Abstract:
A cheese making appliance with a cooking vessel, a curd stirring assembly in the cooking vessel, and a controller for the cooking vessel and stirring assembly. The controller controls the temperature of the cooking vessel over a period of time, and turns the stirring assembly on and off and controls its speed, depending on the programmed cycle for a particular type of curd product that is to be made.

Description:
PRIORITY/CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority date of the provisional application entitled Home Cheese Making Device filed by Timothy W. Heald on Mar. 6, 2008 with application Ser. No. 61/034,478, the disclosure of which is incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention generally relates to an apparatus for making cheese, and more particularly to a home food processing appliance for processing milk into cheese curd. 
       BACKGROUND OF THE INVENTION 
       [0003]    The process of making cheese curds for consumption or for creating consumable cheeses is very tedious and precise. It requires exacting control over the time/temperature of the milk/coagulum/curd mass and gentle, timely stirring of the mass to promote the uniform and timely curd formation necessary for quality cheese curds for a desired type of cheese. Cheese making is an age old process, and is done commercially in large equipment. What is needed is a device small enough to be used in a home to make family sized quantities of cheese. Such a device also needs heating and stirring process controls, and a stirring mechanism. 
       SUMMARY OF THE INVENTION 
       [0004]    Objectives of the invention include providing a small, easy to use appliance for use in the home kitchen that is capable of producing a variety of cheese curd products suitable for processing into a variety of cheeses. 
         [0005]    Another objective is to provide a small, easy-to-use appliance for use in the home kitchen that is capable of producing other milk-based coagulum, non-curding products such as cream cheese and yogurt, in addition to being able to pasteurize raw milk. 
         [0006]    These objectives are accomplished by this invention, which includes a cooking appliance, a rotary cheese curd stirrer, and an electronic controller unit. The cooking appliance consists of a cooking vessel and a cooking vessel lid which closes the cooking. This can take the form of a heat unit into which the cooking vessel can be placed. The heating unit can also be built into the cooking unit, as in a slow cooker. 
         [0007]    A rotary stir assembly is included, and is configured to rotate near the bottom of the cooking vessel to stir the curd as it forms from milk. An upper stir assembly can be included, to aid in stirring the curd in the cooking vessel. 
         [0008]    As the heating unit provides heat to the cooking vessel, the rotary cheese curd stirrer scrapes the bottom of the cooking vessel and mixes the contents, in order to assure a consistent temperature throughout and prevent the milk-based contents from scalding or burning. An electronic controller unit is included, and is configured to control both the temperature of the cooking vessel and the timing, direction, and speed of the stirring action of the rotary cheese curd stirrer in such a manner as to produce the desired products. 
         [0009]    One version of the device has a rotary cheese curd stirrer which forms a lower stir assembly that, in addition to stirring and preventing scalding and burning, prevents the curds from matting and settling to the bottom of the cooking vessel with an upper stir assembly and stir paddles on both the upper and lower stir assemblies. The stir paddles on the upper stir assembly can form a solid, or partially solid, stationary curtain to provide counter stirring against the rotary cheese curd stirrer and paddles. Further, the upper and lower stir paddles are configured in such a manner as to be inclined, in order to rake the curds down from the top and lift the curds up from the bottom. The upper stir paddles extend between the lower stir paddles in such a manner as to shear any matted cheese curds. The upper stir assembly may also be configured so as to rotate in the opposite direction of the rotary cheese curd stirrer in order to provide improved counter stirring of the curds. 
         [0010]    A preferred home cheese making device has an electronic controller unit that senses the temperature of material inside the cooking vessel through the use of an infrared sensor or an immersion sensor. Using predefined and user defined recipes, the controller turns the heating unit on or off as needed to achieve and maintain the temperatures necessary to produce the selected product. In addition, the controller starts and stops the rotary action of the rotary cheese curd stirrer as needed to produce the selected product, and controls the speed and direction of rotation of the upper and lower stirring assemblies. 
         [0011]    The standard procedure for making most types of cheese curds can consist of up to six distinct steps. Each step can consist of any or all of the following parameters: duration time, start temperature, end temperature, mixer on duration, mixer off duration, mixer delay and step indicator. The six step indicators are: Preheat, Ripen, Curd, Cook, Warm 1, and Warm 2. All parameters are dependent upon the type of cheese curd/coagulum being made, e.g., the parameters for cheddar cheese curds will be different than the parameters for Parmesan cheese curds or yogurt coagulum. 
