BACKGROUND OF THE INVENTION
Microwave ovens are becoming more and more widely used in both homes and restaurants.
Such ovens, however, often do not take full advantage of reflected microwave radiation in cooking and do not brown the meat on the outside as well as they might. Efforts to solve this have included partially cooking the food in a microwave oven and finishing the cooking in a normal oven, or cooking the food in the usual way, freezing it, and using the microwave oven only for thawing and heating.
Browning of meats can be partially accomplished by the present cooking vessel without absolute need for a second step.
SUMMARY OF THE INVENTION
This present invention provides a method and apparatus for cooking foods in a microwave oven and giving them the palatability people are accustomed to from normal oven cooking. It utilizes the fact that liquid fat drippings from foods such as meat absorb more energy and so reach far higher temperatures in the presence of microwaves than does the meat itself (for example 400.degree. F. as compared to 150.degree. F.). Consequently, with a properly structured cooking vessel, the liquid fat drippings are removed from the area beneath the foods, are heated by electrical microwave energy, and in turn, heat the air in the oven to heat the exterior of the meat to encourage browning.
The cooking vessel includes a base and top and a series of food-supporting ribs across the upper surface of the top. The food rests upon the ribs during and, if desired, after cooking. These ribs define grooves between them on the upper surface. The grooves slope gently toward either a remote reservoir, or a channel leading into a remote reservoir, in the cooking vessel, and so carry the hot fat away from the meat.
The vessel has downwardly extending sides, defining a chamber. The heat from the hot liquid fat in the grooves, channel, and reservoir is carried through the upper surface of the vessel to warm the air in the chamber below.
The vessel may be made from any suitable material usable in microwave ovens and should also be usable in ordinary ovens. Preferably, it is made of a metal-free stoneware body, since such stoneware is virtually transparent to microwaves, is strong, can stand temperatures beyond 600.degree. F., and has a good appearance so the vessel may also be used for serving at the table.
In use, the food to be cooked is placed on the vessel and supported by ribs. The ribs hold the food above the grooves in the upper surface of the vessel so that it will not obstruct the flow of fat through the channels. As the food is heated by microwave radiation, liquid fat drips from the food and into the grooves below. It flows down the grooves, into the channels, if used, and then enters a remote reservoir.
The fat, being liquid, will absorb considerably more microwave energy (on a volume basis) than does the food or the ambient air inside of the oven. The fat, therefore, reaches a considerably higher temperature than the food or air. For example, when roasting pork to a serving and eating degree of "doneness", the fat has been found to reach 400.degree. F. while the roast itself reaches only 150.degree..
As the heated fat flows down the grooves underneath the food, heat from the fat is radiated to the food and assists in cooking; further, the surrounding air is heated through convection; the hot air assists in browning the surface of the meat.
More importantly, when the liquid fat accumulates in the reservoir, it continues to receive microwave energy and remains at, or increases, its high temperature. In turn, it heats the air in the oven which enhances the browning of the food.
Since the sidewalls of the vessel define a chamber in the hollow region beneath the upper surface of the vessel, heat from the hot liquid fat is also transmitted through the dish to the air confined in the chamber underneath, further heating the air confined therein. As a result, the cooking vessel may also be used as a serving dish; and the heated air in the chamber will assist in keeping the food warm.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one embodiment of the invention, positioned inside of a microwave oven and holding a roast.
FIG. 2 is a top plan view of this embodiment.
FIG. 3 is a side elevational view of this embodiment.
FIG. 4 is a vertical sectional view of this embodiment looking in the direction of the arrows 4 on FIG. 2. It shows the ribs, grooves, and reservoir.
FIG. 5 is a vertical sectional view of this embodiment looking in the direction of the arrows 5 on FIG. 2. A roast is shown (in dotted outline) supported by the ribs. Note that the ribs are arcuate in shape and form a generally concave, cylindrical supporting surface and that there is a centrally-located channel.
