1. Pressure. 2. Centrifugal power. 3. Dialysis.
1. Pressure. The roots being put into a proper crushing machine are soon reduced to an uniform pulp, which in some manufactories is subjected to pressure wrapped in linen cloths under stone or iron rollers, and in others is placed in bags and placed under the Bramah or hydraulic press, the resulting juice being collected in proper receptacles.
2. Centrifugal power. This method is that generally employed for separating the juice from the pulp, which thus yields between 50 or 60 per cent. of juice. A weak saccharine solution, also used in sugar manufacture, is afterwards obtained by mixing the residue of the pulp with water, and subjecting it to the same process.
3. Dialysis. The application of the principle of diffusion for the extraction of the sugar from the beet-root originated with M. Robert. The fresh roots, cut into thin slices, are immersed in a little more than their own weight of water heated to about 120° F. The crystalloid sugar thus diffuses out through the cell membrane which encloses it into the surrounding water, leaving the pectous and colloid matters, such as albumen, gum, &c., behind. The operation which is so managed as to bring the same water into contact with successive quantities of root, yields a saccharine solution of nearly the same strength as the natural juice. The solution so obtained is, after concentration and the usual methods, converted into sugar. The same process is said to have been tried with cane sugar, and with equally satisfactory results.
The succeeding stages of the manufacture of beet sugar, such as refining, liming, decolorising, &c., are the same as those already described under cane sugar.
Beet sugar is in every respect identical with cane. It was discovered in 1747 by Marggraf, of Berlin, but it did not come into use until about the beginning of the present
century, its manufacture at this period in France being necessitated by an edict of the first Napoleon’s, which prohibited the importation of cane sugar into that country.
The engraving represents a vacuum pan much used in the French sugar refineries.
Fig. 1 gives a perspective, and fig. 2 a sectional view of this evaporating pan.
