Art. LIII.—On the Sugar Values of Beet-roots grown in the Waikato District
[Read before the Auckland Institute, 5th September, 1881]
During the session of 1880 a paper was read before this Institute entitled “On the growth of Sugar-beet in New Zealand,” by Dr. S. M. Curl.* In this paper the writer very ably reviewed the subject and placed much valuable data before us, but when speaking of the values of sugar in the different varieties of beetroot examined by him, he claimed to have found as high as 17.5 per cent. This excessive amount, and the fact that Parliamentary Papers had been published giving analysis of New Zealand grown beets, showing much less favourable results, and the absence of any details of examination, led me to take up this subject with the view of practical operations should the experiments justify it. About this period also, I had interested myself in the matter of sugar-best, owing to some superior seed having been brought from Hamburgh by Mr. G. S. Graham, and finding it had been distributed amongst some of the Waikato settlers for planting,
I undertook the examination of the roots when they should be sufficiently grown. Mr. W. A. Graham, of Tamahere, who had taken a very great interest in the matter, had papers printed according to a plan drawn out by myself, and forwarded to those settlers who had undertaken to grow the roots. These papers were designed to obtain data for the future guidance of a company, should one be formed through any satisfactory result of these experiments, and were divided into columns requesting information, as follows:—
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|From whom forwarded, and name of estate.||Character of soil, and whether drained, etc.||Whether manured or otherwise; if manured, state character of manure.||Whether from imported seeds, or from where obtained.||Give approximate of weight to the acre if possible.||Analytical Results.|
|% of beet sugar.||Notes.|
While the reverse of the paper was headed
“Special Notes” [Add here anything of interest to obtain complete details.] and also my address, to which the roots when required or matured were to be forwarded.
The first instalment I received was from Mr. L. O'Neill, Hamilton, and came to hand on the 28th January. There were three roots, grown from seed imported by Mr. Lavers, and resulted as follows:—
No. 1.—Weight, 2 lbs. 2 ozs.; percentage of cane-sugar 10.95
" 2.—" 1 " 2 " " " " 10·17
" 3.—" 0 " 12 " " " " 13.55
On the 24th February, one month later, Mr. O'Neill again forwarded a parcel of four roots from the same crop. Taking the largest of them, weighing 2 lbs. 2 ozs., I found the percentage of sugar to be 14.25, the three others I aggregated with a like percentage of 14.25.
Finally, on the 24th August I received a parcel of five roots from the same grower, which had been removed from the ground and stored, some of which are on the table. Two of these I have examined, with the following results:—
No. 8.—Weight, 2 lbs. 7 ozs.; percentage of sugar 11.40
" 9.—" 2 " 0 " " " " 14.25
The further examination of these roots I will speak of again, in relation to the specific gravity of the juice.
On the 18th of February I received three roots from Mr. Ralph, Huntley, marked sugar-beet. They were of a full red-coloured skin, but I have obtained no knowledge of the name of the seed or where procured. Result of analysis:—
No. 1.—Weight, 51bs. 5 ozs.; percentage of sugar 4–31
" 2.—" 12 " " " 7.50
" 3.—" 9 " " " 11.87
This root No. 1 was a well-shaped one, of large proportions, very watery, but with a very low percentage of sugar. This is the lowest result I have obtained, and far below any other. At the same time its excessive size would lead to the conclusion that its value in sugar was low.
One more parcel I received of unknown seed, from Raglan, through Mr. Will, comprising five small roots, badly formed, the largest of which, weighing 1 lb. 12 ozs., yielded a percentage of sugar, 8.14.
I now proceed to note the results of the seed obtained by Mr. Graham from Hamburgh, and which had been distributed as already noted. There were three kinds in all.
No. 1.—Genuine white small Wanzlebenel Imperial.
No 2.—Deppe's pure white improved Silesian Imperial.
" 3.—Extra sacaharine Red-top Imperial.
In the following notes I will simply call these varieties by their respective numbers—1, 2, and 3.
On the 10th March I received three roots, one of each variety, from Mr. R. Watson, Pukerimu.
