (101), and a neck (103) located between the main body (101) and the head (102); The heat exchange structure (1), the temperature regulating component (2), and the liquid supply pump (4) are all installed on the main body (101), and the brewing head (3) is connected to the head (102); The neck (103) includes a knob housing (1021), which is rotatably connected between the main body (101) and the head (102). A rotary encoder (104) is provided inside the knob housing (1021), and the rotary encoder (104) is drivenly connected to the knob housing (1021). The controller (5) is electrically connected to the rotary encoder (104).

10. The coffee machine (100) according to claim 9, characterized in that, A first transmission gear (1032) is provided on the inner circumferential surface of the knob housing (1021). A second transmission gear (1033) and a transmission shaft (1034) are also provided inside the knob housing (1021). The first transmission gear (1032) meshes with the second transmission gear (1033). The transmission shaft (1034) connects the second transmission gear (1033) with the rotary encoder (104).

11. A method for preparing cold brew coffee, wherein, The method includes: preheating coffee powder with hot water, then dripping cold water into the preheated coffee powder to obtain cold brew coffee liquid; The temperature of the hot water is 40–70°C; the temperature of the cold water is 2–15°C.

12. The method according to claim 11, wherein, The temperature of the hot water is 45–60℃; the water injection rate is 0.3–1.0 ml / s; and the steaming time is 15–60 s. The mass ratio of the coffee powder to the hot water is 1:(1-2.5).

13. The method according to claim 11, wherein, The temperature of the cold water is 3-8℃; the injection flow rate of the cold water is 0.05-0.6 ml / s.

14. The method according to claim 11, wherein, The total mass of the hot water and the cold water is 5 to 15 g relative to 1 g of the coffee powder.

15. The method according to claim 11, wherein, The steaming process and the drip filtration are carried out in a brewing device, which is equipped with a filter element. The brewing device includes a coffee filter cup; the filter components include paper coffee filter paper, metal coffee filter mesh, and coffee filter cloth.

16. The method according to claim 11, wherein, The coffee beans are roasted to one or more of the following levels: light, medium, medium-dark, and dark. Optionally, the coffee beans are sourced from Yunnan, Ethiopia, and Colombia.

17. The method according to claim 11, wherein, The method further includes: grinding and sieving coffee beans to obtain coffee powder; the particle size of the coffee powder is 200-1600 μm.

18. The method according to claim 11, wherein, The hardness of the hot water and the cold water is each between 20 and 200 ppm.

19. The method according to claim 11, wherein, The method also includes storing the cold brew coffee liquid at 5°C.

20. Cold brew coffee liquid prepared by the method according to any one of claims 11-19.

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