THE A N A L Y S T . BUTTER EAT, ITS ANALYSIS AND COMPOSITION. By E. W. T. JONES, F.C.S. Read at a Meeting of the Xociety of Public Analysts, at Burlington Bouse, on 14th March, 18’77. THERE have been two valuable papers on this subject read before this Society, never- theless I venture to bring the matter forward again, although not with pretentions to much originality: but first, to draw attention t o a few points that appear to have been overlooked by other contributors on this subject; second, to detail a method for the estimation of the soluble and insoluble acids in Butter Fat which combines expedition with accuracy, compiled from the processes of Messrs.Angel1 and Hehner, and Drs. Muter and Dupr&, to all of whom I acknowledge my obligations; thirdly, to lay before you Some trustworthy analytical results appertaining t o this subject ; and fourthly, to offer some remarks suggested by my analyses and work on the matter.I had thought of restricting myself to the analysis of butter fat, but I find it con- venient just to mention the empirical test introduced by Mr. Bell, of the Inland Revenue Laboratory, viz. : taking the sp. gr.of the fat at 100 Fahr. The sp. gr. test is, perhaps, of greater value than the melting point determination towards judging of the genuineness of butter fat, having an advantage over the melting point in that the observation may agree by any number of observers, with due precaution, whereas with the melting point almost every operator has his little idiosyncrasies as to manipulation, and thus results seldom compare favourably, the sp.gr. or the comparative weights of the same bulk of butter fat and water a t the same temperature is more definite, and cannot differ with different observers, if done carefully. The reason I am touching this sp. gr. test is t o point out the precaution to be observed in preparing a fat for taking its sp. gr. I find that fats must not be kept melted longer than absolutely necessary, or heated higher than looo, like Dr.Muter recommends for drying butter; beyond being detrimental to the accuracy of the test, I shall show it is a procedure at least superfluous for preparing the €at for further analysis. Having observed that when butter fats were left for some time at a temperature of 50° their sp. gr. became sensibly increased, I left one under such condition during the day, and falling to ordinary temperature at night, for a period of several weeks, the sp.gr. at the commencement was 912.1, and at the end of the time was 915.9. It is highly probable that nearly this sp. gr. was attained long before this time, for I hare frequently observed an advance of about 0.5 in a few hours at this temperature, but if exposed to a higher degree the increase in sp.gr. is much more rapid. To try the influence on the sp. gr. of butter fat the plan recommended by Dr Muter for drying butter, viz., treating to looo, I took a quantity of filtered butter fat, which I carefully ascertained by two experiments had a sp. gr. 912.1, then exposed it for an hour to a temperature of looo, using a thermometer as a stirrer, when, upon taking the sp.gr. after such treatment, I found it had increased 1 * 5 O , or instead of being 912-1, it had become 913.6, I therefore look upon Dr. Muter’s sp. gravities of butter fat20 THE ANALYST. as somewhat too high. The butter in question, too, had gained weight, 36.5400 grms. became 36.5795. Now this fat had been prepared by simply melting the butter at a temperature under 1009, and, as soon as melted, and the curd, salt, &c., had subsided, decanting and filtering into a clean, dry bottle, the whole process not occupying more than an hour.Here then we have fat in a fit state to have its ~ p . gr. taken. As soon as possible I proceed by putting the bottle and fat upon the top of my water oven, where the temperature soon falls just below 50°, then fill the sp.gr. bottle, furnished with a thermometer and a lipped neck, which holds a supply of fat for contraction through a capillary on the stopper, when the temperature has descended to exactly looo Fahr. the superfluous fat is immediately removed, and the bottle cleaned and weighed. I can empty the bottle, refill, and weigh any number of times with a difference of only a milligramme or so, or not at all affecting the first decimal in the gravity.The experiment shewing the effect of further heat on the sp. gr. of butter €at also proves, by no loss of weight being sustained, that the fat was dry, and in a fit state for further