Picric acid ( Fleck ). Evaporate down about one-half liter of beer to consistency 

 of sirup, mix the residue with ten times the amount of absolute alcohol, filter, wash, 

 and evaporate the alcoholic solution to dryness, treat this residue with water as long 

 as the water is colored, evaporate down the watery extract to dryness and extract 

 with ether. The ether will contain picric acid in a state pure enough to weigh, if 

 not absolutely pure. The ether may be driven off and the picric acid taken up by 

 chloroform or benzol and crystallized from either solvent. 



TESTS FOR VEGETABLE COLORS. 



Caramel may be examined for. in general, as directed under wines. In addition, 

 Schuster recommends agitating the beer with tannin solution. Pure beer will be 

 decolorized, while the presence of caramel prevents decolorization. Griessmayer 

 (1881) recommends adding to a beer highly colored twice its weight of ammonium 

 sulphate crystals and three volumes of strong alcohol, and when agitated, if the beer 

 be pure, complete decolorization will take place and a deposit will form, either 

 brown or black if the coloration is due to malt. If colored with caramel the solution 

 will remain brown and a gray or brownish deposit will be formed. 



IV. Canned Vegetables. 



Extract with acidified 80 per cent alcohol or extract with immiscible solvents and 

 proceed as usual. Lendrich & states that it is not unusual for dried pease, either in 

 the whole or split condition, to be artificially colored. They are generally treated 

 with talc to give a polished surface. Colors employed are green or orange-yellows, 

 and may be detected by shaking with 50 per cent alcohol and decanting the latter 

 after about five minutes. Natural pease give a colorless solution. The following 

 table c shows the behavior of the coloring matter from some vegetables extracted 

 with 80 per cent alcohol: 



Behavior of coloring matters extracted from vegetables with SO per cent alcohol. 



Correspondenz-Bl. Verein. anal. Chem., 3, 77. 

 b Zts. Nahr. Genussm., 1904, 1. 

 c Prepared by the writer. 