No. 1.—Weight, 13 ozs.; percentage of sugar 13.57
" 2.—" 1 lb. 1 oz.; and No. 3 (weight, 12 ozs.), I treated in the aggregate, with the result of 15 per cent. of sugar, this being the highest value obtained.
On the 2nd of April I received a parcel of five roots from Mr. E. B. Walker, Cambridge, the weights of which were between 1 lb. 1 oz. and 1 lb. 15 ozs. and were of the three varieties, but without anything to distinguish them. These I treated in the aggregate with the result of 13.57 per cent, of sugar. Taking the best proportioned root of the parcel, weight 1 lb. 10 ozs., I found it to contain 15 per cent, of sugar.
On the 10th August I received samples of the three kinds of root already named, from Mr. T. Goodfellow, Alexandra, which gave the following results:—
No. 1.—Weight, 1½ lbs., percentage of sugar 12.66
" 2.—" 1½ " " " 11.40
" 3.—" 2½ " " " 9.82
These roots arrived with the crowns removed. I had, therefore, no apportunity of observing whether there had been any late growth of leaves, but from the freshness of the roots and the results above quoted, I should think they had been left in the ground, and not dug up at maturity and stored.
I have now given the results of the examination of roots grown in the different parts of the Waikato, and will not unnecessarily multiply the details for you, but take as a last experiment the result of analysis of roots grown upon Mr. Graham's estate at Tamahere. It was my desire to
examine these roots while they grew, and, if possible, to note the time at which they became matured, and on that account, the crop having been sown late, I received samaples of the three varieties on the 8th February, resulting as follows:—
No. 1.—Weight 1 lb. 1 oz.; percentage of sugar 8.90
" 2.—" 1 " 6 " " " 7.50
" 3.—" 0 " 9 " " 8.38
These roots were immature, and consequently the results were low. On the 26th March I received another parcel of the three kinds from the same estate, yielding as follows:
No. 1.—Weight, 1 lb. 2 oz.; percentage of sugar 10.55
" 2.—" 2 " 2 " " " 11.87
" 3.—" 1 " 7 " " " 11.17
On the 7th of May I visited the ground and chose samples of the three varieties which were still in the ground, rather overgrown with weeds and certainly having been left too long in the earth, the leaves still growing vigorously, the result no doubt of the late rains which had then been falling. Still they were fine roots, averaging from 1 to 3lbs. They had been planted too far apart, and much space had been lost and room given for weeds to accumulate in. Being rather pressed for time I was unable to make a separate examination of these roots, and therefore I treated them in the aggregate with a result of 12.79 per cent, of sugar.
Finally, on the 29th August, I received samples of each variety fresh from the ground where they had still been allowed to remain, though fully four months had elapsed since they had reached maturity. These roots had been growing vigorously, a large crop of young leaves shooting up at the expense of the sugar stored up in the root. The result of the analyses, though low, has surprised me at the amount even yet left in the roots.
No. 1.—Weight, 2 lbs. 9 ozs.; percentage of sugar 7.42
" 2.—" 2 lbs. 4 " " " 6.47
" 3.—" 3 " 5 " " " 8.65
Three of this parcel of roots were forwarded by Mr. Graham to Dr. Hector, Wellington, for analysis, with the result appended.
“Results of Analysis.—Three roots of Sugar-beet for sugar. Received 13th September, reported on 23rd September, 1881.
No. 1.—Weight, 1 lb. 2 oz.; sugar per cent 8.42
No. 2.—" 1 " 10 " " " 8.01
" 3.—" 2 " 10 " " " 6.94
“These are fairly good yields.” W. Skey.
In reference to the methods of analysis and the sampling of the roots, I may remark that in every case, to ensure a true average, I have punctured the root from crown to apex, taking the core for purposes of analysis, as it is a well known fact that the sugar is not found in equal proportions through-
out, the root being richer in sugar in the lower than in the upper portion. Having thus obtained a fair average of the root, I have accurately weighed and then pulped the assay portion in a mortar with distilled water, and inverted the sugar in the ordinary manner with dilute sulphuric acid, making my quantity up to a known amount, from which I have charged the burette in the ordinary way.
