14:8 VOLUMETRIC AND INDIRECT ESTIMATION OF FAT. 



capacity, and the product to be tested is weighed into this. The 

 author has not found this advantageous. 



Cream and Clotted Cream. Mix from 50 to 100 grammes of 

 the sample to be tested well, fill the cup with this, dry the outside 

 and weigh. Place the cork carrying the cup in the butyrometer, 

 add 6 c.c. of clear hot water through the upper opening, then 

 1 c.c. of amyl alcohol and 6-5 c.c. of acid, and shake well ; add 

 6 c.c. more hot water, shake again and whirl in the machine. 

 Read after one minute's standing in the water-bath. 



Butter. Melt about 10 to 20 grammes in a small closed bottle 

 at 40 C. (104 F.) and shake violently till solid ; fill the cup, 

 and weigh. Add 12 c.c. of cold water, and 1 c.c. of amyl alcohol 

 and 6-5 c.c. of acid. Shake well and proceed as before. 



Cheese. Mix 10 to 20 grammes in a mortar till of even con- 

 sistency. Fill the cup and weigh ; transfer the bulk of the 

 cheese from the cup to the butyrometer, by inserting the cork 

 and shaking gently ; add 6 c.c. of hot water and 6-5 c.c. of acid 

 and shake till the cheese is dissolved. Now add 7 c.c. of hot 

 water and 5 drops of amyl alcohol (from the pipette), shake well 

 and whirl in the machine. Stop the machine after about two 

 to three minutes, take out the butyrometer, add a further 1 c.c. 

 of amyl alcohol, and place for a minute in the water-bath at 

 60 to 70 (sav 150 C to 160 F.) ; whirl again and read after a 

 minute's standing in the water-bath. 



For Skim Cheeses whirl three times and add 8 c.c. of hot 

 water instead of 7 c.c. 



Calculation of Kesults. The percentage of fat in the sample 

 is found by dividing the number of degrees read off on the stem 

 of the butyrometer by the weight taken, thus 



Butter wt. 0-76 gramme. Reading 62 Fat = /p=~ = 81-6 per cent. 



Cream wt. 0-90 49 C - -^ = 544 



U'VMJ 



Cheese wt. 0-68 ., 22 r = -?L= 32-35 



U'Oo 



Water Estimation in Butter, Margarine, etc. A special 

 form of butyrometer is used for this ; it consists of an elongated 

 bulb 5 c.c. in capacity, connected by a graduated tube with a vessel 

 in which a cork carrying a cup of 3 c.c. capacity is inserted. 

 The only reagent necessary is diluted sulphuric acid, made by 

 diluting commercial sulphuric acid (sp. gr. 1-820 to 1-825) with 

 an equal bulk of water ; before use this should be cooled to the 

 ordinary temperature, and decanted from- any deposit of lead 

 sulphate. 



Five c.c. of diluted sulphuric acid are measured into the buty- 

 rometer, which is placed open in the machine, and whirled for 



