BUTTER DEFECTS 521 



3. The clearer and deeper yellow blotches in mottled butter are 

 caused by absence, or the relatively small number of the very small 

 droplets or by the presence of a larger number of large droplets, or 

 both. Both, the absence of any water droplets and the presence of 

 relatively large droplets and aggregates of drops, minimize the 

 refraction and deflection of the rays of light, permitting the 

 rays to enter sufficiently to give the butter a clearer and more 

 translucent body and revealing more of the natural golden yellow 

 color characteristic of butterfat. 



4. The reason why unsalted butter always has an opaque whit- 

 ish color, and never is mottled, lies in the fact that in unsalted but- 

 ter, regardless of the amount of working, the water is always pres- 

 ent in the form of exceedingly minute and innumerable water drop- 

 lets of uniform size and distribution, giving the entire body of but- 

 ter a uniform opaque whitish appearance. The permanency of this 

 uniform white appearance is due to the absence in unsalted butter 

 of agents capable of breaking this fine emulsion of water-in-fat. 



5. The reason why salted butter always has a clearer and 

 deeper yellow color than unsalted butter, lies in the fact that the 

 salt, due to its action on the curd and to its great affinity for 

 water, draws the more loosely held small droplets together into 

 larger aggregates, it makes the emulsion of water-in-fat less 

 complete, it diminishes the refraction and deflection of the rays 

 of light and makes the butter more translucent. 



6. Salted butter at the churn is never mottled, because, even in 

 insufficiently worked butter the distribution of the large droplets 

 at the conclusion of the working process is sufficiently complete to 

 hide the localized sections of the very minute droplets. 



7. Salted butter, when insufficiently or unevenly worked, in- 

 variably becomes mottled upon standing, because in such butter the 

 fusion and the emulsification of brine and water are incomplete. 

 Owing to the difference in concentration, and to osmosis be- 

 tween brine and water, interchange and migration of brine and 

 water takes place in the butter at rest. This causes the more loosely 

 held, larger water droplets to run together into larger aggregates and 

 the portions of butter containing these fewer but larger droplets 

 show themselves as and represent the clearer, more translucent and 

 deeper yellow blotches of mottled butter. 



