XV. METHODS FOB THE ANALYSIS OF DISTILLED LIQUORS. 



1. Specific Gravity. Provisional. 

 Determine at 15.6 C. as described on page 83, under " XIII. Wine." 



2. Alcohol by Weight. Official. 



Weigh into a distilling flask 20-25 grams of the sample, dilute with 100 cc of 

 water, distil nearly 100 cc, and either weigh distillate or make to volume at 

 15.0 C, and determine the specific gravity. Obtain the percentage of alcohol 

 by weight corresponding to the specific gravity from Table II (p. 203) ; multiply 

 this figure by the weight of the distillate and divide by the weight of the sample 

 taken to obtain the per cent by weight of alcohol. 



3. Alcohol by Volume. Official. 



From the specific gravity of the distillate obtained under " 2 " find the per- 

 centage of alcohol by volume from Table II (p. 203). Multiply this figure by the 

 volume of distillate (calculated from the specific gravity) and divide by the 

 volume of the sample, thus obtaining the percentage of alcohol by volume in the 

 original sample. 



4. Extract. Official. 



Weigh or measure (at 15.6 C.) 100 cc of the sample, evaporate nearly to 

 dryness on the water bath, then transfer to a water oven, and dry at the tem- 

 perature of boiling water for two and one-half hours. 



5. Ash. Provisional. 



Proceed as directed under "VI. General Methods" (p. 38), employing the 

 residue from the determination of the extract (4). 



6. Acidity. Provisional. 



Titrate 100 cc (or 50 cc diluted to 100 cc if the sample is dark in color) 

 with tenth-normal alkali, using phenolphthalein as indicator. One cubic centi- 

 meter of tenth-normal alkali is equal to 0.006 of acetic acid. 



7. Ethereal Salts. Provisional. 



Use 50 cc of the distillate prepared as follows : Add 25 cc of water to 200 cc 

 of the sample and distil slowly 200 cc, using a mercury valve to prevent loss 

 of alcohol. Exactly neutralize the free acid with tenth-normal alkali, add from 



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