AU2011224042B2 - A lidding system - Google Patents

Abstract

Abstract A lid for a closing a loaf tin to form a vessel for proofing and baking a sandwich loaf. The loaf tin including a rectangular base and four walls extending upwardly from the edges of the base to define a space for receiving dough. The lid including a rectangular ceiling 5 and four walls extending downwardly from the edges of the ceiling to define a space for receiving a portion of the dough as it expands during proofing and baking; and being dimensioned to be at least partly slidingly received within the walls of the loaf tin to be lifted by the dough, as the dough expands, without blow out. At least two walls of the lid being of non-uniform vertical depth to present a non-linear lower edge to the dough. A 10 vessel including the lid, a set of lids and a set of vessels is also disclosed. '1 8 8 IG 2b

Description

P/00101Il Regulation 3. AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Invention Title: A lidding system The following statement is a full description of this invention, including the best method of performing it known to us: 2 A lidding system Field of the invention The invention relates to proofing and baking sandwich loaves of bread. Background of the invention 5 The baking of loaves of bread is traditionally carried out by placing dough pieces into an open topped bread tin. For the avoidance of doubt, 'tin' as used herein has its usual meaning in the context of baking: an upwardly open container; in particular 'tin' does not imply construction from any particular material. As the dough pieces prove and rise during the baking process, the dough rises above 10 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 fit conveniently into lunch boxes, toasters and sandwich makers. Neat square loaves are also desirable for handling efficiencies downstream of the baking process. By way of example, distorted loaves can snag and cause difficulties during bagging. 15 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. This name is misleading because the lid does not drop in to the tins. As each dough piece proves and rises during the baking process, it flattens against the drop in lid. To ensure that a consistent square top is achieved, the tin is dimensioned 20 so 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 sets of 2, 3 or more tins and the planar "drop in lid" fits over all 2 or 3 tins to close the tins.

3 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. 5 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 off the tin too far, thus causing "blow out" 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 form an unsightly ledge. The "blow out" may close the air space between adjacent strapped 10 baking tins, causing insufficient heat flow between the sides of adjacent tins sharing the "drop in lid". These 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. 15 The baking of the sides of the middle loaf or loaves in the set 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 times 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 20 by the uneven heat transfer within the oven. This problem is increased in "key-hole" loaves where the distorted loaf further restricts convective air flow. Ovens that are too hot or too cold also affect the finished shape of the loaf. 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 25 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. Summary of the Invention Whilst square loaves desirably fit neatly into toasters and lunch boxes etc, the inventors have recognised that customers often display a preference for loaves with the 4 appearance of "natural variation" over the appearance of mechanised precision resultant from various existing approaches to baking. There is a need to address the problems of "blow out" and uneven baking profiles in the baking of loaves of bread, yet it is desirable to avoid the appearance of mechanical 5 precision. The present invention is directed to addressing at least some of the abovementioned problems. One aspect of the invention provides a vessel for proofing and baking a sandwich loaf, the vessel including a loaf tin and a lid for closing the loaf tin; the loaf tin including a rectangular base and four walls extending upwardly from 10 the edges of the base to define a space for receiving dough; the lid including a rectangular ceiling and four walls extending downwardly from the edges of the ceiling to define a space for receiving a portion of the dough as it expands during proofing and baking; and the lid being dimensioned to be at least partly slidingly received within the walls 15 of the loaf tin to be lifted by the dough, as the dough expands, without blow out; wherein at least two walls, and preferably each wall, of the lid being of non uniform vertical depth to present a non-linear lower edge to the dough. As will be described, in preferred embodiments, the non linear edges interact with the crust formation process during baking to influence the shape and extent of the bloom 20 line to produce a desirably non-uniform appearance and conceal various undesirable features. Preferably the lower edges of the two long walls of the lid each include equally spaced high portions for late contact with the dough to conceal joints between the dough portions the number of high portions being one less than the number of dough portions.

