CA1189334A - Coffee roaster - Google Patents
Coffee roasterInfo
- Publication number
- CA1189334A CA1189334A CA000408617A CA408617A CA1189334A CA 1189334 A CA1189334 A CA 1189334A CA 000408617 A CA000408617 A CA 000408617A CA 408617 A CA408617 A CA 408617A CA 1189334 A CA1189334 A CA 1189334A
- Authority
- CA
- Canada
- Prior art keywords
- roaster
- horizontal support
- support
- beans
- radiant heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Apparatuses For Bulk Treatment Of Fruits And Vegetables And Apparatuses For Preparing Feeds (AREA)
- Tea And Coffee (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The specification describes a roaster for roasting seeds, nuts, coffee beans or the like. The roaster is provided with a tray or support adapted to hold a layer of the product to be roasted. The tray has perforations in the bottom thereof, the diameter, numbers and spacing being such as to prevent components of the layer from falling through while permitting a current of hot air coming from beneath to pass uniformily through the layer. The specification also describes a method of roasting seeds, nuts, coffee beans or the like.
The specification describes a roaster for roasting seeds, nuts, coffee beans or the like. The roaster is provided with a tray or support adapted to hold a layer of the product to be roasted. The tray has perforations in the bottom thereof, the diameter, numbers and spacing being such as to prevent components of the layer from falling through while permitting a current of hot air coming from beneath to pass uniformily through the layer. The specification also describes a method of roasting seeds, nuts, coffee beans or the like.
Description
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, SPECIFICATION
Coffee roasters heretofore have been relatively elaborate and have involved a multiplicity of moving parts.
A need exists fox a simplified coffee roaster which can be employed for domestic use and which will adequately xoast coffee beans and which has no moving parts~
Generall~ speaking, coffee roasters heretoore, including those which are intended for small scale commercial use or for domestic use, have employed active means for tumbling a mass of coffee beans as they are roasted, such tum~ling action being intended to promote uniform exposure of the beans to each other, to the walls of the roaster and to hot air. Such roasters required rather elaborate equipment such as stirrers, rotating drums or spheres, blowers, e-tc.
Hereinafter coffee roasters and coffee roasting will be referred to. However, the apparatus and method of the invention are also applicable to roasting other seeds and nuts, e.g. sunflower seeds, pumpkin seeds, hazelnuts, almonds, peanuts and cereal grain such as corn and wheat. Muts may be roasted in the shell where such is practical or the nuts may be shelled.
There is a need for a coffee bean roaster having no moving parts and which requires only a source of heat and access to ambient air. There is also a need for coffee bean roasters which are disposable.
~ It is an object of the invention to provide improvements in coffee roasters.
It is a further and particular object of the invention to provide a simplified coffee roaster adapted for domestic use which employs no moving parts.
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Yet another object is -to provide a commercial version of my domestic, simplified coEfee roaster having a minimum of moving parts and equipped -to provide continuity of operation.
Another object is to provide a disposable coEfee bean roas-ter.
Another object is to provide a simplified method oE
roasting coEEee beans.
In accordance with the present invention there is provided a roaster adapted to roast green coffee beans which comprises: (a) ~ hori~ontal support formed by a sheet of non-combustible heat conductive material formed with a multiplicity of openings which are small enough to retain a thin layer of coffee beans on the upper surface of the support r the number, pattern and area of the openings being such that radiant heat and hot air will pass freely and uniformly through the support, ~b) the horizontal support having an upper surface and a lower surface and being formed beneath the lower surface with projecting portions o-f the material of the support which project below the lower surface and which serve as chimneys and heat conductors, (c) a rim surrounding the upper surface of the horizontal support - having a height not substantially greater khan required to prevent the roas-ting beans from falling from the suppor~, (d) a reflector above and Eorming with the horizontal support an upper space, the reflector being capable of reflecting radiant heat back upon a layer of coffee beans on the support, such reflector being so designed and placed that it will-not materially impede evacuation by convection of gases and smoke generated by the roasting process, f ~
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(e) a source of radian-t heat beneath and spaced from the horizontal support adap-ted to heat uniformly the hori20ntal support and a layer of coffee beans supported thereon, (f) there being a lower space be-tween the horizontal support and the source of radiant hea-t which is substantially unobstructed~ the design and conEiguration of the horizontal support, the reflector and the source of radiant heat being such that during roasting of coffee beans on the horizontal support air heated by the source of radiant heat moves freely, uniformly and directly upwardly from the source oE radiant heat through the lower space, the horizontal support and the layer of cofEee beans into the upper space and thence out of the roaster, such movement being induced substant,ially solely by the source of radiant heat whe.reby the green coEfee, beans are heated by the combination of radiation, conduction and convection to their isothermal point~ moisture is evaporated from the beans at such isothermal point and the temperature of the dried beans then rises to ef:Eect roasting of the beans and development and retention of a desirable flavor.
The above and other objects will be apparent from the ensuing description and the appended clailns.
Certain embodiments of the invention are illustrated by way of example in the accompanying drawings, in ~hich:
Figure 1 is a perspective view of a coffee roaster in-tended for domestic use, a portion of the exterior wall being broken away to reveal the interior of the roaster;
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Figure 2 is a vertical mid-sec-tion t.aken along the line 2-2 of Figure l;
Figure 3 is a perspective view of a con-tinuous co:E:Eee roaster employing the principl.es of the domestic roas-ter of E'igures 1 ancl 2, but being adapted :Eor con-tinuous operation, and hence for commerical use.
Figure 4 is a perspec-tive view of another embodiment of the invention which is employed in an oven.
Figure 5 is a vertical section taken -through an oven and through the roaster of Figure 4.
Figure 6 is a perspective view of one embodiment of the roaster of the present invention, Figure 7 shows the roaster of Figure 6 in an oven during the roasting process, the roaster being shown in vertical mid-section;
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Figure 8 shows another embodiment adapted for use in the open on top of a hot plate or other open source of heat;
Figure 9 shows the roaster of Figure 6 enclosed by a removable cover and with a supply of green co~fee beans ready for use;
Figure 10 shows the manner in which the coEfee roas-ters of Figures 6 or 8 may be nested together.
Figure 11 shows another and preferred way to package the roaster of Figure 6.
Figure 12 is a section along the line 7-7 of ~igure 16.
Referring now to Figures 1 and 2, the co~fee roaster is generally designated by the reference numeral 10, and it:
comprises a cylindrical housing 11 having handles 12 and a cover 13 which has a central opening 14 and a handle 15. The housing 11 and the cover 13 may be made of any suitable material, such as, for example, cast iron, steel, copper, brass or aluminum.
Heat resistan-t glass, for example, Pyrex* and heat resistant plastic may also be used. The_housing need not be cylindrical~
For example, it may be rectangular. A plate 16 is provided having uniformly spaced perforations 17 of a size such that the~
will hold coffee bean~ shown at 18, but of sufficient size and number to allow and promote operation as described hereinafter The perforated plate 16 may be supported on a ledge or it may be held in place by welding or by friction. Housing 11 and plate 16 may be an integral unit.
