THE BAKERS GUIDE

they invert the order of the rotatory action of the original cane sugar. (See polarization^)

A short description of the manufacture of sugar will be useful knowledge in helping us to understand more about this impor- tant member of our raw material family. There are four pro- cesses in the preparation of the ordinary commercial sugar — extraction of the juice, clarification and defecation, refin- ing, and crystallization. The sugar exists in the cells in a state of solution in the fluid which constitutes the juice or sap of the plant; this juice is extracted by pressure, by mill or press. This crude juice contains, besides sugar, water, earthy insoluble matter, albumen, wax, soluble colouring matter, and soluble salts. To prevent fermentation, the defecation process follows as quickly as possible after the expression of the juice. This is by defecating the juice with slaked lime or mono-sulphite of lime made into a cream, and added until the acids, acetic and lactic, in the sugar have been neutralized, then heat is applied, and when the process is com- pleted (first by filtration and then by defecation) the juice is tapped off, and is then refined by allowing it to percolate through animal charcoal, which cleanses it from the colouring and other soluble organic matter. It is then evaporated by means of a vacuum pan, and caused to separate into crystals ; the mother liquor that is left is drained off. When large grains are wanted for the market in the form of white crystals, the mass is put into a revolving perforated basket and the centrifugal force due to rotation forces the loose syrup through perforations, while the large solid grains remain behind.

The first running of syrup from the first crop of crystals is reboiled and sometimes refiltered through the charcoal, and more crystals are formed, and this is carried on through second and third or more runnings, until the last syrup is so poor in sugar that difficulty is found in getting it to crystallize any more, and this final residue is the treacle and syrup of commerce.

This is a rough outline of a process (there are several modifi- cations) much more complicated than roller flour milling, and I have touched upon it chiefly for the purpose of pointing out that every succeeding formation after the first and second must be of a weaker and lower grade, and with the near approach to a certainty of there being some glucose in it, because after the length of time the operation has been in progress inversion will be caused by something, and whenever glucose is present the sugar is weaker in saccharine, and will also more easily decompose when being made up into goods, and the further also that these processes are carried on the more certainty there is of discolourizing by con- tact with vessels in which it is carried on. These lower grades