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It is important to understand the functions of ingredients used in a dough, in order to comprehend the process of yeast baking.
YEAST
Yeast is a living organism. In the presence of warmth
and the addition of sugar and moisture the yeast will grow and produce
carbon dioxide, which acts as a raising agent. The dough then rises, ensuring
that the final product is light in texture. During the baking process the
gas escapes and the shape of the loaf is retained.
FLOUR
Wheat flour is normally used, although other types of
grain flours such as rye, buckwheat, oats and barley may also be used.
These types of grain have less gluten and it is therefore essential to
add a percentage of wheat flour which has a higher gluten content. Gluten
is an elastic substance found in wheat flour and through kneading, the
gluten develops to form a framework around the carbon dioxide; which helps
the product to hold its shape.
Types of Wheat Flour:
CAKE FLOUR is the whitest, most refined flour available and produces a light, fine bake.
WHITE BREAD FLOUR is light and creamy in colour due to the small percentage of bran present. This flour is generally used in most types of white bread.
BROWN BREAD FLOUR or sifted meal provides the same volume and texture as that of white bread flour. The colour however, is darker due to a higher percentage of bran.
WHOLEWHEAT FLOUR contains practically all the bran
and wheat germ present in the wheat grain. This bread is naturally coarse,
heavy and dark in colour. For a finer and lighter texture, substitute half
of the wholewheat flour with cake or bread flour.
LIQUID
The liquid should be 400C, or body temperature. It is
most important that you prepare the lukewarm water correctly. The above
temperature is obtained by adding one part boiling water to two parts of
cold water. Cold liquid slows the growth of yeast down, whilst too hot
liquid destroys the yeast cells. The amount of liquid used, is determined
by the type of flour and the natural moisture of the flour. Too little
liquid prevents the gluten from stretching and produces a smaller baked
product which stales rapidly. It is difficult to state the correct amount
of liquid, as the amount and quality of the gluten in flour is not always
the same. The absorption ability of the flour is also affected by temperature
and humidity. A mixture of milk and water can be used to increase the nutritional
value and enhance the taste and texture of the product. Milk should be
scalded to lukewarm, before it is added.
SALT
Salt controls the fermentation process, improves the
flavour and strengthen the gluten in the flour. Yeast is destroyed by direct
contact with salt and spices. This can be prevented by first mixing these
ingredients with the flour, before adding the yeast. The general ratio
is 2ml yeast for 250ml flour.
EGGS
Eggs are mainly used in sweet bakes. They contribute
to a finer texture, rich colour and additional flavour. In most cases eggs
may be substituted with oil, without affecting the taste. In the case of
a rich cake dough, the addition of oil can possibly produce a dry textured
product. Egg yolk makes the gluten more pliant, ensuring a better texture.
It is standard to use "large" eggs when baking.
Salt controls the fermentation process, improves the flavour
and strengthens the gluten in the flour. Yeast is destroyed by direct contact
with salt and spices. This can be prevented by first mixing these ingredients
with the flour, before adding the yeast. The general ratio of salt is 2
ml to 250 ml flour.
SUGAR
A small amount of sugar is a good source of food for
the yeast. It sweetens the dough and gives an attractive brown crust. Too
much sugar will, however, retard the growth of yeast. Avoid direct contact
of yeast with sugar, as the fermentation process will take place more quickly
than desired.
FATS
All types of shortening, such as butter, margarine and
oil contribute to the flavour and keeping quality of a bread. A moderate
quantity increases the elasticity of the dough and produces baked products
which are greater in volume. As a high quantity of fat retards the development
of gluten, it is advisable to knead the fat into the dough only after the
dough has been made. For better results, butter and margarine of a firm
texture are recommended. Lard gives a soft crust with a light texture,
whilst oil not only gives a fine texture and thin crust, but also prevents
the bread from crumbling when it is sliced.
OTHER
Ingredients such as dried fruit and cheese, cause a heavy
dough. This dough takes longer to rise and requires more yeast in proportion
to the quantity of flour. Cheese and fruit must always be added after the
first rising period, whereafter, the dough can be shaped as desired.
IMPROVERS
To speed up the rising process Vitamin C (Ascorbic Acid),
can be added. It is available in tablet form from most pharmacies. Dissolve
125 mg Vitamin C (Ascorbic Acid), in a little of the prescribed liquid.
This should be sufficient for 1kg flour.