Popular Science Monthly/Volume 25/September 1884/Sorghum as a Source of Sugar
|SORGHUM AS A SOURCE OF SUGAR.|
THE important part which sugar plays in our national and domestic affairs is, probably, not fully appreciated, except by those who have given the subject special study. Accustomed as we have become to hearing of the enormous output of our mines, it is at first somewhat difficult to realize that, in 1881, the people of the United States paid for foreign sugar, and imposts thereon, over fifty-seven million dollars more than the value of all the gold and silver bullion produced in the same year.
In the year 1882 our imports of sugar and molasses amounted to nearly one and one fifth million tons, costing one hundred and fifty million dollars, nearly one third of which sum was paid as import taxes. There is no other article, or class of articles, upon which our Government levies duty which yields a revenue equal to that obtained from foreign sugar.
This useful staple furnishes nearly one fourth (24·3 per cent) of the amount received for import duties, and more than one seventh (14·6 per cent) of the total income of the nation.
That the demand for sugar is increasing much more rapidly than our population, is shown by the increased consumption per capita. The value of the sugar used in 1882 was fully one sixth greater than the amount in 1881. In 1790 to 1799 the average annual consumption of sugar per person was 9·05 pounds, while in 1882 the amount was not far from fifty-five pounds.
In order to obtain the sugar that we need, we find it necessary to buy of nearly every tropical and sub-tropical country. By far the greatest amount (forty per cent) comes from Cuba. Next in order are the Spanish possessions (three and a half per cent), Porto Rico (two and a half per cent), the Sandwich Islands and the Dutch East Indies (each one per cent), while twenty-seven other countries unite to furnish nearly forty per cent. It will be seen that there remains only about twelve per cent for home production. This is strictly true, for, to quote a recent authority, "From the statistics it appears that, during the past twenty years, the United States have produced less than thirteen per cent of their sugar-supply, and little more than twenty-one per cent of the molasses consumed."
If, therefore, our Cuban sugar-supply were suddenly arrested by insurrection or international complications, we might for a season be in an exceedingly embarrassing position. Possibly some other country would ultimately come to our relief; but it is very probable that, for a time, there would be a scarcity of sugar, which would result in unusually high prices. Such a condition of things would surely direct the thoughts of consumers and capitalists alike to our very inadequate provisions for the manufacture of sugar in Louisiana and adjacent Southern States, and the fact would be evident that we could not extend the domestic production of sugar from the cane to approximate our demands. The reason lies in the fact that the sugar-cane is essentially a tropical plant, and is seldom or never thoroughly ripened in our semi-tropical Southern States. Early frosts compel the planters to harvest the canes while yet considerably short of maturity, and consequently before the development of as large a percentage of sugar as is reached in warmer climates.
This climatic disadvantage is so serious as to confine the profitable manufacture of sugar from the sugar-cane, in this country, to a very limited area, and to especially favorable seasons. This fact is emphasized and proved by reference to statistics which show that the amount of sugar produced in Louisiana in one year is frequently nearly twice as great as that obtained the next season.
Obviously, if it is desirable to produce our own sugar, the tropical sugar-cane can not be regarded as the chief source of supply, and we must place our dependence upon some plant better adapted to our varied soils and limited rainfall.
The sugar-beet has much to commend it; it is successfully raised in France, Germany, and Austria, and furnishes, at the present time, thirty per cent of the sugar consumed by civilized nations. But the sugar-beet requires special soil, special fertilizers, skillful cultivation, and, above all, an abundance of rain, which must come at just the right time to be of the greatest service. These conditions are well understood in Europe, and the tracts of country where beets may be profitably grown for sugar are known as "beet-sugar belts" upon the agricultural maps. Investigation has shown that the American beet-sugar belt is confined to a comparatively small portion of certain Northern and Middle States. It is possible that an important fraction of our sugar may yet be obtained from this source; but it is doubtful whether we should entertain hopes that this may ever be our chief dependence.
If, then, this country is to produce its own sugar, it is evident that some plant must be selected which, in one or more varieties, is adapted to our widely varied conditions. It must mature in the temperate Northern States as well as in the more genial climate of Southern California and the States bordering on the Gulf of Mexico. It must be easily cultivated—a plant of rapid growth, which, when mature, does not deteriorate until the season of severe frosts, thus insuring a long "working period," in which it may be converted into marketable sugar and molasses. Above all, it must furnish a juice rich in sugar, while containing a minimum of impurities.
