370 BOARD OF AGRICULTURE. 



CHAEACTEBISTICS OF A GOOD BUTTER. 



Creamery buttei- is more highly valued than that made in a small way, becaase 

 the conditions of its manufacture are better understood, the machinery more per- 

 fect, and the cream used in better condition. In this way a butter is secured of a 

 pleasant color and agreeable flavor. 



In respect to chemical and physical composition, a good butter should present 

 the following characteristics, viz: 



1. The percentage of water should not exceed twelve. In most of the samples 

 examined it was less. 



2. The percentage of salt may varywithin large limits. In fact, many persons 

 prefer butter perfectly fresh, while others like a large amount of salt. It is doubt- 

 ful whether the small percentage of salt added ordinarily to butter acts as a pre- 

 servative. Its only use seems to be one of taste. Judging from the table, 3 per 

 cent, appears to be the amount of salt in American butter, the variation being 

 from a minimum of 1.23 per cent, to a maximum of 6.15. The percentage of salt, 

 therefore, is not to be much regarded in making our estimate of purity. It would 

 probably have to go above 8 per cent, before it could be regarded as an adultera- 

 tion. 



CURD. 



3. How much curd can a good butter have? This is a difficult question If 

 a butter should have no caseine in it at all, it would be a strong presumption in 

 proof of adulteration. If it has too much, its keeping properties are impaired. 

 One per cent, of curd cannot be regarded as an excessive quantity. The best but- 

 ter, however, should contain less than this amount. On account of the great diffi- 

 culty of estimating the percentage of curd, it would not be safe to use common 

 fats as adulterants. The specific gravity of butter fat is about 912, water being 

 taken at 1,000. On the other hand, tallow and lard have a relative weight of only 

 900 or less. This is a slight difference, and yet it is a valuable one when the ques- 

 tion of adulteration is raised. But the difierence is so small that only the most 

 careful work in determining the specific gravity with strict attention to tempera- 

 ture and manipulation, gives it any value. Inasmuch as most of the fats which 

 are used as butter surrogates are liquid at 40 degrees C. (104 degrees F.) This 

 temperature of determination has been used in the foregoing analyses. 



The numbers given were not obtained by calculation, but by direct comparison 

 with distilled water at the same temperature. While this method is not absolutely 

 correct, owing to slight differences in the rates of expansion of water and oils, it 

 yet gives the comparative difierences, and these are of the greatest importance in 

 such analyses. A butter aflbrding a fat whose specific gravity, taken as above, 

 falls below 910, would have its genuineness subjected to doubt. 



SATTXRATION EQUIVALENT. 



5. The quantity of alkali required to saponify the fat, is another means of 

 judging of the purity of a butter. Butter fat contains an acid (butyric) which has 

 a lower molecular weight than the oleic, margaric, and palmic acids, which form 



