Cooley's Cyclopaedia of Practical Receipts Volume I Part 117

A small drop of the fat which has been previously melted and heated to several degrees above its melting-point, but has been allowed to cool again to near its setting point, is put on the surface of the cold mercury. This is best done by means of a thin gla.s.s rod about one eighth of an inch in diameter, the end of which has been rounded off in the blow-pipe flame.

It is important that the drop should be very small, and its temperature when placed on the mercury not much above its melting point, for if it be too hot it will spread over the surface of the mercury, which is not desirable.

If the rounded end of the rod be slightly dipped into the melted fat, and then brought to the surface of the mercury, a small hemispherical particle will attach itself there and speedily congeal, becoming more or less opaque in doing so. The weight of one of these hemispherical ma.s.ses, which should not be more than the eighth of an inch in diameter, will be from 1/50 to 1/10 of a grain. Having placed the drop of fat upon the mercury, the bulb of a thermometer, with sufficiently minute graduations, is introduced into the mercury and hot water poured into the basin. The heat is thus communicated to the contents of the small beaker slowly through the water in the larger beaker, and the rise of temperature in the mercury may be easily regulated, and should take place at the rate of about one degree per minute.

The mercury, by virtue of its comparatively good conducting power, acquires a uniform temperature throughout, which is indicated by the thermometer, and at the same time communicated to the fat. The fat when the temperature approaches its melting point becomes partially transparent, and if the stem or elongated bulb of the thermometer be now brought up against it, the moment fusion takes place the liquid fat will run into the channel formed by the repulsion of the mercury and the outside of the thermometer tube. This process presents the following advantages:--

1. The heat-conducting power of the mercury, on which the fat is placed, ensures the equalisation of the temperature as indicated by the thermometer, and at the same time communicated to the fat.

2. The direct contact of the fat with the mercury, without the intervention of a bad conducting medium, such as gla.s.s, ensures a more immediate and correct indication of the temperature at which liquefaction takes place than would otherwise occur.

3. The minuteness of the quant.i.ty of fat operated upon reduces to a minimum the time occupied in its melting, and thus facilitates the determination with exactness of its melting point.

4. The time occupied in preparing small tubes and charging them with the fat is saved, and several experiments in succession may be easily and rapidly made with the same apparatus. The author observed that in b.u.t.ter as well as other fats, such as tallows, there were at least two melting points, dependent upon the way in which the fat had been previously subjected to the action of heat, and that they may differ in b.u.t.ter to the extent of 3 or 4 F.; the low melting point being that of the fat after it has been heated to several degrees above its first melting point, and the higher melting point being that of fat which has been previously melted to the lowest possible temperature, and then immediately allowed to congeal.

5. Professor w.a.n.klyn carefully weighs one gram of b.u.t.ter, and heats it in a platinum dish of the size shown in the accompanying figure, from four to six hours or even more--in short, until it ceases to lose weight. The loss of weight is the water, which should be calculated and expressed in per-centages.

_Fat._ The dried b.u.t.ter is now to be heated with ether (the ether should be made to boil by floating the dish in hot water). Several successive portions should be taken, the whole pa.s.sed through a filter, the filter well washed with ether, and the filtrate evaporated to dryness and weighed.

_Caseine and Ash._ The residue from which the fat and water have been extracted is now to be taken, carefully weighed, then burned down to a low red heat; the residue remaining is the ash, the loss the caseine.

[Ill.u.s.tration: b.u.t.ter-a.n.a.lysing dish.]

The amount of ash, practically speaking, is the salt, but if there be any doubt as to its composition, the chlorine maybe estimated by a volumetric solution of nitrate of silver, and further examined.

The following table shows the composition of a few genuine and other b.u.t.ters, examined according to the same, or at least to a similar process to the one described:--

--------------------+------+-----------+------+--------+-----------------+------------------ Ash, Fat. princ.i.p.ally Water. Caseine. Quality. Salt. --------------------+------+-----------+------+--------+-----------------+------------------ Fresh Devons.h.i.+re 827 11 162 162 Good. w.a.n.kLYN.

b.u.t.ter. Normandy b.u.t.ter. 821 18 161 161 " "

Jersey b.u.t.ter. 78491 8528 10445 2536 " ANGELL AND HEHNER.

