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ON THE DECORTICATION OF CEREALS. 
four hours, the mixture had not become in the least coloured, proving, as I think, that 
the action of Ure’s test for pyroxylic spirit depends on the presence of one or other of the 
impurities usually existing in wood naphtha, and not on any power which the alkali 
possesses of decomposing the methylic alcohol itself. 
ON THE DECORTICATION OF CEREALS. 
What is understood by the decortication of grain ? It is a system by which the exte¬ 
rior envelope is taken off, so that there remains only the kernel of flour ; in other words, 
decortication does to the grain what most persons do to fine fruit before eating, namely, 
they peel it, in order that the bitterness or coarseness of the skin may not diminish the 
flavour and goodness of that which is within. 
Thus, decorticated grain is without the bitterness which the skin communicates, whe¬ 
ther it be for making bread or for distillation; in fact, any one who has not tasted bread 
made from decorticated corn does not know the natural taste of wheat flour. 
Corn is the most valuable of the farinaceous foods of man, and it is important to know 
if the flour of old corn can be improved by decortication. Look, then, to the structure 
of a grain of corn, beginning from the outside. We find a gummy and resinous pellicle 
in order to protect the grain, at the same time not stopping the power of absorption, 
and it is easy to understand that this pellicle easily gets discoloured and charged with 
dust that must impart a bad taste ; after this pellicle there is a thinner skin, distilling the 
air and nourishing the kernel as through a thin veil. There is a third envelope, formed 
of impalpable dust, which acts as a sponge, absorbing the damp and stopping putrefaction, 
and giving a longer life to the kernel. These three envelopes form the brans, and un¬ 
der these three there is a thin skin, called in science “ testa.” This skin sticks to the 
floury kernel, and surrounds it like a cuirass, and the object of the decorticator is to take 
off this cuirass, and strip it completely without injuring it. 
After the testa we come to the germ of the grain, which surrounds the kernel like a 
crown, enlarging it towards the embryo. This is the flour par excellence. Then come 
the particles the most glutinous, then the centre. 
One can understand that in completely taking off the three brans of old wheat, or of 
Egyptian wheat, before grinding, the flour will necessarily be better. If the three brans 
be preserved separately, the inner one will be found in the form of a fine, black, bitter, 
bad-smelling dust. 
What advantages, then, are to be obtained by decortication ?—The answer is 10 per 
cent, increase in quantity of flour (at least upon wheat), and from 12 to 15 per cent, in 
barley and oats, and at the same time a finer colour and a better taste. The next ques¬ 
tion which arises is, “ Ought the grinding of decorticated grain to be done in the same 
manner as undecorticated grain?” The answer is, “No.” Having shown that the finest 
flour for taste and nourishment adheres to the skin, the grain must be pulverized to detach 
this flour from its envelope. You must then grind as fine as possible, so as not to heat 
the flour, then dress through a dressing machine, of which the coarsest silk will not let 
through more than the third or fourth degree of fineness,—thus you will obtain 80 per 
cent, of the weight of corn; then you will either regrind or redress the remainder, so as 
to have 90 parts of flour from 100 parts of the corn decorticated. The 90 parts of flour 
will make a delicious and nourishing bread. 
As to decortication in a hygienic point of view, the flour of decorticated corn at 90 per 
cent, is more nutritious than ordinarily ground corn at 78 or 80. All the chemists (in 
France) who have analysed and compared flour from decorticated and undecorticated corn, 
find 5 and 6 per cent, more gluten in the former than in the latter. The formation of 
the grain shows us that it must be so. In grinding undecorticated grain, to prevent the 
third bran from spoiling the colour of the flour, the stones are put so far apart that a 
large portion of the flour is suffered to escape in the brans, and we have seen that the 
exterior flour is richest in gluten and in phosphoric principles. 
As in the ordinary millering, the greater part of this excellent flour is left in the bran, 
so flour from undecorticated corn extracting 78 to 80 per cent, of the weight of the corn, 
is inferior in nourishment and in flavour to the flour of decorticated com extracting 90 
per cent, of the natural weight of the corn. 
