U.S. patent application number 13/432795 was filed with the patent office on 2012-07-26 for system and method for preparing naan bread.
This patent application is currently assigned to FGF BRANDS, INC.. Invention is credited to Sam Ajmera, John Gordon, Dragan Janus.
Application Number | 20120189743 13/432795 |
Document ID | / |
Family ID | 39229659 |
Filed Date | 2012-07-26 |
United States Patent
Application |
20120189743 |
Kind Code |
A1 |
Ajmera; Sam ; et
al. |
July 26, 2012 |
System And Method For Preparing Naan Bread
Abstract
A method and system for preparing naan bread is provided. A
conveyor oven is used to bake flattened and pre-shaped naan bread
loaves. The conveyor oven uses high temperature gas heat to bake
the naan, imparting traditional characteristics such as the
slightly smoky or scorched appearance. The oven interior is
preferably lined with stone, granite, clay or porcelain to enhance
baking and provide traditional flavour.
Inventors: |
Ajmera; Sam; (Maple, CA)
; Gordon; John; (Markham, CA) ; Janus; Dragan;
(Concord, CA) |
Assignee: |
FGF BRANDS, INC.
Concord
CA
|
Family ID: |
39229659 |
Appl. No.: |
13/432795 |
Filed: |
March 28, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13040790 |
Mar 4, 2011 |
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13432795 |
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12310827 |
Apr 27, 2010 |
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PCT/CA2006/001612 |
Sep 29, 2006 |
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13040790 |
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Current U.S.
Class: |
426/95 ; 426/302;
426/502; 426/94 |
Current CPC
Class: |
A21D 8/02 20130101; A21D
13/00 20130101; A21B 1/48 20130101 |
Class at
Publication: |
426/95 ; 426/94;
426/502; 426/302 |
International
Class: |
A21D 13/00 20060101
A21D013/00; A21D 8/02 20060101 A21D008/02 |
Claims
1. A high temperature conveyor-oven baked naan bread having a
crisp-chewy consistency, a visibly bubbled surface texture and an
oiled, slightly scorched top surface, the bread being packaged
cooled or frozen, with instructions for re-heating when made in
accordance with a method comprising the steps of: (a) preparing a
naan bread dough; (b) dividing and forming the dough into balls;
(c) rising the round balls of dough; (d) flattening the round balls
into generally circular discs; (e) stretching each disc into an
irregular non-circular shaped loaf; (f) loading the shaped loaves
onto a conveyor and spraying the loaves with oil immediately prior
to baking; and (g) running the conveyor through a gas oven at a
temperature of at least 700.degree. F. for a period of time
sufficient to bake the loaves to a crisp-chewy consistency, having
a visibly bubbled surface texture and a slightly scorched top
surface.
2. A high temperature conveyor-oven baked naan bread having a
visibly bubbled surface texture and an oiled, slightly scorched top
surface, the bread being packaged cooled or frozen, with
instructions for reheating, when made in accordance with a system
comprising: a naan bread dough preparing station for: preparing a
naan bread dough; dividing and forming the dough into round balls;
and rising the round balls of dough; a loaf shaping station for:
flattening the round balls of dough into generally circular discs;
and stretching each disc into an irregular non-circular shaped
loaf; a conveyor oven station for; spraying the loaves with oil
immediately prior to baking; and baking the shaped loaves by
running the shaped loaves on a conveyor through a high temperature
gas oven at a temperature of at least 700.degree. F. for a period
of time sufficient to produce baked naan breads each having a crisp
chewy consistency, a visibly bubbled surface texture and a slightly
scorched top surface.
3. The high temperature conveyer-oven baked naan bread of clam 2,
wherein the oven comprises an interior surface at least a portion
of which is stone, granite, clay or porcelain.
4. The high temperature conveyer-oven baked naan bread of clam 3,
wherein the system allows the bread to contact the portion of the
interior surface made of stone, granite, clay or porcelain as it
bakes.