analysis, and I have said it was prepared by simply melting and then filtering.Another experiment was made to prove this : 5 grms. of the fat from a butter simply melted and filtered was placed in a flat dish and exposed for two hours to the heat of 1000, the loss on re- weighing was only *0005 grm. ; upon exposure for about eight hours longer, it gained -0135, or -27 per cent. The fat wants no special drying, simply melt the butter and filter the supernatent fat, which, IF CLEAR, is ready for general examination; if sp.gr. is to be taken, let the same be done at once, or else the fat kept solid till required. Saponification I find very easily accomplished at about 50°, or without boiling, at such a temperature fats can be perfectly saponified in less than half-an-hour, by occasional attention and with only a little alkali, thus avoiding any error from loss of volatile acid, pointed out by Dr.Dupri:. The next point, and one of importance, in my estimation, is that the insoluble fatty acids must not be dried in an air bath, however strictly kept to loo* C, for it is impossible to get the weight constant, on account of the evaporation that goes on,-even in a water oven at full boil, a continual evaporation occurs, though not to the same extent.From some butters 5 to 10 milligrarnmes per hour is lost in a flat dish, with the insoluble acids, from 5 grms. of butter. The following shews oGe experiment of prolonged drying :- 1st weight . . . . . . . . . . . . . . . . . . 61.8665 2nd, 4 hour after . . . . . . . . . . . . . . . . . . 3rd) 1 ,, . . . . . . . . . . . . . . . .. . 61.8600 61.8635 4th, 1 ,, . . . . . . . . . . . . . . . . . . 61.8415 5th, 1 ,, . . . . . . . . . . . . . . . . . . 61.8310 6th, 1 ,, . . . . . . . . . . . . . . . . . . 6108310 7th, 1 ,) . . . . . . . . . . . . . . . . . . 61,8290 8th, 1 ,, . . . . . . . . . . . . . . . . . . 61.8280 9th, 1 ,, . . . . . . . . . . . . . . . . . 61-8205 The weight of the dish was 57.4080. The percentage of fatty acids according t o the 1st weighing, is 89.17 per cent., and by the last 88.25 per cent. The insoluble fatty acids must be dried with great care, by exposure, during short intervals, in a water oven, the surrounding water preferably only just boiling.THE ANALYST.21 The solutions I employ for the saponification of the fat and estimation of the a. Approximately semi-normal alcoholic potash solution-28 grms., roughly weighed, of the best potassic hydrate, dissolved to a litre with rectified alcohol sp.gr. 840. It is usually cloudy when first made, but if left in the flask for a few hours can be readily decanted clear enough for use. 6 . Approximately semi-normal sulphuric acid-say 25 grms. of the strong acid made to a litre with distilled water.The relative strength of the potash and acid solutions must be ascertained by pipetting off 50 cc. of the potash into a beaker and noting how much of the acid is required for neutrality as a guide to the quantity of acid to be used far the decomposition of the soap. soluble and insoluble fatty acids are :- c. Deci-normal soda solution of exact strength- 1 cc. containin .004 Na.380. equal t o *0088 84 Hs 0 2 For the saponification I use flasks from 220 to 250 cc. capacity, which are carefully balanced, then 5 grnis. added to the weights, and butter fat quietly poured into the flask from the small bottle into which it mas filtered, until the balance shows that a shade over 5 grms. has been poured in. I either ascertain the excess by weights or else remove the same by meane of a stirring rod, this latter is really easily accomplished, but, of course, it is a matter quite at the option of the operator whether he takes exactly 5 grms.or approximately such quantity. Having weighed off into flasks 5 or 6 such lots, the next step is to add the alcoholic pptash solution, this I do from a fast delivering 50 cc. pipette, great care being required here to deliver an exactly like amount in each case, because an alcoholic solution does not leave the glass like an aqueous one, such difficulty however may be overcome by always allowing the pipette to drain exactly the same time, say half a minute.It mill be observed that with semi-normal solutions any difference of one drop over or under will only make half the error that would so occur from normal solutions.50 cc. of the alcoholic potash is delivered into each flask con- taining fat, and also two lots into two about quarter Iitre beakers, which are then put aside for telling the exact excess in deci-normal