BREAD
Good food needs good bread and to make good bread
one needs to understand the components (ingredients) that are used in bread
making, and their functions. The basic ingredients are Flour, Salt, Yeast and
Water.
Before we go on to discuss the different components of bread, let us
first list the different types of dough.
Bulk Fermented Dough: This is the process that most bakers use to
prepare bread. Flour and salt are blended with yeast and water and mixed to
smooth clear dough. The dough is then covered to prevent drying out and a skin
forming, and then giving a period of bulk fermentation. Here all the
ingredients are mixed at once and allowed to ferment. The dough is then knocked
back (de gassed) after about two thirds of the fermentation has taken place and
then kneaded to encourage further yeast activity. In addition, to equalize the
dough temperature. When the fermentation is complete, the dough is weighed off
into loafs/rolls. The total fermentation can vary from one to twelve hours,
depending on the recipe.
No Time Dough: This process speeds up the fermentation process by
adding an improver that contains chemicals that would naturally be produced by
fermentation, given a little more time. Flour, Yeast, Salt and water with the
improver are blended into a dough, but the mixing is continued for almost
double the time. Until the gluten is developed sufficiently. It is preferable
to use a machine rather than mixing by hand. When mixing is complete, the dough
is ready for scaling (weighing). A little extra yeast is added in recipes using
improvers, as the quick fermentation does not allow the yeast to grow to its
normal levels. As this process does not allow time for the gluten to mellow
properly, about 4% extra water must be added to compensate. The extra water
will increase the yield, which should pay for the improver. No time dough is
ideal for those kitchens with limited time, space and facilities. Improvers
also assist prolonged quality maintenance. Improvers also help make reasonable
quality bread that has less gluten (weak flour)
Ferment and Dough: This process is meant for heavily enriched
dough’s, to allow yeast to become accustomed to the high amount of fat and
sugar, which have been added, and which will slow yeast activity. In the first
stage, the ferment yeast is blended into a thin batter and fermented with about
20% of the flour mentioned in the recipe and with all the water. Fermentation
depends on the yeast content. It is best fermented in a prover or in similar
conditions. The first ferment is then blended with the rest of the flour, salt,
fat and perhaps milk powder to form a dough. This is the second or the dough
stage and is bulk fermented for roughly the same time as the ferment. The dough
can then be scaled.
TEMPERATURE
It is important to maintain the ideal dough temperature, which controls
the speed of fermentation. Even for basic bread dough, it is necessary to be
exact to get the best from the raw material. The best temperature for
fermentation is between 25°C and 28°C. Above 32°C, fermentation is
rapid but gets progressively weaker. Under 24°C, fermentation is
slow. As water temperature can be readjusted, it is the medium that controls
the temperature of the dough, determines the water temperature and the rule of
thumb is the doubling method. Double the required dough temperature, take the
temperature of the flour and subtract that from the above number. The result is
the required water temperature. If the dough is required at 28°C, and the flour
temperature is 18°C, then 2x28=56, 56-18=38. Therefore
the water temperature should be 38°C. Water is
essential to bread making to hydrate the insoluble wheat portions forming
gluten. Dissolve the salt, sugar and soluble proteins and form an elastic
dough. Water has a marked effect on the speed of fermentation – a thin batter
fermenting faster than a tight dough. The water content in dough will vary
according to the water Absorption Powers (WAP) of various flours.
THE COMPONENTS
SALT – good bread needs salt to offset the blandness and bring out the
flavors present. It is also necessary to stabilize the gluten, help retain the
moisture and control the fermenting yeast, which in turn will affect the crumb
or texture of bread and the crust color. Fermentation is too rapid in dough
with too little salt, which checks the growth of yeast so more sugar is
converted to gas. Because the gluten is also weakened, it offers less
resistance to the gas expansion, leaving too much volume and loose crumb
texture. The bread lacks brightness and the flavor is insipid. Too much salt seriously
retards yeast activity. Excessive amounts will stop fermentation. With the
yeast activity slowed down, there is a corresponding of the tightening of the
gluten resulting in a smaller volume. At worst, the result is a heavy, rubber
like mass with a taste of excessive salt.
