Frother for milk-based beverages

Abstract

A stirring means 3 for a frother for making a hot chocolate beverage, the stirring means 3 configured to rotate in a liquid to mix the heated liquid. The stirring means 3 comprises a whisk 10 consisting of multiple coils, the whisk 10 being attached to a support. The stirring means 3 further comprises a basket 20 located above the whisk 10, the basket 20 comprising one or more slots for allowing the heated liquid to melt or dissolve the hot chocolate beverage ingredients.

Description

[Technical field]

[0001] The present invention relates to a frother for milk-based beverages and an agitator for a frother. [Background technology]

[0002] Espresso-based coffee drinks, such as lattes and cappuccinos, are becoming increasingly popular, and consumers want to be able to make these drinks easily and reliably. Traditionally, baristas have been trained to create the hot milk and foam required for these drinks by using steam from an espresso machine to heat and froth milk in a jug. Creating the right amount of hot milk and foam without burning the milk or damaging the jug requires some training and experience. Additionally, small espresso machines are difficult to use to handle the milk.

[0003] Many independent milk frothers are manufactured, suitable for domestic or small commercial use. EP 1 656 866 discloses a frother comprising a tank for receiving a milk-based liquid food with a magnetic beater. A magnetic beater drive system generates a magnetic field which drives the beater in rotation within the tank. The system, the beater and the beater positioning unit disrupt or prevent a symmetrical circulation of the liquid around the centre of the vertical axis of the tank. A heating unit is arranged in relation to the tank for heating the liquid. This is used to prepare a foam from the milk-based liquid food.

[0004] GB 2454421 discloses an apparatus for frothing milk which comprises a rotating heating element which is inserted into the milk, the apparatus being provided with a whisk for frothing and a paddle attachment for achieving a creamier finish. Summary of the Invention [Problem to be solved by the invention]

[0005] A further problem with known frothers is that the milk tends to burn onto the rotating heating element as the user pours the milk immediately after the frother has frothed it. If this is not cleaned quickly, the burnt residue becomes difficult to remove and affects future performance. The standard approach to this has been to reduce the temperature at which the milk is heated to around 60°C, but at this temperature the frothed milk is not suitable for other beverages such as hot chocolate, which require higher temperatures to achieve a good mouthfeel.

[0006] Known milk frothers and hot chocolate makers use a small DC motor to rotate the whisk. The motor's drive shaft is either directly connected to the whisk through a mechanical coupling or indirectly connected by a magnetic coupling. These motors have little torque and therefore stall easily. Also, the magnetic couplings in the motor can slip and become out of phase.

[0007] An additional problem arises when making a hot chocolate beverage. The load required to rotate the milk and chocolate mixture in the jar is greater than with milk alone. Also, the use of chocolate flakes rather than chocolate powder places a greater rotational load on the system. This greater rotational load has two effects: the whisk motor may stall (or the magnetic coupling may slip) or a smaller vortex may form. If the drive motor stalls or the coupling slips, the user must stop the cycle, reposition the whisk, and start the cycle again. Sometimes the cycle cannot be resumed because chocolate has gotten under the whisk and the coupling cannot reconnect. In such cases, the user is forced to discard the partially consumed beverage and start over.

[0008] A smaller vortex results in less (or no) exposure of the whisk to the air, which reduces the amount of air introduced to form the foam and creates an undesirable drink viscosity, such as warm chocolate milk rather than hot chocolate.

[0009] GB 2486872 represents a significant advance in domestic milk frother technology, but is limited to use with milk and is a single cup design, which is the industry standard capacity. To design a milk frother with a larger capacity than known milk frother designs and suitable for making hot chocolate would require sending more power to the motor, which could cause the motor to stall or the magnetic drive to disconnect. With known frother designs, this increased power could result in less stability or premature wear.

[0010] The present invention therefore seeks to provide a frother that can be used for the wider and larger production of beverages, especially milk-based beverages. [Means for solving the problem]

[0011] According to the invention there is provided a stirring means for a frother for making a beverage. The frother comprises a tank for containing a liquid and a magnetic drive means configured to drive the stirring means. The tank has substantially vertical walls and a flat bottom. The stirring means comprises a whisk configured to rotate in the liquid to mix the heated liquid. The frother further comprises heating means configured to heat milk or a milk-based liquid. The magnetic drive means is arranged outside the tank and below the flat bottom of the tank. The whisk consists of a number of coils. The whisk is attached to a support. The stirring means further comprises a basket arranged above the whisk. The basket comprises one or more slots for the heated liquid to melt or dissolve beverage ingredients.