soda of the sulphuric acid used to decompose the soap. The flasks, closed with glass marbles, are now placed upon the top of the water oven, where the fat melts, and, by occasional circular agitation, saponifies at a temperature under 50° C in a short time.After perfect solution has taken place, they are allowed to remain for an hour or so, and then diluted with cold or slightly warm distilled water-the solutions must therefore still remain perfectly clear. With such dilution as I name 1: find it unnecessary to evaporate off the alcohol.Into each flask, and also into the two beakers containing the amounts of potash, is run from a narrow burette about 1 cc. more of the approximately semi-normal acid than that found to be required for such a quantity. If the potash neutralized 44.6 cc. of the acid, I would run into the soap exactly 46 cc. The excess of the acid over the potash is afterwards care- fully found by deci-normal soda, and the two experiments should agree within a tenth or two; this quantity must be deducted from the soda taken when estimating the soluble acids.By always proceeding in this way, and taking the relative strength of the acid and potash paripasszc with the expcrirnent, any error is avoided that would otherwise occur by change in the strength of the potash or difference in the temperature of the laboratory, which, too, is important, on account of the alcoholic and aqueous solutions having22 THE ANALYST. different co-efficient8 of expansion.The flasks, after addition of the acid, are rnearzy filled with water and gently agitated, placed on the water oven till the fatty acids form a clear stratum, they are then allowed to cool, and I find it advantageous t o allow them t o stand all night, the fat thereby firmly sets and does not so retard t'he filtration as when filtered in an hour or so after artificial cooling.On the following morning the solutions from the cakes of fat are poured into a filter, the common white filtering paper of greater substance and porosity than the Swedish being preferable.When the whole solution is on the filter the flasks are rinsed with 15 to 20 cc. of cold distilled water, and this is poured off, and about 150 cc. of hot water added, which melts the cake of fat, and a brisk circular motion is given t o the contents for a minute or two, then the fat allowed to rise and cool. In the meantime the filters are rinsed with a spray of cold water several times.The fat in the flasks is soon ready to decant from, and the washings pass through the filter very rapidly. The process of washing is again repeated, and final rinsing with cold water and draining leaves the insoluble fatty acids free from acid soluble in water ; the filtrate will now amount to about 600 cc. In several experiments I have used another lot of hot water, and filtered this by itself, the acidity was never equal to more than a few tenths of a cubic centimetre of deci-normal soda, I therefore consider that two good washings with hot water and their accompanying rinsings remove practically all the soluble acidity.The atrates are now treated with deci-normal soda, the amount for excess of sulphuric acid added deducted, the remainder being the index of the soluble acids of the butter, which are calculated as butyric acid.The insoluble fatty acids in the flasks and the small amount that may have passed on to the filter paper are allowed to remain till the following day, by which time the latter become air dried and in a fit state t o rinse with ether ; the fat in the flasks is melted and poured, together with the rinsings of ether, into counterpoised flat dishes with per- pendicular sides, about 3 inches across and inch deep, and the filter papers are also thoroughly washed with ether, the funnels being covered during the process.The dishes are now placed in a warm situation to allow the ether to quietly evaporate; they are then placed on the top of the water oven and a little absolute alcohol added, t o cause the drops of water to dissipate, in this warm situation the alcohol goes, and then the dishes are placed in the water oven for half-an-hour, taken out, cooled under a dessicator, and weighed, again put in for 20 minutes or so, and cooled and weighed again, and if only a milligramme or so lost the weight taken as constant.I have stated my method of proceeding in full detail, even at the risk of being wearisome, because I have found it to work so satisfactorily, any number of repetition8 coming out concordant with ordinary care, and