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Pastries
7 Pastries
7.1 We have been experiencing considerable variability in processing our short and puff paste products; sometimes we have problems with paste shrinkage and on other occasions we get stickiness. We have checked our weighing systems and can find no problems with ingredient additions. We have no climatic temperature control in the factory or ingredient storage facilities, are these likely to be significant contributors to the problems? Producing and using pastes at consistent temperatures is very important in ensuring consistent processing and optimum final product quality. Ideally you should be controlling ingredient and environment temperatures along with the delivery of a consistent paste temperature ex-mixer. To advise you on the best way to eliminate your problem we need to consider the various influences. Ingredient temperatures Flour and fat are the main ingredients to concern us. Since your flour is stored in non-insulated silos you must expect the temperature of this ingredient to vary with changes in climatic conditions. The common way of coping with such variations is to adjust the temperature of the water added to the mix (see 7.5). Remember that water levels are low in pastes by comparison with those used in bread dough, so the cooling potential of the recipe water is lower. You need to make sure that you have an adequate supply of chilled water and often you may need to resort to the addition of ice or an ice-water mix. In colder periods you may need to provide heated water. Relatively high levels of fat are added to the base dough of pastry products
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and so variations in fat temperature will contribute to variations in paste temperature. It is best to keep the fat at a constant temperature and only try to adjust paste temperatures ex-mixer using water at the appropriate temperature. The functional properties of fats are related to their `temperature histories' and it is best not to subject them to too many warm and cold cycles. Ideally you should hold your fat at a similar temperature to your processing environment or slightly lower than your ideal paste temperature ex-mixer. If you are using re-work added to the mixer then you should ensure that this is at a constant temperature. If it comes from a chilled environment then you should make sure that the temperature throughout the batch is uniform. Processing temperatures Ideally you should have a constant processing temperature. This is particularly important if you have long rest periods or are using fats that are particularly temperature sensitive. You will find that pastry lift is directly related to paste processing temperature for a wide range of laminating fats (see Fig. 42).
Fig. 42 Effect of processing at temperatures of 12 and 19ëC on puff pastry lift.
In the manufacture of laminated products variations in paste temperature can directly affect the integrity of the layers. Higher processing temperatures often result in breakdown of the layering as the laminating fat `oils'. In such cases the paste becomes sticky and is usually compensated for through the increased use of dusting flour on the plant or by lowering the added water level both of which introduce other problems. Low paste temperatures make the dough firmer and more difficult to sheet. Commonly this means that extra sheeting pressure is applied during processing, which can then lead to breakdown of the layering of the laminations. Most laminating fats will lose some of their plasticity at lower temperatures and this can lead to loss of layer integrity and subsequent pastry lift.
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7.2 We are looking to start production of croissant. In my travels I have seen many variations on products that are called croissant. Why are there so many different forms and how are they made? An essential feature of the products that we call croissant is that they are made from a laminated dough, that is one which comprises alternate layers of a fermented dough and a suitable fat. Most people consider the origins of the product to be in central Europe and a number of legends suggest that they are associated with conflicts between the Western world and the Turkish empire of the Middle Ages. One story suggests that they were a special bread to celebrate the role that bakers played in saving Vienna from attack ± the traditional crescent shape being a symbol associated with the invaders. The primary shape of the croissant, which is thick in the middle and thin at the ends, comes from rolling a triangular shaped piece of dough cut out from a thinly sheeted laminated paste. Whatever the true origins of croissant it does appear that the first shapes were in the form of a crescent with the two thin ends curved inwardly towards one another. The main regional variations to this shape include forms in which the two `horns' are stretched to join together to form a ring (common in Spain) and others where the croissant is not curved and remains straight (common in Germany). Another variation, which is often considered to be very important, is related to the definition of the `shoulders' formed on the piece after rolling the paste triangle; in some cases they should be prominent, while in others they should not. In addition to variations in shape we now commonly see variations in size. Many baked products have changed in form since their first introduction, as they have evolved to meets consumer needs and marketing strategies. For example, in its `classic' form the croissant should have a very flaky texture, which can often leave a mass of crumbs behind when it is eaten. This does not suit all tastes and new forms have evolved in which the flakiness of the product has been reduced and begun to assume a more `bun-like' texture. We leave it to you to decide which form of croissant you wish to make. However, whatever your choice, the characteristics of croissant are controlled by a few key recipe and process features. In summary these features are: · · · · · · · · · ·
The quality characteristics of the flour. The mixing of the base dough. The quality characteristics of the laminating fat. Yeast level in the base dough. The ratio of laminating fat to base dough. The numbers of fat layers created during lamination. Roll gap settings during sheeting. Resting periods between lamination and sheeting stages. Paste processing temperature. The triangle size of the unit croissant.
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· Recycling paste trimmings. · Prover conditions. There are also some significant interactions which need to be considered in the successful manufacture of croissant. The quality characteristics of the flour In general strong flours are needed for croissant production but it is important to form an extensible gluten to avoid problems during the sheeting and lamination stages. Using stronger flours will commonly mean that longer resting periods are required between individual sheeting and laminating stages. The mixing of the base dough The common practice is to `under-develop' the base dough by comparison with bread production. This is said to allow for the extra development that occurs when the dough and paste are sheeted, and it is true that the pressure of the sheeting rolls does transfer some energy to the dough. However, it is the rheological character of the base dough leaving the mixer that is most important if a uniform and cohesive sheet is to be formed. Under-development during mixing does not automatically deliver the appropriate dough rheology. The quality characteristics of the laminating fat The laminating fat will be extruded onto the base dough before the initial folding stages (in small bakeries it may be applied as sheets) and it is important that the fat is plastic enough to form as complete an initial layer as possible to help with lift in baking (BPS, pp. 124±5). Butter is a popular fat used in the manufacture of croissant but its melting point is low and this makes it difficult to use without refrigeration of the paste during production (see 7.6). Yeast level in the base dough The level of yeast in the base dough will depend on a number of other recipe, e.g. the level of sugar, and process factors, e.g. processing and final proof temperatures. The production of carbon dioxide gas by the yeast in the base dough will disrupt the layered structure of the product, especially during proof, and this can reduce lift. The ratio of laminating fat to base dough In the manufacture of croissant the ratio of laminating fat to base dough has less impact on pastry lift than would be the case with puff pastry. This is because of the disrupting effect of the yeast activity. The level of laminating fat will have a significant effect on the eating quality of the product and its flavour, especially if butter is used as the laminating fat. The numbers of fat layers created during lamination As a general rule, relatively few fat layers are created in croissant, typically 18± 32. This is in contrast to puff pastry production where the numbers will be two
