Something about sugar

by George M. Rolph

SUGAR CANE AFFECTED BY THE SEREH, JAVA

SEEDLING CANES, JAVA

Before the outbreak of the sereh, seed for new plantations was obtained exclusively from tops of ripe cane, but when the disease became prevalent, it was found that cuttings taken from sereh-infected cane gave diseased yields, while cuttings from cane grown in districts not affected by the sereh produced cane that did not suffer so greatly from the disease. At the beginning of the trouble, cuttings from outside healthy districts were used, but as the disease spread, the demand for sound cuttings increased while the sources of supply became fewer. Finally, plantations were established in remote districts free from disease and they were carefully quarantined. Here seedlings were grown from young cane cut at full length, and in this way sound seed was obtainable at all times. Formerly, seed was only to be had in the grinding season, which frequently occasioned delays in planting. The new plan not only enabled the cane growers to stamp out the sereh, but even after the disease had been practically eradicated it was continued because of its manifest advantages.

Seedlings used for planting are cut into lengths, each having three eyes. Unhealthy stalks and any showing the presence of insect pests or fungi are culled, while the sound pieces are carefully disinfected. The seed thus prepared is placed horizontally in the furrows end-to-end and covered with earth. At first water is applied at four- or five-day intervals, afterward less frequently, until the cane has attained a considerable height. About this time the rainy monsoon sets in and further irrigation is not needed. The stalks are banked several times during the early period of growth and fertilizing accompanies the second and third banking. Until comparatively recently the fertilizer consisted of nitrogenous substances, while potash and phosphoric acid were considered of no value. The first investigations concerning fertilizers were made on rich lands that had been irrigated with river water when the wet rice crop was being grown, and the water brought with it sufficient potash and phosphates for the needs of the cane. In such cases it was shown that adding these substances to the soil was unnecessary and that nitrogen was the only element that could increase the yield of cane. Hence groundnut cakes and sulphate of ammonia were used almost entirely. It has been proved, however, by more thorough study that much ground is low in phosphates, and this fertilizer has been added with excellent results. As regards potash, the soil of Java seems to contain sufficient for cane cultivation.

When the cane leaves become sufficiently thick to shade the ground the weeds die. Borers, beetle larvae and termites are caught during the early growing period, but all labor stops with the last banking and the advent of the wet monsoon. When the wet season is over, the cane is trashed and samples of the growing cane are taken from the fields and tested in the laboratory of the factory to determine the degree of ripeness. As soon as the roads become dry enough to admit of cane-laden carts passing over them, the harvesting of the ripest cane begins. The cane is dug up by the roots, care being taken to leave as little as possible of the roots in the ground. The roots and the earth adhering to them are removed, together with the leaves and tops, and the clean cane is loaded on cars to be taken to the mill.

Formerly carts drawn by oxen and buffaloes were used to transport the cane to the factory, but the crop has grown to such proportions that cattle-drawn carts have had to give way to the rail. Today nearly every plantation has its own railroad with permanent and portable tracks, over which the cane moves in cars hauled by cattle or locomotives.

Having been unloaded at the mill, the cane is taken to the crushers on carriers. Three sets of rolls are generally used and water is sprayed on the cane before the last crushing, after which the bagasse is fed to the furnaces as fuel. The juice is strained to free it from fragments of cane and leaves, then milk of lime is added and heat applied. The heavy impurities settle at the bottom, the clear juice is drawn off and the remaining juice is separated from the foreign matter in the filter presses. Another method is to treat the juice at a low temperature with a large admixture of milk of lime, and afterward with carbonic acid or sulphurous acid until all the lime is neutralized. Then all the juice is clarified by filtration without the settling operation. Next follow evaporation, refiltering, boiling to grain and separation of the crystals from the mother liquor in centrifugal machines.

In 1903 the Java manufacturers began to make a bid for the British Indian trade. After some experimenting they succeeded in producing an almost-white raw sugar, which at once found favor in India, where sugar refined by the bone-char process was objected to for religious reasons. Statistics compiled for the year 1912 show that this so-called “Java white” represented 39.2 per cent of the entire output; 26.2 per cent was muscavado, 29.9 per cent European assortment and 4.7 per cent second sugars.