64 THE ANALYST. ON THE ANALYSIS OF HONEY. BY OTTO HEHNER. Read bejbre the Society of Pzcb&c Anat?y8t8. THROUGE the kindness of a number of pro,minent members of the British Beekeepers’ Association, I have recently been put into possession of a large number of samples of honey of undoubted genuineus. I n many instances the origin of the honey was known, that is to say, the kind of blossom from which it was derived, as far as this is possible. Some of the samples were extracted from the comb by the beekeepers, many of them by myself. I was urged by the Association referred to, to undertake an investigation into the nature of honey, and, if possible, to devise some means for the discovery of its adulteration, on account of the injury done to vendors and producers of the genuine article by the competition of wholesale manufacturers and importers of spurious products.The information available consists mainly of a paper by Dr. J. Campbell Brown, ANALYST, vol. 3, p. 267 ; and of a chapter on Honey in Dr. J. Bell’s work on Food, vol. 1, p. 115. Most other works on Food also deal with the subject of honey, but do not to give precise instructions for the detectiou of addtei*&tion. Dr. Campbell Brown comes to the conclusion that genuine hmey contains from 15.5 t o 19.5 per cent. of water expelled at looo; from 5 to 11 per cent. of “water expelled at a much higher temperature and loss,” very small amoun& of insoluble and mineral matters, the rest being almost equal quantities of levdose and dextrose, cane sugar being in all probability absent.l i e finds that aU the samples he examined are more or less levorotatory, a solution of 16.26 grms. in 100 0.0. of water polarising from - 3.2 to - 5 O at 60’ Tab. Dr. Brown’s paper might be held to give suf€icisntly precise information available for the examination of honey, were it not more or less contradicted by Dr. J. Bell. In five analyses of honey Dr. Bell h d e the proportion of water to vary from 17.10 to 23.32 P.c., glucoses from 66.5 to 740, and he gives as third principal constituent a mgar not .identified, only partly fermentable, without direct action upon cuprie tartrate, but gradually converted into glucose, when boiled for severttl hours with diluteTHE ANALYBT. 65 ~ ~~ sulphuric acid. The amount of this “ sugar not identified” varies from 4-48 to 10-12 per cent, There are also smaU quantities of gum, wax, and inorganic matter, their total varying from *8 to 3.6 p.0, Singularly enough, Dr. Bell is silent about the polarising energy of the samples he examined.He atates that Glucom cannot be detected by chemical means, and only 6y thepoZwi8cope, when in sufficient quantity to change the angle of rotation beyond the limits found in genuine honey ;” but as ho does not give these limits, nor, indeed, a single polariscopic observation, one cannot but consider this statement as a bit of that gratuitous information which confronts the chemist in so many works on Food, and which give an air of profoundity to the author, without imparting knowledge to the reader. This is all the more extraordinary in the present instance, as Dr.Bell claims to have discovered a ‘‘sugar not identified,’’ and surely the polariscope would have been an invaluable help in identifying the sugar in question. It is at once seen on analysing honey, that, on adding the percentage of water (loss by drying at 100’) to that of glucose either before or after treatment with acid, it is impossible to sum up to 100. The difference is variable, from 8 to 19 p.c. Dr. C. Brown considers this to be (‘ water expelled at higher temperatures,” Dr. Bell an unfermentable sugar, not reducing copper solution. Since saccharine materials even when anhydrous lose water on being heated little beyond looo (and even below) and since it is quite impossible to fix upon any particular point at which all water is removed and yet decompoaition has not commenced, Dr.Brown’s statement is fairly open to doubt. The following awlyses are not complete. I have not estimated the amounts of mineral and insoluble matters, as unlikely to afford any important aid in judging of the genuiness of samples, and only in about one half of the analyses have all estimation which I now believe to be essential, been cawed out, namely, the loss on drying at looo, glucose by Fehling before and after inversion by heating with 10 p.0. hydrochloric acid to about 70’ ; rotatory power of a 10 p.0. soZution both before and after fermentation, and solid matter after f emen tation. Two to three grammes of the honey take several days to become constant in weight by drying at looo. The fermentation was produced in a 10 per cent. solution, by the addition of a pinch of yeast, the fluid being kept for five or six days at about 30’ C.Stronger solutions do not ferment well, and become mouldy before all glucose has disappeared. After the evolution of carbonio acid had practically ceased, the solutions were made up to the original bulk, the glucose titrsted, and subtradtsdfrom the totd solids obtained by evapo- rating 10 c.c the difference representing minerd, insoluble, and unfermentable matters. In the following analyses, all figures (except polariscopic indioations) are percentages calculated upon the original honey. The rotstory power represents divisions on the 8oleil-Ventzke instrument. I. From bar frame hive, taken in 1880, during flowering of beam ; clear, L~colushire.2. Straw hive, September, 1881 ; thyme and glover, mystdine. Y ? 