YEAST – is a living organism of the fungal family of plants, which
changes sugar into CO2 (carbon di oxide), alcohol and other by-products. The
gas is caught up in the gluten network, which aerates the dough. The second
function of yeast, equally vital to producing quality bread, is to assist the
ripening or mellowing of the gluten in the dough, so that when the item is
baked, the gluten is in a condition, which gives evenly to the expanding gases
and at the same time retains them (gases). For fermentation to occur, yeast
needs a source of glucose (a simple sugar). Small amounts of glucose and
fructose in the dough are fermented directly by the yeast. Other sugars and
carbohydrates are converted to glucose by enzymes in the flour. Yeast must be
in a good condition to work efficiently. It should be cool to the touch and a
creamy color. If it is dark ad of a soft sticky consistency, with an unpleasant
odor, then it should not be used. Small quantities can be kept pressed into a
small bar and stored in a cool place. Yeast works best between 25C and 28C.
Above this, the fermentation is rapid but gets progressively weaker as the
temperature increases until 55C to 60C, when yeast is killed. Between 23C and
25C, yeast works slowly, till at 25C, fermentation stops. It should never be
mixed with dry salt or sugar or dispensed in a strong solution of either, which
will kill the yeast. As a living organism, it can never be dissolved in liquid.
FLOUR - there are two basic types of flour used for bread making, whole
meal and strong white flour. Whole meal flour contains whole-wheat grains, with
nothing added or taken away during processing, Strong with flour has higher
protein content and therefore more gluten than soft cake flour. Whole meal flours
have a higher water absorption rate than white flours so the dough may be
stickier. Extra enzymes in the bran coating of the grain speed up the dough
ripening so the dough temperature should be a little cooler to slow down the
fermentation. Because the physical and chemical changes in the dough are more
rapid, whole meal dough needs shorter fermentation.
GLUTEN - Without gluten in the dough, there could be no bread. Gluten is
developed in bread during the manipulation (mixing) of the dough, when two proteins
– glutenin and gliadin combine in the presence of moisture (water) to form
gluten. Gluten strands traps the gas generated by the yeast and holds it in the
dough structure. When it coagulates, it becomes the framework of the dough, so
that it does not collapse. Gluten is conditioned by many factors including the
amount of yeast and how active it is, the amount of salt and water in the
dough, fermentation time, dough temperature, the acidity of the dough and
manipulation (kneading). Given good material and correct balance, nothing
contributes to good bread making than properly made dough. The kneading,
fermentation and the knocking back are also important. Proper mixing gives
gluten the opportunity to absorb the maximum water and become thoroughly hydrated.
IMPROVERS - contain chemicals, which would be produced in dough naturally,
given time, under the skilled eye of the baker. The are used in no Time dough,
1 to 1 1/2 % for rich dough and 2½% in leaner dough. For basic bread goods 2%
improver are added to the flour, water salt and yeast, and is calculated on the
basis of the flour only. For dough that is enriched with fat and sugar and
eggs, 1 to 1 1/2% is enough. The active ingredients in a typical improver would
include sugar, pure emulsifier, soya or guar flour, ascorbic acid (vitamin C)
and enzyme active malt flour.
RETARDATION
Retardation is the arresting of fermentation at
temperatures between 2°C and 4°C. It enables the dough to be made in bulk,
retarded and then baked through the day as and when required. This ensures
freshness and standard quality. Enriched dough which ferments slowly, retard
the best and can be kept for up to 72 hours. Retardation can be done in two
ways: the dough is given between 50-70% of its Bulk Fermentation
Time (BFT), then rolled out in 3 kgs-4kgs pieces to quickly take out its heat,
and then refrigerated. In the second method, the dough is again given 50-70% of
its BFT and then made into pieces, refrigerated and then kneaded, and then
brought back to room temperature. The final proving should not be forced. The
dough should be cooled before retarding as a high temperature will extend
fermentation before retardation is effective. To avoid crusting of the dough,
it should be kept in the refrigerator at 75% humidity or in polythene bags.