Fearful of the conversion of the woody fibre into glucose, and a consequent false increase of the results, I have frequently checked this process by filtering off the diffused juice from the pulp, well washing the latter, and then inverting the sugar contained, but in all these cases the pulp still retains a small amount of saccharine matter, but the difference between these two methods is so small as not to cause much disparity, and here I will give one experiment to show the difference. A root of the Bed-top Imperial, weighing 2½ lbs., was taken, and two cores from the puncture tube fairly chosen, to the weight of 2 grammes each, pulped, and the one inverted with the pulp, the second filtered, the pulp washed and the filtrate inverted; the percentage of sugar being 9.82 in the first portion, and 9.50 in the second. The difference I attribute to the sugar still left in the pulp. The methods by which I have determined the percentages of sugar, have been with Fehling's copper solution, and Knapp's mercuric cyanide solution, both volumetric analyses, the former being in my opinion the most accurate. To ensure precision, I have frequently inverted pure anhydrous cane sugar, and estimated my standard solutions with it, and therefore feel justified in saying that the analyses given by me in this paper are reliable.
In addition to the chemical analysis we have the specific gravity, this being a very reliable guide to the value of sugar present, and this I have obtained after expression of the juice on several occasions by means of the balance. Before concluding this portion of my paper on the chemical manipulations, it will be interesting in a few cases to note the relative proportions between the chemical values and the specific gravities.
The root already mentioned as having been received from Mr. Walker, Cambridge, and which I estimated to contain 15 per cent, of sugar, was grated until it had lost weight equal to 200 grammes, the juice from which being expressed equalled 128 c.c, added water to the pulp and macerated, pressed to near dryness and made up the amount with water to 200 c.c. Found the specific gravity of the pure juice before adding water to be 1.08087, and the percentage of cane sugar in the 200 c.c. to be 14.35, the difference being the amount of sugar still retained by the pulp. Again a root from Mr. O'Neill was grated, 1lb. of which yielded 14½ozs., weight of juice, and 1¾oz. pulp. The specific gravity equalled 1.0528, and the percentage of sugar in the juice was 11.4.
One more experiment I will give, that of a root weighing 21lbs. of which 14 zs. was grated, yielding 12 ozs. juice and 2 ozs. pulp; the specific gravity of the juice being 1.0653, and the percentage of sugar present 14.25
There is one point in connection with this subject which deserves more than a passing notice, and that is in reference to the presence of chlorides, and especially that of chloride of sodium—common salt—this being so detrimental as to result in a loss of 5 per cent. of sugar for every 1 per cent. of the salt. When making my examination for sugar I have also tested for the presence of chlorine, but only to find a trace in any of the Waikato beetroots with the exception of those now before you, which, having been left in the ground at least four months too long, are heavily charged with chlorides. One interesting feature is in the absence, beyond a trace, of chlorides in the roots received from Raglan, already mentioned, and this though grown in the vicinity of the sea. I may state that I have not estimated the amount of chlorides, but simply as a qualitative test.
The distribution of the seed in the Waikato alone was in consequence of its distance from the sea and the very favourable situation and comparative absence of chloride of sodium from the pumice soil, but its cultivation in other portions of the Auckland district fairly deserves a trial.