A heating element 19 is provided whlch is shown in the form of an electric coil having open spaces between the turns of the coil and having a plug 20 which may be plugged into an extension cord which, in turn, may be plugged into a wall socket.
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* Trademark Other sources of heat may be provided; Eor example, the housing 11 may be placed over an electric heating coil or gas burner of a kitchen stove. The source of heat may be an integral part of the roas-ter, for example, the coil 19 may be fixed to the housing 11 tbut separable Eor cleaning, replacement or repair) or the roaster itself may be without a heating element but adapted to be placed over a source of heat such as an electric coil or a gas burnex of a stove.
In operation, coffee beans, as shown at 18, are placed on the perforated plate 16. Prefereably a single layer or layers of a few beans in thickness is employed. As many as six to eight beans in thickness may be employed but may require shaking once or twice during roasting. After the cover 1~ has been put in place, electric current (assuming that the heating element 19 is an electric coil) is turned on. Air is drawn in through the spaces between the turns of the coil and heat passes upwardly from the coil by convection, as shown by the wavy arrows and through the perforations in the plate 16, and thence through the coffee beans 18, effectively heating them and causing roasting. Heat is radiated back onto the beans by the cover 13 as indicated by the downwardly pointing arrows but the opening 14 (or a multiplicity of smaller openings) allows rapid venting of water vapor, other gases and smoke. Green coffee beans have about 12 to 20 percent moisture content which is driven off by heat together with other gases and smoke. It is important that such gases (including water vapor) and smoke be vented rapidly;
otherwise roasting does not occur as desired. It is also important that heat be reflected back, principally by radiation, from the cover.
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Several ~ea~ures of the construction combine to achieve rapid and uniform heating and roasting of the beans. Heat is con-veyed by convection owing to the passage oE hot air through the perforations 17. ~leat also is applied by radiation from the heating element 19 and by reflection o~ heat from the cover 13. At the level of the coffee beans 18 heat is also applied by conduction through the material of the plate 16 and heat is also applied by conduction from the wall o~ the housing to beans around the perimeter of the mass o~ beans.
Further the beans, as they are roasted, move due to the con-version of liquid moisture into vapor. Such motion of the beans, together w th the sources c~ heat ~s described above, have the efect of heating and roasting the beans uniformly such that more rapid heating, drying and roasting in some areas than in others is minimized.
The beans undergo change in two stages In the first stage the beans are dried by the evaporation o~ moisture, which is carried away by the current of hot air. The second stage is roasting of the dried beans. This occurs when moisture is driven out and the temperature of the beans rises above the boiling point of water. This stage is marked by a change of color from green to various shades of brown.
In at least one prior patent, U.S. Patent 3,964,175 issued June 22r 1976 to Sivetz, a mass of coffee beans is levitated by blowing hot air through a mass of beans. In my roaster the flow of air is gentle and no significant levitation occurs. Motion of the beans is slight and is due mainly if not entirely to evaportion of moisture and expansion of the vapor. The beans move about but are not levi-tated. One may use a blower or vacuum to speed up the drying ~ .,~
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stage but such is not necessary and i-t adds a complication.
As stated above the beans change in color from green to a shade or shades of brown. This may be observed through the opening 14 or -through the cover if it is transparent. A
temperature of about 425 to 475~ for about lO to 20 minutes has been Eound to be suitable. Experience will suffice to determine, by observation, when the desired degree oE roasting is complete, e.g. light, French, etc. It is also desirable to bring the beans quickly to and above their isothermal point, i.e., the point at which moisture begins -to boil off.
The beans may be allowed to cool in the roaster.
Preferably, however, the cover is removed, the housing is lifted by its handles and the beans are poured out to cool outside the roaster, after which they may be stored and ground as desired~
instead of using a separate heating element and perforated support t the two may be combined by employing a plate 16 which incorporates resistance elements and which also is perforated as shown, such being supported so that there is an air space beneath the heating element through which air may be drawn.
Referring now to Figure 3 a roaster generally designated as 30 is shown, which operates on essentially the same principle as the roaster of Figures l and 2, but it is adapted for continuous operation and, therefore, for commercial usage. The roaster 30 comprises an open feed hopper 31 and a roaster housing 32 ex-tending beyond the hopper and comprising side walls 33, a top cover 34 formed with a slot 35 which serves as an opening com-parable to and serving the same purpose as the opening 14 in Figures l and 2. A barrier 36 effectively seals off the housing jr/~
32 from the open hopper 31. ~ perforated, continuous belt 37 having perforations 38 is provided which is trained about roller 39a and 39b, one of which is driven by suitable means (not shown).
The belt may be, ~or example, a wire screen. Between the upper and lower par-ts of the belt 37 there is an electric heating coil ~1. A box 45 is provided having sidewalls ~6, front and rear walls 47 and 48 and a bottom 49. CofEee beans shown at 18 are supplied to hopper 31. The rate at which they are roasted is controlled by any one or more of three variables, namely, the current flowing through the heating coil 41, the speed of the rollers 39a and 39b and the length of the upper part of the belt 37. It will be apparent that, although the device of ~igure 3 employs a moving part, namely ~he belt 37, its operation is simple and is comparable to that of the roaster in Figures 1 and 2. The housing 32 confines the current of hot air from the coil 41 and causes it to flow up through the belt 37 and the beans 18; the cover 34 reflects heat back on the beans; and the opening 35 allows the air to carry away water vapor, other gases and smoke. Side walls 33 perform the same function as the wall of the housing 11. The belt 37 performs the same function as the pla-te 16 in supporting the beans, in allowing passage of hot air and, by conduction, equalizing the flow of heat to the beans. The belt is preferably of metal, e.g. a metal screen, to promote transfer of heat. The belt may incorporate resistance elements which can be heated electrically to take the place of the heating coil ~1. Supply of beans to the belt may be by hand or by an automatic feed. A single layer or a layer several beans thick is supplied Instead of an open hopper a rotary type of feed of known construction may be used which supplies beans in ir/i ~
increments and which closes off the belt from the ambien-t atmosphere. Further, the open outlet end of housing 32 may be adequake for venting air, water vapor and other gases so that venting slot 35 is unnecessary. Instead o~ applying heat from below by coil 41, heat may be applied Erom aboveO
In the description hereinabove and in the drawings, whole beans are described and are shown. The beans, however, may be comminuted before they are roasted. The term "beans"
as used in the claims is intended to include whole beans, which are preferred, but also comminuted beans. Preferably, however, whole beans are roasted. Among other things, during roasting of whole beans, the skins separate and form chaff which can be removed by shakiny the roasted beans in a sieve or vegetable strainer. Also, while green beans have been referred to above, partially or wholly dehydrated beans (whole beans or comminuted beans) may be roasted. The use of dehydrated beans will ac-celerate roasting because the time needed for removing moisture from green beans will be saved.
