13 



All the analysts reporting on fluorids had no difficulty in detecting its 

 presence in sample No. 1. 



The sulphurous acid estimation in the same sample also gave satis- 

 factory results. 



CONCLUSIONS AND RECOMMENDATIONS. 



It is greatly to be regretted that there are in use several tables for 

 the determination of alcohol and extract, and that the estimations are 

 not made by different analysts at a standard temperature. The investi- 

 gations undertaken have not been arranged so as to show which of the 

 various tables is the most reliable, nor what temperature is the most 

 suitable for alcohol estimations. The results, however, do indicate the 

 necessity of the adoption of standard tables and a standard tempera- 

 ture. The brewing schools all employ the Balling extract table; Bul- 

 letin 65 gives both Schultz and Ostermann's and Ellion's tables. If 

 one of the tables is to be preferred above the other it should be recog- 

 nized as the standard table. In 1903 President Davidson, of the asso- 

 ciation of official agricultural chemists, in his annual address recom- 

 mended that the temperature at which apparatus is graduated should 

 be changed to one more nearly in accordance with room temperature. 

 In 1904 the referee on beer repeated the recommendation and called 

 attention to a revision of the alcoholometric tables. The use of a 

 standard temperature of 20 C. seems to be growing rapidly in this coun- 

 try. It is being employed by the Bureau of Standards and many food 

 chemists, and it can be but a short time before it will be the accepted 

 standard temperature. The referee therefore suggests that a committee 

 be appointed by this association for the purpose of revising the alcoholo- 

 metric tables now given in Bulletin 65, that they may be adopted for 

 use at this new temperature. 



It is further recommended that the following methods of beer 

 analysis be adopted as official for this association. 



PEOPOSED OFFICIAL METHODS OF BEER ANALYSIS. 

 1. PREPARATION OF SAMPLE. 



Transfer the contents of the bottle or bottles to a large flask and shake vigorously 

 to hasten the escape of carbon dioxid, care being taken that the beer is not below 

 15 C., since below this temperature the carbon dioxid is letained in the beer and is 

 liable to form bubbles in the pycnometer. 



2. SPECIFIC GRAVITY. 



Determine specific gravity at 20 C. by means of the pycnometer, by a small accu- 

 rately graduated hydrometer, by a Westphal balance, or by a Westphal plum.met on 

 the analytical balance. 



3. ALCOHOL 



(A) DISTILLATION METHOD. 



Measure 100 cc of the liquid at 20 C. into a round-bottomed distillation flask, add 

 50 cc of distilled water, and if the beer is markedly acid, 0.1 or 0.2 gram of precipi- 

 tated calcium carbonate, connect with condenser, and distil off 90 cc into an accurately 

 graduated 100 cc stoppered flask, care being taken to prevent loss of alcohol during 

 the distillation. This is best accomplished by inserting a two-holed rubber stopper 

 in the mouth of the flask, through one hole of which passes an adapter which is 

 tightly filled to the end of the condenser and through the other a small funnel filled 



[Cir. 33] 