DOUGH ENRICHMENT
Dough is sometimes enriched with fat, milk or egg
yolks, to increase the food value, add to the taste and flavour, and to produce
a softer crumb (texture) and also to retard staling. Salt will have to be
reduced when using salted butter. Fermentation is slower in enriched dough, so
the dough should be kept a little softer and for a slightly longer time.
POINTS TO NOTE
- Take careful note of the formula/recipe and the method,
- See that the scales are accurate and the scale pans are clean.
- Carefully weigh the flour, sieve it, and take temperature,
- Calculate water temperature and measure.
- - Disperse yeast in a little water, add salt in the rest of the water and add to the flour,
- Mix thoroughly until clear and elastic.
- -Take the dough temperature and cover the dough to prevent skin formation. - Prove in a place at the correct temperature or in the prover.
- Knock back when proved according to the BFT.
- Prove rolls in the prover or at controlled temperature and humidity.
- Cover with greased polythene sheet to prevent skin formation
- Egg/starch wash and cutting is best done when the dough is ¾ proved.
- Rolls are baked at 230°C with steam.
STEPS IN BREAD MAKING OPERATIONS
SELECTION AND
WEIGHING OF RAW MATERIAL: To start with, the ingredients should be
correctly scaled and weighed as per a good recipe. Baking is a science, it is
essential to begin correctly with the right ingredients in the correct
proportions.
FERMENTATION: the dough should be fermented for the
proper length of time, during which the yeast cells act on the sugars and
produce carbon dioxide and alcohol. A number of physical and chemical changes
take place during this time.
Physical changes include:
steady increase in the volume of the dough and can be up to five times
its original volume
increase in temperature by about 5°C to 6°C
Increase in the number of yeast cells by about 26% in straight dough and
56% in sponge dough.
Loss of moisture
Change in the consistency of the dough – it becomes soft, elastic and
extensible
Chemical changes include:
the PH of the dough reduces from 5.5 to 4.7 due to the production of
acetic acid, lactic acid, sulphuric acid and hydrochloric acid
formation of maltose by diastatic enzymes by acting on starch
production of carbon dioxide and alcohol by enzymatic reactions
Mellowing of the gluten by proteolytic enzymes present in the flour and
yeast.
Fermentation time will depend on:
type of flour
quantity of the yeast
temperature of the dough
presence of yeast food (sugar)
FERMENTATION CONTROL
It is important to control the fermentation so that the gas production
and the gas retention coincide as closely as possible. If the peak of gas
production in the dough is reached before its gas retention capacity is at a
maximum, then much of the gas will be dissipated and not enough will be left to
aerate the dough when its extensibility is at its highest point. On the other
hand if the dough reaches its optimum gas retention capacity before gas
production is at its highest rate, much of the gas will be lost subsequently.
Hence, fermentation control is important to have the development of gas
production and gas retention capacities at a parallel and even rate.
GAS PRODUCTION:
Gas production will increase with:
addition of malt and sugar
the increase of yeast concentration
the presence of yeast food
high temperature of the dough (35°C)
Gas production decreases with:
addition of salt
excess amounts of yeast foods
higher temperature of the dough (above 35°C)
GAS RETENTION
Gas retention is governed by chemical and physical factors such as
minerals, moisture, PH, proteolytic enzymes and oxidising agents, mixing, dough
expansion, punching (knocking back).
FERMENTATION LOSSES
The weight loss in fermented dough is in the range of 0.5 to 4%.
However, under average conditions it is 1%. The loss in weight is normally
attributed to the loss in moisture, which depends on the temperature and the
relative humidity. Minor loss may be attributed to the escape of carbon
dioxide.
KNOCK BACK
Punching of the dough in between fermentation periods:
increases the gas retention of the dough
Equalises the temperature throughout the dough and ensures more even
fermentation.