Referring now to Figure 4 another embodiment of the roaster o~ the invention is there shown. It comprises a tray generally designated by the reference numeral 60 formed by sidewalls 61, end walls 62 and a bottom portion 63 formed with perforations 64. The side walls 61 have downward ex-tensions 61a and the end walls 62 have downward extensions 62a.
The tray is provided with handles 64a.
Referring now to Figure 5, this tray is deposited in a typical oven generally designated by the reference numeral 65 comprising side walls 66, a bottom 67, a top 6~, an upper electric heating element 70 and a lower heatiny elemen-t 71.
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The oven has a rear wall 75 and a front door (not shown). The oven is also provided, as is usual, with a vent at the Eront (not shown) through which gases may escape. The tray is sup-ported wi-thin the oven upon a conventional wire rack (not shown) which are standard features of domestic ovens.
In operation either the top element 70 or the bottom element 71 is turned on. The natural convection pattern of the oven will cause air to rise through the openings 64 in the tray 60, thence through the beans. If the bottom element 71 is turned on, the top 68 of the oven will act as a reflector of radiation. If the top element is turned on, it will radiate heat onto the beans and induce an upward current of air. The significant space is that surrounding the layer of beans. Uni-formity of temperature, hence uniformity of roasting, is promoted in this space by a number of factors including reflection of heat by the cover 68, convection currents, the chimney effect of the side and end walls 61 and 62 and their downward ex-tensions 61a and 62a, and the conduction of heat by the material of the tray.
Added features for the various embodiments of the invention include a temperature regulator to control temperature of the roaster, a timer to shut off the input of heat after a predetermined time and a reflectance meter to sense the color of the beans. Instead of a reflectance meter, a smoke detector may be used which will lndicate the completion of roasting by sensing concentration of particulate matter in the effluent gas and smoke. A reflectance meter or smoke detector may actuate an audible or visual signal or by suitable electronics, it may turn off the heat. These ad3uncts are useful but they are not jr/~3 3~
necessary. In the appended claims whenever the texm "coEEee beans" or "coffee" is used, i-t is to be unders-tood that other seeds and nuts may be used in place of coffee.
Referriny now to Figures 6 to 12 of the drawings (which illustrate a less expensive and disposable type oE roaster) and preliminarily to Figure 6, the coEfee roaster i5 generally designated by the reEerence numera] 110. I-t is preferably made of a foil which is sufficientLy heavy to allow normal handling, storage and shipment and to allow manipulation by -the ultimate user. For example, aluminum foil having a -thickness of about 0.0035 inch may be employed for this purpose. This roaster comprises a botto~ portion 11 formed with openings or per-Fora---tions 112 and a rim 113 completely surroundiny the bottom por-tion 111. Cof-fee beans are shown at 11~ in this roaster. The rim may be formed with a bead 113a.
The perforations 112 may be formed conveniently by pierciny from above and leaviny downwardly projecting portions o me-tal 112a. These perforations and downward projections may also be formed by molding. I have found that these down-ward projections aid materially in the roasting process, e~idently by acting as heat conductors and/or as ch~eys to aid the draught in roasting.
Referring now to Figure 9, this figure shows how the coEfee roaster of Figure 6 (likewise that of Figure 8) may be packaged. The package lS yenerally designated by the reference numeral 115, the roaster proper beiny indicated by the reference numeral 110 in Figure 6. The roaster 110 is completely enclosed in a suitable wrapper 116. This may be, as shown, a transparent wrapper such as cellophane, polyethylene-or any transparent film * Trademark - , - 10 -~ jr/
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material which is suitable for use in contac-t with food products.
Alternatively, it may be an opaque material such as paper or aluminum foil. An alternative pac]~aging is shown in Figures 11 and 12 and is described below. The beans may be enclosed in a bag as in Figures 11 and 12.
Referriny now to Figure 7, an oven is shown which is generally designated by the re~erence numeral 125, the interior oven cavity being indicated as 126. Within this cavity there is a support 127 for the roaster 110 and beneath this support are heating coils 128. As will be seen, hot air rising from the coils 128 ascends through the openings 112 in the bottom 111 of the roaster 110. As explained in my copending appli-cation, the coffee beans will first undergo a drying phase ana then, when all or most of the moisture has been removed they will tend to pop and jump about. Roasting then takes place.
The completion of roasting is indicated when the beans assume a uniformly brown hue. Experience will indicate the hue of brown according to the user's preference.
Referring now to Figure 8, a modified roaster is provided which is generally designated by the reference numeral 130. The roaster proper comprises a rim 131 and a bottom por-tion 132 with openings 133 and it also comprises a downward ex-tension of the rim 131 as shown at 131a. It is also provided with a cover 135 formed with an opening 136. This may form a snap fit with the rim 131 or it may lie loose on it. The roaster 130 is shown sitting on a hot plate 137 of a stove 138. This embodiment with its cover 135 and a lower rim 131a is better suited than the embodiment of Figures 6 and 7 to an open source of heat. The oven 125 in Figure 7 provides an ~r/~
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enclosure and a support spaced above the source of heat. The embodiment of Figure 8 may, however, be used, with or without the cover 135, in an oven. ~ownward projections 133a corres-ponding to projections 112a in Figure 7 are shown. These need not be present but are preferred.
The perforations 112 in Figure 6 and 133 in Figure 8 are preferably uniformly distributed. The individual perfora-tions are preferably not so small as to impede air flow or so large that the beans fall through. They preferably provide an open area, e.g., about 15 -to 75 percent of the total area on the bottom of the tray, sufficient to bring abou-t rapid roasting.
The rim is preferably greater than the average diameter of the coffee beans. A rim 113 or 131 typically extends five eighths of an inch above the bottom 111 or 132 of the tray.
Referriny now to Figures 11 and 12 the roaster of Figures 6 and 7 is shown within which are one or more packages 140 of coffee beans each constituting a suitable portion of coffee. The bag material may be cellophane, polyethylene or other suitable film material and it may be printed with adver-2G tising material or instructions. The roaster and bags of coffeebeans are enclosed in a paper board box 141 having side walls 142, end walls 143, a bottom 144 and a top 145. The top has a hole 146 formed in it for viewing the contents which may be covered, if desired, with a clear plastic sheet (not shown). One or both ends 143 may be hinged with a tab to fit in the box for enclosure during shipment and storage and which can be pulled out for access.
Referring again to Figures 6 to 12 in their entirety, the perforations 112 and 133 are illustrative. Different patterns jr~
., may be used, e.g., spiral, concentric circles, straight lines of perforations on staggered centers, etc. Fur-ther, the roaster body need no-t be circular; it may be angular. The perforations may be provided by cells as in an egg crate type of structure.
