Note: Descriptions are shown in the official language in which they were submitted.
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A lidding system
Field of the invention
The present invention relates to a lidding system for the baking of items such
as bread
and in particular square sandwich loaves of bread.
Background of the invention
= The baking of loaves of bread is traditional carried out by placing dough
pieces into a
open topped bread tin. As the dough pieces prove and rise during the baking
process,
the dough rises above the height of the tin to produce a domed shaped top of
the baked
loaf of bread.
More recently, square sandwich loaves of bread have become popular due to
their
ability to conveniently fit into lunch boxes, toasters and sandwich makers.
Square
sandwich loaves are formed by placing a simple sheet steel panel, commonly
known in
the industry as a "drop in lid", on top of the tin. As the dough piece proves
and rises
during the baking process, it flattens against the lid. To ensure that a
consistent square
top is achieved, the rising loaf ideally lifts the lid slightly off the bread
tin as it bakes.
When baking is complete, the lid is ideally 15 to 20 mm above the tin, resting
on top of
the loaves. Square sandwich loaves are typically produced by placing a sausage
shape
dough piece into a bread tin (or pan). These tins are strapped together in
straps of 2, 3
or more tins and the planar "drop in lid" fits over all 2 or 3 tins to close
the tins.
While this lid has been in universal use over the past 50 years or so, it is
not without its
disadvantages. Firstly, in the proving process, a standard process prior to
baking, the
dough pieces prove in the tin and rise to just beneath the lid. The height of
the dough
piece when placed in the oven is critical in producing a consistently high
quality product.
If the dough height is too low baking bread will not rise sufficiently to be
squared off by
the lid. If the dough height is too high, the baking bread will rise too high
thereby lifting
the lid of the tin too far, thus causing "blow our of the loaf top. The "blow
out" of the loaf
top occurs when the top of the rising loaf spreads out laterally against the
lid to from an
unsightly ledge. The "blow our may close the air space between adjacent
strapped
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baking tins, causing insufficient heat flow between the sides of adjacent tins
sharing the "drop in
lid". This causes the sides of the loaves to under bake and hence collapse.
The collapsed loaf sides
combined with the unsightly top ledge creates a distorted loaf, known as a
"key-hole" which is
difficult to slice and bag. As a consequence, these distorted loaves may be
rejected as waste.
Secondary, the baking of the sides of the middle loaf or loaves in the strap
can be difficult,
especially in non-convection type ovens. To overcome this problem, slots have
been placed in the
lids, in the areas between the tins, to assist in the convective air flow up
between the tins. Despite
this, baking dough pieces are often longer than necessary to obtain a crust on
the sides of the
middles loaf or loaves. As a consequence, the baking quality is diminished by
the uneven heat
transfer within the oven. This problem is increased in "blow out" loaves where
the distorted loaf
further restricts convective air flow.
It is well known in the bakery industry that sandwich or "squares", as they
are commonly known,
must be constantly monitored while in the proof stage to ensure that they do
not over proof and
expand too high in the tins. There is no means of correcting over-proof, as
pushing the dough
down simply deflates the proof, thus adversely affecting quality.
Therefore, there is a need to address problems of "blow out" and uneven baking
profiles in the
baking of loaves of bread. The present invention is directed to addressing at
least some of the
abovementioned problems.
Summary of the invention
According to the present invention, there is provided a loaf tin and lid for
proofing and baking
bread loaf, the loaf tin including a rectangular base and four walls extending
upwardly from the
edges of the base for receiving dough, the lid including a rectangular top
portion and four side
portions extending downwardly from the top portion to define a void beneath
which the dough is
contained; the four side portions of the lid fitting within the interior of
the loaf tin and adjacent to
the walls to close the void, such that during proofing and baking when the lid
is lifted by rising
dough as it expands and the level of the dough rises, the four side portions
of the lid remain within
the walls of the tin.
The four side portions of the lid may have a lower edge which does not rise
above the level of the
walls during baking. A set of loaf tins and lids for proofing and baking
square sandwich loaves
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may including two or more loaf tins and lids, and the two or more lids being
connected together
by a connecting bar to arrange the loaf tins and space the loaf tins apart and
provide venting regions
between the adjacent vessels.
According to the present invention, there is provided a lidding system for use
with loaf tins in the
production of bread loaves including a plurality of lids connected together to
cover a plurality of
loaf tins, the lidding system being provided with venting regions between the
lids corresponding
to space between adjacent loaf tins, each lid covering a loaf tin, the lid
including the four side
portions of the lid which define a void beneath which the dough is contained,
the four side portions
fitting within the interior of the loaf tin and adjacent to the walls to close
the void, such that during
baking when the lid is lifted by rising dough during proofing and baking as it
expands and the level
of the dough rises, the four side portions of the lid remain within the walls
of the tin.