5 As there are generally four dough portions, the long walls of the lid each include three high portions. The non-liner lower edges may be formed by a series of tangentially connected arcs defining a vertically wavy pattern. Preferably each respective non-linear lower edge in 5 substance varies in depth by about 15mm from its lowest point to its highest point. Most preferably each non-linear lower edge is at about the same depth. The walls of the lid may be substantially planar. The vessel may be predominately formed of sheet metal. Another aspect of the invention provides a set of vessels for proofing and baking 10 sandwich loaves, the set including two or more of the above vessels; first interconnecting structure; and second interconnecting structure; the loaf tins being arranged in a horizontal array and held in relative disposition 15 by the first interconnecting structure, the lids being arranged in an array complementary to the array of loaf tins and held in relative disposition by the second interconnecting structure; whereby the array of lids are handled as a unitary body and selectively engaged with the loaf tins, and when so engaged each lid is at least partly received within a loaf tin. 20 Another aspect of the invention provides a lid for a closing a loaf tin to form a vessel for proofing and baking a sandwich loaf, the loaf tin including a rectangular base and four walls extending upwardly from the edges of the base to define a space for receiving dough; 6 the lid including a rectangular ceiling and four walls extending downwardly from the edges of the ceiling to define a space for receiving a portion of the dough as it expands during proofing and baking; and being dimensioned to be at least partly slidingly received within the walls of the loaf tin to be lifted without blow out 5 by the dough, as the dough expands, at least two walls of the lid being of non uniform vertical depth to present a non-linear lower edge to the dough. Another aspect of the invention provides a set of the lids for closing loaf tins, arranged in a horizontal array, to form a set of vessels for proofing and baking sandwich loaves, the set of lids including 10 two or more of the above lids; and interconnecting structure; the lids being arranged in an array complementary to the array of loaf tins and held in relative disposition by the interconnecting structure; whereby the array of lids may be handled as a unitary body and selectively engaged 15 with the loaf tins, and when so engaged each lid is at least partly received within a loaf tin. Another aspect of the invention provides a method of proofing and baking a sandwich loaf including forming an elongate dough piece; 20 dividing the dough piece at spaced locations along its length to form dough portions; placing at least some of the dough portions into a loaf tin at respective orientations to produce a cross grained loaf; 7 fitting to the loaf tin a lid having at least two walls which each include spaced high portions for late contact with the dough portions to conceal joints between the dough portions. The various aspects of the invention are complementary. Each aspect may incorporate 5 features described in respect of the other aspects. Dough pieces baked under preferred forms of this lidding system rise all the way into the enclosed void and up against the lid. The dough piece first bakes onto the lid shape, creating a crust on the upper portion of the sides of the loaf of bread. The additional conductive heat transfer of the side portions to the upper portion of the sides 10 of the loaf of bread ensures the faster formation of a crust, thus preventing "blow out" which occurs in this region when the conventional lidding system is used. Brief description of the drawings Figure la is a top view of a conventional lidding system; Figure 1b is a side view of the conventional lidding system of Figure 1a for use with the 15 strapped baking tins; Figure 2a is a top view of a set of vessels in accordance with an embodiment of the present invention; Figure 2b is a side view of the set of vessels of Figure 2a; Figure 3a is an end view of a set of lids in accordance with an embodiment of the 20 invention; Figure 3b is a plan view of the set of lids of Figure 3a; Figure 3c is a side view of the set of lids of Figure 3a; 8 Figure 4 is a plan view of a blank for a lid in accordance with an embodiment of the invention; Figure 5a is a side view of a loaf produced with existing baking equipment; Figure 5b is a plan view of a loaf produced using a vessel in accordance with an 5 embodiment of the invention; and Figure 6 is a schematic side view of a vessel in accordance with an embodiment of the invention carrying yet-to-be proofed dough. Detailed description of the embodiments Figures 1(a) and 1(b) show an existing set of vessels including three rectangular loaf 10 tins 2 held in position by interconnecting structure in the form of strap 9 which is a metal (steel) band. Each tin 2 includes a base 2A and four walls 2B. The lidding system includes a lid 1 made from a sheet of plate steel material having slots 3 formed therein and extending through the lid 1. The slots 3 are positioned on the lid to correspond to the gap between the loaf tins 2 so that air can circulate and rise up between the tins. 15 This is intended to provide even heating of all of the tins in the strapping 9. The lid 1 includes walls 7B extending downwardly from its planar horizontal ceiling portion 7A. The walls 7B are positioned to reside on the outside of the group of tins 2 as shown. As can be seen from Figures 1(a) and 1(b), when the dough rises within the tins 2, the walls 7B of the lid are sit on the outside of the tin from the dough and thus do not 20 contact the dough to bake and form a crust on all sides of the top of each loaf. Furthermore, the slot 3 in the lid 1 of conventional lidding systems are thought to be inadequate because they do not provide sufficient flow of air, and "blow out" can further restrict, and even totally block, air flow around the tins and between the lid spacing 3. Referring to a preferred embodiment of the present invention I figures 2a and 2b, the set 25 of vessels includes three lids 8 and three tins 2. The tins 2 are substantially identical to those of the prior art including a base 2A and walls 2B. A first interconnecting structure 9 in the form of strap 9 which is a metal (steel) band holds the tins together. Each tin 2 includes a base 2A and four walls 2B. Each lid has a horizontal ceiling portion 4, and four walls 5. The ceiling is a rectangular piece. The walls 5 extend downwardly from its edges. The ceiling portion 4 and four walls 5 define a void underneath the lid to receive 5 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 corners from the lids. Desirably the walls 2B of the vessel, walls 5 of the lid are not entirely vertical, but rather diverge outwardly from their respective base 2A or ceiling 4. This outward divergence 10 makes it easier for the baked bread to be removed from the vessel and reduces the incidence of loaves being damaged due to a portion being stuck in the tin or lid. Desirably the floor and the ceiling of each vessel are of about the same width. The divergent walls 2B, 5 define an internal volume the sides of which bulge slightly outwards. In turn, during baking, the loaf takes on a correspondingly outwardly bulged 15 shape. Conveniently this slight outward bulge tends to counteract the loaf's tendency to shrink upon cooling, whereby the shrinking tends to draw the outwardly bulged portions inward to present a straighter, squarer, side to the loaf. Preferably the lids 4 are connected together by a second interconnecting structure. The second interconnecting structure is a connecting portion 6 which includes two 20 longitudinal rigid members 10 equally spaced along a central lateral axis. It will be appreciated that the connecting portion 6 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 25 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 between the lids, the present invention enables quicker, more even cooking of the loaf 10 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 interior of each of the baking tins 2 and adjacent to the side walls of the baking tins. 5 The baking tins are typically strapped together with a specified spacing between each tin. This is in contrast to conventional lidding systems (Figures Ia and 1b), where the side portions 7 are designed to slide over the exterior of the group of baking tins 2. Each wall 5 has a non-linear lower edge 5A associated with the depth of each wall 5 varying along its length. The edges 5A are presented to the dough to create a non 10 linear marking on the side of the loaf in the plane of the side of the loaf. This avoids the appearance of mechanical precision associated with other modes of baking. Figure 2B illustrates a preferred variant of the wall 5 having non linear lower edges 5A formed by a series of arcs tangentially connected at end points to define a smooth, continuous, vertically-wavy pattern. Of course other forms of non-linear edge are possible; eg. the 15 edge might have a stepped or jagged appearance. Figures 3A, 3B and 3C illustrate a set of lids 13 in accordance with a further embodiment of the invention. Each lid 8' is relevantly similar to lid 8 of the previous embodiment. In the set 13, the lids 8' are interconnected and held in relative disposition by formed sheet metal interconnecting structure 10'. The interconnecting structure 10' 20 includes a short horizontal tab 10A' at each of its ends forming handles by which the set 13 may be listed as a unitary structure to engage and disengage a complementary array of tins. Figure 5A illustrates a sandwich loaf 14 having a straight horizontal line 14A running along its side. The line 14A results from a prior art approach to baking and give the loaf 25 the appearance of 'machine like perfection' considered undesirable by consumers. In contrast, the loaf 16 of figure 5B, produced using a vessel in accordance with an embodiment of the invention, has an "imperfect" wavy marking along its side creating a more 'natural' appearance which is desired by consumers.