the process, too, is exceedingly simple in work.I have frequently conducted six experiments at a time, as well as proceeding with other work. The following tabulations set forth the results I have obtained with only the ordinary care requisite for any analytical work, and I think they will be found generally consistent and the duplicates practically good.To strengthen my hands I sent one sample to our worthy president, Dr. DuprB, who has kindly taken the sp. gr., and estimated the soluble and insoluble fatty acids. By arrangement our respective results, as under, were made known to each other by a cross post, to be absolutely independent :- Dr.Dupr6. E. W. T. Jones. Specific Gravity ... 911.1 911.2 Soluble Acids .. , 4.60 4.50 4.39 4'44 per cent. Insoluble b i d e ... 89.00 89.80 89-96 89.88 ,, 1st. 2nd. Mean.THE ANALYST. 23 - With the exception of the insoluble acids, it mill be observed that the results are exceedingly satisfactory.We shall hear whether Dr. Dupr6 has observed the volatility of the insoluble acids, which otherwise may account for the difference between us on this point. TABLE I. BUTTERS OF KNOWN PURITY. CLEAR FAT. A I3 C D Sp. Gr. @ 100" Fahr. ... .., . ..... 912.3 910.5 911.9 911.2 3.76 5.1 2 4.50 Soluble Acids, calculated as Butyric . ..... ... . . . ... .. , ...... Insoluble Acids .... .. ..... .... ... 89.00 90.44 88.86 89-80 88.61 90.13 88-82 89.96 1 2; 3.73 4.98 4.39 CLEAR FAT. F G H 1 Sp. Gr. @ 100" Fahr. ... ...... ... 913.3 913.3 912.2 913.5 Soluble Acids, calculated as 5.44 5.69 5.1 9 4.69 8.41 5-62 5.45 4.54 Insoluble Acids ... . . . . . . . . . . , . . . . 88.1 1 88.32 88-79 89.46 88.1 8 88.36 88.37 89.63 Butyric . . . . . . . . . ... . . . . . . .. . . . . j TABLE 11. BUTTEBB, WHICH FBOM THEIR HIBTORY ARE BELIEVED TO RE GENUINE. A B C D E Sp. Gr.. ...... . .... ...... ... . ...... .... .... 910.8 910.9 910.9 910.9 911.1 Soluble Acid .. . . . . . . . ... .. . . . . ... . .. . . . 4.15 4.66 4.49 4.91 4.78 4.17 4-52 ... ... ... Insoluble Acids ..... ...... ...... ... . .. 90.13 lost 89.92 89.64 89.78 90.07 90.18 ... ... ...G H I J E Sp, Gr ..................................... 911.3 912.1 911.7 911.4 911.2 Soluble Acid ........................... 4-91 5.17 5.05 4-37 4.40 4.85 ... ... 4-61 4-22 Insoluble Acids ............. . ....... ... 89.68 89.72 89.96 ... 90.82 89-78 ... ... 90.18 90'72 TABLE 111. BUTTER SUBMITTED UNDER SALE OF FOOD AND DRUGS' ACT. Desoription. Sp. Gr ............. Soluble Acids .. . Insoluble Acids Description. Sp. Or .... ..... .... Soluble Acids ... Insoluble Acids A Pnlt. 913.1 5.27 ... ... I 912.4 Salt. 5.86 88.63 ... B Canadian. ... 5.63 ... ... ... J Salt. 911.9 5.52 89.40 ... I.. C Irish. ... 5.45 5.44 88.84 88-56 K Salt. 911-3 5.62 89.53 ... ... D E Salt. Salt. ... ... 5-63 5.57 ... ... ... ... L Ed 911.6 911.0 Salh Canadian. 5.38 5.35 ... ... 89-53 89.39 ...... F Salt. ... 5.17 ... ... ... N ? 909.6 4.73 4.68 90.35 90.24 G Salt 912.9 5.68 88.39 ... ... 0 ? 911.9 5.14 89.66 ... ... E 912.5 5.51 5.39 88-64 88.72 J 912.1 5-26 6.29 88-54 88-28 F 911.0 4.85 89.95 ... ... 1 9 12.4 5.19 89.19 ... ... H Pelt. 912.8 5.93 88.68 ... ... P 3 911.9 5.37 88.92 ... ...24 THE ANALYST. TABLE 111.. Q R S Description. ? Fresh. ? Sp.Gr ,.......,,... Pu’ot cno’. 910.1 910.5 Soluble Acids ... 4.54 3.89 4.31 ... 3-85 ... Insoluble Acids 90.24 90.87 90.58 ... 91.00 ... --GWznued. T U V Fresh. ? Salt. 909.1 912.0 912.0 3.33 4-98 5.03 3-29 ... 4.91 91.60 89.18 89.43 91.86 ... 89-11 TABLE IT. PUTTER SUBETITUTES AND OTHER FATS. A B C D E F G H Kame of Substance. Oleine Margarine. Margarine. Lard. Beef Mutton Beef Pork Sp.Gr. ,.....I ..... 904.3 903.7 904’0 904.6 .., 904-1 905.8 910.2 Soluble Acids ... 0.24 0.17 0.33 0.10” ... O ’ l O * 0*12* 0*07* Insoluble Acids ... 95.44 95.88 95.78 95.36 95.20 95.58 95.26 94-92 Now as to our position for detecting the adulteration of butter with foreign fat. I t will be seen that the specific gravity of fat from pure butter may range from 910.5 t o 913.5, the former truly is an exceptional case, but cannot be lost sight of.I am of opinion that it would be unwise to make a rule of passing over a butter as genuine, judging solely from specific gravity, whatever it may be in the face of the knowledge that the specific gravity of fats can be raised by being submitted to certain conditions of heating. If a single test is desirable for ascertaicing which samples of butter are worth a full analysis, the estimation of the soluble acids is the most reliable, and scarcely less