FIG. 6 is a partial sectional view of this embodiment looking in the direction of the arrows 6 on FIG. 2. It shows one of several undercut portions that may be provided for handholds.
FIG. 7 is a perspective view of a second embodiment of the invention.
FIG. 8 is a top plan view of this embodiment.
FIG. 9 is a vertical sectional view of the embodiment looking in the direction of the arrows 9 on FIG. 8. It shows horizontal ribs, sloping grooves, and a channel on one side.
FIG. 10 is a vertical sectional view of this embodiment looking in the direction of arrows 10 on FIG. 8.
FIG. 11 is a top plan view of a third embodiment of the invention in which the grooves slope to the side and the receiving channel is along the periphery.
FIGS. 12 and 13 are side elevational views of this embodiment.
FIG. 14 is a sectional view of this embodiment looking in the direction of the arrows 14 on FIG. 11.
FIG. 15 is a sectional view of this embodiment looking in the direction of the arrows 15 on FIG. 11.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A First Embodiment
Turning to the drawings, FIG. 1 is a perspective view of a customary microwave oven 2 with a window 3 in front. A cooking vessel 4 carrying a roast 6 may be seen through window 3. Those portions of the cooking vessel and of the roast which would not be seen through the window are shown in dotted lines.
One embodiment of cooking vessel 4 is shown in FIGS. 1 through 6. The broad configurations of the structure are probably best seen initially in FIGS. 3 and 5. The vessel 4 is a hollow, stoneware unit having a top portion 9 with an upper surface 8 monolithically formed with a base 10. Base 10 includes an upper rim 12 and a downwardly extending circular skirt 14. Skirt 14 may have inwardly turned flanges 16 at its bottom to provide more of a support surface, but the bottom portion is generally open. Thus, top 9 with its upper surface 8 and base portion 10 are integral together and define an inner chamber 18.
Turning to the configuration of upper surface 8, it has a food holding portion that is generally arcuate and semi-cylindrical in appearance (concave as viewed from above), and outer walls 26. The outer walls 26 connect with the base 10 along the rim 12.
The food holding portion of upper surface 24 includes ribs 28 extending above surface 24 and defining grooves 30 between them. The grooves 30 lead to a channel 32 at their lower-most portion which, in turn, feeds into a reservoir 38.
Since the ribs 28 extend above upper surface 24, the food, such as roast 6, rests upon the ribs and is raised above the bottom of grooves 30. Ribs 28 are generally narrow or pointed (triangular in cross-section) so that the area of ribs 28 actually in contact with the roast 6 is relatively small compared to the area of the surface of roast 6 which is above grooves 30. The pointed cross-sectional nature of ribs 28 and the relative surface areas is shown by noting the points 29 on the ribs 28.
Grooves 30 are adapted to receive liquids such as liquid fat drippings from a roast, or fluids used for basting the food being cooked. The grooves are sloped so that the drippings will drain down the grooves 30 into channel 32; and channel 32 is sloped to cause the drippings to drain into reservoir 38. Reservoir 38 is preferably positioned remote from roast 6, i.e., not underneath the roast. Ribs 28 should have a height above the bottom of grooves 30 sufficient to permit the flow of the liquid fat through the grooves without being obstructed by the food.
If desired, skirt 14 may include several indented portions 20 (see FIGS. 2 and 6). These will permit the user to reach under the rim 12 and use rim 12 as a handle for carrying vessel 4.
The cooking vessel 4, shown by FIGS. 1 to 6 is used as follows:
A roast 6 is placed on the upper surface 24 of vessel 4 and rests upon the upper tips 29 of ribs 28, above the downwardly sloping grooves 30. Vessel 4 may then be picked up by rim 12 at the indented portion 20 and placed in microwave oven 2.