The great objection to the presence of salt, either from the proximity to sea air, fertilization of the ground with it, or from an abnormal amount being naturally present, is owing to the impossibility of freeing the sugar from this substance, and in consequence the estimation of chlorides is only second in importance to that of the sugar present. So inimical is this salt that M. Baruchson says:—“In some instances the undue proportion of this salt in sugar has nearly rendered the sugar unsaleable; and so generally is this recognized abroad, especially in Germany, that the manufacturers in contracting with the growers of the root stipulate that it shall not be grown on certain soils, and often even name the manure which shall be used.” It is owing to this substance, and the want of sufficient care in eliminating the molasses that beet-sugar at one time was strongly objected to on account of the taste, and even here I have heard complaints of the same character. On this subject Grant, in his “Beetroot Sugar” remarks:—” There was formerly a prejudice in the minds of many people against beet-sugar; but it is perfectly well ascertained, that, if properly refined, it cannot be distinguished from the best sugar of sugar-cane, either by taste, appearance, or chemical analysis: the two are identical.” Again, on page 24 he remarks: “The cost of producing from the beet a pure white sugar, entirely free from unpleasant smell or taste, is but a trifle more than is required to produce a lower grade. In Germany refined loaf sugar is produced directly from the beet. In France the brown is first produced, and then refined. Within
the last two years, however, sugar has been produced of such purity and whiteness, that it has been sold directly for consumption without refining; and there is no question that the peculiar odour of the beet may be entirely got rid of in the manufactory.” I will quote one more authority on this subject, and that one of the highest we could have. I allude to Crookes, who says in his work “Manufacture of Beetroot Sugar”:—” Crystalized beetroot sugar is perfectly identical in composition with cane-sugar, and is indistinguishable from it by the sight, the taste, or by chemical tests.
Proceeding from the foregoing facts to summarize my results, I find that the value of sugar obtained from the whole of the roots examined by me last season under 3½ lbs. in weight is a percentage of 11.66, but this average includes the immature ones from Tamahere, made when they were but half-grown, and also these roots now before us, which, having remained in the earth so many months after coming to maturity, have deteriorated considerably. If then we exclude these, the average result of the rest shows a percentage of 12.45; but as some of the roots examined were practically too small for manufacturing purposes, I propose to exclude all under 1 lb. weight, and thus reduce the average to roots between one and three pounds weight, this being a useful size for manufacturing purposes, large enough to pass safely through the washing machine without being lost or clogging the bars, and yet not too large to materially reduce the percentage of sugar. By this exclusion the average is 12.29, my highest being 15 and lowest 9.82.
In arriving at these results, I do so after a series of experiments extending over the past seven months, in which time I have made upwards of eighty analyses and examined more than sixty beetroots grown in different parts of the Waikato, many of them raised under very unfavourable conditions: some I found over-run with weeds, of others cattle had destroyed the leaves, while the majority were planted too far apart, and in almost all cases not sufficiently earthed-up, in consequence of which a portion of the sugar contained in the root, exposed to sun and air, becomes converted into other substances. Yet, notwithstanding all these disadvantages, the average of all the analyses made by me, with the exception of one root weighing over 5 lbs., was 11.66, while the exclusion of those which would under no circumstances be permitted to enter a sugar factory brought up the total to 12.45, an average return so favourable that it would result in a very large profit were it achieved in the countries where beet-sugar factories are established.
That these results are not exceptional is, I think, shown by the wide area over which I have obtained my supplies for examination; and that it will be fully equalled on the large scale is shown by the unskilled manner in which some of these roots were planted and tended, and also by the request, which in many instances was adhered to, that no manure should be used.
So far from this, I feel convinced that with due attention, proper cultivation, and suitable manuring, a higher percentage will be obtained than from those which the past season's growth has furuished us with; and should a factory be established for the conversion of beet-sugar, I believe the true economy of procedure would be in the purchase of roots at a fixed rate per ton, with an additional schedule price for every degree of sugar above a minimum, a practice which works beneficially amongst some of the German factories; especially would this be the case in the colonies, where the higher price of labour would naturally lead us to seek for the maximum of sugar from a minimum of root. It is not within the scope of this paper to dilate upon the value to this district should such an industry find a home amongst us, but the benefits would be so great and varied, while the returns which I have now brought before you give so large a promise of success, that I hope the early future may find such an establishment situated where it would be most profitably worked—in the centre of the Waikato district—where soil, temperature, and the absence of sea air proclaim its fitness for the growth of the beet; and to show the results of a factory in full working order, I will conclude by reading the result of eight years' working of the North German Sugar Company, as extracted from their books by Mr. G. S. Graham:—
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|Process.||Year.||Quantity of Beetroot.||Percentage of Sugar.||Rate of Dividend.||Beetroot. Quantity manipulated per diem.|
|By hydraulic pressure.||1870–71||208,575||9.13||32%||1,400|
|By diffusion,||1874–75||194,370||10.37||30 "||2,500|