5. The high temperature conveyer-oven baked naan bread of clam 2,
wherein the oven comprises top and bottom heating sources, for
baking the bread from above and below, and for imparting a scorched
appearance to parts of the bread.
6. The high temperature conveyer-oven baked naan bread of clam 5,
wherein the top heating source is located approximately 15 to 30 cm
from the conveyor.
7. The high temperature conveyer-oven baked naan bread of clam 5,
wherein the top and bottom hearing sources comprise a gas burner,
and wherein the burner does not touch the bread as it is
baking.
8. The high temperature conveyer-oven baked naan bread of clam 7,
wherein the burner is angled to indirectly bake the bread moving on
the conveyor.
9. The high temperature conveyer-oven baked naan bread of clam 2,
wherein the oven comprises a housing having: an exterior steel
shell; an interior baking cavity lined at least in part with stone,
granite, clay or porcelain; and an intermediate insulating layer
between the shell and the baking cavity, comprising sand-filled
panels and loosely packed rock wool.
10. The high temperature conveyer-oven baked naan bread of clam 9,
wherein the oven housing is tunnel shaped having a tunnel through
which the conveyor passes.
11. The high temperature conveyer-oven baked naan bread of clam 10,
wherein the tunnel is a linear tunnel, having a dough entry portion
that is separate from and located away from a baked bread exit
portion.
12. The high temperature conveyer-oven baked naan bread of clam 2,
wherein the system further comprises a cooling and packaging
station for cooling naan breads from the oven and packaging the
breads for refrigerated or frozen storage prior to consumption in a
re-heated form.
13. The high temperature conveyer-oven baked naan bread of clam 2,
wherein the conveyor is operable at a speed to permit up to 8000
breads to be put through the oven per hour.
14. A high temperature conveyor-oven baked naan bread having a
visibly bubbled surface texture and an oiled, slightly scorched top
surface, the bread being packaged cooled or frozen, with
instructions for re-heating, when made in an oven comprising: a
high temperature gas oven having an interior surface at least a
portion of which is stone, granite, clay or porcelain; a baking
conveyor for receiving naan bread loaves to be baked at a
temperature of at least 700.degree. F., the baking conveyor running
each loaf through the gas oven for a period of between
approximately 20 seconds and approximately 50 seconds.
15. The high temperature conveyor-oven baked naan bread of claim
14, wherein the naan bread loaves contact the portion of the
interior surface made of stone, granite or porcelain as they
bake.
16. A high temperature conveyor-oven baked naan bread of claim 14,
wherein said oven comprises top and bottom heating sources for
banking the loaves from above and below, and for imparting a
scorched appearance to parts of the loaves.
17. A high temperature conveyor-oven baked naan bread having a
visibly bubbled surface texture and an oiled, slightly scorched top
surface, the bread being packaged cooled or frozen, with
instructions for re-heating, when made in an oven comprising: a
high temperature gas oven having an interior surface at least a
portion of which is stone, granite, clay or porcelain, the oven
having top and bottom heating sources; a baking conveyor for
receiving naan bread loaves to be baked and running them through
the oven at a temperature of at least 700.degree. F., wherein the
baking conveyor is less than 30 cm from the top heating source.
18. The high temperature conveyor-oven baked naan bread of claim
17, wherein the top and bottom heating sources comprises a gas
burner, and wherein the burner does not touch the loaves as they
are baking.
19. The high temperature conveyor-oven baked naan bread of claim
18, wherein the burner is angled to indirectly bake the loaves
moving on the baking conveyor.