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or three times greater. Once again it is the disrupting effect of the yeast activity that has to be taken into account and so the aim is to try and keep the fat and dough layers intact to gain lift and contribute to the flaky eating character of the final product. Roll gap settings during sheeting A key aim during sheeting is to avoid breaking up the fat layers in the paste, as this will allow the ready escape of steam from the base dough and restrict lift in the oven. The roll gap settings which are used are strongly influenced by the rheological character of the base dough and the need to achieve a particular width ready for the laminating (folding) stage which follows sheeting. Resting periods between lamination and sheeting stages Resting periods are helpful in adjusting the rheological character of the paste. Longer periods help the paste to relax and make it easier to sheet; easier sheeting leads to less damage of the dough and fat layers and makes it easier to achieve the required sheet widths for further processing. However, longer processing times permit greater yeast activity and so a balance must be struck between the two requirements. Paste processing temperature The control of paste processing temperature is important in retaining the integrity of the fat layers; too low and the fat will be brittle, too high and the fat will readily turn to oil. Lower processing temperatures helps limit yeast activity before final proof. The triangle size of the unit croissant The dimensions of the triangle are important in determining the final appearance of the croissant. We suggest that you try rolling a few different shaped triangles and see which one you prefer. Recycling paste trimmings There will always be some trimmings from the paste sheet during production. You can re-use these by adding them to the mixer but you must control their level and age in order not to introduce unwanted product variation (see 7.3). Prover conditions Your chosen proof temperature should be lower than used with bread to avoid oiling of the fat and loss of lift. Prover temperatures in the range 30±32ëC are usually suitable with a humidity of 70±80%. Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.3 What is the best way to use pastry trimmings? At present we are feeding them back into the sheeting stages The production of trimmings in the manufacture of pastry products is inevitable; they mostly come from trimming the paste sheets during processing. It is common practice on automatic plants to gather them at various processing points and feed them back during the sheeting stages, though in some cases they may be added directly into the mixer to be incorporated with fresh ingredients. Puff pastry trimmings are often used as a means of incorporating fat into the base dough. To make the best use of trimmings there are a number of important factors to consider. They include the following. Age and condition All pastes contain microflora which are capable of changing the pH of the trimmings and contributing to spoilage and the generation of off-odours and flavours. Such reactions are time and temperature dependent and so it is best to have a standard length of time in which the trimmings are used and a fixed storage temperature under which they are held. If the trimmings are gathered automatically on your plant then the time will typically be too short for any significant effects. If you are keeping the trimmings for any length of time then the lower paste pH that you get contributes to pastry shrinkage. Temperature Storing trimmings at reduced temperatures before use is a useful way of maintaining lower paste temperatures for processing. If you choose to do this, you should ensure that the temperature in a given batch of trimmings is as uniform as possible; for example, by spreading them out on sheets rather than holding them in tubs for chilling. You may also need to ensure that they do not unduly dry out. Level of addition Bakers often see the re-incorporation of trimmings as a financial issue. However, in many cases they should be seen an `ingredient', as their condition can have direct impact on the quality of the paste during processing and the baked product. In some cases the `standard' paste product cannot be made without trimmings being present and it may be necessary to produce a paste at the start of a production run to act as though they were trimmings. This is especially true if the trimmings are kept for any length of time (the pH effect) or held at reduced temperatures. It is worth noting that the continued re-use of trimmings will lead to a progressive concentration of sub-components in production and this may have unwanted effects, e.g. increasing concentration of paste relaxants, which may make the paste sticky. This is usually dealt with by incorporating a `break' into the production cycle when any unused trimmings are sent to waste.
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7.4 We are manufacturing savoury short pastry products that are blocked out to shape and lids by sheeting a paste with the same formulation. We wish to increase our production rate and are considering reducing or eliminating the rest periods in the production sequence. Can you advise us on their function and any consequences that we may face if we change them? Rest periods are used in the manufacture of pastry products at different points in the production sequence. Their primary function is to allow for the modification of the rheological properties of the paste so that its subsequent behaviour is optimised and the required final product characteristics are achieved. The rheological properties of the paste are largely determined by the degree of gluten development that occurs in the mixing and machining of the paste. Following mixing and machining, the rheological properties of the paste change with resting time; the longer the resting time, the greater the rheological change (the rate of change will also be influenced by the temperature at which the paste is resting). Commonly the rheological changes are referred to as `relaxation' of the paste. Savoury short pastry products typically have less gluten development than puff paste and resting periods tend to be relatively short after mixing to make it easier to obtain the required shape and reduce the risk of shrinkage when forming (blocking) of the pastry shape. The resting period may apply to the bulk paste before dividing or the individual units (billets) after dividing. If you are going to reduce the resting period then you may need to modify the paste rheology in some other way; such as the addition of a paste `relaxant'. The most common paste relaxant is L-cysteine hydrochloride, which acts on the protein network and reduces the strength of gluten formation in the paste, which in turn, reduces the need for resting periods. Proteolytic enzymes may be used but these tend to be less effective. Caution should be exercised when using a paste relaxant in a production environment that yields high levels of paste trimmings. Since the paste trimmings will be re-used in subsequent mixings there is a gradual build-up of the level of the relaxant as production continues and a point may be reached at which problems with paste stickiness may be experienced. An alternative way of reducing paste resting times may be through the addition of extra water to the paste at the initial mixing stage. The extent to which this can be practised will depend on the capabilities of the plant to operate with a softer paste. If you take this approach then you may also have to consider a small reduction in mixing time, as higher initial water levels tend to lead to greater potential for gluten formation in the mixer. One function of resting periods not always appreciated relates to the temperature of the paste, especially in the production of pie pastry where the use of hot water is practised. In this case part of the rheological change in the paste comes from the cooling of the paste after mixing.
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7.5 What method should we use to calculate the water temperature to deliver a consistent final paste temperature at the end of mixing? Most paste preparation methods are designed to minimise energy transfer during mixing. Nevertheless, we recommend that you take into account any temperature gain that might be experienced. First, you should make a number of pastes in which you record the main ingredient temperatures ± flour, fat (not laminating fat) and water ± and the final paste temperatures that were achieved for your given mixing time. You may already have such data in your records and you could use these. Next, calculate the ingredient contributions by summing the individual contributions of weight and temperature multiplied by their specific heat capacity. For example: 100 kg flour @ 20ëC 2000 0.4 30 kg fat @ 20ëC 600 0.7 30 kg water @ 10ëC 300 1.0 Total heat input 2900 Total heat input/total mass 2900/160 which gives an expected base paste temperature of 18.1ëC Actual paste temperature was 20.5ëC Thus temperature rise was 2.4ëC The approximate water temperature for future mixes could then be calculated using the following formula: Total mass ingredients (required paste temperature ÿ temperature rise) ÿ (Heat input from flour and fat) / Mass of water There will be small errors in the last calculation because the specific heat capacities of the ingredients used are not taken into account, but since the variations in ingredient masses will be very small for a given recipe, the method still has practical value. If you are making laminated pastries then the choice of the final mixed base paste temperature should be matched with that of the laminating fat for ease of processing. This approach will also optimise the integrity of the fat and dough layers after lamination. If the base paste and the laminating fat temperatures are not matched, there will be transfer of some heat from the warmer to the colder component but unless you are using long resting times, the practical effect will be small.
