11 



MAX HENIUS. 



Fluorids. We "have found that when no fluorid has been added to a beer, 200 cc 

 of such beer, when tested for fluorin according to adopted method, will not show 

 any appreciable etching on glass. We also found that barley in its natural condition 

 did not contain enough fluorin in 10 grams to etch glass. If, therefore, fluorin is 

 present in a beer to such an extent in 200 cc, that it can be made to etch glass, it is, 

 in our opinion, safe to say that a fluorid has been added to the beer. When used, 

 the fluorid is added in the proportion of one pound to 150 barrels, or approximately 

 0.0025 per cent. Of this fluorid two-thirds or 0.0016 percent is fluorin, that is, 16 

 mg of fluorin per liter. 



The coating on the glass is made of a mixture of paraffin and wax. The tested 

 flat glass lies tight on top of the platinum crucible and a small tin vessel filled with 

 chopped ice is placed on top of this glass. The markings in the wax are not to be 

 done with a lead pencil, but with a pointed piece of soft wood. 



A slight etching not visible in the reflected light, but visible when breathing upon 

 the glass, should not be considered a fluorin reaction, as such reaction, in some 

 instances, was obtained when absolutely pure sulphuric acid was employed, and even 

 a slight etching visible in the reflected light without breathing upon the glass does 

 not necessarily indicate the addition of fluorids, since these have been found to be 

 a normal constituent of many waters and brewing materials. 



Sulphites. According to Graf, analyses made by him showed' in ordinary German 

 and Austrian beers from 3 to 23 mg of sulphurous acid per liter; in Frankish beers 

 from to 89 mg per liter. As sulphured hops may introduce from 3 to 7 mg of sul- 

 phurous acid per liter and by action of yeast (according to Graf) appreciably more, 

 say, 10 mg per liter,, it is seen" that 17 mg of sulphurous acid may be found in beer to 

 which no sulphites have been added. 



We have, in our laboratory, found 13 mg of sulphur dioxid in beers free from sul- 

 phites. As the amount of meta-bisulphite of potassium when used in beer is one 

 pound to 60 barrels, or about 84 mg of sulphur dioxid per liter, it is safe to say 

 that when only one half as much, or 17 mg per liter, is found, no sulphites have been 

 added. Since this quantity will not preserve, and the addition of a corresponding 

 amount of sulphites would therefore be barren of result, any amount up to this 

 limit should be allowable. 



COMMENTS BY ASSOCIATE REFEREE. 



The results as compiled show two things clearly. They express the 

 value of standard methods for analytical work. The ten analysts 

 working upon a sample of beer which, although pasteurized, was still 

 subject to change in composition during the weeks or months that 

 lapsed before the analysis was made, obtained for the most part very 

 concordant results, the personal error usually being so small as to be 

 negligible. On the other hand, the determination of the several factors 

 by the different methods showed marked variations. In the prepara- 

 tion of the sample, the same result was obtained when the carbon dioxid 

 was removed by snaking, as when the beer was poured from one beaker 

 to another. Either method removes the carbon dioxid completely. 

 The specific gravity of the beer is practically the same at 15 C. as at 

 20 C. when compared with water at the same temperature, there being 

 but 0.0001 difference in the average, results. 



The various methods suggested for the determination of alcohol give 

 fairly concordant results. The use of the Zeiss immersion refrac- 

 tometer gives results practically identical with those obtained by taking 

 the specific gravity of the distillate. The only precaution necessary 

 is that of watching the temperature at the time of reading. 



When it is not possible to distil the alcohol a correct estimation 

 may be made by use of the formula A^Bj B 2 )H-15, when A= read- 

 ing on immersion refractometer, B t = reading of beer, B 2 = reading 



#Zts. fur das gesammte Brauwesen, 1904, 27: 617. 

 [Cir. 33] 



