Barley is the grain generally chosen for producing malt, although
others may be used. It is first soaked in cold water till it is
softened; it is then spread out about two feet thick on the floor of
the malt-house, where it begins to germinate, in the same manner as
if sown in the earth; this is allowed to go on so far only till the
first part of the root and stem make their appearance, in the form
of a little bud and a fibre. During germination the malt gives out
a poisonous gas called “carbonic acid,” and becomes warm, in fact it
would become too warm and be injured, but it is kept stirred by means
of wooden shovels from time to time, and the temperature ascertained
by means of a thermometer. As the process of germination goes on,
all the starchy matter naturally contained in the grain becomes
changed into sugar, and the malt, when made, has a sweetish taste.
As soon as the germination has proceeded to a certain extent it is
stopped by drying; for this purpose the malt is put into a kiln and
heated almost to scorching--if but slightly, it is called pale malt
or “amber,” if more, “brown malt” or roasted malt. Malt, if kept
dry, will remain a long time unchanged. It is used for producing
beer and vinegar, and for “wash,” from which all the raw spirit used
in England is distilled. Whiskey is also distilled in Scotland and
Ireland from malt.
Malt has the property of converting the starch of barley unmalted
into sugar while in contact with it. For example, if barley were
ground and boiling water poured on it, it would form a thick sort
of paste, which is because it contains starch only; while malt
treated in the same way, sinks to the bottom, and leaves a clear
limpid “wort,” which can be strained off, because the starch is
changed into sugar, which is soluble. Now, if equal parts of malt
and ground barley be also treated in the same way, the malt very
shortly converts the starch of the barley into sugar, and the result
is the same as if all had been malt. This was once a matter of great
importance to the brewers, who thereby saved the heavy duty imposed
upon malt.