11 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 5 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 10 rises it fills the void 14 which is formed beneath 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 walls 5 and the ceiling 4, creating an initial crust on the upper portions of 15 the loaf. During baking the loaf continues to expand after the initial crust creation. To accommodate this expansion, the initial crusts tend to break along the lower edge of the lid. As the dough continues expanding, the initial crust continues to bake and harden whereas the region of the break in the initial crust tends to grow forming a region of 20 relatively thin crust referred to as a bloom line. The adoption of a lid having a non uniform lower edge has been found to produce a bloom line of variable width thus enhancing the desirably "natural" appearance of the loaf. The texture of a square loaf can be improved by a process referred to as cross graining. Cross graining involves forming an elongate dough piece, referred to as a sausage, and 25 then cutting the sausage at spaced locations along its length to form separate dough portions. The dough portions are placed into the loaf tin at orientations in which each dough portion is rotated 90 degrees about a vertical axis so that the faces of the dough portions defined during division sit against the internal walls of the loaf tin and an axis of each dough portion previously aligned with the sausage extends transversely across the 30 loaf tin.

12 During baking the dough pieces expand and merge together, although joints between the dough portions remain visible on the exterior of the loaf. These joints are thought to be aesthetically undesirable. The inventors have discovered that by coordinating the shape of the non uniform lower 5 edges of the lids with the joints of the dough portions the appearance of the bloom line can be manipulated to be concealed at the bloom line, and thereabout, the joint between the portions. It has been found that the higher portions of the non uniform edges contact the dough later or not at all, as the dough expands during proofing and baking, resulting in more a 'natural' bloom line and more effective concealment of the 10 joint between the dough portions. This contributes to the finished loaf having a more 'random', less moulded, appearance. Figure 6 illustrates a vessel 20 carrying four dough portions 22 arranged to form a cross grained loaf. The dough portions 22 as shown are yet to be proofed. The lower edge 5A" of the lid includes three equally spaced high portions 5C for late contact with the 15 dough. Preferred variants of the invention incorporate three high points spaced along the length of each long edge of the lid, preferably equally spaced, to conceal the joints between four dough portions. Of course the lid might incorporate other high points between these high points. 20 It is also contemplated that a lid having two high points, or a lid having four high points might be used to bake a loaf from three or five dough portions, but it has been found that four dough portions is a preferable compromise between desirable cross graining and handling an excessive number of dough portions and an excessive number of joints between dough portions.