Normandy b.u.t.ter. 82643 2915 9305 5137 " b.u.t.ter from Ventnor. 86280 6600 3831 3289 Found to be "

adulterated with foreign fat. b.u.t.ter from London. 8750 1559 23981 6880 Adulterated with "

water. " " 47119 2689 42358 7834 Adulterated with "

water, and contains an excess of curd. --------------------+------+-----------+------+--------+-----------------+-----------------

6. _A Method of Detecting Meat Fats in b.u.t.ter._ Mr Horsley, writing to the 'Chemical News,' September, 1874, says:--"My starting point is, that fresh b.u.t.ter is permanently soluble in methylated ether, sp. gr. 0730 at the temperature of 65 Fahr. But with the view of seeing if any other substance it may contain could be precipitated from it, I took, say, 20 or 25 grains of fresh b.u.t.ter, placed it in a small test-tube, and poured over it one drachm of methylated ether, and on corking the tube it readily dissolved after a few minutes' agitation. I then added 30 drops of methylated alcohol, 63 o. p., and agitated again, but nothing was precipitated. I, therefore, made another experiment with 15 grains of b.u.t.ter and 10 grains of prepared mutton fat, dissolved them in 1 drachm of ether first, and added 30 drops of alcohol, when in less than half an hour the fat was precipitated in a room heated to 68 Fahr. Next, in order to see the effects upon mixtures of known fats, such as lard, beef, mutton, and tallow fats properly melted together in proportions of 60 grains of b.u.t.ter and 40 of fat, and stirring till cold, I found that each of them could, by a similar procedure, be precipitated in a few minutes. In one case, that of mutton, I filtered off the ethereal liquid, and collected the residue, and obtained as much as 30 per cent. of what had been used; so that there is no longer any doubt about easily detecting fatty adulterations in b.u.t.ter. Lastly, I would observe that crystallisation of b.u.t.ter, out of the ethereal solution at a lower temperature than 65, must not be mistaken for the fats precipitated by alcohol alluded to, as the b.u.t.ter, besides being so much lighter, occupies the upper layer, and is different in character and easily remelted by the application of the warm hand for a minute or so.

"Further experiments have proved that half an hour suffices to effect the full precipitation of fats from the ethereal solutions by the addition of 20 drops or so of alcohol to the drachm of ether, containing not more than 25 grains of the adulterated b.u.t.ter; after which the tube should be agitated and its contents projected on to a small double filter, washed with a little alcohol, and the residue whilst moist sc.r.a.ped off, and transferred to a watch-gla.s.s to dry. In this way loss by melting and absorption into the paper is obviated.

"The following were the proportions of fats I recovered, viz.--

Lard 60 per cent.

Mutton fat 75 "

Beef fat 95 "

The precipitated mutton fat is powdery, and white as snow. Lard and beef are more adherent and greasy; for that reason mutton makes the firmest compound."

7. _On the Cooling of Fats._ At a meeting of the University of Edinburgh Chemical Society, held on March 13th, 1878, a paper on the above subject was read by Mr Treharne, M.B.C.M., wherein the author states:--"If equal bulks of the fats of mutton, beef, pork, and b.u.t.ter, and palm oil be heated to 100 C. in small flasks fitted with a thermometer through the cork, and then allowed to cool by radiation under the same conditions for each, temperature is found to fall regularly to a certain point (which is different for each of the facts above named) and then to rise to a certain turning point. These turning points are approximately as follows:--

For Mutton fat 40 C.

" Beef " 285 C.

" Pork " 265 "

" b.u.t.ter " 235 "

" Palm oil 210 "

The extent of the rise in temperature is different in each fat, being greatest in that of mutton, and least in that of b.u.t.ter and palm oil. The extent of the rise is also greater within certain limits the greater the quant.i.ty of fat employed; but as a rule the turning point is pretty constant for the same fat. There is also a little difference in the turning points and the extent of rise according to the part of the carcase from which the fat has been taken. If temperature and time be taken as co-ordinates, and the rate of cooling be represented by curves, these latter will be characteristic of the respective fats. A mixture of equal parts of mutton and b.u.t.ter fats does not give a curve intermediate between those of its two components; but is such as to indicate that less heat is given out on cooling (to 20 C say) than in the case of b.u.t.ter, which, compared with mutton fat, gives off very little heat."

For further information on the subject of 'b.u.t.ter' the reader is referred to a Report by Mr Bell--the princ.i.p.al of the Chemical Laboratory at Somerset House--to the Board of Inland Revenue, included in a return made to the House of Commons in 1876.

_Preservation._ 1. Melt the b.u.t.ter in a stoneware or a well-glazed earthen pan set in a water bath at a heat not exceeding 180 Fahr., and keep it heated, skimming it from time to time until it becomes quite transparent; then pour off the clear portion into another vessel, and cool it as quickly as possible by placing the vessel in very cold water or ice. This is the method employed by the Tartars who supply the Constantinople market. In this state it may be preserved perfectly fresh for 6 or 9 months, if kept in a close vessel and a cool place. This is the plan so strongly recommended by M. Thenard. Mr Eaton states that b.u.t.ter melted by the Tartarian method, and then salted by ours, will keep good and fine-tasted for two years.