         [0012]    The first step is to preheat the milk to starting temperature while stirring occasionally. The second step is ripening, wherein the milk is kept at a constant temperature for a desired period of time while stirring occasionally. The third step is curd where the milk becomes a coagulum mass and is kept at a constant temperature for a period of time with no stirring. The fourth step is cook, where the temperature of the cubed coagulum mass is slowly raised from the coagulating temperature to the final cook temperature over a period of time—generally around one degree F. per minute. During this fourth cook step, the mass must be gently stirred occasionally to prevent the cubed coagulum mass settling at the bottom of the cooking container. This stirring keeps the cubes of coagulum suspended in the whey, which allows the cubes of coagulum to eject the whey and become curds. The cubes of coagulum begin as very fragile entities and can be easily mashed in the stirring action. Thus, the control of the stirrer mechanism is critical. The stirrer cycle can be delayed for a period of time—called healing—and then mixing begins. The optional fifth and sixth steps are the warm steps where the cheese curd and whey solution are kept at a constant temperature with or without stirring as determined by the cheese curd recipe. 
         [0013]    This invention accurately and precisely performs these steps as necessary for a desired type of cheese curd. This invention allows existing home kitchen cooking devices, such as a rice cooker, slow cooker or a pot on a heating surface, to be used to make quality cheese curds for a variety of cheeses. In addition, the precise time/temperature control feature of the invention allows the invention to be a versatile cooking device—such as a rice cooker, steamer, slow cooker, yogurt maker, and milk pasteurizer. 
         [0014]    The purpose of the Abstract is to enable the public, and especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection, the nature and essence of the technical disclosure of the application. The Abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way. 
         [0015]    Still other features and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description describing preferred embodiments of the invention, simply by way of illustration of the best mode contemplated by carrying out my invention. As will be realized, the invention is capable of modification in various obvious respects all without departing from the invention. Accordingly, the drawings and description of the preferred embodiments are to be regarded as illustrative in nature, and not as restrictive in nature. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0016]      FIG. 1  is a side cross sectional view of the device of the invention 
           [0017]      FIG. 2  is a plane view of a control panel of the invention. 
           [0018]      FIG. 3  is a side view of a control panel of the invention. 
           [0019]      FIG. 4  is a view of the bottom of the control panel. 
           [0020]      FIG. 5  is a top view of a curd stirrer of the invention. 
           [0021]      FIG. 6  is a side view of a curd stirrer of the invention with a stationary paddle. 
           [0022]      FIG. 7  is a side view of a curd stirrer of the invention. 
           [0023]      FIG. 8  is a side view of a version of the upper and lower stirrers of the invention. 
           [0024]      FIG. 9  is a side view of a scraping portion of a curd stirrer. 
           [0025]      FIG. 10  is a top view of a stirring arrangement of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    While the invention is susceptible of various modifications and alternative constructions, certain illustrated embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims. 
         [0027]    In the following description and in the figures, like elements are identified with like reference numerals. The use of “e.g.,” “etc,” and “or” indicates non-exclusive alternatives without limitation unless otherwise noted. The use of “including” means “including, but not limited to,” unless otherwise noted. 
         [0028]    The invention is a portable countertop food processing appliance, configured for the preparation of cheese curds from milk. One version of the cheese making appliance of the invention is shown in  FIG. 1 . The version shown in  FIG. 1  includes a cooking vessel  14  and a cooking vessel lid  12 . Also shown in  FIG. 1  is a rotary cheese curd stirrer  16  and an upper stir assembly  18 . The rotary cheese curd stirrer  16  is configured to rotate inside the vessel  14  and is driven by a drive shaft  20 . The drive shaft  20  is powered from an electronic controller unit  22  which includes a motor  56 . In the configuration shown in  FIG. 1 , the rotary cheese curd stirrer  16  includes a number of stir paddles  24 , which break up coagulated cheese curd, and also scrape the bottom of the cooking vessel  14 . A cross-section of part of the cheese curd stirrer is shown in  FIG. 9 . A bottom edge  26  of the cheese curd stirrer  16  travels on or close to the bottom of the vessel  14 , and tends to scrape cheese curd which may accumulate on the bottom of the vessel. 
         [0029]    In the version shown in  FIG. 1 , the upper stirrer assembly  18  is a vane which is approximately as wide as the diameter of the cooking vessel  14 . The vane can be a solid or perforated plastic unit which can be fairly thin, with a bottom edge  26 . Bottom edge  26  may be straight or toothed to intermesh with the stir paddles  24  of the rotary cheese curd stirrer  16 . The upper stir assembly can be configured to be stationary, and in its stationary position it would provide counter stirring against the cheese curd being rotated and agitated by the cheese curd stirrer  16 . 