Claims (21)

1. A vessel for proofing and baking a sandwich loaf, the vessel including a loaf tin and a lid for closing the loaf tin; the loaf tin including a rectangular base and four walls extending upwardly from 5 the edges of the base to define a space for receiving dough; the lid including a rectangular ceiling and four walls extending downwardly from the edges of the ceiling to define a space for receiving a portion of the dough as it expands during proofing and baking; and the lid being dimensioned to be at least partly slidingly received within the walls 10 of the loaf tin to be lifted by the dough, as the dough expands, without blow out; wherein at least two walls of the lid are of non-uniform vertical depth to present a non-linear lower edge to the dough.

2. The vessel of claim 1 wherein each wall of the lid is of non-uniform vertical depth to present a non-linear lower edge to the dough. 15

3. The vessel of claim 1 or 2 wherein said non-liner lower edges are formed by a series of tangentially connected arcs defining a vertically wavy pattern.

4. The vessel of claim 1, 2 or 3 wherein at least the two long walls of the lid have a non-uniform vertical depth

5. The vessel of claim 4 wherein lower edges of the two long walls of the lid each 20 include equally spaced high portions for late contact with the dough to conceal joints between dough portions.

6. The vessel of claim 5 wherein the number of high portions is one less than the number of dough portions. 14

7. The vessel of any one of claim 2 to 6 wherein each respective non-linear lower edge in substance varies in depth by about 15mm from its lowest point to its highest point.

8. The vessel of any one of claims 2 to 7 wherein each non-linear lower edge is at about the same depth. 5

9. The vessel of any one of claims 1 to 6 wherein the walls of the lid are substantially planar.

10. A set of vessels for proofing and baking sandwich loaves, the set including two or more vessels in accordance with any one of claims 1 to 7; first interconnecting structure; and 10 second interconnecting structure; the loaf tins being arranged in a horizontal array and held in relative disposition by the first interconnecting structure; the lids being arranged in an array complementary to the array of loaf tins and held in relative disposition by the second interconnecting structure; 15 whereby the array of lids are able to be handled as a unitary body and selectively engaged with the loaf tins, and when so engaged each lid is at least partly received within a loaf tin.

11. A lid for a closing a loaf tin to form a vessel for proofing and baking a sandwich loaf, 20 the loaf tin including a rectangular base and four walls extending upwardly from the edges of the base to define a space for receiving dough; 15 the lid including a rectangular ceiling and four walls extending downwardly from the edges of the ceiling to define a space for receiving a portion of the dough as it expands during proofing and baking; and being dimensioned to be at least partly slidingly received within the walls of the 5 loaf tin to be lifted by the dough, as the dough expands, without blow out; at least two walls of the lid being of non-uniform vertical depth to present a non-linear lower edge to the dough.

12. The lid of claim 11 wherein each wall of the lid is of non-uniform vertical depth to present a non-linear lower edge to the dough. 10

13. The lid of claim 11 or 12 wherein said non-liner lower edges are formed by a series of tangentially connected arcs defining a vertically wavy pattern.

14. The vessel of claim 11, 12 or 13 wherein at least the two long walls of the lid have a non-uniform vertical depth

15. The lid of claim 14 wherein the lower edges of the two long walls of the lid each 15 include equally spaced high portions for late contact with the dough to conceal joints between dough portions.

16. The vessel of claim 15 wherein the number of high portions is one less than the number of dough portions.

17. The lid of any one of claims 12 to 16 wherein each respective non-linear lower 20 edge in substance varies in depth by about 15mm from its lowest point to its highest point.

18. The lid of any one of claims 12 to 17 wherein each non-linear lower edge is at about the same depth. 16

19. The lid of any one of claims 12 to 18 wherein the walls of the lid are substantially planar.

20. A set of the lids for closing loaf tins, arranged in a horizontal array, to form a set of vessels for proofing and baking sandwich loaves, the set of lids including 5 two or more of the lids of any one of claims 11 to 19; and interconnecting structure; the lids being arranged in an array complementary to the array of loaf tins and held in relative disposition by the interconnecting structure; whereby the array of lids may be handled as a unitary body and selectively 10 engaged with the loaf tins, and when so engaged each lid is at least partly received within a loaf tin.

21. A lid for a loaf tin substantially as hereinbefore described with reference to the accompanying drawings.