[0012] Preferably, the beverage ingredient comprises chocolate flakes.Preferably, the basket comprises a plurality of concentric rings spaced apart from one another.

[0013] The agitator design of the present invention advantageously prevents the basket mechanism that holds the chocolate in the milk frother from stalling the motor and / or dislodging the magnetic or similar drive coupling with larger chocolate flakes. Chocolate flakes tend to behave like small rods or pieces of glass. They tend to naturally form clumps because their shape causes them to intertwine with each other. These clumps move around in the jar and cause the agitator to stall or the magnetic coupling to slip before the chocolate softens or melts. In the frother of the present invention, such flakes are dissolved into the liquid with little movement. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view of the frother. [Diagram 2] FIG. 2 is a perspective view of the stirrer. [Diagram 3] FIG. 3 shows chocolate flakes. [Figure 4] FIG. 4 shows yet another agitator design. [Diagram 5] FIG. 5 shows the basket in detail. [Figure 6] FIG. 6 shows yet another agitator design. [Figure 7] FIG. 7 shows yet another agitator design with an upstand. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention may be suitably implemented as a stirring means for a frother for making a beverage. The frother comprises a tank for containing a liquid and a magnetic drive means configured to drive the stirring means. The stirring means comprises a whisk configured to rotate in the liquid to mix the liquid. The frother further comprises heating means configured to heat the liquid. The magnetic drive means is arranged outside the tank. The whisk comprises a number of coils, the whisk being attached to a support. The stirring means further comprises a basket arranged above the whisk, the basket having one or more slots for allowing the heated liquid to melt or dissolve beverage ingredients.

[0016] In the stirring means, the beverage ingredient may comprise chocolate flakes, pieces or buttons.

[0017] In the stirring means, the slot may be defined by a plurality of spaced apart concentric rings.

[0018] The slot may have edges, with opposing edges spaced apart by 2-6mm.

[0019] The cross section of the concentric rings may be circular, diamond or teardrop shaped.

[0020] The multiple rings may be joined by multiple radial arms, some of the radial arms having a first length and some of the radial arms having a second length.

[0021] The stirring means may comprise radial arms extending from an axial spindle, the radial arms having curved surfaces to reduce resistance to the liquid within the frother.

[0022] In the agitator, the basket may be clipped onto or formed integrally with a spindle so as to be rotatable during use.

[0023] In the stirring means, the plurality of rings may be spaced apart from adjacent rings with greater spacing towards the centre of the whisk.

[0024] The agitation means may comprise an upstand arranged to disrupt the rotational flow of the liquid in use.

[0025] The upstand may be located adjacent to the spindle.

[0026] The present invention can be suitably embodied as a hot chocolate maker (one embodiment of a frother) equipped with any one of the stirring means described above.

[0027] Exemplary embodiments of the invention will now be described in more detail with reference to the drawings.

[0028] 1 is a perspective view of a milk frother comprising a tank 1 with substantially circular outer and inner periphery for containing the milk to be frothed, and a handle 5. A magnetic drive means 2 is provided beneath the underside of the tank 1, which drive means 2 is arranged to provide a drive force to a removable stirring means or agitation means 3 arranged within the tank without any mechanical connection penetrating the wall of the tank 1. The removable agitator or agitation means 3 is supported at the bottom of the tank 1 so as to remain centred and so that a drive mechanism can provide a drive force to the agitator.

[0029] A heating plate 4 is positioned below the bottom of the tank 1, the heating plate being adapted to heat the milk in use. The frother is provided with control means for controlling the operation of the heating plate and independently controlling the operation of the magnetic drive means. The control means can be either a single ECU or a separate PCB. The magnetic drive means can also have multiple speeds so that the liquid is not frothed depending on the beverage to be produced. For example, follow-up baby milk is not frothed.

[0030] In use, the control means is configured to switch off the heating plate a predetermined time before the whisk stops stirring, thereby allowing the whisk to pass milk over the heating plate for a predetermined time to remove residual heat from the plate. The length of time depends on the dimensions of the tank, the speed of the whisk and the desired temperature of the milk. An exemplary length of the predetermined time is about 10 seconds. Possible times range from 6 to 20 seconds.