20. A high temperature conveyor-oven baked naan bread having a
visibly bubbled surface texture and an oiled, slightly scorched top
surface, the bread being packaged cooled or frozen, with
instructions for re-heating, when made in an oven comprising: a
high temperature gas oven having an interior surface at least a
portion of which is stone, granite, clay or porcelain; a baking
conveyor for receiving naan bread loaves to be baked at a
temperature of at least 700.degree. F., the baking conveyor running
each loaf through the gas oven for a period of between
approximately 20 seconds and approximately 50 seconds; wherein the
oven further comprises a housing having: an exterior steel shell;
an interior baking cavity lined at least in part with stone,
granite, clay of porcelain; and an intermediate insulating layer
between the shell and the baking cavity, comprising sand-filled
panels and loosely packed rock wool.
21. The high temperature conveyor-oven baked naan bread of claim
20, wherein the housing is tunnel shaped, having a tunnel through
which the conveyor passes.
22. The high temperature conveyor-oven baked naan bread of claim
21, wherein the tunnel is a linear tunnel, having a dough entry
portion that is separate from and located away from a baked bread
exit portion.
Description
[0001] This application is a divisional of U.S. Ser. No. 13/040,790
filed Mar. 4, 2011, which is a divisional of U.S. Ser. No.
12/310,827 filed Apr. 27, 2010, which is a 371 of PCT/CA2006/001612
filed Sep. 29, 2006, the disclosures of which are incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] A system and method is provided for preparing naan
bread.
BACKGROUND OF THE INVENTION
[0003] Naan is a type of flatbread traditionally made in Central
and South Asia and now enjoyed worldwide, especially as an
accompaniment to Indian foods, such as curries. It is made from a
leavened dough that is flattened and baked in a cylindrical or
urn-shaped oven known as a tandoor.
[0004] A traditional tandoor consisted of a clay baking layer
encased in a masonry or earth housing. An insulating layer of sand
was provided between the clay layer and the housing. The tandoor
was heated by charcoal or wood burned in the bottom of the baking
chamber.
[0005] To bake naan breads in a traditional tandoor, pieces of
flattened dough were slapped by hand or baking pad onto the
extremely hot inside walls of the oven. A hook was used to remove
the baked naan after a short baking time.
[0006] The basic process for baking naan has not changed for
centuries. Modern tandoor ovens use different materials (such as
steel housings and ceramic interiors) and different heating options
(such as electric heating elements or gas burners). However, the
basic shape of the tandoor, and the vertical wall-based baking
process have not changed.
[0007] In spite of improvements in materials, many purists believe
that there is no substitute for the flavour imparted by baking naan
with a traditional stone or clay oven. However, the traditional
tandoor design has a number of drawbacks--material issues and poor
safety.
[0008] Naan must be baked at very high temperatures to impart the
sultry smoky characteristic that is its signature. Clay ovens, in
particular, are known to crack under prolonged exposure to high
heat. Cracks can cause the traditional sand fill that is used to
insulate the oven to leak into the baking chamber, potentially
getting into the food. It is seldom possible to effectively patch a
clay oven once it cracks. Accordingly, it becomes necessary at
regular intervals to replace a tandoor oven.
[0009] Traditional baking methods are also dangerous even for
skilled operators. The inside of the tandoor oven reaches
temperatures often in excess of 700.degree. F. (370.degree. C.). In
order to slap the raw naan dough onto the inside walls of the
tandoor, the operator must stick a portion of his arm into the
oven. Any slight contact with the walls of the tandoor can result
in severe burns. The top openings of the oven are often relatively
small (approximately 1-2 ft across, or approximately 30-60 cm),
increasing the difficulty to maneuver the bread into place without
contacting the oven surfaces.
[0010] In a traditional tandoor, a baker can only bake a small
number of naan at a time due to the small size of most tandoor
ovens and due to the quick baking process requiring constant human
involvement and attention. Consequently, a tandoor operator bakes a
steady stream of tiny batches of breads for "a la minute" serving
and consumption.
[0011] However, these traditional naan baking processes do not lend
themselves readily to larger commercial scale production.
