PURCHASE OF MILK AND CREAM IOI 



as standard, as a standard which is practical for one state or 

 locality might not be at all practical elsewhere. But in the 

 leading dairy districts it is generally considered that cream 

 classified as first grade should be what is called sweet cream, 

 containing not to exceed 0.20 or 0.25 per cent acid and be free 

 from taint or foreign flavors. Second-grade cream is generally 

 understood to be cream of a higher acidity; it may even include 

 cream of a sharp acid flavor but should be free from undesirable 

 foreign flavors. Cream below second grade in quality should be 

 classified under the head of third grade. 



At some creameries the acidity is the only factor on which 

 the quality is based, while other creameries have a more elabo- 

 rate method of cream judging, exemplified by the following 

 method adopted by the Iowa State College: flavor, 45; acidity, 

 25; richness, 20; body and cleanliness, 10. 



A. Flavor. Flavor is judged by tasting the cream and by 

 grading it in accordance with the quality of butter that may be 

 made from it under ideal conditions. 



B. Acidity. Cream is scored perfect on acidity when con- 

 taining 0.2 of i per cent acid or less. For each ,0.1 of i per cent 

 acid in excess of this amount should be deducted three points 

 from the perfect score. 



The acidity of the cream may be determined by a decinormal 

 alkali, using phenolphthalein as an indicator, or by an alkali 

 solution prepared from alkali tablets. It is often most conven- 

 ient to prepare the solution of such a strength that it will be 

 applicable for the rapid determination method. By this method 

 the solution is prepared by adding one, two, or three tablets 

 to each ounce of water. For taking the sample of milk or cream 

 to be tested, use is made of a dipper of the same size as a No. 

 10 cartridge. The same amount of the prepared solution is 

 added. If the mixture, after being thoroughly mixed, is pink 

 the milk or cream is as sweet as required. If the mixture is 

 white the milk or cream contains a higher degree of acidity 

 than is desired. If we adopt a standard of i/io per cent acidity 

 then a solution is prepared by adding one tablet to each ounce 

 of water; for a 2/10 per cent acidity standard two tablets are 



