66 
LABORATORY MANUAL 
EXERCISE NO. 50 
Object: To determine the specific gravity of condensed milk. 
Procedure: By knowing the fat tests and solids not fat of the milk enter¬ 
ing into the manufacture of condensed milk, and then again 
testing the condensed milk for these constituents, it is possible 
to determine the concentration. 
A. Take 50 grams of thoroughly mixed condensed milk, weigh 
into a tared beaker, and wash with enough warm water into a 
flask to make exactly 250 cc. Cool to 60° F. and obtain the 
specific gravity with an accurate lactometer. Designate the 
reading expressed as specific gravity as “a.” 
B. Calculate the density of the condensed milk as follows: 
1 
sp. gr. of condensed milk =-. 
6-5a 
C. The concentration ol the condensed milk, if the specific gravity 
and fat content of the original is known, is determined as fol¬ 
lows: 
as 
Concentration (C) =-. 
aisi 
a—solids not fat of condensed milk. 
s—specific gravity of condensed milk.. 
ai—solids not fat of milk used. 
Si—specific gravity of milk used. 
Observations: 
Sample 
Sp. gravity of dilution 
Sp. gravity of condensed milk. 
1 
/ 
2 
Conclusions: 
Questions: (1) Give the four states leading m the manufacture of con¬ 
densed and evaporated milk. 
(2) What is the difference between condensed and sterilized milk? 
(3) Why is sugar often added to condensed milk during its manu¬ 
facture? 
(4) What is the approximate difference in composition between or¬ 
dinary condensed and sweetened condensed? Give figures. 
References: F. & W. 264, 307. 