Accordingly, naan is largely considered a bread for restaurant
consumption, and not a food purchased to consume at home. Home
cooks, unless they have access to a tandoor, are not likely to be
able to enjoy hot naan bread with a meal. Methods of cooking naan
in an electric or gas home oven have been suggested, but such
methods are generally considered to produce an inferior product as
home ovens are simply not hot enough to mimic a tandoor.
[0012] A need therefore exists for a method of preparing naan that
allows for commercial-scale production, using safe modern
equipment, without sacrificing the traditional flavour and texture
of a tandoor-baked naan.
SUMMARY OF THE INVENTION
[0013] According to a first aspect of the invention, a method of
making naan bread is provided. Naan bread is prepared by: [0014]
(a) preparing a naan bread dough; [0015] (b) dividing and forming
the dough into balls; [0016] (c) rising the round balls of dough;
[0017] (d) flattening the round balls into generally circular
discs; [0018] (e) stretching each disc into an irregular
non-circular shaped loaf; [0019] (f) loading the shaped loaves onto
a conveyor; and [0020] (g) running the conveyor through a high
temperature gas oven for a period of time sufficient to bake the
loaves to a crisp-chewy consistency, having a visibly bubbled
surface texture and a slightly scorched top surface.
[0021] Preferably, the oven temperature is at least 700.degree. F.
Preferably, the conveyor speed is approximately 60 feet/min and the
resident oven time for each loaf is between approximately 20-50
seconds.
[0022] At least part of the dough may be coated with an oil or fat
prior to baking.
[0023] The stretching step in step (e) is preferred for making a
more-authentically shaped naan bread. Preferably, the stretching is
done by hand, for instance to form the dough into a teardrop, or
oblong shape. Preferably, each loaf may be shaped into a unique
shape. At step (e), other shaping or prepping may be performed, for
instance, the dough may be stretched the dough and/or pressed to
impart deliberate unevenness over areas of the surface.
[0024] Preferably, the thickness of the round discs following step
(d) is between approximately 2-5 mm. Preferably, the thickness of
the shaped loaves following step (e) is between approximately 1.5-3
mm.
[0025] Various methods may be used to rise the dough before the
pressing and shaping steps. A steam proofer may be used.
Preferably, the balls of dough may be conveyed during the rising
step on a conveyor tray proofer.
[0026] Depending on the humidity and temperature (an acceptable
range being within the general knowledge of those skilled in the
art), the balls of dough may be left to rise for between
approximately 45 and approximately 60 minutes.
[0027] Prior to rising, the balls of dough may be pre-weighed for
approximately even weight.
[0028] Various dough formulations are possible. The dough is
preferably a leavened dough, such as a yeast-leavened dough or a
baking powder-leavened dough. Alternatively, the dough may
comprises a sour dough. In any of these formulations, the dough may
contain a souring ingredient.
[0029] Preferably, the dough is baked by employing heating sources
above and below the loaves. After baking, the loaves may be cooled
and packaged to be sold as re-heatable naan bread. The cooling step
may employ a cooling spiral.
[0030] According to a second aspect of the invention, a naan bread
is provided, which is made by the foregoing method.
[0031] According to a third aspect of the invention, a
conveyor-oven baked naan bread is provided having a crisp-chewy
consistency, a visibly bubbled surface texture and a slightly
scorched top surface.
[0032] According to a fourth aspect of the invention, a naan bread
making system is provided, comprising: [0033] a naan bread dough
preparing station for: [0034] preparing a naan bread dough; [0035]
dividing and forming the dough into round balls; and [0036] rising
the round balls of dough; [0037] a loaf shaping station for: [0038]
flattening the round balls of dough into generally circular discs;
and [0039] stretching each disc into an irregular non-circular
shaped loaf; and [0040] a conveyor oven station for: [0041] baking
the shaped loaves by running the shaped loaves on a conveyor
through a high temperature gas oven for a period of time sufficient
to produce baked naan breads each having a crisp-chewy consistency,
a visibly bubbled surface texture and a slightly scorched top
surface.