[0031] This special arrangement has the advantage that the milk can be heated to a higher temperature than normal, but by the time the milk is poured from the frother the bottom of the tank is cool enough so that the remaining milk in contact with the tank does not burn. For example, with the frother of the present invention it is possible to heat milk to 75°C, which is suitable for making hot chocolate, whereas with most prior art devices the milk is only heated to around 60°C, because at higher temperatures the milk would unacceptably burn on the surface of the frother.

[0032] Figure 2 is a perspective sectional view from above of a stirrer according to a first embodiment of the invention, suitable for use with large chocolate flakes as illustrated in Figure 3. The stirring means 3 comprises an upright wall 7 which is connected to an axial spindle 9 by two radial arms 8. The wall of each arm is provided with a notch into which a clip of the cover fits to hold the cover in place. The spindle 9 extends above and below the radial arms 8. A whisk 10 is rotatably mounted on a rotatable drive shaft (support) at the lower end of the spindle 9, which drive shaft is housed within the spindle 9. The wall shown is annular, but it does not have to be a continuous annular wall.

[0033] The agitator is provided with a basket 20. The basket may be clipped onto the spindle 9 or may be formed integrally with the spindle. The basket must be attached to the agitation means / spindle so that it rotates when in use and does not fall off when the beverage is poured. The rotation of the basket promotes mixing by moving the flakes outwards and into the vortex of the milk. The basket has a number of grooves (slots) which allow the fluid to pass through the basket, the width of which is on the order of 2-2.5mm. The rotation also reduces the load on the motor-drive coupling. The chocolate mass can rotate with the rotating milk, rather than being stationary and acting like a brake.

[0034] In use, the agitator and basket are mounted in a tank, preferably filled with milk followed by chocolate or other beverage ingredients. The basket, which receives the chocolate flakes in the milk frother, keeps the chocolate up and away from the rotating agitator, preventing the motor from stalling or dislodging the magnetic or similar drive coupling. The milk initially begins to bubble slowly beneath the chocolate. Once the milk reaches the chocolate's melting temperature, the speed is increased to raise the height of the milk in the frother, allowing the chocolate to melt and begin to mix with the milk. The basket also keeps the chocolate away from the frother's heating plate, making it easier to clean.

[0035] The basket walls are not necessary. Removing the walls allows the basket to be slimmer, which gives more design freedom for adjusting the stirrer height. The basket height also affects the amount of foam and chocolate residue that remains in the stirrer. Depending on your hot chocolate recipe, you may need to modify the required height.

[0036] The basket design can be angled up or down, as well as the flat version shown in Figure 2. This adjusts how the chocolate is positioned during the whipping cycle, affecting the amount of foam and chocolate residue left in the stirrer. Alternatively, the basket can be essentially flat and have no walls, which allows it to be reversible for height adjustment.

[0037] The spacing of the concentric rings that form the slots in the basket can be even or uneven, which helps control the amount of foam and reduces the residue of unmelted chocolate that may be left at the end of the cycle.

[0038] The basket may comprise two or more radial arms that attach concentric rings to a central shaft, the radial arms may be straight or curved. The cross section of the concentric rings may be circular, diamond or teardrop shaped to reduce the chance of unmelted chocolate settling in the basket.

[0039] Figure 4 shows yet another agitator design. The agitator 30 of Figure 4 also has an upright wall 7 which is connected to an axial spindle 9 by three radial arms 38. The wall of each arm has a notch into which a clip on the cover fits to hold the cover in place. The spindle 9 extends above and below the radial arms 38. At the lower end of the spindle 9, a coiled whisk (not shown) is rotatably mounted on a rotatable drive shaft which is housed within the spindle 9. The wall shown is an annular wall, but it need not be a continuous annular wall.

[0040] By using three arms, each arm can be made thinner, with the same overall strength as with two arms. Each arm can be provided with an aerofoil section as shown in Figure 5, reducing the resistance to the flow of the liquids (initially milk, but later including the cocoa mass). The reduced resistance has the advantage that smaller bubbles are formed in the mixture, improving the organoleptic properties of the beverage.

[0041] Depending on the recipe you use with your hot chocolate maker, the ratio of chocolate to milk may be higher, which may put a greater strain on the motor and coupling. A typical hot chocolate drink uses about 35g of chocolate and 220ml of milk. This will make one cup of hot chocolate. Other recipes include 35g of chocolate and 120ml of milk to make a cold frozen milk, or 70g of chocolate and 120ml of milk to make a chocolate dipping sauce or pudding.

