276 Chemical Tests and Analyses 



lactose calculated as invert sugar and calculate the diiference as 

 sucrose. 



MILK SOLIDS 



Deduct the per cent sucrose from the per cent total solids. The 

 difference represents the per cent milk solids. 



Evaporated Milk 



PREPARATION OF SAMPLE 



Shake the can of evaporated milk vigorously before opening. 

 If, upon opening the can, separated cream or small lumps of butter 

 are found to adhere to the seams and around the junction of the 

 ends and the body, set the can in a water bath at 130 degrees F. for 

 ten minutes or until all fat is completely dissolved. Then pour the 

 entire contents into a beaker and pour back and forth several times 

 until a homogeneous mixture is secured. If it is known before 

 opening the can that the. contents are separated, submerge the whole 

 can in a water bath at 130 degrees F. for ten minutes, then shake, 

 open and proceed as above. 



If it is desired to use a 40 per cent solution, as directed under 

 the determination of the individual ingredients, weigh accurately 

 40 grams of the properly mixed contents of the can into a 100 c.c. 

 graduated flask- Add 60 c.c. water and mix thoroughly by shaking 

 or stirring. 



SPECIFIC GRAVITY 



Aerometric Method 

 APPARATUS 



Beaume hydrometer. — Use a special Beaume hydrometer with 

 a scale ranging from five to twelve points, graduated to tenths de- 

 grees and mercury-weighted. Length over all eleven inches, length 

 of spindle six inches, length of empty bulb four inches and width 

 of empty bulb seven-eighths inch. 



Hydrometer jar. — ^Use a glass or tin cylinder with substantial 

 base. Minimum height ten inches and minimum width one and a 

 half inches. 



DBTBRMINATION 



The Beaume hydrometer is graduated to read correctly at 60 

 degrees F. (15.5 degrees C). For every degree Fahrenheit above 