It is claimed, by those who have given this sugar problem a very considerable amount of study, that in the better varieties of sorghum many or all of the above conditions are satisfied, and that, with intelligent culture and manufacturing methods, this country may not only produce all its own sugar, but may do its share toward supplying the ever-increasing demand abroad. These claims, if well supported, are deserving of careful study by all who desire to see the agricultural and manufacturing resources of this country more fully developed than at present.
The sorghum-plant (Sorghum saccharatum) belongs to the great family of grasses (Graminaceæ), and it may be termed a second-cousin to the tropical sugar-cane (Saccharum officinarum) on the one hand, and ordinary Indian corn (Zea mays) on the other. In some of its varieties it looks not unlike broom-corn (Sorghum vulgare), to which it is also related.
There are many modifications, or so-called "sub-varieties," of sorghum, which differ greatly in height, size, weight, and general appearance. Some varieties mature in Minnesota in about one hundred days from planting (as the Early Amber), while other varieties are only ripened to perfection in the Southern States (as the Honduras). Although there are more than one hundred real or imaginary "sub-varieties" of sorghum within the limits of the United States, it is probably safe to say that the question of profitable sugar-production may be determined from experiments made with a few typical varieties, originally known as Chinese and African.
The first Chinese sorghum was imported into this country in 1853, from the noted house of Vilmorin, in France. In 1857 the African varieties, some sixteen in number, were brought to this country from Natal by an English merchant, named Leonard Wray. "To these African varieties the general name imphees was given, while to the variety from China the name Chinese sugar-cane was given." So-called hybrids have been extensively advertised, yet the weight of evidence is against hybridization of the different sorghums, and the new varieties are probably the products of mixed seed.
During the progress of the civil war, sorghum played no unimportant part in helping to supply a portion of the deficiency in our imports of sugar. In many of the Western States, notably Ohio and Illinois, great amounts of sorghum-molasses were made by the farmers with crude and inexpensive apparatus. Usually the sirup had a peculiar, sharp taste, due to imperfect purification of the juice, the use of lime for this purpose not being generally understood. As a rule, also, the canes were crushed while still unripe, and consequently not containing the maximum amount of sugar. In spite of these unfavorable conditions, the reports that sugar had crystallized from these sirups were not infrequent.
At the close of the war many who had made sorghum-sirup again preferred to buy foreign sugar and molasses. The introduction of glucose-sirups may also have been instrumental in diverting attention from sorghum, and, for ten or more years, comparatively little was heard of the new sugar-plant.
About the year 1876 it was again brought into public notice through very favorable results, obtained by farmers in the Northwestern States, in the production of sirup from the variety known as Minnesota Early Amber.
So many and frequent were the requests that this plant be investigated, that General William G. Le Duc, a Minnesota man, upon his accession to the office of Commissioner of Agriculture, in 1877, determined that the possibilities of this sugar-plant should be accurately ascertained for the benefit of all who were concerned.
Accordingly, in 1878, the work was commenced by Professor Peter Collier, Chemist of the Agricultural Department, at Washington, and his investigations were continued through the years 1879 to 1882, inclusive.
One of the principal objects of this work was the determination of the precise quality of sorghum-juices at different periods in the development of the plant, in order to show at what stage the greatest amount of available sugar was present in the juice. It was shown, by thousands of analyses, that fully-matured plants yielded the greatest amount of sugar, and that the period during which this amount was maintained was full three months for some of the varieties which matured most rapidly.
It was shown that some kinds of sorghum matured quickly, and were well adapted to the short, hot summer season of the Northern States, while other varieties ripened more slowly, and were best adapted for cultivation in the Southern States.
It was demonstrated also that, when mature, the best of the different varieties were practically identical as regards the percentage of available sugar in the juice.
The amount of crystallizable sugar in the juice of mature sorghum varies between fourteen and sixteen per cent; there are also present about one to two per cent of uncrystallizable sugar ("glucose"), and two to three per cent of other solids, part of which are removed from the juice by the purifying processes employed in sugar-making. When well purified, sorghum, cane, and beet sugar are identical in composition and properties.
Among other valuable data obtained during these investigations, were recorded the length of time, after seeding, before the plant reached maturity; the length of the period during which the juice contained a profitable amount of available sugar (i.e., the "working period"); the height, weight, and percentage of juice for the stalks of each variety of sorghum at each stage in its development; and numerous other facts of importance to the practical sugar-maker.