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7.6 We are making puff pastry, Danish pastries and croissant using all butter and often have problems with the processing of the pastes and feel that we do not get the best of quality from the final products. What are the best processing temperatures and conditions when using butter with such products? Butter has a positive marketing image because of its `natural' associations and is a popular fat to use in pastry making. The melting profile of butter makes it a particularly pleasing fat for incorporating into pastry products but unfortunately it is not the easiest of fats to use in processing. Butter has a relatively low melting point (BPS, pp. 38±40) and a tendency to `oil' during pastry processing, creating problems with sheeting. To overcome this particular problem you will need to ensure that the dough temperature after mixing and the paste processing temperatures are kept as low as possible. This may mean you will have to air-condition the pastry processing area. The data illustrated in Fig. 43 show how important the effect of paste processing temperature can be on the lift of all-butter pastries. It is equally important that the processing temperature is not too low because butter lacks plasticity at lower temperatures and the integrity of the layering in the pastry will be lost with subsequent loss of lift.
Fig. 43
Effect of processing at temperatures of 19 and 12ëC on puff pastry lift when using butter.
The low melting point of butter also creates problems for proving Danish pastries and croissant, so you will find it an advantage to restrict the temperature in the final prover to around 30ëC with a relative humidity of 60±75%. These conditions will help avoid flow and loss of boldness and shape. Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.7 We would like to reduce the level of fat that we use to make our puff pastry but would like to retain pastry lift. Can you provide us with some guidance as to how we might achieve our objectives? As you know the laminating fat plays a major role in delivering lift in puff pastry and other laminated products. As soon as you reduce the ratio of laminating fat to base dough you will experience some loss of lift. However, there is some potential for making other changes to your recipe and process which may be of help. You have not provided any specific recipe or production details so we can only provide you with general guidance. The first point to make is that the potential for reducing fat levels depends on the ratio of fat to base dough and the number of laminations that you are giving the paste during processing. The general pattern is that for any ratio of laminating fat to base pastry, lift increases to reach a maximum before falling as the number of laminations increases. The loss of lift comes from the crushing and loss of integrity of the dough layers in the paste. Depending on the ratio of laminating fat to base dough and the number of laminations that you are giving then it may be possible to use less with fewer laminations to maintain pastry lift. You could investigate using a stronger flour to maintain the integrity of the dough layers but if you do then you may need to lengthen the resting times that you are using during processing. This may be difficult on a plant with a fixed throughput. With stronger flours you may find that increasing the mixing time has some positive benefit on pastry lift. This is akin to using more energy on the mixing of bread dough. Commonly pastry dough is less developed than bread dough but extending the mixing time well beyond that normally considered appropriate, e.g. from 2 to 5 and even 10 minutes, can produce a more extensible gluten network, which retains the integrity of the dough layers in the paste during sheeting. If you do lengthen the mixing time to such an extent then you may need to use crushed ice to help you control the final base dough temperature. As noted in 7.1 you may find that you can adjust the processing temperature to a lower value and still maintain lift. Any potential benefit from this type of change will be influenced by the type of laminating fat that you are using; for example see Fig. 43 which illustrates the effect of processing temperature when using butter. Lowering the processing temperature increases dough resistance to deformation and so again you may need to adjust paste resting times to avoid problems with product shaping. The addition of trimmings tends to reduce pastry lift, especially if they are being folded into the paste during sheeting. There are two options, you could reduce the overall level of trimmings that you add or you could change to mixing the trimmings into the base dough. Adding the trimmings at the mixer roughly reduces their negative impact on pastry lift by about 50%.
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7.8 Some of the short pastry cases that we make for restaurants to fill and serve have been returned to us as being `mouldy' on the base. We were surprised as we thought that the water activity of the shells was too low to support mould growth and when we examined the bottom of the pastries we can see that there is a discoloration but we do not think that it is mould. Can you identify what has caused the discoloration and how to eliminate it? We can confirm that the problem is not related to mould growth even though the discoloration has a similar appearance to mould colonies (see Fig. 44). Almost certainly the problem is related to a chemical reaction between the pastry base and the pans in which they are held before baking. The paste will be slightly acid and this accelerates a reaction between the paste and a source of iron to form iron compounds which turn dark when the pastry is baked-off.
Fig. 44
Dark marks on the base of refrigerated pastry shells.
You are storing the unbaked pastry pieces in a refrigerator overnight before they are baked and such discolorations are sometimes seen with retarded dough pieces (BPS, p. 113). It is a little surprising that you have had this problem, as the moisture content of the pastry base will be somewhat lower than that of dough, but it may be that there was some condensation on the pastry bases when they were transferred to refrigerated storage and this may have encouraged the reaction. The most obvious course of action would be to make and bake the pastry bases without refrigerating them. If this is not possible, you should look at the condition of your pans and discard any which are scratched or damaged. Alternatively, you could block the pastries into foil cases placed in the pans. Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.9 We are having problems with the custard tarts that we make. The pastry shell is very pale coloured but if we increase the baking time, we find that the custard filling is not very stable and shrinks away from the case during storage. If we raise the baking temperature, the custard filling boils and breaks down during storage. Can you give us any advice on how to get a better pastry colour without causing problems with the filling? Too much heat input increases the loss of water from the custard causing it to shrink away from the pastry case and crack. During storage the low water activity of the egg gel allows more water to escape and it will continue to shrink and, as illustrated in Fig. 45, cracks may appear on the surface. Excessive heat input during baking causes the egg custard to boil and the gel to break down ± a process often referred to as syneresis (BPS, p. 145). The sample that you provided is just beginning to show this problem.
Fig. 45 Cracks on the surface of custard tarts.
It is always difficult to find the best combination of baking time and temperature in the manufacture of egg custards to yield the required pastry colour without compromising the filling qualities. Rather than trying to colour your pastry by changing baking conditions, you could substitute a portion of the sucrose in the paste recipe with dextrose; this is a reducing sugar and will colour more readily than sucrose. If you have no dextrose then you can use a glucose syrup, remembering to make allowance for the water in the glucose syrup. Dextrose and glucose syrup are less sweet than sucrose (weight for weight) but as you are only replacing a portion of the sucrose, you may not notice the difference in flavour. Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.10 We are experiencing distortion of our pastry shapes. We have measured the shrinkage but find that it is not even. We have also noticed that the laminated products are experiencing some variation in product lift. What might be the causes of these problems? There are quite few causes of pastry shrinkage (BPS, p. 129) which include using a flour that has too high a protein content and over-mixing the paste, which yields excessive gluten formation in the paste or base dough for laminated pastries. Often paste shrinkage can be minimised by making resting periods longer (BPS, p. 128). If this is not possible on an automatic production line, you can consider adding a paste relaxant such as L-cysteine hydrochloride. You describe the problem as being uneven shrinkage, which suggests that it is not an ingredient or mixing problem but more likely to be related to paste processing. Check that resting times are being controlled and that you are not experiencing undue production stoppages. If such issues are not the cause of the unevenness in product shrinkage then you will need to look more closely at your paste sheeting and product cutting methods. You should examine the way that you are using paste trimmings. If you are feeding them in during sheeting, you should make sure that they are being uniformly distributed across the paste sheet. If you are adding them back at the mixing stage then they should be recycled at regular time intervals and in regular proportions to your virgin paste and ideally, they should be at a consistent temperature. When sheeting short pastes, the forces are all aligned in one direction along the length of travel down the plant, which aligns the gluten network in a particular direction, and when different shapes are cut from the sheet, the paste elasticity can cause distorted shrinkage especially with round or complex shapes. The most common way of reducing this problem is to employ a cross-pinning roller; this is a small wheel which moves rapidly backwards and forwards at right-angles to the direction of the paste sheet just before the cutter and its action helps even out the stresses in the sheet. If you have one, make sure that it is doing its correct job, if you do not have one then you may want to fit one. The process of laminating paste will even out some the stresses referred to above, though employing a cross-pinner before cutting the shapes is still a good idea. However, there is a more fundamental processing problem for you to consider, namely that after the paste has been folded and is then re-sheeted, a characteristic `w-shaped' pattern is formed in the paste (see Fig. 46). This occurs in many plants because of the characteristic `lapping' motion while the paste is still moving down the plant. The spread of the `w' depends on the number of laminations that you are giving the paste with respect to the speed of the plant. At edges of the laminated paste there can be tendency for the laminating fat to be expressed from within the layers when they are sheeted and if more laminations are carried out, it becomes re-distributed in the subsequent layering. Thus in some parts of the paste sheet there are small variations in the dough to
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fat ratios and this contributes to variations in lift and shrinkage. The extent of the variation can be assessed by sampling products across the sheet width and extending along the band to cover at least one full `w' formed of the sheet (e.g., as shown by the shaded sections in Fig. 46).
