The Lactometer and Its Applwatipn\ ItU 



latter is likely to char the sugar in the ice cream, thus 

 giving difficulty in reading the results. Nine grams of 

 either the frozen or melted sample are weighed into a 

 Babcock milk bottle, which is then filled almost to the 

 neck with the mixture of the two acids given. This is 

 heated for a few minutes until black, when the bottle is 

 whirled in the tester and water added to bring the fat 

 column within the graduations of the neck, as in the 

 regular Babcock test. The reading multiplied by two 

 gives the per cent, of fat in the ice cream. 1 



Questions. 



1. Why is it difficult to get accurate tests of skim milk by 

 the Babcock test? 



2. Mention at least three precautions that should be taken 

 in testing skim milk. 



3. Should more acid be used for full milk than for skim 

 milk, or more for skim milk than for whey? Why? 



4. How much fat is probably present in a sample of skim 

 milk which shows no fat on being tested in a skim milk bottle? 



5. What per cent, of fat does each division of a double- 

 necked skimmilk test bottle represent? 



6. How can (a) butter, (b) cheese, (c) unsweetened and 

 sweetened condensed milk be tested with the Babcock test? 



7. If 8.4 gr. cheese give a reading of 12.2% on the neck of a 

 test bottle, what per cent, of fat does the cheese contain? 



8. What is the per cent, of fat in a sample of cheese, of 

 which 4.2 grams contained enough fat to fill the space in the 

 neck of a Babcock milk test bottle from 1.7 to 9.5 mark? 



9. How can the per cent, of fat in ice cream be determined? 



J An apparatus for determining the amount of overrun (214) in the 

 manufacture of ice cream has been devised by G. H. Benkendorf of 

 Wis. exp. station (see bull. 239 of the station). 