[0042] Preferably, the oven's interior surface has at least a
portion made from stone, granite, clay or porcelain. According to
the system, the bread may be allowed to contact the portion of the
interior surface made of stone, granite, clay or porcelain as it
bakes.
[0043] Preferably, the oven has top and bottom heating sources, for
baking the bread from above and below, and for imparting a scorched
appearance to parts of the bread. The top heating source may be
located approximately 15 to 30 cm from the conveyor. The top and
bottom heating sources may comprise a gas burner. The burner does
not touch the bread as it is baking. The burner may be angled to
indirectly bake the bread moving on the conveyor.
[0044] The oven housing may be composed of: [0045] an exterior
steel shell; [0046] an interior baking cavity lined at least in
part with stone, granite, clay or porcelain; and [0047] an
intermediate insulating layer between the shell and the baking
cavity, comprising sand-filled panels and loosely packed rock
wool.
[0048] Preferably, the oven housing is tunnel shaped and a conveyor
passes through the tunnel. Preferably, the tunnel is a linear
tunnel, having a dough entry portion that is separate from and
located away from a baked bread exit portion.
[0049] The system may further include a cooling and packaging
station for cooling naan breads from the oven and packaging the
breads for refrigerated or frozen storage prior to consumption in a
re-heated form.
[0050] The system is preferably adapted for preparing up to 8000
breads per hour.
BRIEF DESCRIPTION OF THE FIGURES
[0051] FIG. 1A is a diagram of a traditional tandoor oven (prior
art) showing the housing in cutaway to reveal the clay baking
chamber.
[0052] FIG. 1B is a diagram of a traditional tandoor oven (prior
art) showing naan breads baking on the inside walls.
[0053] FIG. 2 is a view of a rack of naan dough balls rising before
the baking process.
[0054] FIG. 3 is a view of a pressing station where round balls of
dough are pressed into circular discs.
[0055] FIG. 4 is a view of a shaping station where circular discs
of dough are stretched and shaped before baking.
[0056] FIG. 5 is a side view of the entry point of the automatic
oil spray prior to entering the oven for baking the naan bread
loaves.
[0057] FIG. 6 is a view of the exit point of the oven for baking
naan bread loaves before entering the spiral cooler prior to
packaging.
[0058] FIG. 7 is a view of a finished baked naan, showing bubbled
surface and classic scorch marks.
[0059] FIG. 8 is a diagram of oven operation showing top and bottom
heating elements (burners) with simulated flow diagram of heat
waves and exhaust fumes.
[0060] FIG. 9 is diagram of the oven construction showing layers of
housing materials.
DETAILED DESCRIPTION OF THE FIGURES
[0061] As shown in FIGS. 1A and 1B, the traditional tandoor oven
(which is still widely used) consists of a cylindrical or
urn-shaped structure with fuel placed in the bottom. The baking
surfaces are actually the walls of the tandoor. Bread dough is
slapped onto the inside walls where it bakes in this peculiar
vertical "hanging" fashion with the heat of the wall surface and
where it is perfumed by the smoky hot air from the burning charcoal
or wood. Baked naans are removed by hook from the wall. The baking
time is short (approximately 1-2 minutes). An operator tends to the
oven producing many small batches of bread. Still, a skilled naan
baker may only be able to produce about 90 naan in an hour.
[0062] Baked naan has a characteristic appearance and texture. A
sample illustration of the naan baked according to the present
invention is shown in FIG. 7. The surface has a bubbled appearance,
and the bread may have characteristic smudges or scorched areas.
Traditionally, naan bread is shaped by hand and an uneven, rustic
appearance is considered desirable. This also provides contrasts in
texture as parts of the baked bread may be thicker and chewier,
while other parts may be thin and cracker-ish.
