As now developed, the processes of making sugar from sorghum are as
follows:
_First_, The topped cane is delivered at the factory by the farmers
who can grow it.
_Second_, The cane is cut by a machine into pieces about one and a
quarter inches long.
_Third_, The leaves and sheaths are separated from the cut cane by
fanning mills.
_Fourth_, The cleaned cane is cut into fine bits called chips.
_Fifth_, The chips are placed in iron tanks, and the sugar
"diffused," soaked out with hot water.
_Sixth_, The juice obtained by diffusion has its acids nearly or
quite neutralized with milk of lime, and is heated and skimmed.
_Seventh_, The defecated or clarified juice is boiled to a
semi-sirup in vacuum pans.
_Eighth_, The semi-sirup is boiled "to grain" in a high vacuum in
the "strike pan."
_Ninth_, The mixture of sugar and molasses from the strike pan is
passed through a mixing machine into centrifugal machines which
throw out the molasses and retain the sugar.
The process of the formation of sugar in the cane is not fully
determined, but analyses of canes made at different stages of growth
show that the sap of growing cane contains a soluble substance having a
composition and giving reactions similar to starch. As maturity
approaches, grape sugar is also found in the juice. A further advance
toward maturity discloses cane sugar with the other substances, and at
full maturity perfect canes contain much cane sugar and little grape
sugar and starchy matter.
In sweet fruits the change from grape sugar to cane sugar does not take
place, or takes place but sparingly. The grape sugar is very sweet,
however.
Cane sugar, called also sucrose or crystallizable sugar, when in dilute
solution is changed very readily into grape sugar or glucose, a
substance which is much more difficult than cane sugar to crystallize.
This change, called inversion, takes place in over-ripe canes. It sets
in very soon after cutting in any cane during warm weather; it occurs in
cane which has been injured by blowing down, or by insects, or by frost,
and it probably occurs in cane which takes a second growth after nearly
or quite reaching maturity.
To insure a successful outcome from the operations of the factory, the
cane must be so planted, cultivated and matured as to make the sugar in
its juice. It must be delivered to the factory very soon after cutting,
and it must be taken care of before the season of heavy frosts.