308 BUTTER. 



Temperature of Churning. — The best temperatiires for 

 churning are as follows : — 



Recently separated cream (quick churning), about 8° C. (46-4° F.) 



(slow churning), „ 13° C. (55-4° F.) 



Sour cream, winter, . . . „ 18° C. (64-4° F.) 



summer, . . „ 13° C. (55-4° F.) 



If the butter is churned at too high a temperature, it will 

 contain more water than at medium temperatures. Butter 

 churned at very low temperatures also contains more water than 

 at medium temperatures ; this appeal's to be due to the fact 

 that in the one case the fat is too liquid, and in the other too 

 solid, for the maximum effect of squeezing out the watery portion 

 on working to be attained. Butter which is quickly churned by 

 violent impact also has a tendency to contain more water than 

 that churned more slowly. This may be explained by the 

 hypothesis that if the nuclei are quickly formed several globules 

 of fat may coalesce simultaneously and enclose more buttermilk 

 than if they coalesced singly. 



When the cream churned is very sour the solids not fat may 

 contain precipitated casein ; in this case the ratio of solids not 

 fat to water is high. 



If the temperature at which the butter is churned and worked 

 be too high, very large percentages of water (up to 50 per cent.) 

 may be found ; this may be very materially reduced by cooling 

 the butter for several hours and re-working. 



Various substances — rennet, pepsin, sodium carbonate, etc. — 

 have been used to increase the yield of butter ; this eiiect is 

 attained by increasing the water contained in the butter. 



An article is sold under the name of " miJk blended" butter, 

 which is made by working milk into butter ; the water is thereby 

 raised to 22 to 26 per cent., and the solids not fat are correspond- 

 ingly increased. 



Casein, to which sufficient alkali is added to make it soluble, 

 and often containing a little gelatine, condensed milk, and milk 

 powders are also sometimes added to butter. 



Preservatives in Butter. — Besides salt, various other sub 

 stances are used as preservatives ; the most usual are mixtures 

 of borax and boric acid, though formalin, salicylates, sulphites, 

 fluorides, and potassium nitrate have also been employed. 



The Proximate Analysis of Butter.— The proximate analysis of 

 butter indicates, not whether the sample is genuine or otherwise, 

 but its condition, and affords some clue as to its mode of pre 

 paration. 



The usual data to be determined are water, solids not fat, fat, 

 salt, and preservatives. It is also occasionally of interest to 

 determine the actual curd, or the casein. 