Fig. 46
Typical processing pattern on laminated pastes.
To reduce the variation you will need to reduce the length of each `w' so that they spread over a shorter distance and this usually requires the plant speed to be slowed down; such a change may not be possible, as it will reduce the plant throughput. Alternatively you may find that a change in the number of laminations that you give the paste will reduce the degree of variability that you are experiencing. Commonly lift and shrinkage go hand-in-hand so that a reduction in the number of layers may give you less shrinkage; you will need to carry out some trials to see if the loss of lift is acceptable to you. Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.11 We have been receiving complaints from customers that our short pastry which we use for meat pie products has an unpleasant eating character that they describe as `waxy'. The comments are most often related to the base pastry in the pies. Why is this? The sensory characteristic that you describe is directly related to the type and properties of the fat that you are using. The crispness of the pie paste that you are making and its retention throughout life is of prime importance in delivering a product which consumers consider to be appropriate ± soft and soggy pastry is most often associated with `staling' in pastry terms. All bakery fats are a mixture of oil and solid fat fractions (BPS, pp. 38±9). In pastry making one of the ways in which pie pastry crispness is maintained is by using a fat with a high melting point fraction. However, if the melting point of the fat is above that of the temperature in the human mouth then it does not `melt in the mouth' and leaves behind a waxy sensation, which is most often referred to as `palate cling'. The problem is also linked with the proportion of the fat component with the high melting point, the greater the proportion of the high melting fat fraction, the greater the sensation of palate cling. This particular problem is often seen with animal fats, which are more popular in meat pie production because of their contribution to product flavour and with hydrogenated fats. When the unbaked product enters the oven the fat component begins to melt and becomes oil. Ultimately all of the solid fat fractions will become liquid. Under the influence of gravity some of the liquid fat drains into the base pastry and fills up the small voids that are present in the paste from mixing and processing. In addition to fat from within the paste there will be a significant contribution from the fat in the meat fillings that you are using. Since the fat comes from an animal source then it will have a high melting point. The combination of the two drainage processes increases the proportion of fat that is present in the base paste and so makes the problems of palate cling more noticeable in that area of the pie. Since you are unlikely to be able to make a suitable meat filling with a low melting point fat, we suggest that you change to a lower melting point fat in the preparation of your short paste, which should help reduce the problem. Reference
and YOUNG, L.S. (2000) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.12 We have been trying to freeze fully proved croissant for later bake-off. Can you identify the important criteria for their successful production? There is significant interest in freezing fermented and proved dough pieces with the intention that the pieces are removed from the freezer and transferred straight to the oven for baking. This would make the product very convenient to use in a range of bake-off environments. However, there are some significant technical challenges to overcome. As is well known, yeast cells die during freezing and subsequent storage. This means that when the dough pieces are removed from the oven there is no potential carbon dioxide gas production from the yeast. In addition, during storage the carbon dioxide gas that has already been evolved in the proof phase gradually leaks out of the dough. In the prover the carbon dioxide gas diffuses into the nitrogen gas bubbles trapped in the dough but during freezing and storage the diffusion process is reversed and in some cases this leads to collapse of the dough structure. The freezing of proved laminated pastries is more successful than that achieved with bread doughs. This is because the mechanism by which croissant and Danish doughs expand does not rely exclusively on the release of carbon dioxide gas but is more closely related to the pressure of steam generated during baking which is trapped between the dough layers of the paste. In broad terms this means that frozen proved laminated products still have the potential to expand and yield products of relatively `normal' appearance. The most important criteria for frozen proved laminated doughs are essentially the same as those that would apply to the product when freshly produced. The only exception may be that the pieces are not fully proved before being transferred to the freezer, as a small degree of proof may still occur in the dough pieces in their initial phase of freezing. As a general principle, if the recipe and process will make a good fresh product, it will make an acceptable one if frozen. There tends to be a small loss of product quality with freezing. It is important to ensure that the dough pieces are quickly frozen and once frozen are not allowed to defrost and be refrozen. This can be a very damaging process and is more damaging than would be the case with unproved frozen dough. Care should also be taken to limit moisture losses at any stage during freezing and storage. The products should be stored in moisture-impermeable film and if they are wrapped in bulk, e.g. in boxes, it may be necessary to overwrap the bulk container. Bulk wrapping of products is possible but be careful to avoid having large numbers of dough pieces in a box or too many boxes stacked on top of one another. The increased pressure on frozen dough pieces at the bottom of a stack can cause them to defrost and become deformed in shape.