expeditious or tedious than taking the specific gravity; the small quantity of the fat required could be obtained in a few minutes, saponiikation effected, and, with very little hindrance to other work, the soluble acids obtained t o judge of the desirability of making a full investigation, which, I consider, would be due to all butters whose fat gave practically less than 5 per cent.of soluble acid, calculated as butyric acid, but do not let me be understood t o say that I should pronounce any biitter adulterated, simply because it gave less than that amount of soluble acid, this would be evident folly in the face of my analyses, though I am of firm conviction that amongst them are represented more unfavourable samples than will often be met with; it may be reasonably expected that during the winter months butters are worse than at milder seasons of the year, and it was not wholly unintentionally that this t,ime was chosen, I think it desirable to obtain the worst possible specimens of pure butter.I am not witEout grounds for believing that the soluble acids in genuine butter, made during the summer months, will be always well over 5 per cent., indeed nearer 6 per cent. It is not unworthy of remark that every sample of salt butter that I have examined has given over 5 per cent. of soluble acids, a decomposition of the natural butter fat being probably prevented by the salt, for I find that salt butters may be left for a week or two without depreciation, as far as soluble acids are concerned; on the other hand, that it is desirable that “fresh” should be melted at once, and the curd and water allowed to subside, after which the fat may be kept for a long time without depreciation for analyses.I am fully persuaded that the low per centage of soluble acids in some of my samples of genuine butter is due to fermen- tative changes before churning the cream, which is not so abundant during the winter * Experimental errors, Butter.Dripping. Dripping. Dripping. Dripping.THE ANALYST. 25 months, and is kept longer. In French butter the soluble acids seldom reach 5 per cent., which may be due to depreciation, the custom in Prance being for each butter maker to send his butter on to the market in a rough lump, these lumps are purchased by the wholesale dealer, who blends them together to make one quality and colour, during which process it is likely a change may occur.At the farm where B and D, table I., were made, I ‘ butter powder,” made by a firm of Pharmaceutical Chemists at Lincoln, consisting of bicarbonate of soda, with about 4 per cent. of carbonate of magnesia, is used; this has probably some influence on the composition of the fat.I haye made two or three experiments, proving that butter fat being washed with warm water does not alter in composition. I have determined the soluble acidity generated by keeping, for a short time, five samples of fresh butter, the extreme outside being rejected.Some of the remainder being treated with hot water gave the following results :- Per centage as Butyric Acid On Butter. On Fat. No. 1, 5 days ... ... ... -077 -09 Y ? 27 6 9 , ... ... ... *038 *04 ,Y 37 17 Y, ... ... ... -111 -14 9, 4, 18 ?, ... ... ,.. -115 -13 ?? 5, 18 97 ... ... ... -114 *17 It will be remembered that Dr. Muter, in his paper, and also in his remarks on Dr.Iiupr6’s paper, said, he considered no analysis of butter perfect unless the soluble and insoluble acids together reached 94 per cent.” and as Dr. Dupr6’s figures rarely did so, he looked upon his soluble acids as generally too low ; now I am inclined to agree with Dr. Muter, that the soluble and insoluble acids together should amount to about 94per cent,, which, be it observed, is the case with almost every one of my analyses, but, I think, that if anything was wrong with the analyses Dr.Dupr6 put forth, it was that the insoluble acids were too low. Dr. Dupr6 himself recognized a difklculty in not getting 100 per cent. when the acids were calculated into their respective glycerides, but considered it due to reckoning the soluble acids as butyric, when some higher acids were present, this is probably a correct explanation for st degree, but, I think, the volatility of a portion of the insoluble acids is the main cause of the deficiency.If the mean of my results of the sample sent to Dr. Dupr6 be calculated into glycerides, they will be found nearly to make the 100 per cent. I n the discussion which took place- Dr.Muter said that if by his paper he led anybody to suppose that he