[0063] In accordance with traditional recipes, naan is produced
from a soft wheat flour dough, which may be yeast- or baking
powder-leavened. It may be prepared using water or milk (or a
combination). A souring ingredient may be used to promote bubbling
in the dough. Flavouring and conditioning ingredients may be added
(such as buttermilk, garlic and cilantro). Before or after baking,
the dough may be oiled or brushed with ghee (clarified butter).
[0064] As an illustrative example, a naan bread dough may be made
according to the following formula:
flour--53 wt-%
sugar--2.5 wt-%
baking powder--1.45 wt-%
salt--1.4 wt-%
yeast--0.05 wt-%
water--14 wt-%
liquid egg--2.5 wt-%
buttermilk--23 wt-%
butter ghee--0.75 wt-%
oil--2 wt-%.
[0065] This is merely one possible formulation. It will be
understood by persons skilled in the art that other combinations of
flour, liquid and leavening (with or without additional fats,
sugars, and flavour additives) are possible.
[0066] A commercial horizontal dough mixer may be used to bring the
ingredients together (not shown). The dough may be fermented at
this stage. A preferred fermentation time is approximately 8 hours
to develop desirable yeast activity and souring in the dough. The
dough mass is then divided into small balls (ranging from about
100-160 gms each). The balls may be weighed for sizing purposes.
More or less even or uneven weights may be desirable for different
applications. The dough balls 100 are allowed to rise in trays on
racks (for about 45 minutes at about 29.degree. C.). The rising
process is shown at FIG. 2. A steam proofer may be used with racks
as shown in FIG. 2. Alternatively, a "traveling" or conveyor tray
proofer may be used (not shown), retaining the same dough proofing
ability, with improved efficiency.
[0067] After rising, the dough balls are pressed or rolled against
work surface 120 into circular discs 110. As shown in FIG. 3, a
dough sheeting machine may be used to arrive at substantially
circular/elliptical discs. The desired thickness of each disc
(depending on the type of naan) may be approximately 2-5 mm, each
disc being approximately 6-10'' (15-26 cm) in diameter.
[0068] The circular discs 110 may then be stretched in a second
station 160 into shaped loaves 140 ready for baking. As shown in
FIG. 4, the loaves may be hand-shaped, or mechanical shaping
processes may be used (not shown). Preferably, the stretched
thickness of each loaf of raw dough is approximately 1.5-3 mm.
[0069] The shaping process may also involve embossing the dough or
impressing finger prints into the dough to make a deliberately
uneven surface. This adds to the contrasting textures in the
finished baked product.
[0070] As shown in FIG. 4, the prepping surface may be a conveyor
leading to the oven conveyor 170. This conveyor 170 transports the
pre-shaped loaves directly into and through the oven. FIG. 5 shows
an entry point to the oven. The entry is quite small (only 4'' (10
cm)) to provide just enough clearance for the conveyor bearing the
thin loaves to enter the oven proper, while preventing heat
escape.
[0071] The structure of the oven 150 is best shown in the diagrams
in FIGS. 8 and 9.
[0072] A special "traveling" (conveyor) tandoor gas oven 150 is
preferably used. Gas is preferred for efficiency and the ability to
generate very high temperature heating. A standard blower system is
used to circulate heated air and exhaust fumes and smoke (not
shown). Other oven arrangements may be possible. It may be
possible, for instance, to use electric heating elements, or to
combine gas and some other combustible heat source (e.g. wood chip
or charcoal). Of critical importance is the ability to generate a
heated oven environment in excess of 700.degree. F. (370.degree.
C.). For naan baking, it is preferred that the arrangement of
burners provide heat from below and above, simulating the heat
pattern of the traditional tandoor oven. This contributes to better
browning of the naan and simulates the heat "chimney" effect in a
traditional tandoor. As shown in FIG. 8, an inlet exhaust 290, a
combustion exhaust 300 and an outlet exhaust 310 may be provided.
The heat generated bakes the loaves in the oven proper 230 with
heat from above and below the loaves.