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7.13 What characteristics should we specify for the flour that we use for making savoury and sweet short pastes? Usually the specification for pastry flours is not very comprehensive because there is no need for significant gluten formation in the paste, and recipe water levels are much lower than would be used in bread making. The general view is that soft wheat flours with a moisture content of around 14% and a protein content of 8±10% are suited to the manufacture of both savoury and sweet paste products. It is probably advisable to avoid flours with low Falling Numbers, since they are high in cereal alpha-amylase. This is because it is common practice to recycle paste trimmings in product and the trimmings may be stored for some time before being used. During the storage period the alpha-amylase will act on the starch in the flour causing the paste to soften and become sticky. This may later cause problems during paste processing. We note that you are making unbaked paste products, which you subsequently chill for a period before they are baked. Because you are making such products, you should specify that the flour has a low ash (see 2.1) or grade colour figure (see 2.12). The need for an ash specification is not related to the colour of the baked pastries but to the potential for enzyme-assisted oxidation of the polyphenols naturally occurring in wheat bran. During refrigerated storage the oxidation reaction can cause the bran particles to become dark brown or black in colour. The larger the size of the bran particles, the more evident the dark spots will appear. If the bran is finely divided then the paste may assume a grey, almost dirty appearance. The oxidation reaction will continue as long as the products are held in refrigerated storage. The same problem can occur with both savoury and sweet pastes and can also be a problem with puff pastry stored under refrigerated conditions (BPS, p. 132). Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
7.1 We have been experiencing considerable variability in processing our short and puff paste products; sometimes we have problems with paste shrinkage and on other occasions we get stickiness. We have checked our weighing systems and can find no problems with ingredient additions. We have no climatic temperature control in the factory or ingredient storage facilities, are these likely to be significant contributors to the problems? Producing and using pastes at consistent temperatures is very important in ensuring consistent processing and optimum final product quality. Ideally you should be controlling ingredient and environment temperatures along with the delivery of a consistent paste temperature ex-mixer. To advise you on the best way to eliminate your problem we need to consider the various influences. Ingredient temperatures Flour and fat are the main ingredients to concern us. Since your flour is stored in non-insulated silos you must expect the temperature of this ingredient to vary with changes in climatic conditions. The common way of coping with such variations is to adjust the temperature of the water added to the mix (see 7.5). Remember that water levels are low in pastes by comparison with those used in bread dough, so the cooling potential of the recipe water is lower. You need to make sure that you have an adequate supply of chilled water and often you may need to resort to the addition of ice or an ice-water mix. In colder periods you may need to provide heated water. Relatively high levels of fat are added to the base dough of pastry products
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and so variations in fat temperature will contribute to variations in paste temperature. It is best to keep the fat at a constant temperature and only try to adjust paste temperatures ex-mixer using water at the appropriate temperature. The functional properties of fats are related to their `temperature histories' and it is best not to subject them to too many warm and cold cycles. Ideally you should hold your fat at a similar temperature to your processing environment or slightly lower than your ideal paste temperature ex-mixer. If you are using re-work added to the mixer then you should ensure that this is at a constant temperature. If it comes from a chilled environment then you should make sure that the temperature throughout the batch is uniform. Processing temperatures Ideally you should have a constant processing temperature. This is particularly important if you have long rest periods or are using fats that are particularly temperature sensitive. You will find that pastry lift is directly related to paste processing temperature for a wide range of laminating fats (see Fig. 42).
Fig. 42 Effect of processing at temperatures of 12 and 19ëC on puff pastry lift.
In the manufacture of laminated products variations in paste temperature can directly affect the integrity of the layers. Higher processing temperatures often result in breakdown of the layering as the laminating fat `oils'. In such cases the paste becomes sticky and is usually compensated for through the increased use of dusting flour on the plant or by lowering the added water level both of which introduce other problems. Low paste temperatures make the dough firmer and more difficult to sheet. Commonly this means that extra sheeting pressure is applied during processing, which can then lead to breakdown of the layering of the laminations. Most laminating fats will lose some of their plasticity at lower temperatures and this can lead to loss of layer integrity and subsequent pastry lift.
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7.2 We are looking to start production of croissant. In my travels I have seen many variations on products that are called croissant. Why are there so many different forms and how are they made? An essential feature of the products that we call croissant is that they are made from a laminated dough, that is one which comprises alternate layers of a fermented dough and a suitable fat. Most people consider the origins of the product to be in central Europe and a number of legends suggest that they are associated with conflicts between the Western world and the Turkish empire of the Middle Ages. One story suggests that they were a special bread to celebrate the role that bakers played in saving Vienna from attack ± the traditional crescent shape being a symbol associated with the invaders. The primary shape of the croissant, which is thick in the middle and thin at the ends, comes from rolling a triangular shaped piece of dough cut out from a thinly sheeted laminated paste. Whatever the true origins of croissant it does appear that the first shapes were in the form of a crescent with the two thin ends curved inwardly towards one another. The main regional variations to this shape include forms in which the two `horns' are stretched to join together to form a ring (common in Spain) and others where the croissant is not curved and remains straight (common in Germany). Another variation, which is often considered to be very important, is related to the definition of the `shoulders' formed on the piece after rolling the paste triangle; in some cases they should be prominent, while in others they should not. In addition to variations in shape we now commonly see variations in size. Many baked products have changed in form since their first introduction, as they have evolved to meets consumer needs and marketing strategies. For example, in its `classic' form the croissant should have a very flaky texture, which can often leave a mass of crumbs behind when it is eaten. This does not suit all tastes and new forms have evolved in which the flakiness of the product has been reduced and begun to assume a more `bun-like' texture. We leave it to you to decide which form of croissant you wish to make. However, whatever your choice, the characteristics of croissant are controlled by a few key recipe and process features. In summary these features are: · · · · · · · · · ·
The quality characteristics of the flour. The mixing of the base dough. The quality characteristics of the laminating fat. Yeast level in the base dough. The ratio of laminating fat to base dough. The numbers of fat layers created during lamination. Roll gap settings during sheeting. Resting periods between lamination and sheeting stages. Paste processing temperature. The triangle size of the unit croissant.
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· Recycling paste trimmings. · Prover conditions. There are also some significant interactions which need to be considered in the successful manufacture of croissant. The quality characteristics of the flour In general strong flours are needed for croissant production but it is important to form an extensible gluten to avoid problems during the sheeting and lamination stages. Using stronger flours will commonly mean that longer resting periods are required between individual sheeting and laminating stages. The mixing of the base dough The common practice is to `under-develop' the base dough by comparison with bread production. This is said to allow for the extra development that occurs when the dough and paste are sheeted, and it is true that the pressure of the sheeting rolls does transfer some energy to the dough. However, it is the rheological character of the base dough leaving the mixer that is most important if a uniform and cohesive sheet is to be formed. Under-development during mixing does not automatically deliver the appropriate dough rheology. The quality characteristics of the laminating fat The laminating fat will be extruded onto the base dough before the initial folding stages (in small bakeries it may be applied as sheets) and it is important that the fat is plastic enough to form as complete an initial layer as possible to help with lift in baking (BPS, pp. 124±5). Butter is a popular fat used in the manufacture of croissant but its melting point is low and this makes it difficult to use without refrigeration of the paste during production (see 7.6). Yeast level in the base dough The level of yeast in the base dough will depend on a number of other recipe, e.g. the level of sugar, and process factors, e.g. processing and final proof temperatures. The production of carbon dioxide gas by the yeast in the base dough will disrupt the layered structure of the product, especially during proof, and this can reduce lift. The ratio of laminating fat to base dough In the manufacture of croissant the ratio of laminating fat to base dough has less impact on pastry lift than would be the case with puff pastry. This is because of the disrupting effect of the yeast activity. The level of laminating fat will have a significant effect on the eating quality of the product and its flavour, especially if butter is used as the laminating fat. The numbers of fat layers created during lamination As a general rule, relatively few fat layers are created in croissant, typically 18± 32. This is in contrast to puff pastry production where the numbers will be two