The perforations may be round or angular and if angular, they may be square,~triangular or pentagons.
Various materials of construction may be used. If the roaster is intended for sustained re-use, it will be made of sturdier, e.g., thicker, material. If it is intended for a single use or a few uses, it may be made of lighter, e.g., thinner, material. A foil thickness of about 0.0035 inch is recommended.
Aluminum is the preferred material. It is widely and economically available in an assortment of thicknesses; it is resistant tc heat and oxidation; it is non-toxic and acceptable as a packaging agent and as a utensil in contact with food; and it is attractive in appearance. However, other materials, e.g., copper or stainless steel, may be used, also ceramic material, organic polymers such as Tef~on which are suitable for cooking utensils and glass.
The perforations 112 and 133 in Figures 7 and 8 are ~0 described above as being formed by punching or piercing a solid sheet of metal, i.e., the bottom of the tray. However, the tray bottom may be formed otherwise, e.g., by molding, or by coiling a strip of metal, e.g., a strip of aluminum, into the shape of a spiral in which case the spaces between the turns of the coil will serve as the openings or perforations and will function like the holes 112 and 133 and the vertical strips will serve as the down-ward projections 112a and 133a. Also a network of separate pieces may be assembled, such as in an egg crate type of structure and the openings or cells formed by such a structure will perform the jr/~ 13 -33;3~L
function of the holes 112 and 133 and the material separating the open spaces or cells will perform the function of the projections 112a and 133a.
The roaster of Figure 6 may be used on an open source of heat such as the hot plate oE Figure 8 by providing it with a bottom support to keep the bottom 11 out of dixect contact with the source of heat and with a cover having an opening.
The roasters of the present invention (Figures 1 to 12) are also applicable to the roasting of other beans and of ~0 nuts, e.g., sunflower seeds, pumpkin seeds, hazel nuts, almonds, peanuts and cereal grains such as corn and wheat.
It willj therefore, be apparent that new and advan-tageous cof~ee roasters have been provided which are also useful for roasting other beans and nuts.
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, SPECIFICATION
Coffee roasters heretofore have been relatively elaborate and have involved a multiplicity of moving parts.
A need exists fox a simplified coffee roaster which can be employed for domestic use and which will adequately xoast coffee beans and which has no moving parts~
Generall~ speaking, coffee roasters heretoore, including those which are intended for small scale commercial use or for domestic use, have employed active means for tumbling a mass of coffee beans as they are roasted, such tum~ling action being intended to promote uniform exposure of the beans to each other, to the walls of the roaster and to hot air. Such roasters required rather elaborate equipment such as stirrers, rotating drums or spheres, blowers, e-tc.
Hereinafter coffee roasters and coffee roasting will be referred to. However, the apparatus and method of the invention are also applicable to roasting other seeds and nuts, e.g. sunflower seeds, pumpkin seeds, hazelnuts, almonds, peanuts and cereal grain such as corn and wheat. Muts may be roasted in the shell where such is practical or the nuts may be shelled.
There is a need for a coffee bean roaster having no moving parts and which requires only a source of heat and access to ambient air. There is also a need for coffee bean roasters which are disposable.
~ It is an object of the invention to provide improvements in coffee roasters.
It is a further and particular object of the invention to provide a simplified coffee roaster adapted for domestic use which employs no moving parts.
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Yet another object is -to provide a commercial version of my domestic, simplified coEfee roaster having a minimum of moving parts and equipped -to provide continuity of operation.
Another object is to provide a disposable coEfee bean roas-ter.
Another object is to provide a simplified method oE
roasting coEEee beans.
In accordance with the present invention there is provided a roaster adapted to roast green coffee beans which comprises: (a) ~ hori~ontal support formed by a sheet of non-combustible heat conductive material formed with a multiplicity of openings which are small enough to retain a thin layer of coffee beans on the upper surface of the support r the number, pattern and area of the openings being such that radiant heat and hot air will pass freely and uniformly through the support, ~b) the horizontal support having an upper surface and a lower surface and being formed beneath the lower surface with projecting portions o-f the material of the support which project below the lower surface and which serve as chimneys and heat conductors, (c) a rim surrounding the upper surface of the horizontal support - having a height not substantially greater khan required to prevent the roas-ting beans from falling from the suppor~, (d) a reflector above and Eorming with the horizontal support an upper space, the reflector being capable of reflecting radiant heat back upon a layer of coffee beans on the support, such reflector being so designed and placed that it will-not materially impede evacuation by convection of gases and smoke generated by the roasting process, f ~
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(e) a source of radian-t heat beneath and spaced from the horizontal support adap-ted to heat uniformly the hori20ntal support and a layer of coffee beans supported thereon, (f) there being a lower space be-tween the horizontal support and the source of radiant hea-t which is substantially unobstructed~ the design and conEiguration of the horizontal support, the reflector and the source of radiant heat being such that during roasting of coffee beans on the horizontal support air heated by the source of radiant heat moves freely, uniformly and directly upwardly from the source oE radiant heat through the lower space, the horizontal support and the layer of cofEee beans into the upper space and thence out of the roaster, such movement being induced substant,ially solely by the source of radiant heat whe.reby the green coEfee, beans are heated by the combination of radiation, conduction and convection to their isothermal point~ moisture is evaporated from the beans at such isothermal point and the temperature of the dried beans then rises to ef:Eect roasting of the beans and development and retention of a desirable flavor.
The above and other objects will be apparent from the ensuing description and the appended clailns.
Certain embodiments of the invention are illustrated by way of example in the accompanying drawings, in ~hich:
Figure 1 is a perspective view of a coffee roaster in-tended for domestic use, a portion of the exterior wall being broken away to reveal the interior of the roaster;
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Figure 2 is a vertical mid-sec-tion t.aken along the line 2-2 of Figure l;
Figure 3 is a perspective view of a con-tinuous co:E:Eee roaster employing the principl.es of the domestic roas-ter of E'igures 1 ancl 2, but being adapted :Eor con-tinuous operation, and hence for commerical use.
Figure 4 is a perspec-tive view of another embodiment of the invention which is employed in an oven.
Figure 5 is a vertical section taken -through an oven and through the roaster of Figure 4.
Figure 6 is a perspective view of one embodiment of the roaster of the present invention, Figure 7 shows the roaster of Figure 6 in an oven during the roasting process, the roaster being shown in vertical mid-section;
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Figure 8 shows another embodiment adapted for use in the open on top of a hot plate or other open source of heat;
Figure 9 shows the roaster of Figure 6 enclosed by a removable cover and with a supply of green co~fee beans ready for use;
Figure 10 shows the manner in which the coEfee roas-ters of Figures 6 or 8 may be nested together.
Figure 11 shows another and preferred way to package the roaster of Figure 6.
Figure 12 is a section along the line 7-7 of ~igure 16.
