38 Kansas Academy of Science. 



alcohol, and much valerianic acid. The constituent having the 

 characteristic aroma of coffee is said to be nitrogenous and not a 

 phenol, as has been assumed heretofore. The exact isolation has 

 not been possible so far. It is well known that the roasting of 

 coffee carries with it antiseptic and deodorant properties. This is 

 evidently inherent in the volatile products of roasted coffee, and 

 possibly due to phenols present in these volatile products. 



Our own experiments in the investigation of the volatile aro- 

 matic constituents of roasted coffee have led us to the conclusion 

 that these when isolated are extremely volatile. For example, when 

 chloroformic and petroleum ether solutions of the coffee are evapo- 

 rated at extremely low temperatures it is found that the aroma 

 evaporates and diffuses through the air at a lower temperature 

 than that at which the ethereal liquids evaporate. We have en- 

 deavored, therefore, to resort to another method of recovering the 

 volatile aromatic oil, which consisted in placing in a retort 500 gm. 

 of finely powdered coffee and connecting the retort with a con- 

 denser and two receivers in tandem, the first receiver being re- 

 frigerated with ice and salt and the second refrigerated with liquid 

 air. Only a few drops of a colorless liquid was recovered from the 

 dry distillation in the second receiver. It is nearly colorless and 

 has an odor suggesting that of capronic acid. It is very powerful 

 and penetrating, diffuses very rapidly in the air, and when highly 

 diluted with atmospheric air suggests the odor of coffee. The dis- 

 tillate obtained in the first receiver, of a yellowish-brown color, has 

 an ammoniacal odor. But it is evident that the characteristic 

 aroma of roasted coffee is due to a mixture of different compounds 

 not obtained by any such process. We have not been able to pur- 

 sue further this investigation, but hope at some future time to re- 

 cover a sufficient amount of the distillate mentioned to purify the 

 same and to make an analysis of it. The claim that oil of coffee 

 may be obtained by distilling coffee with steam under pressure 

 and collecting the distillate by means of ether and then evaporating 

 the ethereal solution does not seem to us to be well founded, as we 

 have not been able to obtain a volatile oil by this process which 

 has the suggestion of the aroma of coffee. As we have said, ethe- 

 real and chloroformic solutions of the volatile products usually 

 leave behind on evaporation little or no residue that are character- 

 istic of the aromatics in coffee, these aromatics becoming evapo- 

 rated on evaporation of the solvent, even though the solvent is 

 evaporated at a very low temperature. 