2. Saltpetre and white sugar, of each 1 oz.; best Spanish great-salt (or Ches.h.i.+re large-grained salt), 2 oz.; all in very fine powder; mix thoroughly, and add 1 oz. of this mixture to every lb. of b.u.t.ter, and thoroughly incorporate them together. The b.u.t.ter thus prepared is then to be tightly pressed into clean glazed earthenware vessels (or well-seasoned casks), so as to leave no vacuities. This plan is recommended by Dr Anderson, who declares that "b.u.t.ter so prepared will keep in a cool place for years; and will bear a voyage to the East Indies, if packed (stowed) so as not to melt." It does not taste well before it has stood for three or four weeks, after which it acquires a rich marrow-like flavour, which no other b.u.t.ter ever possesses. A good method to preserve the b.u.t.ter from the air is to fill the pots to within an inch of the top, then to lay on it some coa.r.s.e-grained salt to the depth of a 1/4 to 1/2 an inch, and lastly to cover each pot with a slate, plate, or other flat article. The salt by long keeping runs to brine, which forms an air-tight layer on the top of the b.u.t.ter, and may at any time be very easily removed by turning the pot on one side.

3. Fresh b.u.t.ter, 21 lbs.; salt, 1 lb.; saltpetre, 1 oz. These are the common proportions for the best salt b.u.t.ter of the shops.

4. Fresh b.u.t.ter, 18 lbs.; salt, 1 lb.; saltpetre, 1-1/2 oz.; honey or fine brown sugar, 2 oz. Superior to No. 3.

_Concl. Remarks._ It may be useful to know that rancid b.u.t.ter may be restored, or, in all cases, greatly improved, by melting it in a water bath with some fresh-burnt and coa.r.s.ely powdered animal charcoal (which has been thoroughly freed from dust by sifting), and straining it through clean flannel. A better and less troublesome method is to well wash the b.u.t.ter first with some good new milk, and next with cold spring water.

Butyric acid, on the presence of which rancidity depends, is freely soluble in fresh milk.

The turnip-flavour arising from the cows being fed on turnips or cabbages is said to be removed by one or other of the following methods:--1. When the milk is strained into the pans put to every 6 galls. 1 gal. of boiling water.--2. Dissolve 1 oz. of nitre in a pint of spring water, and put a 1/4 pint of the solution to every 15 galls. of milk.--3. Keep back a 1/4 pint of the sour cream when you churn, and put it into a well-scalded pot, into which you are to gather the next cream; stir that well, and do so with every fresh addition. Each of these methods come on good authority, but we are bound to say that our own experience does not confirm their constant success. We have found that the addition of a handful of salt to the water used to wash the b.u.t.ter is as good a plan as any.

=b.u.t.ter, Ancho'vy.= From anchovies (boned and beaten to a paste), 1 part; b.u.t.ter, 2 parts; spice, q. s.

=b.u.t.ter-colouring= (from Paris). A mixture of 40 per cent. of chrome yellow with some fat coloured with annatto. (Fluckiger and Weil.)

=b.u.t.ter, Clar'ified.= Fresh b.u.t.ter melted in a water bath, allowed to settle, and the clear portion poured into an earthenware basin or pot, set in cold water, so as to cool it as quickly as possible, without allowing it to crystallise. It keeps a long time without becoming rank. See b.u.t.tER, No. 1 (_ante_).

=b.u.t.ter, Hon'ey.= Fine Narbonne honey, 2 to 4 oz.; mixed with good b.u.t.ter, 1 lb. Used as a delicacy for children, and by the sick and aged.

=b.u.t.ter, Lem'on.= See b.u.t.tER, ORANGE.

=b.u.t.ter, Melt'ed.= This well-known sauce may be prepared of excellent quality as follows:--Beat up about 1 oz. of fine flour with 4 oz. of b.u.t.ter, in the cold, until they are evenly and thoroughly mixed, then add 4 or 5 table-spoonfuls of hot milk, put the whole into a small saucepan, and continue shaking it, all in one direction, until it simmers very gently; lastly, remove it from the fire, and pour it into the b.u.t.ter-boats for use. These last should be filled with hot water, and then emptied and wiped dry, before putting the melted b.u.t.ter into them. See SAUCES.

=b.u.t.ter, Or'ange.= _Prep._ 1. From 6 eggs, 2 oz. of powdered sugar, and 4 oz. of b.u.t.ter, well beaten together with a little orange-flower water.

Sometimes 1 or 2 oz. of blanched almonds, or of almond-paste, is added.

2. b.u.t.ter, 1 lb.; syrup of orange peel, 4 oz. Both are eaten as a delicacy. LEMON b.u.t.tER, is made in a similar manner.

=b.u.t.ter of An'timony*.= Trichloride of antimony.

=b.u.t.ter of Caca'o.= See CO'COA, and CO'COA-NUT OIL.

=b.u.t.ter of Nut'megs.= Collected from the surface of the water in the still, after the distillation of the essential oil of nutmegs.

=b.u.t.ter of Ro'ses.= Obtained by distilling damask roses. It separates slowly from the water in the receiver. It has little smell, and is hence used to dilute the odour of musk, ambergris, and civet.

=b.u.t.ter of Wax.= Prepared by distilling bees'-wax. A fact.i.tious kind is also made.