[0073] The conveyor in the "traveling" tandoor oven has
specially-designed trays which in turn hold clay, granite or
porcelain tiles, specially designed to withstand high temperatures
(up to 1000.degree. F.) and vibrations caused by traveling at
various speeds (between approximately 2-80 ft/min.). Conveyor speed
is preferably controllable by external controls (not shown).
[0074] In a preferred embodiment, the temperature of the oven is
set at approximately 700.degree. F. At a conveyor speed of 20-50
feet/minute, the baking time per naan is approximately 35-75
seconds, dependant on thickness and size of naan produced. The
conveyor operated at this speed allows continuous production
averaging about 4000-8000 naan per hour, dependant on baking time
and size of product. One of the challenges in operating a conveyor
oven for this purpose has been to find a temperature and baking
time suitable to produce a high-quality, authentic naan having a
desirable texture, size and taste, while taking advantage of the
process efficiencies of the conveyor arrangement and production
improvements.
[0075] As particularly shown in the diagram in FIG. 8, the tunnel
of the oven may be a linear path. Alternatively, the entry and exit
may be positioned proximate to each other, the conveyor operating
in a loop formation, or some other arrangement.
[0076] Preferably, at the oven exit, the conveyor removes the baked
naans 190 onto a separate conveyor 180 for delivery to a cooling
area (not shown). Naan baked at 700.degree. F. enters the cooling
spiral at approximately 200.degree. F., being cooled to ambient
temperature (approximately 70.degree. F.) before packaging.
Post-cooling, the naan can be packaged at a packaging station and
the temperature reduced still further for refrigerated or frozen
storage (not shown).
[0077] It has been found that the present method allows naans to be
pre-baked for resale as a re-heatable product for home use. The
product, removed from its packaging, can be re-heated in a
conventional oven, in a pan on a conventional stove top or by
microwave. A few drops of water may be sprinkled on the surface of
the naan prior to re-heating to re-hydrate the naan and improve the
baking. If desired, the naan may be topped with various toppings
such as roasted garlic, butter ghee, parmesan cheese, grilled
roasted vegetables, or pizza ingredients may be added by the
consumer and/or the surface brushed with olive oil.
[0078] The tandoor oven construction is particularly shown in FIG.
9. The oven cavity 230 is surrounded by stone cladding 240 (e.g.
granite or another food-approved stone material). This is in turn
supported by a carbon steel layer 250. A layer of sand 260 follows,
which is a traditional insulator in tandoor ovens. Next,
loosely-packed (12 lb/ft.sup.2) rock wool 270 is used to further
insulate. Finally, the structure is encased in stainless steel 280.
This multi-layer structure of granite (clay, stone or porcelain) in
combination with sand is believed to be unique among
high-temperature conveyor ovens. The oven structure allows baking
at 800.degree. F. while containing the internal heat. Preferably,
the exterior steel housing is maintained at a low temperature (less
than 100.degree. F.).
[0079] Preferably, the height of the baking cavity 230 is
approximately 18'' from the surface of the conveyor 170. The width
of the tunnel is preferably approximately 56''. The tunnel's length
may vary, but a length around 20-30 ft has been found useful. The
entry and exit portions may have reduced height to prevent heat
escape (either part of the housing may be lowered downward to
partially cover the entry and exit, or a separate heat shield may
be provided in the form of inlet and exit hoods with Teflon.RTM.
curtains (not shown).
[0080] The oven preferably further includes an exhaust fan fitted
with oil separators to condense any airborne oil particles from the
baking process (not shown).
[0081] The foregoing description illustrates only certain preferred
embodiments of the invention. The invention is not limited to the
foregoing examples. That is, persons skilled in the art will
appreciate and understand that modifications and variations are, or
will be, possible to utilize and carry out the teachings of the
invention described herein. Accordingly, all suitable
modifications, variations and equivalents may be resorted to, and
such modifications, variations and equivalents are intended to fall
within the scope of the invention as described and within the scope
of the claims.
* * * * *