Referring now to Figures 1 and 2, the co~fee roaster is generally designated by the reference numeral 10, and it:
comprises a cylindrical housing 11 having handles 12 and a cover 13 which has a central opening 14 and a handle 15. The housing 11 and the cover 13 may be made of any suitable material, such as, for example, cast iron, steel, copper, brass or aluminum.
Heat resistan-t glass, for example, Pyrex* and heat resistant plastic may also be used. The_housing need not be cylindrical~
For example, it may be rectangular. A plate 16 is provided having uniformly spaced perforations 17 of a size such that the~
will hold coffee bean~ shown at 18, but of sufficient size and number to allow and promote operation as described hereinafter The perforated plate 16 may be supported on a ledge or it may be held in place by welding or by friction. Housing 11 and plate 16 may be an integral unit.
A heating element 19 is provided whlch is shown in the form of an electric coil having open spaces between the turns of the coil and having a plug 20 which may be plugged into an extension cord which, in turn, may be plugged into a wall socket.
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* Trademark Other sources of heat may be provided; Eor example, the housing 11 may be placed over an electric heating coil or gas burner of a kitchen stove. The source of heat may be an integral part of the roas-ter, for example, the coil 19 may be fixed to the housing 11 tbut separable Eor cleaning, replacement or repair) or the roaster itself may be without a heating element but adapted to be placed over a source of heat such as an electric coil or a gas burnex of a stove.
In operation, coffee beans, as shown at 18, are placed on the perforated plate 16. Prefereably a single layer or layers of a few beans in thickness is employed. As many as six to eight beans in thickness may be employed but may require shaking once or twice during roasting. After the cover 1~ has been put in place, electric current (assuming that the heating element 19 is an electric coil) is turned on. Air is drawn in through the spaces between the turns of the coil and heat passes upwardly from the coil by convection, as shown by the wavy arrows and through the perforations in the plate 16, and thence through the coffee beans 18, effectively heating them and causing roasting. Heat is radiated back onto the beans by the cover 13 as indicated by the downwardly pointing arrows but the opening 14 (or a multiplicity of smaller openings) allows rapid venting of water vapor, other gases and smoke. Green coffee beans have about 12 to 20 percent moisture content which is driven off by heat together with other gases and smoke. It is important that such gases (including water vapor) and smoke be vented rapidly;
otherwise roasting does not occur as desired. It is also important that heat be reflected back, principally by radiation, from the cover.
~r/l~
33~
Several ~ea~ures of the construction combine to achieve rapid and uniform heating and roasting of the beans. Heat is con-veyed by convection owing to the passage oE hot air through the perforations 17. ~leat also is applied by radiation from the heating element 19 and by reflection o~ heat from the cover 13. At the level of the coffee beans 18 heat is also applied by conduction through the material of the plate 16 and heat is also applied by conduction from the wall o~ the housing to beans around the perimeter of the mass o~ beans.
Further the beans, as they are roasted, move due to the con-version of liquid moisture into vapor. Such motion of the beans, together w th the sources c~ heat ~s described above, have the efect of heating and roasting the beans uniformly such that more rapid heating, drying and roasting in some areas than in others is minimized.
The beans undergo change in two stages In the first stage the beans are dried by the evaporation o~ moisture, which is carried away by the current of hot air. The second stage is roasting of the dried beans. This occurs when moisture is driven out and the temperature of the beans rises above the boiling point of water. This stage is marked by a change of color from green to various shades of brown.
In at least one prior patent, U.S. Patent 3,964,175 issued June 22r 1976 to Sivetz, a mass of coffee beans is levitated by blowing hot air through a mass of beans. In my roaster the flow of air is gentle and no significant levitation occurs. Motion of the beans is slight and is due mainly if not entirely to evaportion of moisture and expansion of the vapor. The beans move about but are not levi-tated. One may use a blower or vacuum to speed up the drying ~ .,~
jr/ - 5 -3~
stage but such is not necessary and i-t adds a complication.
As stated above the beans change in color from green to a shade or shades of brown. This may be observed through the opening 14 or -through the cover if it is transparent. A
temperature of about 425 to 475~ for about lO to 20 minutes has been Eound to be suitable. Experience will suffice to determine, by observation, when the desired degree oE roasting is complete, e.g. light, French, etc. It is also desirable to bring the beans quickly to and above their isothermal point, i.e., the point at which moisture begins -to boil off.
The beans may be allowed to cool in the roaster.
Preferably, however, the cover is removed, the housing is lifted by its handles and the beans are poured out to cool outside the roaster, after which they may be stored and ground as desired~
instead of using a separate heating element and perforated support t the two may be combined by employing a plate 16 which incorporates resistance elements and which also is perforated as shown, such being supported so that there is an air space beneath the heating element through which air may be drawn.
Referring now to Figure 3 a roaster generally designated as 30 is shown, which operates on essentially the same principle as the roaster of Figures l and 2, but it is adapted for continuous operation and, therefore, for commercial usage. The roaster 30 comprises an open feed hopper 31 and a roaster housing 32 ex-tending beyond the hopper and comprising side walls 33, a top cover 34 formed with a slot 35 which serves as an opening com-parable to and serving the same purpose as the opening 14 in Figures l and 2. A barrier 36 effectively seals off the housing jr/~
32 from the open hopper 31. ~ perforated, continuous belt 37 having perforations 38 is provided which is trained about roller 39a and 39b, one of which is driven by suitable means (not shown).
The belt may be, ~or example, a wire screen. Between the upper and lower par-ts of the belt 37 there is an electric heating coil ~1. A box 45 is provided having sidewalls ~6, front and rear walls 47 and 48 and a bottom 49. CofEee beans shown at 18 are supplied to hopper 31. The rate at which they are roasted is controlled by any one or more of three variables, namely, the current flowing through the heating coil 41, the speed of the rollers 39a and 39b and the length of the upper part of the belt 37. It will be apparent that, although the device of ~igure 3 employs a moving part, namely ~he belt 37, its operation is simple and is comparable to that of the roaster in Figures 1 and 2. The housing 32 confines the current of hot air from the coil 41 and causes it to flow up through the belt 37 and the beans 18; the cover 34 reflects heat back on the beans; and the opening 35 allows the air to carry away water vapor, other gases and smoke. Side walls 33 perform the same function as the wall of the housing 11. The belt 37 performs the same function as the pla-te 16 in supporting the beans, in allowing passage of hot air and, by conduction, equalizing the flow of heat to the beans. The belt is preferably of metal, e.g. a metal screen, to promote transfer of heat. The belt may incorporate resistance elements which can be heated electrically to take the place of the heating coil ~1. Supply of beans to the belt may be by hand or by an automatic feed. A single layer or a layer several beans thick is supplied Instead of an open hopper a rotary type of feed of known construction may be used which supplies beans in ir/i ~
increments and which closes off the belt from the ambien-t atmosphere. Further, the open outlet end of housing 32 may be adequake for venting air, water vapor and other gases so that venting slot 35 is unnecessary. Instead o~ applying heat from below by coil 41, heat may be applied Erom aboveO
In the description hereinabove and in the drawings, whole beans are described and are shown. The beans, however, may be comminuted before they are roasted. The term "beans"
as used in the claims is intended to include whole beans, which are preferred, but also comminuted beans. Preferably, however, whole beans are roasted. Among other things, during roasting of whole beans, the skins separate and form chaff which can be removed by shakiny the roasted beans in a sieve or vegetable strainer. Also, while green beans have been referred to above, partially or wholly dehydrated beans (whole beans or comminuted beans) may be roasted. The use of dehydrated beans will ac-celerate roasting because the time needed for removing moisture from green beans will be saved.