[0042] The embodiments of Figures 5 and 6 allow for the production of beverages using larger flakes with a relatively small surface area. The smaller surface area makes it more difficult to dissolve the chocolate in a given amount of milk in a given time (a simple control would be the amount of milk and the time it takes to heat to 67°C).

[0043] The lower the resistance of the stirrer / drive motor, the faster it can rotate. So the less resistance there is in the stirrer, the faster it will rotate and mix the milk and chocolate together faster. At higher speeds it will act like a mixer, breaking down larger pieces of chocolate so they melt faster.

[0044] As it passes through the basket, the debris is exposed to the sharp edges of the support arms (and additional arms compared to the first embodiment), which helps break up the debris in a controlled manner so as not to stall the agitator.

[0045] It has been found that the optimum height of the basket relative to the bottom of the jar is the minimum level of milk required for the recipe. Measurements are taken from the top of the basket.

[0046] Figure 6 shows a further embodiment of the basket. As in the previous embodiment, the basket can be clipped to the spindle 9 or can be integrally formed therewith. The basket therefore rotates during use. The rotation helps to move the flakes outwards and into the milk vortex, enhancing mixing. In this embodiment, the concentric rings 63 are spaced further apart as they approach the centre of the stirrer. The radial arms are also shortened in length with three arms 62 alternating with full length arms 61. By varying the spacing of the concentric rings as they approach the centre of the stirrer, the amount of residual chocolate can be reduced.

[0047] Since the spacing between the rings needs to be smaller than the smallest piece of chocolate flake, more concentric rings may be needed as the diameter of the device increases, and vice versa. Also, more radial arms may need to be added to increase the strength of the basket to support the weight of the chocolate. An exemplary gap between the rings is 4-6 mm.

[0048] Figure 7 shows a further embodiment of the invention in which the innermost ring of the basket has been removed. Instead, an upstand 70 is provided which disrupts the flow of milk in use when the agitator is rotating. The upstand 70 may be formed on the agitation means or on the basket and extends above the height of the basket. The upstand prevents chocolate from collecting or accumulating in the basket. Accumulation of chocolate in the basket may cause the chocolate to start to clump after the ingredients have started to melt, depending on the ingredients' composition.

[0049] Besides chocolate, other milk-based beverage ingredients such as honey are possible. Milk also includes non-dairy milk. A standard hot chocolate recipe consists of 220 ml of milk and 35 g of chocolate.

Claims

1. A stirring means for a frother for making a beverage, the frother comprising a tank for containing a liquid and a magnetic drive means configured to drive the stirring means, the stirring means comprising a whisk configured to rotate in the liquid to mix the liquid, the frother further comprising heating means configured to heat the liquid, the magnetic drive means being positioned outside the tank, the whisk comprising a plurality of coils, the whisk being attached to a support, the stirring means further comprising a basket positioned above the whisk, the basket having one or more slots for allowing the heated liquid to melt or dissolve beverage ingredients.

2. 2. The stirring means of claim 1, wherein the beverage ingredients comprise chocolate flakes, shards or buttons.

3. 2. The agitating means of claim 1 wherein said slot is defined by a plurality of spaced apart concentric rings.

4. 4. The agitating means of claim 3, wherein said slot has edges and the spacing between opposing edges is between 2 and 6 mm.

5. 5. A stirring means according to claim 3 or 4, wherein the cross section of the concentric rings is circular, diamond or teardrop shaped.

6. 5. The stirring means of claim 3 or 4, wherein the plurality of rings are connected by a plurality of radial arms, some of the radial arms having a first length and some of the radial arms having a second length.

7. 5. The stirring means according to claim 1, further comprising radial arms with respect to an axial spindle, the radial arms having a curved surface to reduce resistance to the liquid within the frother.

8. Agitating means according to any one of claims 1 to 4, wherein the basket is clipped onto or integrally formed with a spindle so as to be rotatable during use.

9. 5. A stirring means according to claim 3 or 4, wherein the plurality of rings are spaced more widely from adjacent rings approaching the centre of the whisk.

10. Agitation means according to any one of the preceding claims, comprising upstands arranged, in use, to disrupt the rotational flow of the liquid.

11. 11. The agitating means of claim 10, wherein the upstand is disposed adjacent to the spindle.

12. A hot chocolate maker comprising a stirring means according to any one of claims 1 to 4.

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