Microwave radiation in the oven 2 heats the food, such as roast 6; and when the roast has reached a high enough temperature, the food is considered "cooked". For a roast of pork the "cooked" temperature is approximately 150.degree. F. Meanwhile, while its temperature is increasing, fat on the roast drips from it into grooves 30 and flows down them into channel 32 and then into reservoir 38. This removes much of the free fat from the meat, so a greater percentage of microwave radiation reaches the lean meat itself without being absorbed by the fat.
Radiation in a microwave oven reaches the food both directly and by reflection within the oven. By having the vessel 4 elevated 3/4" to 2", by skirt 14 of base 10, more reflected radiation will reach the underside of the meat. This will promote faster cooking.
Liquid fat and other liquids (such as from basting) normally absorb significantly more energy from microwave radiation than the food being cooked; and the surrounding air absorbs but little if any of the energy. The liquid fat in remote reservoir 38 continues to receive microwave radiation, often radiation that would not reach the roast itself. Thus, it reaches a relatively high temperature. This heats the ambient air which then circulates in the oven by convection. Such serves to brown the meat being cooked and also contributes to the capacity of the oven to cook the food evenly. If fat is removed from the reservoir, the energy will redirect itself more to the meat; for there is no fat to "steal" the energy.
The liquid fat in grooves 30, channel 32, and reservoir 38 also transmits heat energy through the upper surface 8 of vessel 4 and into the hollow inner channel 18 thereunder. This serves to heat the air within the chamber. As a result, if vessel 4 is later used as a serving dish, the heated air within chamber 18 helps to keep the food warm after the vessel has been removed from the oven.
It is best that the width of the grooves 30 be greater than the width of the ribs 28. By increasing the width of the grooves (correspondingly decreasing the width of the ribs), the exposed surface area of the roast, i.e., that portion not in contact with ribs 28, is increased. This permits the fat to more quickly leave the surface of the roast and be removed, and so, it is believed, will increase the total microwave energy absorbed by the roast. Thus, by having the ribs as narrow as possible relative to the grooves, a greater area of the roast is more quickly exposed for cooking. Also, as mentioned above, having points 29 on the upper edges or ribs 28 is also a means of increasing the exposed surface area of the meat.
Though this invention is being described as using liquid fat drippings from meats, the liquid could be something else, such as basting liquids and so, for simplicity, the term "liquid fat" or similar expressions will be used herein to encompass other such liquids.
A Second Embodiment
FIGS. 7, 8, 9 and 10 show another embodiment of the present invention which is particularly adapted for microwave cooking of bacon and eggs, frankfurters and baked beans, or other combination foods. For convenience, the same number have been given to the corresponding parts where apposite.
The dish or vessel 4 has a base 10 with a rim 12 and supporting skirt 14. The top portion 9, with its upper surface 8, in this embodiment, has two recessed food holding sections 22 and 23, for bacon and eggs respectively. Top portion 9 is integral with base 10.
A series of ribs 28 protrude upwardly from surface 8 in recessed section 22. The ribs 28 define a series of downwardly sloping grooves 30 between the ribs. This is similar to the rib-groove structure of the earlier described embodiment, except that the upper surface of the ribs 28 generally defines a plane rather than an arcuate surface.
The surface area of portion 22, as shown in FIGS. 7 and 8, is crescent-shaped. The grooves 30 slope downwardly and inwardly towards portion 23 to channel 34, positioned adjacent to portion 23.
The bacon to be cooked is laid across and supported by the ribs 28. As the bacon is cooked by microwave radiation, liquid fat drips into and flows down grooves 30 to reservoir 38 and becomes much hotter than the bacon. Heat from this liquid fat heats the air and cooks the bacon in much the same manner described for the previously-discussed embodiment. The capability of the vessel to cook the bacon can be enhanced by increasing the width of the grooves relative to the width of the ribs.
Unlike the first embodiment shown, this embodiment does not require the channel 34 to slope towards a reservoir, for the channel itself acts as a reservoir and is sufficiently deep to accommodate the anticipated quantity of liquid fat.
