XVin. BEERS. 



1 PREPARATION OF SAMPLE.— TENTATIVE. 



Remove carbon dioxid by transferring the contents of the bottle to a large flask 

 and shaking vigorously or by pouring back and forth between beakers, care being 

 taken that the temperature of the beer is not below 20°C. 



2 COLOR.— TENTATIVE. 



Determine the depth of color of the sample in a j inch cell with a Lovibond tin- 

 tometer, using the beer scale. Express the result in terms of a i inch cell. 



3 SPECIFIC GRAVITY.— TENTATIVE. 

 Determine the specific gravity at —^-^ b}' means of a pycnometer. 



4 ALCOHOL.— TENTATIVE. 

 Determine as directed under XVI, 4. 



EXTRACT. 



5 Method I.— Official. 



Measure 25 cc. of the carbon dioxid-free beer at 20°C. into a tared, flat-bottomed 

 platinum dish, approximately 85 mm. in diameter, and evaporate just to dryness 

 on a steam bath and heat to constant weight in a vacuum oven at 70°C. 



6 Method 11.— Tentative. 



The immersion refractometer reading of the beer at 20°C. minus the immersion 

 refractometer reading of the distillate at 20°C. times 0.2571 equals the grams of 

 extract in 100 cc. of beer. 



7 Method III.— Tentative. 



Calculate the specific gravity of the dealcoholized beer by the following formula: 

 S = G4- 1- A in which 



S = the specific gravity of the dealcoholized beer; 

 G = the specific gravity of the beer; and 



A = the specific gravity of the distillate obtained in the determination 

 of alcohol. 



From IX, 9, ascertain the per cent by weight of extract in the dealcoholized beer 

 corresponding to the value of S. Multiply the figure thus obtained by S to ob- 

 tain the grams of extract per 100 cc. of beer. 



8 EXTRACT OF ORIGINAL WORT (APPROXIMATE) .—TENTATIVK. 

 Calculate the grams of extract per 100 cc. in the original wort by the following 



formula: 



O = 2A+ E in which 



O = extract of the original wort; 



A = alcohol (grams per 100 cc); and 



E = extract of the dealcoholized beer (grams per 100 cc). 



249 



