152 THE BOOK OF BUTTER 



Mottling of butter may thus be produced entirely in- 

 dependently of the casein. Examination of this butter 

 under the microscope showed that in the portions which 

 were lighter in color, the water was present in the form 

 of innumerable minute droplets, thus rendering these 

 layers opaque, while in the darker portions the droplets 

 of water were much larger but fewer in number, thus 

 rendering the butter more translucent. 



Occasionally it has been thought that certain streaks 

 may have been due to the mashing or crushing of the 

 butter in the bearings of the butter-worker. If this is 

 true, perhaps the explanation by Lee and Sammis con- 

 cerning the effect of the small droplets of moisture on the 

 refraction of light would help to explain the phenomenon. 

 Whatever may be the cause of mottles, it is definitely 

 known that under normal conditions, when butter is 

 thoroughly worked, the color is uniform. It is also 

 accepted that mottles are not found in unsalted butter. 



115. Faded color. — When butter is exposed for only a 

 short time to light and air, it soon loses its color. It 

 may become as white as snow. It is said that when too 

 much neutralizer is added to lower the acidity of cream 

 the color may fade. 



SALT BLISTERS 



116. Cause. — Salt spots on butter are caused by the 

 evaporation of the moisture, thus leaving a deposit known 

 as a "salt blister." When leaky butter is exposed to 

 the air, the blisters are larger than when the butter has 

 been thoroughly worked so that the moisture is incor- 

 porated in minute droplets. Very few blisters should 

 appear on a properly worked product. Excessive salt 

 is not the cause of blisters. 



