According to K. Lintner, the worst features of the present system of
malting are the inequalities of water and temperature in the heaps and
the irregular supplies of oxygen to, and removal of carbonic acid from,
the germinating grain. The importance of the last two points is
demonstrated by the facts that, when oxygen is cut off, alcoholic
fermentation--giving rise to the well-known odor of apples--sets in in
the cells, and that in an atmosphere with 20 per cent. of carbonic acid,
germination ceases. The open pneumatic system, which consists in drawing
warm air through the heaps spread on a perforated floor, should yield
better results. All the processes are thoroughly controlled by the eye
and by the thermometer, great cleanliness is possible, and the space
requisite is only one-third of that required on the old plan. Since May,
1882, this method has been successfully worked at Puntigam, where plant
has been established sufficient for an annual output of 7,000 qrs. of
malt. The closed pneumatic system labors under the disadvantages that
from the form of the apparatus germination cannot be thoroughly
controlled, and cleanliness is very difficult to maintain, while the
supply of oxygen is, as a rule, more irregular than with the open
floors.
[Illustration: IMPROVED PNEUMATIC FILTERING PRESSES.]
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