THE MILLING PROCESS
At the mill, the wheat grain from the farmer is ground into flour. The flour
is used by bakeries to make bread and other products. The miller looks after all
the processes at the mill. Look at Introducing the
grain chain to see a video of a miller.
Using the grain
Each grain of wheat is made up of three distinct parts. First there is the
coarse outer bran layer. Inside the bran layer the grain is
made up of two main parts. The smaller part is called the germ
and the larger part is called the
endosperm. The endosperm is the starchy food store of the
grain.
During milling, the bran, wheatgerm and endosperm are separated out. Then
they can be blended to make different kinds of flour.
The milling process
Mills have been making flour for thousands of years. Flour is made in nearly
every country in the world. In the past, wheat was ground between huge
millstones in windmills or watermills but the flour was coarse. Today’s flour is
much finer because the process uses modern technology. Have a look at this
diagram.
Cleaning
When the wheat arrives at the mill it is cleaned. First it passes through
magnets and metal detectors to remove any metal. Special machines separate any
other seeds, stones or dust that may have got mixed with the wheat.
Conditioning
The wheat is also conditioned. Water is used to soften the bran, which makes
it easier to remove the floury endosperm during milling.
Gristing
The cleaned and conditioned wheat is blended with other types of wheat in a
process called gristing. This means using different types of
wheat and mixing them in different proportions to make different kinds of flour.
The gristed wheat is passed through special rollers called break
rolls. They break each grain into its three parts: wheat germ, bran and
endosperm. The three separated parts are sifted into different streams using a
series of sieves.
The endosperm particles are then passed through a series of smooth rollers (reduction
rolls) to produce white flour. White flour has had the
bran and germ removed so it makes lighter bread.
Mixing
At the end of the milling, the bran, wheatgerm and endosperm have all been
separated out. They can then be blended to make different kinds of flour.
- Wholemeal flour uses all parts of the grain mixed together.
- Brown flour contains about 85% of the original grain, but
some bran and germ have been removed.
- White flour is made from the endosperm only.
Packing
The different flours are packaged and sent to the bakeries. The flour is used
for many types of bread as well as biscuits, pies, cakes and confectionery. Some
of the wheatgerm and bran is used for animal feeds.
As well as being made from wheat, flour can be ground from other crops such
as maize or rice.
