Robusta coffee is by some authorities regarded as inferior in quality to Arabian coffee. Nevertheless, considering the optimism with which robusta coffee is regarded by conservative European experts in tropical crops, coupled with the results obtained in Java, it is confidently believed that robusta coffee is worthy of extended planting in the Philippines.
From the Dutch department of agriculture in Java the Bureau of Agriculture has imported seed of the best robusta coffee available for distribution, as well as a considerable quantity of seed of the ordinary robusta cultivated in that island. All readers who are interested in planting robusta coffee are cordially invited to communicate with the Bureau of Agriculture.
[1] All statistics, and much of the information that applies specifically to robusta coffee have been adapted from “Robusta and Some Allied Coffee Species” by Dr. C. J. J. Van Hall, of the department of agriculture, Buitenzorg, Java, published in the Agr. Bul. of the F. M. S., Vol. I: No. 7, 1913, and from a review of a series of articles on robusta coffee by Dr. E. Wildeman, in the Monthly Bul. of Agr. Intelligence, etc., Vol. IV: No. 4, 1913.
Cane-juice Clarification.
By Cleve. W. Hines, M. S., Station Superintendent.
The clarification of the juice forms one of the most important operations in sugar manufacture, since the higher the purity of the juice to be concentrated, the greater the percentage of sucrose that will crystallize, and the easier it will be to make a marketable sugar. If a high-grade sugar, or even yellow clarified sugar is to be made, this work should receive still greater attention.
Before considering the methods to pursue and the reagents to use, it is well to decide first upon the grade of sugar it is desirable to make. If ordinary centrifugal sugar testing 96° is desired, it will usually be practical to use only lime in the clarification, since in these Islands cane reaches full maturity, and consequently the purity of the normal juice will be quite high, sometimes as high as 90° or 92° (apparent purity). If, however, it is desired to make a white plantation sugar, or granulated sugar, it will be advisable to subject the juice to an acidifying or bleaching treatment, as well as to the lime treatment. Usually sulphurous acid is used for this purpose, but sometimes phosphoric acid, or a form of it, is employed. It is generally best to administer the acidifying agent before the application of the lime, since this raises the acidity and permits a larger amount of the lime to be used. However, this process is reversed by some manufacturers, and very good results are often reported.
In the acidifying of any cane juice, care must be exercised that too high an acidity is not reached, since acids have an inverting effect upon sucrose, thus causing a noticeable loss. This of course depends upon the degree of acidity carried, the temperature maintained, and the methods followed during the time the juice remains acid.