322 



Butter. 



Vol. IX. 



From Boussingault's Rural Economy 

 Butter. 



To understand the preparation of butter 

 thoroughly, it is absolutely necessary to 

 know the physical constitution of the milk 

 from which it is obtained. Now the micro- 

 scope shows us that milk holds in suspension 

 an infinity of globules of different dimensions, 

 which, by reason of their less specific gravi- 

 ty, tend to rise to the surface of the liquid in 

 which they float, where they collect, and by 

 and by form a film or layer of a different 

 character from the fluid beneath; the super- 

 ficial layer is the cream, and tliis removed, 

 the subjacent liquid constitutes the skim- 

 milk. This separation appears to take place 

 most completely in a cool temperature from 

 54° to 60'^ F. 



Allowed to stand for a time, which varies 

 with the temperature, milk becomes sour, 

 and by and by separates into three strata or 

 parts: cream, whey, and curd, or coagulated 

 caseum. By suffering the milk to become 

 acid before removing the cream, it has been 

 thought that a larger quantity of this, the 

 most valuable constituent of the milk, was 

 obtained ; and the fact is probably so ; but in 

 districts where the subject of the dairy has 

 been most carefully studied, it has been found 

 that it is better to cream before the appear- 

 ance of any signs of acidity have appeared. 

 When a knife can be pushed through the 

 cream, and withdrawn without any milk ap- 

 pearing, the cream ought to be removed. 



Buiter is obtained from cream by churn- 

 ing, as all the world knows ; by the agita- 

 tion, the fatty particles cohere and separate 

 from the watery portion, at first in smaller 

 and then in larger masses. The remaining 

 fluid is buttermilk, a fluid slightly acid, and 

 of a very agreeable flavour, containing the 

 larger portion of the caseous element of the 

 cream coagulated, and also a certain portion 

 of the fatty principle which has not been 

 separated. 



The globules of milk appear, from the 

 latest microscopical observations, to be formed 

 essentially of fatty matter, surrounded with 

 a delicate, elastic, transparent pellicle. In 

 the course of the agitation or trituration of 

 churning, these delicate pellicles give way, 

 and then the globules of oil or fatty matter 

 are lefl free to cohere, which they were pre- 

 vented from doing previously, by the inter- 

 position of the delicate film or covering of 

 the several globules. Were the butter sim- 

 ply suspended in the state of emulsion in the 

 milk, we should certainly expect that it 

 would separate on the application of heat; 

 but this it does not : cream or milk may be 



brought to the boiling point, and even boiled 

 for some time, without a particle of oil ap- 

 pearing. Could M. Romanet show any of 

 these pellicles, apart from the oil-globules 

 they enclose, it would be very satisfactory, 

 and would certainly enable us to explain the 

 effect of churning. 



Churning is a longer or shorter process, 

 according to a variety of circumstances; it 

 succeeds best between 5.5° and G0° F. So 

 that, in summer, a cool place, and in winter 

 a warm place, is chosen for the operation. 

 There is no absorption of oxygen during the 

 process of churning, as was once supposed ; 

 the operation succeeds performed in vacuo, 

 and with the churn filled with carbonic acid 

 or hydrogen gas. 



On being taken out of the churn, the but- 

 ter is kneaded and pressed, and even washed 

 under fair water, to free it as much as possi- 

 ble from the buttermilk and curd which it 

 always contains, and to the presence of which 

 must be ascribed the speedy alteration which 

 butter undergoes in warm weather. To pre- 

 serve fresh butter it is absolutely necessary 

 to melt it, in order to get rid of all moisture, 

 and at the same time to separate the caseous 

 portion. This is the process employed to 

 keep fresh butter in all the warmer coun- 

 tries of the world. In some districts of the 

 continent, it is also had recourse to with the 

 same view. The butter is thrown into a 

 clean cast-iron pot, and fire is applied. By 

 and by the melted mass enters into violent 

 ebullition, which is owing to the disengage- 

 ment of watery vapour; it is stirred continu- 

 ally to favour the escape of the steam, and 

 the fire is moderated. When all ebullition 

 has ceased, the fire is withdrawn, and the 

 melted butter is run upon a strainer, by 

 which all the curd is retained. M. Clouet 

 has proposed to clarify butter by melting it 

 at a temperature between 120° and 140° F., 

 and keeping it so long melted as to dissipate 

 the water and secure the deposition of the 

 cheesy matter, after which tlie clear melted 

 butter would be decanted. I doubt whether 

 by this means the water could be sufficiently 

 got rid of, a very important condition in con- 

 nection with the keeping of butter, though 

 certainly all the caseum would be deposited. 



The moisture and curd contained in fresh 

 butter may amount together to about 18 per 

 cent. ; at least we find that we lose about 18 

 lbs. upon every 100 lbs. weight of butter 

 which we melt at Bechelbronn. 



The information which we have on the 

 produce in butter and cheese, from diflferent 

 samples of milk, is very discordant, so that 

 I prefer giving the results of a single experi- 

 ment made under my own eye. From 100 

 lbs. weight of milk, we obtained : 