The plurality of lids may be held together by a connection bar disposed on the
lids. The four side
portions of the lid may have a lower edge which does not rise above the level
of the walls of the
tin during baking.
Brief description of the drawings
Figure la is a top view of a conventional lidding system.
Figure lb is a side view of the conventional lidding system of Figure la for
use with the strapped
baking tins.
Figure 2a is a top view of one embodiment of the present invention.
Figure 2b is a side view of the lidding system of Figure 2a for use with the
strapped baking tins.
Detailed description of the embodiments
Figures 1(a) and 1(b) show an existing conventional lidding system for 3
rectangular loaf tins 2
held in position by strap 9 which is a metal (steel) band. The lidding system
includes a lid 1 made
from a sheet of plate steel material having spacings 3 formed therein and
extending through the lid
1. The spacings 3 are positioned on the lid to correspond to the gap between
the loaf tins 2 so that
air can circulate and rise up
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between the tins. This is intended to provide even heating of all of the tins
in the
strapping 9.
The lid is provided with side 7 extending around the periphery of the lid 1.
The sides of
the lid are positioned to reside on the outside of the tins as shown. As can
be seen from
Figures 1(a) and 1(b), when the dough rises within the two, the sides 7 of the
lid is not
able to contact and thereby bake and form a crust on all sides of the top of
each loaf.
Furthermore, the spacing 3 in the lid 1 of conventional lidding systems
inhibits the flow
of air. Further, the propensity of "blow our of the baked item (typically
bread) to occur
may further restrict, and even totally block, air flow around the tins and
between the lid
spacing 3.
Referring to the Figures 2a and 2b, in a preferred embodiment of the present
invention,
the lidding system includes three lids 8, each having a top portion 4, and
four side
portions 5. The top portion and four side portions form a void underneath the
lid which
contains the rising dough. The lid is typically made of a semi-rigid sheet
material, such
as stainless steel or other suitable food grade heat stable material. As
illustrated in
Figure 2b, the side portions taper at each end to eliminate hard to clean
comers from
the lids.
Preferably the lids 4 are connected together by a connecting portion 6 which
may
include two longitudinal rigid members 10 equally spaced along a central
lateral axis. It
will be appreciated that the connecting portion may alternatively consist of
one
longitudinal rigid member located on the central lateral axis. The width of
the
connecting portion is relatively narrow so that the connecting portion covers
a relatively
small area between each of the lids. This maximises the air space 12 between
the lids
and thus promotes convective air currents, and hence heat transfer, between
and
around the tins.
As mentioned above, with conventional lidding systems the baking of the sides
of the
middle loaf can be particularly difficult in non-convection type ovens, with
the dough
piece in the middle tins requiring longer to form a crust. In addition to
increased spacing
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between the lids, the present invention enables quicker, more even cooking of
the loaf
sides particularly of the centre loaf or loaves though conductive heat
transfer from the
top portion 4 to the side portions 5.
The lids of the present invention are designed to enable the side portions to
fit into the
5 interior of each of the baking tins 2 and adjacent to the side walls of the
baking tins.
The baking tins are typically strapped together with a specified spacing
between each
tin. This is in contrast to conventional lidding systems (Figures la and lb),
where the
side portions 7 are designed to slide over the exterior of the baking tins 2.
As mentioned above, with a conventional lidding system as shown in Figures
1(a) and
1(b) there is no means of correcting overproof, experienced bakers and
rigorous control
over the dough making and proofing stage is required to avoid excessive
wastage due
to poor quality product. The present invention provides a means to minimise
the
wastage through a lidding system which promotes a more robust baking process,
which
is more forgiving to variations in dough preparation and proofing. Thus, the
present
invention is particularly advantageous for use in operations employing trainee
or
inexperienced bakers.
In use, dough is placed into the baking tins 2 and placed into the oven. As
the dough
rises it fills the void 14 which is formed by the top and side portions of
each lid. On the
occasions when the dough is over-proof, the rising dough exerts vertical force
on the
lids, thus causing them to rise. The lids may rise up to about 50mm, without
excessive
"blow out". This is achieved due to the dough first baking to the lid shape,
defined by
the four side portions 5 and the top portion 4, creating a crust on the upper
portions of
the sides of the loaf. This is the region of the loaf which is prone to "blow-
out".
Therefore by forming a crust in the top corner portion of the loaf, of similar
width to the
bottom comer portion of the loaf, the "blow-out" effect is minimised.
