U6 ON COFFEE. 



Cbffee germi- It has long been known, that coffee germinates in boiling 

 nates in boiling wa t er (sec Bomare's Diet. art. Cafe,) and I have verified 



Water ; v * r 



bjt not in alto- this fact. But it does not germinate in boiling alcohol ; 

 kol \ either because the temperature is not sufficiently high, or 



because the water is necessary to its germination, or because 



alcohol destroys its vegetative action. 

 Martinico and I have compared the decoctions and tinctures of three dif- 

 Boorbon coffee f erent sorts f co ff ee . n ose f rom Mocha, Martinico, and 

 alike. ' ' 



the Isle of Bourbon. The last two appeared to me to fur.. 



nish the same principles in the same proportions, but that of 

 M«»cha differ- Mocha differs essentially from the others. Its decoction was 

 •^ much less saturated, its alcoholic tincture was higher co- 



loured; it contained less gum and less gallic acidj but "more 

 resin and more aroma. 



Fffect of roast- 



ing. 



Difficult to 

 roast it to a 

 proper point. 



Fat oil in cof- 

 fee. 



Torref action. 



To know what changes are produced in coffee by roasting, 

 I examined the phenomena that take place during its torre- 

 faction in the open air. 



At first the coffee, being penetrated by the caloric, in- 

 creases in bulk: it crackles, and becomes fawn-coloured : 

 the arillus or pellicle that envelops the seed, separates, and 

 as it is very thin and light the least breath blows it away. 

 The coffee then diffuses a very agreeable aromatic smell. 

 This vapour grows more intense; the seed smokes, and turns 

 brown : presently the smell changes, and becomes slightly 

 empyreumatic; the coffee sweats, and becomes oily on its 

 surface*; it ceases to smoke, and if the action of the fire 

 be continued it is carbonized. 



The interval that separates the instant that the coffee be- 

 comes coloured from that of its carbonization is sufficiently 

 long, to render it difficult to determine the point at which 

 we should stop, in order that the berry may retain its most 

 agreeable properties ; but in order to approximate this point, 



* Mr. Parmentier wrapped up some roasted and sweating coffee 

 in blotting paper. This paper, imbibing the oil, remained greasy 

 and transparent for move than a year, which indicates the existence 

 of a fat oil in the berry. I could not separate any such oil, how- 

 ever, either by pressure, boiling in water, or the action of caustic 

 alkalis. ' 



which 