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or three times greater. Once again it is the disrupting effect of the yeast activity that has to be taken into account and so the aim is to try and keep the fat and dough layers intact to gain lift and contribute to the flaky eating character of the final product. Roll gap settings during sheeting A key aim during sheeting is to avoid breaking up the fat layers in the paste, as this will allow the ready escape of steam from the base dough and restrict lift in the oven. The roll gap settings which are used are strongly influenced by the rheological character of the base dough and the need to achieve a particular width ready for the laminating (folding) stage which follows sheeting. Resting periods between lamination and sheeting stages Resting periods are helpful in adjusting the rheological character of the paste. Longer periods help the paste to relax and make it easier to sheet; easier sheeting leads to less damage of the dough and fat layers and makes it easier to achieve the required sheet widths for further processing. However, longer processing times permit greater yeast activity and so a balance must be struck between the two requirements. Paste processing temperature The control of paste processing temperature is important in retaining the integrity of the fat layers; too low and the fat will be brittle, too high and the fat will readily turn to oil. Lower processing temperatures helps limit yeast activity before final proof. The triangle size of the unit croissant The dimensions of the triangle are important in determining the final appearance of the croissant. We suggest that you try rolling a few different shaped triangles and see which one you prefer. Recycling paste trimmings There will always be some trimmings from the paste sheet during production. You can re-use these by adding them to the mixer but you must control their level and age in order not to introduce unwanted product variation (see 7.3). Prover conditions Your chosen proof temperature should be lower than used with bread to avoid oiling of the fat and loss of lift. Prover temperatures in the range 30±32ëC are usually suitable with a humidity of 70±80%. Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.3 What is the best way to use pastry trimmings? At present we are feeding them back into the sheeting stages The production of trimmings in the manufacture of pastry products is inevitable; they mostly come from trimming the paste sheets during processing. It is common practice on automatic plants to gather them at various processing points and feed them back during the sheeting stages, though in some cases they may be added directly into the mixer to be incorporated with fresh ingredients. Puff pastry trimmings are often used as a means of incorporating fat into the base dough. To make the best use of trimmings there are a number of important factors to consider. They include the following. Age and condition All pastes contain microflora which are capable of changing the pH of the trimmings and contributing to spoilage and the generation of off-odours and flavours. Such reactions are time and temperature dependent and so it is best to have a standard length of time in which the trimmings are used and a fixed storage temperature under which they are held. If the trimmings are gathered automatically on your plant then the time will typically be too short for any significant effects. If you are keeping the trimmings for any length of time then the lower paste pH that you get contributes to pastry shrinkage. Temperature Storing trimmings at reduced temperatures before use is a useful way of maintaining lower paste temperatures for processing. If you choose to do this, you should ensure that the temperature in a given batch of trimmings is as uniform as possible; for example, by spreading them out on sheets rather than holding them in tubs for chilling. You may also need to ensure that they do not unduly dry out. Level of addition Bakers often see the re-incorporation of trimmings as a financial issue. However, in many cases they should be seen an `ingredient', as their condition can have direct impact on the quality of the paste during processing and the baked product. In some cases the `standard' paste product cannot be made without trimmings being present and it may be necessary to produce a paste at the start of a production run to act as though they were trimmings. This is especially true if the trimmings are kept for any length of time (the pH effect) or held at reduced temperatures. It is worth noting that the continued re-use of trimmings will lead to a progressive concentration of sub-components in production and this may have unwanted effects, e.g. increasing concentration of paste relaxants, which may make the paste sticky. This is usually dealt with by incorporating a `break' into the production cycle when any unused trimmings are sent to waste.
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7.4 We are manufacturing savoury short pastry products that are blocked out to shape and lids by sheeting a paste with the same formulation. We wish to increase our production rate and are considering reducing or eliminating the rest periods in the production sequence. Can you advise us on their function and any consequences that we may face if we change them? Rest periods are used in the manufacture of pastry products at different points in the production sequence. Their primary function is to allow for the modification of the rheological properties of the paste so that its subsequent behaviour is optimised and the required final product characteristics are achieved. The rheological properties of the paste are largely determined by the degree of gluten development that occurs in the mixing and machining of the paste. Following mixing and machining, the rheological properties of the paste change with resting time; the longer the resting time, the greater the rheological change (the rate of change will also be influenced by the temperature at which the paste is resting). Commonly the rheological changes are referred to as `relaxation' of the paste. Savoury short pastry products typically have less gluten development than puff paste and resting periods tend to be relatively short after mixing to make it easier to obtain the required shape and reduce the risk of shrinkage when forming (blocking) of the pastry shape. The resting period may apply to the bulk paste before dividing or the individual units (billets) after dividing. If you are going to reduce the resting period then you may need to modify the paste rheology in some other way; such as the addition of a paste `relaxant'. The most common paste relaxant is L-cysteine hydrochloride, which acts on the protein network and reduces the strength of gluten formation in the paste, which in turn, reduces the need for resting periods. Proteolytic enzymes may be used but these tend to be less effective. Caution should be exercised when using a paste relaxant in a production environment that yields high levels of paste trimmings. Since the paste trimmings will be re-used in subsequent mixings there is a gradual build-up of the level of the relaxant as production continues and a point may be reached at which problems with paste stickiness may be experienced. An alternative way of reducing paste resting times may be through the addition of extra water to the paste at the initial mixing stage. The extent to which this can be practised will depend on the capabilities of the plant to operate with a softer paste. If you take this approach then you may also have to consider a small reduction in mixing time, as higher initial water levels tend to lead to greater potential for gluten formation in the mixer. One function of resting periods not always appreciated relates to the temperature of the paste, especially in the production of pie pastry where the use of hot water is practised. In this case part of the rheological change in the paste comes from the cooling of the paste after mixing.
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7.5 What method should we use to calculate the water temperature to deliver a consistent final paste temperature at the end of mixing? Most paste preparation methods are designed to minimise energy transfer during mixing. Nevertheless, we recommend that you take into account any temperature gain that might be experienced. First, you should make a number of pastes in which you record the main ingredient temperatures ± flour, fat (not laminating fat) and water ± and the final paste temperatures that were achieved for your given mixing time. You may already have such data in your records and you could use these. Next, calculate the ingredient contributions by summing the individual contributions of weight and temperature multiplied by their specific heat capacity. For example: 100 kg flour @ 20ëC 2000 0.4 30 kg fat @ 20ëC 600 0.7 30 kg water @ 10ëC 300 1.0 Total heat input 2900 Total heat input/total mass 2900/160 which gives an expected base paste temperature of 18.1ëC Actual paste temperature was 20.5ëC Thus temperature rise was 2.4ëC The approximate water temperature for future mixes could then be calculated using the following formula: Total mass ingredients (required paste temperature ÿ temperature rise) ÿ (Heat input from flour and fat) / Mass of water There will be small errors in the last calculation because the specific heat capacities of the ingredients used are not taken into account, but since the variations in ingredient masses will be very small for a given recipe, the method still has practical value. If you are making laminated pastries then the choice of the final mixed base paste temperature should be matched with that of the laminating fat for ease of processing. This approach will also optimise the integrity of the fat and dough layers after lamination. If the base paste and the laminating fat temperatures are not matched, there will be transfer of some heat from the warmer to the colder component but unless you are using long resting times, the practical effect will be small.
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7.6 We are making puff pastry, Danish pastries and croissant using all butter and often have problems with the processing of the pastes and feel that we do not get the best of quality from the final products. What are the best processing temperatures and conditions when using butter with such products? Butter has a positive marketing image because of its `natural' associations and is a popular fat to use in pastry making. The melting profile of butter makes it a particularly pleasing fat for incorporating into pastry products but unfortunately it is not the easiest of fats to use in processing. Butter has a relatively low melting point (BPS, pp. 38±40) and a tendency to `oil' during pastry processing, creating problems with sheeting. To overcome this particular problem you will need to ensure that the dough temperature after mixing and the paste processing temperatures are kept as low as possible. This may mean you will have to air-condition the pastry processing area. The data illustrated in Fig. 43 show how important the effect of paste processing temperature can be on the lift of all-butter pastries. It is equally important that the processing temperature is not too low because butter lacks plasticity at lower temperatures and the integrity of the layering in the pastry will be lost with subsequent loss of lift.