         [0030]    The upper stir assembly can also be configured by appropriate gearing to rotate in a direction counter to the direction of the rotary cheese curd stirrer  16 , or in the same direction but at a different speed. In either a stationary or a counter rotating configuration, counter stirring is provided against the rotary cheese curd stirrer  16 . The drive shaft shown in  FIG. 1  can be attached to a motor in the cooking vessel lid, or it may be attached to a motor in the base of the cooking vessel  14 . 
         [0031]      FIG. 2  shows a view of the interface console  28  of the electronic controller unit  22 . The interface console  28  of the electronic controller unit  22  provides a display  30 , status indicators  32 , and selection buttons  34  that allow the use to select the program which controls the operation of the device. These operations include the selection of any of the fourteen or more of any curd recipes including: eight cheese curd recipes; two coagulum recipes; two user defined recipes, rice cooker and slow cooker programs; modification of the recipe parameters in starting, stopping and pausing the cheese curd making operation. For operation, the cooking vessel lid  12  with the electronic controller unit  22  is placed on the cooking vessel  14 . The power cord of the cooking vessel may be may be connected to the electronic controller unit  22  with the power cord  38 , and the electronic controller unit can them be plugged into an electrical power source. One power cord can also supply power to both units. 
         [0032]    The embodiment of the invention shown in  FIG. 1  can also be made as a two piece unit in which the two pieces are sold together, the two pieces being the cooking vessel  14  and the cooking vessel lid  12 , with its attached electronic controller unit  22  and attached cheese curd stirrer  16  and upper stir assembly  18 . 
         [0033]    One preferred embodiment of the invention includes an electronic controller unit, and a container lid and matching container, which may be made of stainless steel, crockery or other suitable material. A base unit may be a separate unit, consisting of a gas or electric cooking device capable of heating the said container, to which the mixer/sensor head is wired directly, and on which an electronic controller unit is installed; and a rotary cheese curd stirrer. The interface console of the electronic controller unit provides a display, status indicators, and buttons that allow the user to select the operation of the device. These operations include a selection of any of the 14 or more recipes including: eight cheese curd recipes; two coagulum recipes; two user definable recipes, rice cooker and slow cooker; modification of the recipe parameters; and starting, stopping and pausing the cheese curd making operation. For operation, the mixer/sensor head, lid, and stirring mechanism assembly is placed on/in the container and the container is placed on the base unit which is plugged into an electrical power source. 
         [0034]      FIGS. 2-4  depicts a preferred embodiment of the electronic controller unit in three views.  FIG. 2  depicts the layout of the operator interface of the electronic controller unit.  FIG. 2  shows a representation of the operator interface with respect to the controller unit. Also visible in  FIG. 2  is a lower vent slot  40  that allows air to pass through the upper portion of the unit and cool the microprocessor control system and travel out of the upper vent  42  shown in  FIG. 3 .  FIG. 2  shows the lid release button  44  that is used to release the vessel lid  12  from the electronic controller unit  22 , the locations of the infrared temperature sensor  46 , and the optional thermistor temperature probe and the alignment pin  50 .  FIG. 3  shows the placement of the microprocessor control system in the vented upper section of the electronic controller unit  22 , the vents, and the vinyl overlay  54  that form the operator interface. Shown in  FIG. 2  is the interface system that interfaces the microprocessor control system  52  to the stirrer motor  56  and the 110 VAC heater receptacle by using relays; the infrared sensor or thermistor probe; and the 110 VAC power supply for energizing the controller. Also shown in  FIG. 3  is the mixer mating connector that allows the rotary cheese curd stirrer mechanism  16  to be easily connected and disconnected to the stirrer motor  56  and the electronic controller unit  22 .  FIG. 4  shows the alignment pin  50  (optional hole or grooves and ridges  66 ), the lid knob recess hole  64 , into which the lid knob (not shown) is latched, the infrared  46  or thermistor sensor  48 , and the lid latched switch  62 . 
         [0035]      FIG. 4  depicts the bottom of the electronic controller unit  22 . Shown are: the alignment hole  64  through which the alignment pin  50  passes, optional grooves and ridges  66  to align the lid, the temperature sensor hole  68  through which the temperature of the container contents is sensed, the vent hole  70  through which the heat and steam from the cooking vessel  14  contents are vented to the atmosphere, and the lid knob  72  with the sealed hole  74  through which the drive shaft  20  of the stirrer assembly passes. The lid knob  72  is of a form that allows it to be latched into the controller unit  22  and close the lid latch switch  62 . 