The utilization of waste, or by-products, was carefully considered. It was shown that sorghum-seed is very similar in composition and food-value to common Indian corn, and that the yield of twenty or more bushels per acre will nearly or quite repay the farmer the cost of cultivation. This seed has been successfully used for fattening cattle and swine.
It was shown that the apparently worthless skimmings obtained in the clarification of the juice had a value as fertilizing material, and that from the washings of the tanks and evaporators a considerable amount of pure alcohol or vinegar could be produced at small cost.
The crushed canes ("begasse"), after the removal of the juice, make paper-stock of excellent quality and medium length of fiber. This begasse may be preserved as food for cattle by the method known as ensilage, or may be burned under the boilers, thus furnishing heat, and ashes valuable for fertilizing purposes.
But of greater value were the practical results obtained by Dr. Collier, with small and inexpensive apparatus, whereby he showed what could actually be done in the production of sugar and sirup from sorghum. These results were of more real importance than were the pretentious attempts made in Washington under the direction of a "practical sugar-boiler" from the West Indies, inasmuch as the latter experiments were made with improper and poorly-finished apparatus, and with sorghum not fully matured.
These experiments were also vitiated by the incompetence of the sugar-boiler, whose methods were those adapted to sugar-cane, and not varied to suit the different conditions presented when working with sorghum.
The smaller practical experiments conducted by Dr. Collier have been described in detail by himself, and, with perfect fairness, he has narrated not only successes but failures. All who are accustomed to manufacturing operations are aware that, notwithstanding the apparent simplicity of any new problem, the development of a practical working process involves a large amount of patient investigation, frequent experiments, and a not inconsiderable number of partial or seeming failures before complete success can be attained. But when such a process is thoroughly elaborated, and all its difficulties are appreciated and overcome, the details of manufacture may be safely intrusted to men of ordinary intelligence.
In November, 1881, the National Academy of Sciences appointed a special committee which was intrusted with a detailed investigation of the scientific processes, the analytical results, and the practical experiments and conclusions presented by Professor Collier.
All the members of this committee were men of the highest scientific ability, men whose reputation is world-wide, and whose conclusions must carry conviction. To quote from a recent number of "Science": "That the work has been well done is sufficiently guaranteed by the names of the committee. They were Professor William H. Brewer, Ph. D., of the Sheffield Scientific School; Professor Charles F. Chandler, of Columbia College; Professor S. W. Johnson, M. A., of the Sheffield Scientific School; Professor B. Silliman, M. A., M. D., of Yale College; Professor J. Lawrence Smith, M. D., late of the University of Louisville; and also, not of the Academy, Gideon E. Moore, Ph. D., of New York. Professor C. A. Goessmann, of the Massachusetts Agricultural College, was also a member of and acted with the committee until September 15, 1882, when he resigned."
The fairness and ability of the committee being unquestioned, it is germane, in this inquiry, to consider what their scrutiny of Dr. Collier's work has revealed as to the chances that sorghum may yet prove a valuable source of sugar. The following is taken from their report:
The opinions of men so conservative as are the members of this committee can not be lightly set aside or ridiculed as visionary. That their predictions have, in a measure, been realized, will appear from the returns from the crop of 1883. From a recent work upon sorghum, by Professor Peter Collier, we extract the following:
Sorghum-Sugar produced in 1883.
The season is described as being the most unfavorable for thirty years.
At Hutchinson, Kansas, some 200,000 pounds of sugar, besides a large quantity of molasses.
At Sterling, Kansas, some 200,000 pounds of sugar, besides the molasses.
At Dundee, Kansas, 10,000 pounds of sugar, though their product was mainly sirup, of which 50,000 gallons were made.
At Kinsley, Kansas, 10,000 pounds of sugar, and a large quantity of sirup.
At Lawrence, Kansas, some 10,000 pounds of sugar.
At Rio Grande, New Jersey, 282,711 pounds of sugar and 55,000 gallons of molasses—a large portion of their cane failing to ripen, owing to the unusual season.The Secretary of the Kansas State Board of Agriculture reports the following summary of the year 1883 for Kansas:
|Acres planted in sorghum||102,042|
|Acres manufactured into sirup||48,271|
|Acres planted for forage||53,771|
|Tons of cane manufactured||447,859|
|Gallons of sirup made||4,684,023|
|Value of sirup made||$2,058,127 60|
The value of sirup averaged from each acre $42.65, without counting the product of seed. The yield averaged 9·3 tons of cane per acre.