heated his fat higher than looo, it was an extraordinary oversight on his part, he strongly repudiated it, and any one who knew his process, which he described, would bear him out that, he never had such an intention. I n a discussion which took place on a paper by Dr. Redwood a t a previous meeting, he especially rcferred t o the change which tcok place in butter fat by keeping it hot.He thought he could account for Mr. Jones’ high soluble acids ; he received a sample of the same butter as Dr. Dupr6 did, and analysed a portion himself for which, therefore, he could answer. What he did was the insoluble acids; he made them 89-00 exactly, so that Dr. Dupr6 and himself, working independently, agreed. After having poured off the first soluble you have invariably t o boil ; unless you boil the water: you cannot completely disaolve out the soluble acids.He used an upright; condenser, and washed his acids with boiling water-he learnt that from Nr. Wignor- the upright condenser being one of his, Mr. Wiper’s, laboratory specialities,26 THE ANALYST. Mr. Hehner considered Mr.Jones had furnished a very great argument against his sp. gr. test, though sp. gr. was not of the slightest use in detecting adulteration. The determination of insoluble fatty acid was a special hobby of his, and he should like to defend it against Mr. Jones, who said it was of little value. He thought Mr. Jones wasbed with far too small a quantity of water. He thought it waa absolutly imperative to wash with bding water, and not t o let it cool.He had made several experiments with regard to the change the acids underwent by being subjected to heat, and he found that a great change does go on; the first four hours the fatty acids keep constant, then they increase and slightly decrease afterwards, but the determination is of little value compared with the determination of insoluble fatty acids.Dr. Dupr6 expressed the pleasure he felt a t hearing that some one had come round t o his opinion that ap. gr. is of no use. As he stated in his paper the gravity is of very great importance as showing adulteration, provided it falls below a certain amount, but it is practically useless if the gravity is high. With regard to the high proportion of insoluble fatty acids, he thought the reason given by Dr.Muter, was the correct one. If the soluble fatty acids are perfectly washed he found there was really no loss by drying at a temperature of 105O for an hour, he had melted, weighed, and heated it for an hour at 104O, and then no loss had taken place, He had never considered the soluble fatty acids as any test for the purity of butter ; but as a test for the impurity, he thought nothing was so safe and reliable as the insoluble fatty acids, and he was of opinion that that there was no single test as yet known which could be taken as absolute except it is the estimation of the insoluble fatty acids.Mr. Jones made a few observations in reply. Mr. A. H. Allen, F.C S., Vice-president of the Society of Public Analysts, Public Analyst for the Northern Division of the county of Derby and Borough of Sheffleld, has been appointed Public Analyst for the West Riding of Yorkshire. Mr. A. M. Edger, Analyst for Newcastle, reports having examined 155 samples of food, 52 of which were adulterated-these included 42 milks, 1 butter, 2 lard, 1 oatmeal, 1 tea, 1 pepper and 4 spirits. Mr. F. Sutton, Analyst for Norfolk, reports that out of 17 samples of milk which he examined, 6 were adulterated with from 10 to 60 p.c. of water, one sample of brandy was genuine, and in the borough of Great Yarmouth 16 samples of milk were examined, 11 of which were adulterated and 5 genuine. The following reported statement of the Archbishop of York, at Whitby, will doubtless be read with interest if not amusement. ‘‘ The fact of the matter was that a wholesale system of adulteration was going on, “and the large profits which were made by the sellers of drink could not be made “without adulteration. He found in a book that the receipt for making gin was “glycerine and nitric acid; he assured them it was quite true-glycerine and nitric “ acid made a compound called dynamite.” HEATY PENALTY.-& the Thames Police Court, on the 28th April, Alexander Harryside was fined € 5 , and 23s. costs, for selling mustard adulterated with 20 per cent. of wheaten flour. We have received samples of Glaas Wool from Messrs. Rohde & Co. It appears to us to be a carefully prepared material very suitable indeed for many purposes in the laboratory.