134 MILK AND DAIRY PRODUCTS HART 



N. Engstrom l gives the following analyses as typical of the 

 average composition of salted butter made from ripened and 

 fresh cream respectively : 



Ripened. Fresh. 



Water 13*5 per cent. 12 '8 per cent. 



Fat 83-4 84-0 



Protein 0'6 



Sugar and acid 0'3 



Milk salts... - 0'2 



Common salt 2'0 



0-6 

 0-4 

 0-2 

 2-0 



100-0 ,, 100-0 



The variations in the different sorts of butter can, of course, 

 be very considerable. Good butter ought not to contain less 

 than 82 per cent, fat, and not more than 15 per cent, water, nor 

 should the other components exceed 2 per cent., apart from the 

 salt which has been added. 



EXAMINATION OF BUTTER. 



A. SAMPLING. 



There is no difficulty in obtaining a fair sample of butter for 

 analysis, provided that small portions are taken from different 

 parts of the whole mass. The composition varies considerably 

 in the different parts, and so the sample cannot be taken from 

 one place alone. Special borers are used for taking the samples. 

 They vary in size, and have the form of a segment of a circle 

 when seen in cross section. As will be seen in the figure below, 

 a wooden handle is fixed in the upper part of the borer. 



When taking a sample, the borer is pushed deep into the 

 mass of butter, then turned round once and withdrawn. A 

 cylindrical piece of butter then remains tightly attached to 

 the borer. The sample is put into a wide-mouthed bottle 

 with ground stopper, and other samples are taken from different 

 places and added to the first ; the main sample must weigh not 

 less than 150-200 g. It is necessary to keep samples of butter 

 in tightly closed vessels, otherwise some of the contained water 

 evaporates. 



Samples of butter should never be kept for a long time, 

 otherwise they undergo change and become tallowy, rancid, &c. 

 A cool, dark place is the best in which to keep them. 



1 HandboJc i Mejerihushdllniny (Landtbrukets Bok), Stockholm, 1902, p. 432. 