Referring now to Figure 4 another embodiment of the roaster o~ the invention is there shown. It comprises a tray generally designated by the reference numeral 60 formed by sidewalls 61, end walls 62 and a bottom portion 63 formed with perforations 64. The side walls 61 have downward ex-tensions 61a and the end walls 62 have downward extensions 62a.
The tray is provided with handles 64a.
Referring now to Figure 5, this tray is deposited in a typical oven generally designated by the reference numeral 65 comprising side walls 66, a bottom 67, a top 6~, an upper electric heating element 70 and a lower heatiny elemen-t 71.
- jr/~fi 33~
The oven has a rear wall 75 and a front door (not shown). The oven is also provided, as is usual, with a vent at the Eront (not shown) through which gases may escape. The tray is sup-ported wi-thin the oven upon a conventional wire rack (not shown) which are standard features of domestic ovens.
In operation either the top element 70 or the bottom element 71 is turned on. The natural convection pattern of the oven will cause air to rise through the openings 64 in the tray 60, thence through the beans. If the bottom element 71 is turned on, the top 68 of the oven will act as a reflector of radiation. If the top element is turned on, it will radiate heat onto the beans and induce an upward current of air. The significant space is that surrounding the layer of beans. Uni-formity of temperature, hence uniformity of roasting, is promoted in this space by a number of factors including reflection of heat by the cover 68, convection currents, the chimney effect of the side and end walls 61 and 62 and their downward ex-tensions 61a and 62a, and the conduction of heat by the material of the tray.
Added features for the various embodiments of the invention include a temperature regulator to control temperature of the roaster, a timer to shut off the input of heat after a predetermined time and a reflectance meter to sense the color of the beans. Instead of a reflectance meter, a smoke detector may be used which will lndicate the completion of roasting by sensing concentration of particulate matter in the effluent gas and smoke. A reflectance meter or smoke detector may actuate an audible or visual signal or by suitable electronics, it may turn off the heat. These ad3uncts are useful but they are not jr/~3 3~
necessary. In the appended claims whenever the texm "coEEee beans" or "coffee" is used, i-t is to be unders-tood that other seeds and nuts may be used in place of coffee.
Referriny now to Figures 6 to 12 of the drawings (which illustrate a less expensive and disposable type oE roaster) and preliminarily to Figure 6, the coEfee roaster i5 generally designated by the reEerence numera] 110. I-t is preferably made of a foil which is sufficientLy heavy to allow normal handling, storage and shipment and to allow manipulation by -the ultimate user. For example, aluminum foil having a -thickness of about 0.0035 inch may be employed for this purpose. This roaster comprises a botto~ portion 11 formed with openings or per-Fora---tions 112 and a rim 113 completely surroundiny the bottom por-tion 111. Cof-fee beans are shown at 11~ in this roaster. The rim may be formed with a bead 113a.
The perforations 112 may be formed conveniently by pierciny from above and leaviny downwardly projecting portions o me-tal 112a. These perforations and downward projections may also be formed by molding. I have found that these down-ward projections aid materially in the roasting process, e~idently by acting as heat conductors and/or as ch~eys to aid the draught in roasting.
Referring now to Figure 9, this figure shows how the coEfee roaster of Figure 6 (likewise that of Figure 8) may be packaged. The package lS yenerally designated by the reference numeral 115, the roaster proper beiny indicated by the reference numeral 110 in Figure 6. The roaster 110 is completely enclosed in a suitable wrapper 116. This may be, as shown, a transparent wrapper such as cellophane, polyethylene-or any transparent film * Trademark - , - 10 -~ jr/
3~3~
material which is suitable for use in contac-t with food products.
Alternatively, it may be an opaque material such as paper or aluminum foil. An alternative pac]~aging is shown in Figures 11 and 12 and is described below. The beans may be enclosed in a bag as in Figures 11 and 12.
Referriny now to Figure 7, an oven is shown which is generally designated by the re~erence numeral 125, the interior oven cavity being indicated as 126. Within this cavity there is a support 127 for the roaster 110 and beneath this support are heating coils 128. As will be seen, hot air rising from the coils 128 ascends through the openings 112 in the bottom 111 of the roaster 110. As explained in my copending appli-cation, the coffee beans will first undergo a drying phase ana then, when all or most of the moisture has been removed they will tend to pop and jump about. Roasting then takes place.
The completion of roasting is indicated when the beans assume a uniformly brown hue. Experience will indicate the hue of brown according to the user's preference.
Referring now to Figure 8, a modified roaster is provided which is generally designated by the reference numeral 130. The roaster proper comprises a rim 131 and a bottom por-tion 132 with openings 133 and it also comprises a downward ex-tension of the rim 131 as shown at 131a. It is also provided with a cover 135 formed with an opening 136. This may form a snap fit with the rim 131 or it may lie loose on it. The roaster 130 is shown sitting on a hot plate 137 of a stove 138. This embodiment with its cover 135 and a lower rim 131a is better suited than the embodiment of Figures 6 and 7 to an open source of heat. The oven 125 in Figure 7 provides an ~r/~
;3 3~:
enclosure and a support spaced above the source of heat. The embodiment of Figure 8 may, however, be used, with or without the cover 135, in an oven. ~ownward projections 133a corres-ponding to projections 112a in Figure 7 are shown. These need not be present but are preferred.
The perforations 112 in Figure 6 and 133 in Figure 8 are preferably uniformly distributed. The individual perfora-tions are preferably not so small as to impede air flow or so large that the beans fall through. They preferably provide an open area, e.g., about 15 -to 75 percent of the total area on the bottom of the tray, sufficient to bring abou-t rapid roasting.
The rim is preferably greater than the average diameter of the coffee beans. A rim 113 or 131 typically extends five eighths of an inch above the bottom 111 or 132 of the tray.
Referriny now to Figures 11 and 12 the roaster of Figures 6 and 7 is shown within which are one or more packages 140 of coffee beans each constituting a suitable portion of coffee. The bag material may be cellophane, polyethylene or other suitable film material and it may be printed with adver-2G tising material or instructions. The roaster and bags of coffeebeans are enclosed in a paper board box 141 having side walls 142, end walls 143, a bottom 144 and a top 145. The top has a hole 146 formed in it for viewing the contents which may be covered, if desired, with a clear plastic sheet (not shown). One or both ends 143 may be hinged with a tab to fit in the box for enclosure during shipment and storage and which can be pulled out for access.
