COFFEE AND ESTIMATION OF ITS VALUE. 



By L. E. Sayre, University of Kansas, Lawrence. 



TN volume II, page 50 (1887-88), of the Proceedings of the Kan- 

 ^ sas Academy of Science, there is published an article by the 

 author on the alkaloidal strength of teas. In answer to the ques- 

 tion, Is the alkaloidal strength of tea an index of its commercial 

 value ? it was shown that a negative answer to this question must 

 be given ; that the alkaloidal strength has no relation to the com- 

 mercial price. For example, it was shown that a tea rated at 25 

 cents per pound contained 2.49 per cent, of theine, while a tea at 

 90 cents per pound contained 3.73 per cent, of theine, and that a 

 tea at 60 cents per pound contained 3.67 per cent, of theine, show- 

 ing that commercial price was no index to alkaloidal strength. 

 Applying the same question to coffee, we have found the same to 

 be true. A fine Mocha will contain about 0.64 per cent., while 

 another of a different variety, and about the same price, will con- 

 tain 1.53 per cent of caffeine. 



In determinations of caffeine from coffee recently made in our 

 laboratory, it has been found that the percentage of caffeine in cof- 

 fee varies considerably according to the locality where it has been 

 cultivated. Some coffees have ranked as high as 1.97 per cent, of 

 alkaloid, while it is very commonly the case that an excellent cof- 

 fee, commanding a good price, will yield as low as 0.8 per cent, of 

 the alkaloid. The importance of this fact has never been applied 

 as it might be, as there are some to whom the stimulating effect of 

 caffeine is undesirable, while there is at the same time a demand 

 for a beverage that shall have an agreeable taste. On the other 

 hand, there are others to whom the stimulating effect of caffeine may 

 be an advantage. The quality of roasted coffee is dependent mainly 

 upon the substances which occasion the peculiar aroma. These 

 substances have thus far been practically unknown. Erdmann, in 

 Berichte der Deutschen Chemischen Gesellschaft, 1903, refers to the 

 oil of coffee which has been obtained by treating roasted coffee with 

 steam. The yield from 150 kilograms of roasted and ground San- 

 tos coffee was 83.5 gm., or 0.055 per cent., of an oil of a brown color, 

 of a specific gravity of 1.0844, and a strong odor of coffee. On dis- 

 tillation of the oil, the greater portion passed over between .150 and 

 190° C. in the form of a light-colored oil. This contained furfur 



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