Fig. 43
Effect of processing at temperatures of 19 and 12ëC on puff pastry lift when using butter.
The low melting point of butter also creates problems for proving Danish pastries and croissant, so you will find it an advantage to restrict the temperature in the final prover to around 30ëC with a relative humidity of 60±75%. These conditions will help avoid flow and loss of boldness and shape. Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.7 We would like to reduce the level of fat that we use to make our puff pastry but would like to retain pastry lift. Can you provide us with some guidance as to how we might achieve our objectives? As you know the laminating fat plays a major role in delivering lift in puff pastry and other laminated products. As soon as you reduce the ratio of laminating fat to base dough you will experience some loss of lift. However, there is some potential for making other changes to your recipe and process which may be of help. You have not provided any specific recipe or production details so we can only provide you with general guidance. The first point to make is that the potential for reducing fat levels depends on the ratio of fat to base dough and the number of laminations that you are giving the paste during processing. The general pattern is that for any ratio of laminating fat to base pastry, lift increases to reach a maximum before falling as the number of laminations increases. The loss of lift comes from the crushing and loss of integrity of the dough layers in the paste. Depending on the ratio of laminating fat to base dough and the number of laminations that you are giving then it may be possible to use less with fewer laminations to maintain pastry lift. You could investigate using a stronger flour to maintain the integrity of the dough layers but if you do then you may need to lengthen the resting times that you are using during processing. This may be difficult on a plant with a fixed throughput. With stronger flours you may find that increasing the mixing time has some positive benefit on pastry lift. This is akin to using more energy on the mixing of bread dough. Commonly pastry dough is less developed than bread dough but extending the mixing time well beyond that normally considered appropriate, e.g. from 2 to 5 and even 10 minutes, can produce a more extensible gluten network, which retains the integrity of the dough layers in the paste during sheeting. If you do lengthen the mixing time to such an extent then you may need to use crushed ice to help you control the final base dough temperature. As noted in 7.1 you may find that you can adjust the processing temperature to a lower value and still maintain lift. Any potential benefit from this type of change will be influenced by the type of laminating fat that you are using; for example see Fig. 43 which illustrates the effect of processing temperature when using butter. Lowering the processing temperature increases dough resistance to deformation and so again you may need to adjust paste resting times to avoid problems with product shaping. The addition of trimmings tends to reduce pastry lift, especially if they are being folded into the paste during sheeting. There are two options, you could reduce the overall level of trimmings that you add or you could change to mixing the trimmings into the base dough. Adding the trimmings at the mixer roughly reduces their negative impact on pastry lift by about 50%.
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7.8 Some of the short pastry cases that we make for restaurants to fill and serve have been returned to us as being `mouldy' on the base. We were surprised as we thought that the water activity of the shells was too low to support mould growth and when we examined the bottom of the pastries we can see that there is a discoloration but we do not think that it is mould. Can you identify what has caused the discoloration and how to eliminate it? We can confirm that the problem is not related to mould growth even though the discoloration has a similar appearance to mould colonies (see Fig. 44). Almost certainly the problem is related to a chemical reaction between the pastry base and the pans in which they are held before baking. The paste will be slightly acid and this accelerates a reaction between the paste and a source of iron to form iron compounds which turn dark when the pastry is baked-off.
Fig. 44
Dark marks on the base of refrigerated pastry shells.
You are storing the unbaked pastry pieces in a refrigerator overnight before they are baked and such discolorations are sometimes seen with retarded dough pieces (BPS, p. 113). It is a little surprising that you have had this problem, as the moisture content of the pastry base will be somewhat lower than that of dough, but it may be that there was some condensation on the pastry bases when they were transferred to refrigerated storage and this may have encouraged the reaction. The most obvious course of action would be to make and bake the pastry bases without refrigerating them. If this is not possible, you should look at the condition of your pans and discard any which are scratched or damaged. Alternatively, you could block the pastries into foil cases placed in the pans. Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.9 We are having problems with the custard tarts that we make. The pastry shell is very pale coloured but if we increase the baking time, we find that the custard filling is not very stable and shrinks away from the case during storage. If we raise the baking temperature, the custard filling boils and breaks down during storage. Can you give us any advice on how to get a better pastry colour without causing problems with the filling? Too much heat input increases the loss of water from the custard causing it to shrink away from the pastry case and crack. During storage the low water activity of the egg gel allows more water to escape and it will continue to shrink and, as illustrated in Fig. 45, cracks may appear on the surface. Excessive heat input during baking causes the egg custard to boil and the gel to break down ± a process often referred to as syneresis (BPS, p. 145). The sample that you provided is just beginning to show this problem.
Fig. 45 Cracks on the surface of custard tarts.
It is always difficult to find the best combination of baking time and temperature in the manufacture of egg custards to yield the required pastry colour without compromising the filling qualities. Rather than trying to colour your pastry by changing baking conditions, you could substitute a portion of the sucrose in the paste recipe with dextrose; this is a reducing sugar and will colour more readily than sucrose. If you have no dextrose then you can use a glucose syrup, remembering to make allowance for the water in the glucose syrup. Dextrose and glucose syrup are less sweet than sucrose (weight for weight) but as you are only replacing a portion of the sucrose, you may not notice the difference in flavour. Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.10 We are experiencing distortion of our pastry shapes. We have measured the shrinkage but find that it is not even. We have also noticed that the laminated products are experiencing some variation in product lift. What might be the causes of these problems? There are quite few causes of pastry shrinkage (BPS, p. 129) which include using a flour that has too high a protein content and over-mixing the paste, which yields excessive gluten formation in the paste or base dough for laminated pastries. Often paste shrinkage can be minimised by making resting periods longer (BPS, p. 128). If this is not possible on an automatic production line, you can consider adding a paste relaxant such as L-cysteine hydrochloride. You describe the problem as being uneven shrinkage, which suggests that it is not an ingredient or mixing problem but more likely to be related to paste processing. Check that resting times are being controlled and that you are not experiencing undue production stoppages. If such issues are not the cause of the unevenness in product shrinkage then you will need to look more closely at your paste sheeting and product cutting methods. You should examine the way that you are using paste trimmings. If you are feeding them in during sheeting, you should make sure that they are being uniformly distributed across the paste sheet. If you are adding them back at the mixing stage then they should be recycled at regular time intervals and in regular proportions to your virgin paste and ideally, they should be at a consistent temperature. When sheeting short pastes, the forces are all aligned in one direction along the length of travel down the plant, which aligns the gluten network in a particular direction, and when different shapes are cut from the sheet, the paste elasticity can cause distorted shrinkage especially with round or complex shapes. The most common way of reducing this problem is to employ a cross-pinning roller; this is a small wheel which moves rapidly backwards and forwards at right-angles to the direction of the paste sheet just before the cutter and its action helps even out the stresses in the sheet. If you have one, make sure that it is doing its correct job, if you do not have one then you may want to fit one. The process of laminating paste will even out some the stresses referred to above, though employing a cross-pinner before cutting the shapes is still a good idea. However, there is a more fundamental processing problem for you to consider, namely that after the paste has been folded and is then re-sheeted, a characteristic `w-shaped' pattern is formed in the paste (see Fig. 46). This occurs in many plants because of the characteristic `lapping' motion while the paste is still moving down the plant. The spread of the `w' depends on the number of laminations that you are giving the paste with respect to the speed of the plant. At edges of the laminated paste there can be tendency for the laminating fat to be expressed from within the layers when they are sheeted and if more laminations are carried out, it becomes re-distributed in the subsequent layering. Thus in some parts of the paste sheet there are small variations in the dough to
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fat ratios and this contributes to variations in lift and shrinkage. The extent of the variation can be assessed by sampling products across the sheet width and extending along the band to cover at least one full `w' formed of the sheet (e.g., as shown by the shaded sections in Fig. 46).