Referring again to Figures 6 to 12 in their entirety, the perforations 112 and 133 are illustrative. Different patterns jr~
., may be used, e.g., spiral, concentric circles, straight lines of perforations on staggered centers, etc. Fur-ther, the roaster body need no-t be circular; it may be angular. The perforations may be provided by cells as in an egg crate type of structure.
The perforations may be round or angular and if angular, they may be square,~triangular or pentagons.
Various materials of construction may be used. If the roaster is intended for sustained re-use, it will be made of sturdier, e.g., thicker, material. If it is intended for a single use or a few uses, it may be made of lighter, e.g., thinner, material. A foil thickness of about 0.0035 inch is recommended.
Aluminum is the preferred material. It is widely and economically available in an assortment of thicknesses; it is resistant tc heat and oxidation; it is non-toxic and acceptable as a packaging agent and as a utensil in contact with food; and it is attractive in appearance. However, other materials, e.g., copper or stainless steel, may be used, also ceramic material, organic polymers such as Tef~on which are suitable for cooking utensils and glass.
The perforations 112 and 133 in Figures 7 and 8 are ~0 described above as being formed by punching or piercing a solid sheet of metal, i.e., the bottom of the tray. However, the tray bottom may be formed otherwise, e.g., by molding, or by coiling a strip of metal, e.g., a strip of aluminum, into the shape of a spiral in which case the spaces between the turns of the coil will serve as the openings or perforations and will function like the holes 112 and 133 and the vertical strips will serve as the down-ward projections 112a and 133a. Also a network of separate pieces may be assembled, such as in an egg crate type of structure and the openings or cells formed by such a structure will perform the jr/~ 13 -33;3~L
function of the holes 112 and 133 and the material separating the open spaces or cells will perform the function of the projections 112a and 133a.
The roaster of Figure 6 may be used on an open source of heat such as the hot plate oE Figure 8 by providing it with a bottom support to keep the bottom 11 out of dixect contact with the source of heat and with a cover having an opening.
The roasters of the present invention (Figures 1 to 12) are also applicable to the roasting of other beans and of ~0 nuts, e.g., sunflower seeds, pumpkin seeds, hazel nuts, almonds, peanuts and cereal grains such as corn and wheat.
It willj therefore, be apparent that new and advan-tageous cof~ee roasters have been provided which are also useful for roasting other beans and nuts.
jr/'f~ ',f
Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A roaster adapted to roast green coffee beans which comprises:
(a) a horizontal support formed by a sheet of non-combustible heat conductive material formed with a multiplicity of openings which are small enough to retain a thin layer of coffee beans on the upper surface of the support, the number, pattern and area of the openings being such that radiant heat and hot air will pass freely and uniformly through the support, (b) said horizontal support having an upper surface and a lower surface and being formed beneath the lower surface with projecting portions of the material of the support which project below the lower surface and which serve as chimneys and heat conductors, (c) a rim surrounding the upper surface of said horizontal support having a height not substantially greater than required to prevent the roasting beans from falling from the support, (d) a reflector above and forming with the horizontal support an upper space, said reflector being capable of reflecting radiant heat back upon a layer of coffee beans on the support, such reflector being so designed and placed that it will not materially impede evacuation by convection of gases and smoke generated by the roasting process, (e) a source of radiant heat beneath and spaced from the horizontal support adapted to heat uniformly the horizontal support and a layer of coffee beans supported thereon, 15 (f) there being a lower space between the horizontal support and the source of radiant heat which is substantially unobstructed, the design and configuration of the horizontal support, the reflector and the source of radiant heat being such that during roasting of coffee beans on the horizontal support air heated by the source of radiant heat moves freely, uniformly and directly upwardly from the source of radiant heat through the lower space, the horizontal support and the layer of coffee beans into the upper space and thence out of the roaster, such movement being induced substantially solely by the source of radiant heat whereby the green coffee beans are heated by the combination of radiation, conduction and convection to their isothermal point, moisture is evaported from the beans at such isothermal point and the temperature of the dried beans then rises to effect roasting of the beans and development and retention of a desirable flavor.
(a) a horizontal support formed by a sheet of non-combustible heat conductive material formed with a multiplicity of openings which are small enough to retain a thin layer of coffee beans on the upper surface of the support, the number, pattern and area of the openings being such that radiant heat and hot air will pass freely and uniformly through the support, (b) said horizontal support having an upper surface and a lower surface and being formed beneath the lower surface with projecting portions of the material of the support which project below the lower surface and which serve as chimneys and heat conductors, (c) a rim surrounding the upper surface of said horizontal support having a height not substantially greater than required to prevent the roasting beans from falling from the support, (d) a reflector above and forming with the horizontal support an upper space, said reflector being capable of reflecting radiant heat back upon a layer of coffee beans on the support, such reflector being so designed and placed that it will not materially impede evacuation by convection of gases and smoke generated by the roasting process, (e) a source of radiant heat beneath and spaced from the horizontal support adapted to heat uniformly the horizontal support and a layer of coffee beans supported thereon, 15 (f) there being a lower space between the horizontal support and the source of radiant heat which is substantially unobstructed, the design and configuration of the horizontal support, the reflector and the source of radiant heat being such that during roasting of coffee beans on the horizontal support air heated by the source of radiant heat moves freely, uniformly and directly upwardly from the source of radiant heat through the lower space, the horizontal support and the layer of coffee beans into the upper space and thence out of the roaster, such movement being induced substantially solely by the source of radiant heat whereby the green coffee beans are heated by the combination of radiation, conduction and convection to their isothermal point, moisture is evaported from the beans at such isothermal point and the temperature of the dried beans then rises to effect roasting of the beans and development and retention of a desirable flavor.
2. The roaster of claim 1 wherein said horizontal support and rim are of aluminum foil construction.
3. The roaster of claim 1 wherein said projecting portions are formed by punching the support.
4. A roaster adapted to roast green coffee beans which comprises:
(a) a horizontal support formed with a multiplicity of openings which are small enough to retain a thin layer of coffee beans on the upper surface of the support, the number, pattern and area of the openings being such that radiant heat and hot air will pass freely through the support, (b) a housing for the support which surrounds and confines the support and forms with the support an open upper compartment above the support and an open lower compartment below the support, the height of the upper compartment being substantially equal to or less than the depth of the lower compartment but sufficient to confine a thin layer of coffee beans during roasting, (c) a reflector above the upper compartment capable of reflecting radiant heat back upon a layer of coffee beans on the support, such reflector being so designed and placed that it will not materially impede evacuation, by connection, of gases and smoke generated by the roasting process, and (d) a source of radiant heat at the level of or beneath the horizontal support adapted to heat the horizontal support and a layer of coffee beans uniformly, (e) the space between the horizontal support (a) and the source of radiant heat (d) being substantially unobstructed, the design and configuration of the horizontal support, the housing and the reflector being such that during roasting of coffee beans on the horizontal support air heated by the source of radiant heat moves freely, uniformly and directly upwardly from the source of radiant heat through the lower compartment and through the horizontal support and the layer of coffee beans into the upper compartment and out of the roaster, such movement being induced substantially solely by such radiant heat whereby the green coffee beans are heated by the combination of radiation, conduction and convection to their isothermal point, moisture is evaporated from the beans at such isothermal point and the temperature of the dried beans then rises to effect roasting of the beans and development and retention of a desirable flavor.
