24 



calculated in percentages. The method is based on the fact that caramel is insoluble 

 in ether and that after the treatment with ether the liquid remaining (if colored) 

 can be compared colorimetrically with the original spirits. The authors' original 

 method for separating caramel by means of fuller's earth may be used as a valuable 

 supplementary test. 



III. Malt Liquors. 



NATURAL AND ARTIFICIAL COLORS. 



The natural coloring matter of malt liquors is due to the coloring 

 matter present in the malt and hops used in the preparation of same. 

 The coloring- matter of malt has been examined by Sorb} T and examined 

 spectroscopically. It is an orange yellow color which becomes deeper 

 yellow with ammonia and 50 per cent sulphuric acid. Fermentation 

 modifies somewhat the characteristics of the pure coloring matter. 

 Carbonizing and drying at high heat produces, besides the Original 

 yellow color, a brown color, probably caramel or similar color. 

 Lupulin, the coloring matter of hops, is also yellow. The addition of 

 vegetable extracts for the purpose of furnishing added " bitters " may 

 produce more or less artificial brownish } T ellow shades i. e., chiretta, 

 quassia, wormwood, gentian, aloes, extractives, etc., containing alka- 

 loids, giving color reactions with various reagents. The subjoined 

 table shows the characteristics of some of them, as in testing the resi- 

 dues of malt liquors for color reactions of added colors and extracting 

 them with solvents it would be necessary to take into consideration the 

 influence these alkaloids would produce on such results. 



Absynthin. Easily .soluble in alcohol and ether. Potassium hydroxid produces a 

 brown color, and concentrated sulphuric acid, first a brown color, passing into a 

 green blue. 



Aloin. Soluble in alcohol. Sulphuric acid (hydrous) first red, then orange. Potas- 

 sium hydroxid, a purple red. Nitric acid produces chrysamic and picric acids. 



Cnicin. Soluble in ethyl and methyl alcohol. Cold sulphuric acid gives a red solu- 

 tion, becoming violet on adding water and yellow on adding ammonia. Cold 

 hydrochloric acid (concentrated) gives a green color. 



Daphnin. Soluble in alcohol. Alkalis give a red color, cold iron chlorid solution a 

 blue color, which, when boiled, gives a yellow precipitate, and nitric acid a red 

 color. 



Gentianin. Soluble in alcohol. Sulphuric acid (concentrated) gives yellow color. 

 Nitric acid, dilute, a dark green, which, on addition of water, precipitates green 

 dinitro gentianin. Nitric acid (concentrated) produces trinitro gentianin 

 (yellow). 



Quassiin. Yellow mass when heated. Precipitated by tannic acid. Sulphuric acid 

 (concentrated) no color. 



TESTS FOR COAL-TAR COLORS. 



These will seldom be found, and, aside from fuchsin and picric acid (if added for 

 bitters), need hardly be considered. By evaporating to small bulk and extracting 

 with 80 per cent alcohol, the coal-tar colors may be examined for in the filtrate as 

 given under wines. 



J. Amer. Chern. Soc., 1899, XI, 356. 