3. Ditto, August, 1882 ; glover and lime, arystalline. ,V 4. Bar frame, August 1881 ; glover, dear, ,I 5. Ditto, August, 1880 ; glover, partially crgstaEsed. >9 6, Straw hive, Angust, €880; beans, quite clear. 3)66 THE ANALYST. 7. 8. 9. 10. 11. 12. 28. 14. 15. 16. 17. 18. 19. 20. 21. 1882, from heather, cTstalline, Dundee. 1882, mustard and trumps, very solid. 1883, bees partially fed on mne-mgar syrup ; crystalline, Linoohshire. 1882, no syrup feeding2 clear ; Lincolnshire. Four yeam old, no feeding ; crystalline, Lincolnshire. 1881, Syrian hybrid bees, crystalline, Grmtbm. 1881, from heather, near Perth. 1882, Hertford, crystalline. 1882, heather, Dorset ; comb was crystalline Mom the honey ww pressed.June, 1883, fruit blossom and white glover, Kent, dew. May, 1883, black currant. Kent, clear. 1883, Cinquefoil, Hertford. 1883, Kent. 1883, Ditto Ditto ¶ ? ?9 1881, b h k bees ,J 39 1 2 3 4 6 6 7 8 9 1 0 1 1 Moisture .. 21*0# 17'48 20.04 21*69 20*2*2 23'04 23'26 19-20 20.08 16-31 18-40 Glricose . , .. 64-50 69-27 65*74 68-19 68.17 62-42 68.26 71.57 67-36 67.18 68.90 Differenoe .. 14.46 13.25 14*22 10.12 11*61 1564 8.48 9-23 12.51 16-51 12'70 G1?coseaftsr 1 64.51 73-47 68-23 67-80 67'93 62-90 67*03 71-50 66.72 69*04 69.18 inver8ion 10 p.c. solufion polarises } 0 -1 0 -1 - 2 0 -2 - 2 - 2 0 0 12 13 14 16 16 17 18 19 20 21 Moi&uro .. .. .. 16.96 18-15 16.9% 16.49 12*43 20.88 1i.79 22.69 17-06 18.37 GFluctoRe .. .) *. 68.49 68.17 67-69 64-37 75'34 64-02 66-14 65.42 70.02 118.15 Difference .... 14.55 13-GS 15.33 19.17 12-23 15-10 1347 11.89 12-92 13-48 Glucose after inversion 08.46 62-94 68.60 61-16 72*30 64-14 67.02 65-63 70.35 68.30 10 p, c. solution polarises + 1 0 $. 1 0 - 1 - 11 0 0 0 + I Glumseafterfermentation . . . I .. .. .. 1-37 1-69 nil nil 2.36 Total solids ditto * @ .. .. .. , 4 5-85 6.21 7.67 4*30 6-20 Difference .. .I .. .. .. .. ,. 4-18 4-52 7-67 4.30 3.93 10 p. 0, solution polarises - .. .. .. .. 0 0 0 0 j - 2 nfter fermentation } In the above 21 analyses the amount bf water varies from 12.4 to 23.04 per cent. It is worthy of remark, that the consistencyof the honey, whether fluid or crystalline, does not appear t i be influenced by the percentage of rnoiature. Thus, while sample 18, with 17.79 per cent.of water, is free from crystals, aample 7, with 23-26 per cent., is almost solid. Some honeyacrystallise when a few weeks old, even in the comb (No. 17), othere, of apparently the same composition, remain fluid for years (No. 1). Bee-keepers, how- ever, generally consider that all honey, if genuine, will, in time, become solid. No vendor of genuine honey cap guarantee his article to remain permanently fluid. In seven samples out of the 21 the percentage of glucoee, before treatment with acid, is practically identical with that after inversion. In seven cases the amount has more or less increased, in one case as much as 2.49 per cent. ; in the seven remaining samples the inversion has resulted in an apparent diminution of gluoose, the loss in most oases being small, but in one not less than 5.23 per cent.I do not venture to express any definite opinion as to the cause of this loss, but I believe that the figures indicate the absence of cane-sugar. Even Nos. 9 and 10, produced by bees fed partidy UPOR cane-sugar syrup, show no greater differences before and after inversion than does the rest of the samples. Evidently the cane-sugar i s completely inverted by the bee.67 THE ANALYST. The polarising energy of all samples bu6 one was very small, practically ail, the one sample referred to being presmd by myself from a comb, which wag partially fillsd with crystals ; the resulting honey contained, therefore, an abnormallyl larpje proportion of Ievulose, After fermentation, the polarising power of the five Barnphs twed In tali direction was dao ?zziZ, or very slight;.The whole of the samples gave but a very faint tupbidity with alcoll61, and &h barium chloride. After fermentation, the five samples, 17 to 21, left but from 3.93 to 7.97 per cent. of substances other than glucose, whilst their amount before