For the first years of a new industry such returns can not be considered other than decidedly promising. That the probabilities are strongly in favor of the ultimate success of sorghum as a source of sugar can hardly be doubted; but that the growth of such a vast industry must be gradual, and may at times be checked by the failures of untrained experimenters, is to be expected. It should be borne in mind, however, that one successful trial, resulting in the production of sugar in paying amounts, is of more value in estimating the possibilities of this new industry than are many failures. The development of any great industry is necessarily slow; especially is this true when manufacturers are not guided by previous experience with closely-related crude materials. The perfection of the manufacturing processes for beet-sugar is an illustration of this point.
It may be interesting, in this connection, to trace briefly the history of beet-sugar in France.
In 1747 Margraff presented a memoir to the Berlin Academy of Sciences, describing the methods whereby he had prepared sugar from beets, and urging the importance of his discovery. Little came of this investigation until half a century had elapsed, when Karl Franz Achard, a former pupil of Margraff, again drew attention to the matter. In 1799 he read a paper before the Institute of France, in which he described his methods and results. He exhibited samples of beet-sugar, and made such an impression that the French Institute appointed a commission, consisting of eminent men of science, to repeat Achard's work. They found about six per cent of sugar in beets, and thought that refined sugar could be produced for about eighteen cents per pound, or for less, if improved manufacturing methods were adopted.
MM. Barruel and Isnard were the first to produce beet-sugar on the commercial scale; they obtained only one and a half per cent of inferior sugar, at a cost of thirty cents per pound.
In 1811 M. Drappiez, of Lille, made beet-sugar at a cost of eighty cents a pound. Even this result, which would seem a disastrous failure to most observers, was sufficiently encouraging to justify the famous decree of Napoleon "that 32,000 hectares (79,040 acres) shall be planted in beets; that six experimental schools to give instruction in the manufacture of beet-sugar shall be established, and that 1,000,000 francs [$200,000] shall be appropriated from the budgets for this purpose, and for the experiments in producing indigo." "The importation of sugar and indigo from England and her colonies was prohibited."
With the aid of this liberal appropriation, and of numerous substantial gratuities to individuals, the development of this industry was still slow. In 1826 only 1,500 tons of beet-sugar were produced in France, but after that time the increase was more rapid, and we find France producing 420,396 tons of beet-sugar in 1879.
From small and inauspicious beginnings the beet-sugar industry has slowly grown, until it is securely established in France, Belgium, Austria, and Germany. At present, three eighths of the sugar used by civilized nations is produced by the sugar-beet. In like manner, the production of sugar from sorghum may not attain great proportions until some years have passed, but the plant is richer in sugar and is much more easily cultivated and handled than is the sugar-beet. The production of sorghum-sugar at a profit is less problematical than was the successful manufacture of beet-sugar when Napoleon issued the decree which laid the foundations of the beet-sugar industry in France.
The results of recent investigations of sorghum in the hands of other experimenters, as well as the immense amount of work done at Washington, have been rendered available, for the general reader and those interested in scientific and practical details, by a recent book written by Dr. Collier. In this work, of over five hundred pages, a great number of scientific and economic problems are discussed, and our present definite knowledge of various points, formerly disputed, is clearly stated. The chemical changes occurring in the plant during its development have been recorded with an exactness suited to delight the student of vegetable physiology, while the practical sugar-maker need not look in vain for the latest information as to machinery and manufacturing processes. Farmers wishing to grow sorghum are told what varieties are most likely to succeed in Northern and what other varieties in Southern latitudes, and the best methods of planting, fertilizing, and securing the crop are carefully described.
In fact, this work has been well done, and its completeness is creditable alike to the thoroughness and the ability of the author. It is fortunate for this industry and for the country that these investigations have been prosecuted by a chemist so competent, and it is to be hoped that Congress may see fit to continue this work under the direction of Dr. Collier.
In view of the fact that the special committee of the National Academy has reported as its opinion, based on facts thus far presented, that the production of sugar from sorghum is likely to prove a commercial success, this country can well afford to expend liberal amounts of money for a continuation of these investigations, and for a practical demonstration of the cost of manufacturing sugar on the large scale. If, as a result of several seasons' practical operations, it shall be clearly shown that sugar can be profitably made from sorghum, an industry will speedily be established which will furnish employment for much labor and capital, and will add large sums to the wealth of this nation.
- "Sorghum: Its Cultivation and Manufacture economically considered as a Source of Sugar, Sirup, and Fodder." By Peter Collier, Ph. D., late Chemist of the United States Department of Agriculture, Washington, D. C. Cincinnati: Robert Clarke & Co.