248 METHODS OF ANALYSIS 



20 COLORING MATTERS.-TENTATIVE.. 

 Proceed as directed under XI. 



21 WATER-INSOLUBLE COLOR IN WHISKIES.— TENTATIVE. 



Evaporate 50 cc. of the sample just to dryness on a steam bath. Take up with 

 cold water, using approximately 15 cc, filter and wash until the filtrate amounts 

 to nearly 25 cc. To this filtrate add 25 cc. of absolute alcohol, or 26.3 cc. of 95% 

 alcohol by volume, and make up to 50 cc. by the addition of water. Mix thor- 

 oughly and compare in a colorimeter with the original material. Calculate from 

 these readings the per cent of color insoluble in water. 



COLORS INSOLUBLE IN AMYL ALCOHOL. 



22 Modified Marsh Method.— Tentative. 



Evaporate 50 cc. of whisky just to dryness on a steam bath. Dissolve the 

 residue in water and 95% alcohol by volume and make to a volume of 50 cc, using 

 a total volume of 26.3 cc. of 95% alcohol. Place 25 cc. of this solution in a separatory 

 funnel and add 20 cc. of freshly shaken Marsh reagent (100 cc. of pure amyl alco- 

 hol, 3 cc. of sirupy phosphoric acid and 3 cc. of waterj, shaking lightly so as not to 

 form an emulsion. Allow the layers to separate and repeat this shaking and stand- 

 ing twice again. After the layers have separated completely draw off the lower 

 or aqueous layer, which contains the caramel, into a 25 cc. cylinder and make up 

 to volume with 50% alcohol by volume. Compare this solution in a colorimeter 

 with the untreated 25 cc. Calculate the result of this reading to the per cent of 

 color insoluble in amyl alcohol. 



CARAMEL. 



23 Amthor Test Modified btj Lasche^. — Tentative. 



Add 10 cc. of paraldehyde to 5 cc. of the sample in a test tube and shake. Add 

 absolute alcohol, a few drops at a time, shaking after each addition until the mixture 

 becomes clear. Allow to stand. Turbidity after 10 minutes is an indication of 

 caramel. 



BIBLIOGRAPHY. 



1 Vasey. Guide to the Analysis of Potable Spirits. 1904, p. 31. 



2 Abs. Analyst, 1899, 24: 13; Ibid., 211, 212. 



* Allen. Commercial Organic Analysis. 4th ed., 1909-14, 1: 98. 

 *J. Am. Chem. Soc, 1905, 27: 9M. 

 6 The Brewer Distiller, May, 1903. 



