The malt process
Malting is the controlled germination of cereals, followed by
a termination of this natural process by the application of heat.
Further heat is then applied to ‘kiln’ the grain and
produce the required flavour and colour. A basic rule is that for
malt to be made, the barley must be capable of germination, so
maltsters' source their barley with a minimum germination of 98%.
If you look at the picture to the right of the page, you will see
the following processes:
Step1 before steeping
Step 2 after steeping with the root chit just showing.
Step 3 with germination almost completed, showing the
green malt with its longer root growth.
A simple way to consider it is that a barley kernel is composed
of three parts:
a) The embryo, or germ, which will eventually grow into the
roots and shoots of the new plant.
b) The endosperm, comprising of hard insoluble starch, which
is the food reserve to be used by the growing germ of the grain.
The embryo produces enzymes which travel into the starch, breaking
down the starch walls and changing the condition of the starch
from insoluble to soluble. This change is called the "modification" of
the barley corn. The process must be controlled by the maltster,
otherwise the enzymic conversion will continue, and the soluble
stach will be further converted to sugars, to feed the growing
barley plant. This must be avoided, to prevent loss of useful
brewing extract.
c) The husk, formed by two overlapping halves, which cover the
grain surface, to protect the germ and endosperm.
The maltster's task is to get the endosperm modification to
a certain point, and then stop the process, "locking it
up" by the use of heat. The brewer will then "unlock" the
process when he mashes his milled malt, and completes the conversion
to sugars which will feed the yeast to produce alcohol, whilst
other characteristics in the malt produce strong contributions
to the quality of the final beer.
It is very likely that malting, as part of a brewing operation,
was the first use of biotechnology by man. The development of
brewing cannot be factually dated, but it is likely that the
earliest process was the fermentation of raw grain, an accidental
discovery. The next discovery was likely to have been the use
of bread to produce a fermentable drink. Dr Briggs in "Malts
and Malting" cites a Sumerian reference to kilning malt
for brewing, which has been dated to around 2500 BC. We can therefore
be reasonable sure that some form of malting was in use four
thousand five hundred years ago, and that the basic process is
relatively unchanged.
Although the use of the natural process of change within the
grain, which is the basis of malting, has a very long history,
only in the last fifty years have maltsters' gradually taken
complete control.
That change has been brought about by the breeding and selection
of the barleys best suited to produce malt, the knowledge of
the physical and chemical changes that take place during the
malting process, and the development of techniques for their
most effective control.
The modern maltster is able to source the correct malting barley,
and with a skilful use of water, air, heat and time can produce
a wide range of malts which can differ in flavour, colour and
many other parameters as specified by the maltster's customer.
In the UK most of the grain used for malting is barley, but
a small quantity of wheat is also malted for specific purposes.
For the purpose of this explanatory note all references will
be to the malting of barley.
The above description of the malt process is reproduced by courtesy
of MAGB from their web site at www.ukmalt.com
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