Reduces the retarding effect of excessive accumulation of carbon dioxide
Introduces atmospheric oxygen and stimulates yeast activity
Aids the mechanical development of gluten by the stretching and folding
actions
The first punch is normally given when 60% of the fermentation is
complete and the second punch is given in half the time required for the first
punch.
DIVIDING , ROUNDING AND MOULDING
The function of dough make up is to transform the dough into properly
scaled and moulded dough pieces, which after prooving and baking will yield the
desired bread. The operations involved include:
Scaling (dividing): the dough is divided into individual pieces of pre
determined uniform weight and size. The weight of the dough depends on the
final weight of the dough. Generally, 12% extra dough is weighted to compensate
for the baking losses. Dividing should be performed in the minimum amount of time
to ensure even weight as the dough is scaled on volumetric basis. Longer time
changes the density of the dough due to production of carbon dioxide by yeast,
thereby changing the weight of the divided dough. If there is delay n dividing,
corrective steps such as de gassing the dough or increasing the size of the
dough should be taken. The de gassers are essentially dough pumps which fed the
dough into the hopper and in the process remove most of the gas. The advantage
of using de gassers are:
more uniform scaling
Uniform texture and grain of the bread.
Rounding The dough pieces, which had lost a good part of the gas during the
dividing, is irregular in shape and sticky with perhaps cut surfaces. The
function of the rounding (using a rounder), is to impart a new continuous skin
that will retain the gas as well as reduce the stickiness.
Intermediate Proof: Dough that has undergone dividing and rounding
operations has lost much gas, lacks extensibility and will tear easily. It is
rubbery and will not mould properly. To restore a more flexible and pliable
structure, which will respond well to the manipulations of the moulder, it is
necessary to let the dough rest while the fermentation continues.
Moulding: The dough is now moulded into the required shapes.
FINAL PROOF
The purpose of the final proof is to relax the dough from the stress
received during the moulding operations and to facilitate the production of gas
in order to give volume to the loaf. It also changes the tough gluten to a
good, mellow and extensible character.
BAKING
It is the most important step in bread making and the heat transforms
the unpalatable dough into a light porous readily digestible and flavoured
product. The factors that influence the quality of baked products are the
baking temperature, humidity and the duration of baking (baking time). There
are two types of changes that take place during baking.
Physical Changes:
Film Formation: when the dough is placed in the oven, the effect of heat is the
instantaneous formation of a thin expandable surface film. The length of the
time that the film remains expandable depends on the temperature and the
moisture conditions of the oven.
Oven Spring: Sudden expansion of the dough volume by about 1/3rd of
its original size in the oven is called oven spring. In short, it is the
difference in height of the product, before and after baking. The dough piece
containing millions of minute gas cells, under the influence of heat, begins to
expand. As the pressure in the gas cells increases and causes expansion of cell
walls, the carbon dioxide generated by yeast in the dough is liberated at about
50°C. the freed gas increases the pressure in the gas cells causing
expansion of the dough. The evaporation of alcohol and other low boiling point
liquid increases the gas pressure, leading to an additional expansion of gas
cells.
Chemical changes:
Yeast Activity: the yeast in the dough will generate carbon dioxide and alcohol with
the rate of generation increasing the temperature until the thermal death point
of yeast (60°C) is reached.
Starch Gelatinization: the oven spring due to the softening of gluten in
the early stages of baking is counter acted by the starch swelling which begins
at about 54C. The degree of gelatinizaton is restricted by the limited
availability of water.
Gluten Coagulation: Starch geltinization is associated with water
absorption resulting in the removal of water in gluten as it denatures, Gluten
coagulation sets in at about 74°C and continues till the end of
baking. In this process, gluten is transformed into a semi-rigid cell
structure. The major change that takes place during baking is the re
distribution of water from gluten phase to starch phase.
Bread faults
A good bread should be judged by its volume, bloom, shape, color,
texture, sheen, moistness and flavor. In general, one should examine the
external area and the internal (crumb) area of the bread.
Bread faults can arise from many causes. Flour varies in grade, in
gluten content and quality. Color also varies and so does the maltose content.