         [0036]      FIGS. 5-7  depict a version of the rotary cheese curd stirrer mechanism in three views. The stirrer mechanism consists of three major components: the drive shaft  20 , the stationary paddle  78  and the cheese curd stirrer  16 .  FIG. 5  shows the orientation of the stir paddles  24  on the cheese curd stirrer  16  in respect to the stirrer rotation  100  and the alignment hole  64  (optional pin or grooves and ridges  66 ) in the stationary paddle  78 .  FIG. 6  shows the stationary paddle  78  riding on the guide  82  on the drive shaft  20  and the orientation of the leading edge of the cheese curd stirrer  16  and the stir paddles  24 . As the cheese curd stirrer slowly rotates, the cubed coagulum mass is gently lifted from the bottom of the container by the leading edge  26  of the stirrer  16 . The mass slides up the stir paddles  24  which separates the cubes when some fall back down between the fins.  FIG. 7  shows a different view of the stir paddles  24  of the stirrer  16 , and the mating end  86  of the drive shaft  20 . Also shown are optional positions of the stationary paddle  78 . Instead of remaining co-planar with the drive shaft  20 , the stationary paddle may be inclined at an angle. This provides better vertical circulation of the cubed coagulum mass. 
         [0037]    The upper stir assembly  18  and the rotary cheese curd stirrer  16  are shown in  FIG. 8 . The upper stir assembly  18  and the rotary cheese curd stirrer  16  may both be constructed out of a plastic or food grade material such as stainless steel. The upper stir assembly  18  consists of an upper support  88  that supports the helical upper rakes  90  and helical upper incline fins  92  and is driven in a rotary manner by the gearbox  84 . The drive shaft  20  provides reverse torque to the gearbox  84  and to the rotary cheese curd stirrer and supports the upper stir assembly  18  on the guide  82 . The rotary cheese curd stirrer  16  consists of bottom agitator  94  that supports the helical lower incline fins  96  and the helical lower rakes  98 .  FIG. 9  shows a cross-section of the bottom agitator  94  and shows the bottom agitator leading edge  26  which aids the rotary cheese curd stirrer  16  as it lifts the cubed coagulum mass off of the bottom of the cooking vessel  14  using the helical lower incline fins  96  as it rotates in the bottom agitator rotation direction  100  shown in  FIG. 10 . In addition, the helical lower rakes  98  drag the cubed coagulum mass down from the top and break up any matting that has occurred by dragging the matted curd through the helical upper incline fins  92 . In a similar manner, the helical upper incline fins  92  push the cubed coagulum mass down from the top as it rotates in the upper support rotation direction  102  (shown in  FIG. 10 ) while the helical upper rakes  90  drag the cubed coagulum mass up from the bottom and break up any matting that has occurred by dragging the matted curd through the helical lower incline fins  96 . In this manner, the helical lower incline fins  96  create a vertical agitation motion while the helical upper rakes  90  and helical lower rakes  98  create a radial agitation motion, thus gently preventing the cubed curds from matting. The rotary speed, number of fins, number of rakes, dimensions, angles and geometry of the fins and rakes are dependent on the cooking vessel  14  depth and diameter. 
         [0038]      FIG. 10  is a top view of one preferred embodiment of the stirring assembly of the invention. The upper stir assembly  18  is shown with upper support  88 , gear box  84  attached to the upper support  88  are upper stir paddles  106 , comprising helical upper incline fins  92  and helical upper rakes  90 . The upper rakes  90  and the upper incline fins  92  are angled from their attachment to the upper support  88 , so that they have different and opposite effects due to the rotation of the upper stir assembly  18 . The upper stir assembly direction of rotation is indicated at  102 , thus as the upper stir assembly  18  rotates counterclockwise, the helical upper incline fins  92  tend to lift cheese curds during their passage. However, as shown in  FIG. 8 , the helical upper incline fins are shorter than the helical upper rakes fins  90 . As the upper stir assembly  18  rotates counterclockwise, the helical upper rakes  90  tend to slice through cheese curds and push them down. The upper helical rakes  90  are longer than the helical incline fins  92 . 
         [0039]      FIG. 10  also shows the rotary cheese curd stirrer  16  of the invention, which includes a bottom agitator  94  to which are attached the direction of rotation of the rotary cheese curd stirrer  16  is indicated as being counterclockwise. 
         [0040]    While there is shown and described the present preferred embodiment of the invention, it is to be distinctly understood that this invention is not limited thereto but may be variously embodied to practice within the scope of the following claims. From the foregoing description, it will be apparent that various changes may be made without departing from the spirit and scope of the invention as defined by the following claims.