Fig. 46
Typical processing pattern on laminated pastes.
To reduce the variation you will need to reduce the length of each `w' so that they spread over a shorter distance and this usually requires the plant speed to be slowed down; such a change may not be possible, as it will reduce the plant throughput. Alternatively you may find that a change in the number of laminations that you give the paste will reduce the degree of variability that you are experiencing. Commonly lift and shrinkage go hand-in-hand so that a reduction in the number of layers may give you less shrinkage; you will need to carry out some trials to see if the loss of lift is acceptable to you. Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.11 We have been receiving complaints from customers that our short pastry which we use for meat pie products has an unpleasant eating character that they describe as `waxy'. The comments are most often related to the base pastry in the pies. Why is this? The sensory characteristic that you describe is directly related to the type and properties of the fat that you are using. The crispness of the pie paste that you are making and its retention throughout life is of prime importance in delivering a product which consumers consider to be appropriate ± soft and soggy pastry is most often associated with `staling' in pastry terms. All bakery fats are a mixture of oil and solid fat fractions (BPS, pp. 38±9). In pastry making one of the ways in which pie pastry crispness is maintained is by using a fat with a high melting point fraction. However, if the melting point of the fat is above that of the temperature in the human mouth then it does not `melt in the mouth' and leaves behind a waxy sensation, which is most often referred to as `palate cling'. The problem is also linked with the proportion of the fat component with the high melting point, the greater the proportion of the high melting fat fraction, the greater the sensation of palate cling. This particular problem is often seen with animal fats, which are more popular in meat pie production because of their contribution to product flavour and with hydrogenated fats. When the unbaked product enters the oven the fat component begins to melt and becomes oil. Ultimately all of the solid fat fractions will become liquid. Under the influence of gravity some of the liquid fat drains into the base pastry and fills up the small voids that are present in the paste from mixing and processing. In addition to fat from within the paste there will be a significant contribution from the fat in the meat fillings that you are using. Since the fat comes from an animal source then it will have a high melting point. The combination of the two drainage processes increases the proportion of fat that is present in the base paste and so makes the problems of palate cling more noticeable in that area of the pie. Since you are unlikely to be able to make a suitable meat filling with a low melting point fat, we suggest that you change to a lower melting point fat in the preparation of your short paste, which should help reduce the problem. Reference
and YOUNG, L.S. (2000) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.
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7.12 We have been trying to freeze fully proved croissant for later bake-off. Can you identify the important criteria for their successful production? There is significant interest in freezing fermented and proved dough pieces with the intention that the pieces are removed from the freezer and transferred straight to the oven for baking. This would make the product very convenient to use in a range of bake-off environments. However, there are some significant technical challenges to overcome. As is well known, yeast cells die during freezing and subsequent storage. This means that when the dough pieces are removed from the oven there is no potential carbon dioxide gas production from the yeast. In addition, during storage the carbon dioxide gas that has already been evolved in the proof phase gradually leaks out of the dough. In the prover the carbon dioxide gas diffuses into the nitrogen gas bubbles trapped in the dough but during freezing and storage the diffusion process is reversed and in some cases this leads to collapse of the dough structure. The freezing of proved laminated pastries is more successful than that achieved with bread doughs. This is because the mechanism by which croissant and Danish doughs expand does not rely exclusively on the release of carbon dioxide gas but is more closely related to the pressure of steam generated during baking which is trapped between the dough layers of the paste. In broad terms this means that frozen proved laminated products still have the potential to expand and yield products of relatively `normal' appearance. The most important criteria for frozen proved laminated doughs are essentially the same as those that would apply to the product when freshly produced. The only exception may be that the pieces are not fully proved before being transferred to the freezer, as a small degree of proof may still occur in the dough pieces in their initial phase of freezing. As a general principle, if the recipe and process will make a good fresh product, it will make an acceptable one if frozen. There tends to be a small loss of product quality with freezing. It is important to ensure that the dough pieces are quickly frozen and once frozen are not allowed to defrost and be refrozen. This can be a very damaging process and is more damaging than would be the case with unproved frozen dough. Care should also be taken to limit moisture losses at any stage during freezing and storage. The products should be stored in moisture-impermeable film and if they are wrapped in bulk, e.g. in boxes, it may be necessary to overwrap the bulk container. Bulk wrapping of products is possible but be careful to avoid having large numbers of dough pieces in a box or too many boxes stacked on top of one another. The increased pressure on frozen dough pieces at the bottom of a stack can cause them to defrost and become deformed in shape.
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7.13 What characteristics should we specify for the flour that we use for making savoury and sweet short pastes? Usually the specification for pastry flours is not very comprehensive because there is no need for significant gluten formation in the paste, and recipe water levels are much lower than would be used in bread making. The general view is that soft wheat flours with a moisture content of around 14% and a protein content of 8±10% are suited to the manufacture of both savoury and sweet paste products. It is probably advisable to avoid flours with low Falling Numbers, since they are high in cereal alpha-amylase. This is because it is common practice to recycle paste trimmings in product and the trimmings may be stored for some time before being used. During the storage period the alpha-amylase will act on the starch in the flour causing the paste to soften and become sticky. This may later cause problems during paste processing. We note that you are making unbaked paste products, which you subsequently chill for a period before they are baked. Because you are making such products, you should specify that the flour has a low ash (see 2.1) or grade colour figure (see 2.12). The need for an ash specification is not related to the colour of the baked pastries but to the potential for enzyme-assisted oxidation of the polyphenols naturally occurring in wheat bran. During refrigerated storage the oxidation reaction can cause the bran particles to become dark brown or black in colour. The larger the size of the bran particles, the more evident the dark spots will appear. If the bran is finely divided then the paste may assume a grey, almost dirty appearance. The oxidation reaction will continue as long as the products are held in refrigerated storage. The same problem can occur with both savoury and sweet pastes and can also be a problem with puff pastry stored under refrigerated conditions (BPS, p. 132). Reference
and YOUNG, L.S. (2001) Baking Problems Solved, Woodhead Publishing Ltd, Cambridge, UK.
CAUVAIN, S.P.