When examining the faults in the loaf of bread, the temperature and timings,
methods of manipulation, addition of materials, errors in setting and timing of
machinery, all must be taken into account.
EXTERNAL FAULTS
Lack of volume: The major causes of this fault are
a dough that is too tight and with too little yeast
- Too much salt will
cause under ripening, conducive to small volume.
- Flour with low
maltose will produce bread of less than normal volume. Over bleached flour or
the excess use of chemical improvers, will also produce this fault.
2. Excessive volume:
Dough with
- low salt content
- excess final proof
- loose moulding
will produce a bread of excessive volume
Excess salt decreases the stability of gluten. An excessively slack
dough also produces a bread with excess volume. This can be adjusted by
altering the proving time. A cool oven causes fermentation to continue in the
oven. Therefore there will be too much oven spring
3.Lack of Crust Color: Baking the bread in a cool oven renders the loaf
colorless. The other causes for lack of crust color may be:
- over ripe dough,
due to extended fermentation period (all the sugar is used up)
- excess water
content
- lack of maltose
- lack of salt
1. Excess Crust
Color: The likely causes are
- insufficient
fermentation
- excessive use of
sugar
- flour might have
been milled from sprouted wheat (partially)
- baking too quickly
and at too high a temperature
2. Shell Tops: This is due to
the formation of a crust on top of the loaf before maximum expansion has taken
place. The pressure from within the loaf exerts itself in such a way that the
top of the loaf lifts in the form of a lid.
3. Rough Surfaces: The crust of over
fermented dough is always rough. Use less yeast. Bad molding can also cause
unsightly crust surfaces.
4. Collapsing Bread: Collapsing bread
is caused by insufficient tensile strength of the dough. Such dough is mainly
due to too much water, malt or gluten improvers. Other causes could be
- over proving
- baking in cold oven
- Disturbance of the
dough before entering the oven.
Extraneous matter that may have been an accident, can lodge itself in
the mass of the dough. However there can be no excuse for dark smears caused by
dirty tin grease, finger marks or the dirt from unclean racks and boxes
INTERNAL FAULTS
1. Holes in the crumb:
A dough made from flour weak in gluten, especially when the yeast content is
high, will cause holes, because the gluten has little power of gas retention
and the weaker cells will break down during baking. Faulty manipulation after
bulk fermentation destroys the elasticity of the gluten and therefore the
expansion does not proceed evenly, breakage occurs and large holes are formed
in the mass.
2. Cores Seams Streaks
and Condensation Marks: The most common cause for cores is the incorporation of pellets or
hard flour or dough particles. Another common cause is the turning in of a dry
skin when moulding. Slight over proving or over malting often cause a core near
the bottom of the loaf.
Seams are dense layers
of inedible bread. He careless causes them handling when loading. Movement
of the dough in the oven during baking makes the
delicate dough structure tremble and collapse sufficiently to form a seam or a
heavy uncooked layer.
Streaks are evidence of uneven
manipulation of the dough in the final stages. Loose moulding and insufficient
final proof are also causes of streaks. Dark streaks are also caused by high
maltose flour.
Condensation marks are due to improper packing.
3. Damp Clammy or
Close Crunch:
The common causes are:
- Use of high maltose
flour, milled from sprouted wheat.
- Overloading the
dough with enriching agents
- Use of very weak
flour
- Over machining the
dough
- Wrapping the bread
prematurel
- Development of
a ropy condition
4. Crumbliness: A
slack dough will produce crumbly bread. Crumbliness is related to the degree of
fermentation. If the fermentation is insufficient, then the gluten is not
conditioned and the crumb has neither the resilience nor tensile strength
necessary to whit stand the action of cutting the loaf. Excessive mineral
improvers also cause crumbliness.
Bread Improvers
We refer to flour as being either strong or weak. The strength of flour varies
according to its strength and also according to factors such as starch content,
sugar content, the water absorption power (WAP) of the
flour and even the color. These aspects will affect the final
outcome. In order to make good bread, it is not always possible to use the
right type of flour as the availability may vary. It becomes necessary
therefore to add something to the dough in order to bring the product to a pre
determined standard. This addition should be with discretion on knowledge,
otherwise, the quality of the bread instead of improving, may actually worsen.