Base 10 and surface 8 of recess 22 define a hollow, inner chamber 18 (see FIGS. 9 and 10). As with the first embodiment of the invention, heat from the liquid fat on the upper surface 8 is transmitted to inner chamber 18, heating the air therein.
A recessed, egg cooking section 23 is formed in upper surface 8 adjacent to the bacon section 22. Section 23 is recessed into inner chamber 18 and may be heated by the air in chamber 18.
Eggs may be placed in the recess 23 and cooked in the microwave oven while the bacon is cooking. If, as is often the case, eggs cook more quickly than bacon, they may be added after the bacon is partially cooked.
After the bacon and eggs are cooked and the vessel 4 is removed from the oven, the heated air within inner chamber 18 serves to keep the bacon and eggs warm; and they may be eaten directly from vessel 4. Also, if desired, vessel 4 may include an interfitting top (not shown) to further prevent cooling of the food.
A Third Embodiment
FIGS. 11 to 15 illustrate a third embodiment of the invention useful for cooking items such as chops and fish. Here the grooves slope in two directions toward the periphery of the dish, to a receiving channel; and the channel slopes towards a reservoir at one end. The ribs extend upwardly from the upper surface, and preferably, except for their outer ends, have their upper edges in a common plane.
This embodiment is, functionally, substantially the same as the others. It includes a base 10 with a rim 12 and surrounding skirt 14. The top 9 with upper surface 8 is generally convex (as seen from above) and includes ribs 28, defining grooves 30, and a peripheral channel 35 leading to a reservoir 38. The upper tips 29 or ribs 28 generally lie in the same plane to provide a "flat" surface for the food being cooked. The outer ends 36 of the ribs 28 may, however, be slightly raised to prevent the food from slipping into the peripheral channel 35.
As with the other embodiments, top portion 9 with its upper surface 8, is integral with base 10, and skirt 14, and define an inner chamber 18.
The food to be cooked is placed on the ribs and the dish placed in a microwave oven. As before, liquid fat drips from the food and flows down the grooves 28 to channel 32, and thence to remote reservoir 38. The food is browned in a manner similar to the other embodiments of the invention.
Similarly, the hot, liquid fat transmits heat to the air within inner chamber 18. This keeps the food on the vessel warm after the vessel is removed from the oven.
The type of food to be cooked determines which embodiment of the invention should be used. If the food is bulky in nature, such as a roast or large fowl, it is desirable to use the first embodiment. For multiple food types, such as bacon and eggs, the second embodiment is preferred. And, for foods with generally flat surfaces such as chops, the third embodiment gives best results.
If meat is to be cooked which has fat primarily around the perimeter, such as steak, a combination of the first and third embodiments may be best, i.e., a structure like the first embodiment in which the first flows towards the center, but with the upper surface of the ribs lying in a plane.
Both the first and third embodiments of the invention may be modified to include a "caudle" for basting. This could be done by providing a funnel shaped opening on the bottom surface of the reservoir. A removable, opened top container may then be positioned directly below the opening to receive liquid fat. The container is then removed and its contents poured over the food being cooked in the oven.
The design of cooking vessels using this invention may vary depending upon the type of foods and the nature of the microwave oven. They should be designed, however, to provide adequate grooves and channels and with a slope so that liquid fat or other liquid may flow to a reservoir removed from the food itself and also heat the inner chamber; and the ribs should be dimensioned and spaced to allow the meat to rapidly lose fat as it liquifies. The rib pattern on the upper surface may be varied, being parallel, concentric arcs, a maze, or otherwise, to accomplish the desired result.
As mentioned above, the vessel is preferably made of stoneware, though others may be used. In its design, the material used for the top portion should be thick enough for adequate support but thin enough relative to the heat transmissivity of the material, to permit adequate heat transmission from the hot liquid fat through the top to warm the air in the inner chamber below.