MALT LIQUORS. 291 



should be subjected to a qualitative examination, with a view to ascer- 

 taining if any mineral substances have been added to the beer. 



GLYCERINE. 



The estimation of glycerine is a troublesome and unsatisfactory de- 

 termination to make, and as the information obtained in the case of 

 beer is not sufficient to repay the labor of the analysis, except in special 

 c;ises, I have omitted it. 



The following method is used by the Bavarian chemists : 50cc. of beer 

 are treated with about 3 grams of quicklime, evaporated to a sirup, 

 then mixed with about 10 grams coarsely powdered marble or sand, and 

 brought to dryness. The entire dried mass is transferred to an extraction 

 apparatus, and extracted for six or eight hours with not over 50cc. strong 

 alcohol. To the slightly colored extract is added an equal volume of 

 water-free ether, and the solution after standing a short time is poured 

 into a weighed flask, or filtered through a small filter, which is after- 

 wards washed with a little ether-alcohol. After the evaporation of the 

 ether and alcohol the residue is dried in the air bath at 100 to 105 C. in 

 a loosely-closed flask, until the losses in weight are constant. With 

 beers that are very rich in extract, the ash content of the glycerine may 

 be determined and deducted from the total weight. 



The methods recently published for the estimation of glycerine by 

 its conversion into carbonic acid by sulphuric acid and bichromate of 

 potash have been utilized for its determination in fermented liquors by 

 Legler 1 and promise to prove more expeditious and exact than the 

 old methods. 



PHOSPHORIC ACID. 



The phosphoric acid was determined by means of a standard solution 

 of uranium acetate, except in the case of a few very dark-colored samples, 

 when the analysis was made gravi metrically from the ash by precipita- 

 tion with ammonium molybdate, in the usual way. 



CARBONIC ACID. 



Most investigators have given very little attention to the determination 

 of the carbonic acid in beer, regarding it as of little importance in form- 

 ing an estimate of the quality of the sample examined. The practical 

 consumer, however, is of quite a different opinion and condemns imme- 

 diately a beer which is "flat" or insufficiently carbonated, however 

 worthy it may be in other respects. The reason for its unimportance 

 as a determination is found in the difficulty of the accurate estimation 

 in the beer as supplied to the customer. The usual method of deter- 

 mining it is to measure or weigh out a convenient quantity of the beer 

 into a flask, connect the latter either with an absorbing apparatus for 

 1 Rep. Anal. Chem. 47 Analyst, 1887, 14. See further under wine. 