fermentation was from 11-89 to 15.47. Considering that them quantities include the mineral and insoluble constituents, which, according to Dr. Bell, may amount to as much as 3.6 per cent., and considering further, that even pure sugar leaves, after fermentation, about 6 per cent. of glycerine, beazoic acid, and other unfermentable aubstancea, it appears evident that genuine honey does not contain any unfermentable saccharhe matter, as alleged by Dr.Bell. The following anaIyses amply corroborate this conohion. They elate to samples pur- chased both from dealers of the highest repute in the markot, and to others suspected to be adulterated even be€ore analysed :- 22, Orange blossom honey, 8an Francisco, 2 lbs. Is. 3d., very qystalline, 23. Neighbour and Co., paranteed pure, ci.ystalline. 24. Do. Narbonne honey. 2;. “Fine new honey,” lld. per. lb., crystallised. 26. Finest Swiss honey, guaranteed always to keep clear, no name. 47. Finest Swiss table honey, A. Alt. 28. Hoge’s ptire honey, partially crystallised. 29. Do. English honey clear. 30. Do. Californian honey Dew, dear. 22 23 24 25 26 27 Moisture .. .. .. 17*33 17*i3 15-09 18-86 17-64 18.68 Gluaose , , , , . . ,. . 70.91 9353 73-46 69’52 48-45 49-66 Diff erence .) .... 11.73 8.74 11.45 11-62 34.01 31.66 Glucose after inversion . . . . 70-87 71.28 73.60 65.86 43-33 48-17 lop. c. solutionpolarises .. - 2 0 + 1 + 1 + 56 + 35 Glucoseafterfermentatiori ., .. .. 1-89 1.43 9-02 7’69 Total solids do. .. .. .. .. 5-76 6.20 31.45 25-33 Differenoe .. .. ., .. .. 3.86 4.77 2243 17-14 10 p. c. solution polarises after} “, *, + + + 3o + 28 fermentation ., .. 28 29 30 21.23 18.90 21-26 58.32 20.46 Samples 22 to 25 posaess all charmteristics of the pure samples previously commented upon. They ar0 doubtless genuine. I a h , With an equal degree of certainty, that samples 26 to 30 are adulterated. They all polarise powerfiilly to the right, both before and after fermentation, they are but very partially fermentable, most of them give heavy dextrinous precipitates with alcohol and with barium ohloride much barium sul- phttte.They are productB of the action of sulphuric acid upon starch, consist, in fact, of ( 4 corn syrup,” or of a mixture of the same, with more or less honey. I t is well known that starch sugar, however complete the htversion may be, invariably contains from 15 t4 25 per cent, of uafemontable, dextrorotatory substances. Neubauer’s proceas for the examination of sugbred wines JB founded upon this observation, and has long been used with much success.68 THE ANALYST. All saccharine matters, with the exception of inverted cane-sugar, and which are available for the adulteration of honey, are highly dextrorotatory. If invert-sugar., perfectly free from the acid employed for its preparation, were used as an adulterant of honey, its detection would appear to be a matter of difficulty, if not impossibiiity.At the present time, however, the acid, viz., sulphuric, readily betrays the artificial orif@n of the product, Inasmuch as the polarising power of genuine honeys agrees with that of invert- sugar in which the dextrose very slightly predominates, and as there is at present no saccharine matter known which is fermentable, and without action upon the polarised ray, I incline to the belief, that the 4‘ difference ’’ in the analyses is not due to the presence of saccharine substance. I have made some estimations of the specific gravity of solutions of honey, in the hope that this might afford a means to settle the point; but in every case figure was obtained by reference to tabIes giving the gravity of sugar solutions which was less than the glucose plus ‘‘ difference,” though aomewhat greater than corresponded to tb e glucose alone. While leaving this, the scient-&.c3 aspect of the compostion of honey to be yet examined, I would lay down the following rules for the testing of samples :- Take moisture and glucose before and after inversion as described, the former should not be above 23 per cent., the sugar shouldnot he senaibly greater after inversion than before. Ferment a 10 per cent. solution, take the solid matter after fermentation and subtract from it the per-centage of glucose left udermented. The proportion of unfer- mentable matter should be no larger than would be yielded by a pure glucose solution after fermentation, namely about 5 p. c. Observe polai%hg power of a 10 per cent. solution both before and after fermenta- tion. It should be practically ~zil. Levo-rotation indicates that the honey has become cryatallhe in the comb ; dextro-rotation which i a diminished, but not removed, that there is starch sugar. Test with alcohol and barium chloride : neither should give any notable amount of precipitate . Commsxors OF THE SOCIETY’S PROCEEDINGS.