Bread improvers are substances, which when added to dough, enables the baker to
produce an improved loaf with better keeping qualities, finer textures, softer
crumb, added bloom and enhanced flavor.
There are three main types of bread improvers:
1. Mineral additives
2. Yeast foods
3. Enriching agents
MINERAL ADDITIVES
Mineral bread improvers are used during the milling of wheat flour. They
are commonly used by the baker during production as well. They will include:
- Perusulphates – used by the
miller at the rate of ¼ to ½ oz per 280 lbs (one sack). The perusulphates used
are pottassium and ammonium. Flour treated with perusulphates will take on more
water and an increased yield is obtained.
- Glyceral Mono
Stearate - The mono glyceral ester of stearic acid, which has remarkable
emulsifying power, is used as an emulsion stabiliser and as a crumb softener in
bread.
- Potassium Bromate – It is used by
the miller at the rate of 1 lb per sack (280 lbs). Bromate increases the
stability on the gluten to extend. Bromate has an astringent action on gluten
thereby increasing the use of water in the dough. It also increases the gas
retaining properties of the gluten, thus improving loaf volume.
- Phosphates – Acid calcium
phosphates and ammonium phosphates both have a tightening action on gluten and
since phosphates are a necessary constituent of yeast food, they are both
fermented stimulants. Acid calcium phosphate (ACP) is used at the rate of 1 lb
per sack (280lbs) which can be increased to 2 lbs per sack to inhibit the
development of rope. A phosphate is added at the rate of 8
oz per sack.
- Lime Water – Lime water was used
to retard the fermentation of the dough in hot weather climates. In addition,
it has astringent action on the gluten. As lime is alkaline, it reduces the
acidity of the dough and thus slows the rate of the fermentation. It is used at
the rate of 1 quart per sack.
- Organic acid – Organic acids
are natural constituents of fermented dough. They are added to get the dough
better conditioned. Lactic acid can be added at the rate of 8 oz per sack.
Sussinic acid is added at the rate of 2-4 oz per sack.
YEAST FOODS
Yeast foods indirectly affect the bread in a number of ways by their
effect on fermentation. Malt not only provides food directly to the yeast but
manufactures further supplies as and when needed whilst simultaneously
mellowing and softening the gluten of the flour.
There are two types of malt: diastatic and non
diastatic.
Diastatic malt add to the flavor, it increases the sugar content in the
dough and provides diastatic sugar for the fermentation process. Diastatic
enzymes also contain proolytic enzymes which modify gluten. Non Diastatic malt
serves the dual purpose of providing sugar as well as adding to the flavor.
Flour contains natural sugar. Principally, this is sucrose in varying
amounts. Normally, it is 2.5 –3%. This amount is not sufficient for
satisfactory fermentation. There must be sufficient sugar present for the
production of gas that will give the loaf the required volume and to allow for
the caramelization of the crust during baking. As sugar contains no nitrogen,
they cannot be considered complete foods for yeast, but they produce material
from which CO2 can be produced. Demerara sugar and even treacle can be used in
brown breads as they are excellent for imparting flavor and retaining color.
ENRICHING AGENTS
Enrichment is a way of increasing nutritional value of the bread along
with improvements in volume, texture and the keeping quality of the bread
Fats - Fats have a physical rather than a chemical effect on
dough. As fat is a shortening agent, it reduces toughness, thus making the
product more mellow. It is particularly valuable for use with strong flour with
a tough and harsh gluten content. Fats can be used in small quantities to give
optimum effect. Fat also increases food value. They add to the moistness in
bread thereby retarding staling. They also impart flavor to the bread.
Milk and Milk Products - Whole milk added to
dough has the effect of adding fat as well as sugar, besides calcium salts and
casein.
Eggs – The incorporation of eggs in a bread dough results in many
improvements. Egg adds to the increased volume, better texture and better oven
spring. It is economical to use as it contributes immensely to improved quality
and volume of the product.