(a) a horizontal support formed with a multiplicity of openings which are small enough to retain a thin layer of coffee beans on the upper surface of the support, the number, pattern and area of the openings being such that radiant heat and hot air will pass freely through the support, (b) a housing for the support which surrounds and confines the support and forms with the support an open upper compartment above the support and an open lower compartment below the support, the height of the upper compartment being substantially equal to or less than the depth of the lower compartment but sufficient to confine a thin layer of coffee beans during roasting, (c) a reflector above the upper compartment capable of reflecting radiant heat back upon a layer of coffee beans on the support, such reflector being so designed and placed that it will not materially impede evacuation, by connection, of gases and smoke generated by the roasting process, and (d) a source of radiant heat at the level of or beneath the horizontal support adapted to heat the horizontal support and a layer of coffee beans uniformly, (e) the space between the horizontal support (a) and the source of radiant heat (d) being substantially unobstructed, the design and configuration of the horizontal support, the housing and the reflector being such that during roasting of coffee beans on the horizontal support air heated by the source of radiant heat moves freely, uniformly and directly upwardly from the source of radiant heat through the lower compartment and through the horizontal support and the layer of coffee beans into the upper compartment and out of the roaster, such movement being induced substantially solely by such radiant heat whereby the green coffee beans are heated by the combination of radiation, conduction and convection to their isothermal point, moisture is evaporated from the beans at such isothermal point and the temperature of the dried beans then rises to effect roasting of the beans and development and retention of a desirable flavor.
5. The roaster of claim 4 wherein the horizontal support is of metal construction.
6. The roaster of claim 5 wherein the metal is aluminum.
7. The roaster of claim 6 wherein the horizontal support is a perforated plate.
8. The roaster of claim 5 wherein the reflector is in the form of a cover for the upper compartment which is formed with at least one opening for venting of gases and smoke, such opening or openings sufficing to allow rapid outflow of gases and smoke by convection,
9. The roaster of claim 5 wherein the reflector is spaced from the top edge of the upper compartment and the space between the reflector and such top edge provides for escape of gases and smoke.
10. The roaster of claim 5 wherein the source of radiant heat is secured to the housing at or close to the lower edge of the lower compartment.
11. A roaster adapted to roast green coffee beans which comprises:
(a) a horizontal support formed by a sheet of non-combustible heat conductive material formed with a multiplicity of openings which are small enough to retain a thin layer of coffee beans on the upper surface of the support, the number, pattern and area of the openings being such that radiant heat and hot air will pass freely and uniformly through the support, (b) said horizontal support having an upper surface and a lower surface and being formed with projecting portions of the material of the support which project below the lower surface and which serve as chimneys and heat conductors, and (c) a rim surrounding the upper surface of said horizontal support having a height not substantially greater than required to prevent the roasting beans from falling from the support, said roaster, when provided with a reflector above said rim (c) which forms with said horizontal support an upper space and which serves to reflect radiant heat back upon a layer of green coffee beans on the horizontal support and which allows escape of water vapor, gases and smoke, and when further provided with a source of radiant heat below the horizontal support and with a substantially unobstructed lower space between such source of radiant heat and horizontal support, provides a design and configuration such that during roasting of coffee beans on the horizontal support air heated by the source of radiant heat moves freely, uniformly and directly upwardly from the source of radiant heat through the lower space and through the horizontal support and the layer of coffee beans into the upper space and out of the roaster, such movement being induced substantially solely by such radiant heat whereby the green coffee beans are heated by the combination of radiation, conduction and convection to their isothermal point, moisture is evaporated from the beans at such isothermal point and the temperature of the dried beans then rises to effect roasting of the beans and development and retention of a desirable flavor.
(a) a horizontal support formed by a sheet of non-combustible heat conductive material formed with a multiplicity of openings which are small enough to retain a thin layer of coffee beans on the upper surface of the support, the number, pattern and area of the openings being such that radiant heat and hot air will pass freely and uniformly through the support, (b) said horizontal support having an upper surface and a lower surface and being formed with projecting portions of the material of the support which project below the lower surface and which serve as chimneys and heat conductors, and (c) a rim surrounding the upper surface of said horizontal support having a height not substantially greater than required to prevent the roasting beans from falling from the support, said roaster, when provided with a reflector above said rim (c) which forms with said horizontal support an upper space and which serves to reflect radiant heat back upon a layer of green coffee beans on the horizontal support and which allows escape of water vapor, gases and smoke, and when further provided with a source of radiant heat below the horizontal support and with a substantially unobstructed lower space between such source of radiant heat and horizontal support, provides a design and configuration such that during roasting of coffee beans on the horizontal support air heated by the source of radiant heat moves freely, uniformly and directly upwardly from the source of radiant heat through the lower space and through the horizontal support and the layer of coffee beans into the upper space and out of the roaster, such movement being induced substantially solely by such radiant heat whereby the green coffee beans are heated by the combination of radiation, conduction and convection to their isothermal point, moisture is evaporated from the beans at such isothermal point and the temperature of the dried beans then rises to effect roasting of the beans and development and retention of a desirable flavor.
12. The roaster of claim 11 wherein the material of the roaster is aluminum foil.
13. The roaster of claim 11 including a rim projecting below the horizontal support about its circumference to elevate the horizontal support and provide such substantially unobstructed space.
14. The roaster of claim 13 including a removable cover supported by the said upper rim, having at least one opening to allow escape of water vapor, gases and smoke and serving as a radiant heat reflector.
15. The roaster of claim 11 wherein said projecting portions are formed by punching the support.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000408617A CA1189334A (en) | 1982-08-03 | 1982-08-03 | Coffee roaster |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000408617A CA1189334A (en) | 1982-08-03 | 1982-08-03 | Coffee roaster |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189334A true CA1189334A (en) | 1985-06-25 |
Family
ID=4123329
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000408617A Expired CA1189334A (en) | 1982-08-03 | 1982-08-03 | Coffee roaster |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1189334A (en) |
-
1982
- 1982-08-03 CA CA000408617A patent/CA1189334A/en not_active Expired
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