1 88 ROASTING AND GLAZING. 



operated by steam-power, revolving slowly but regularly, 

 and having a capacity of from 25 to 300 pounds. 



After roasting, the coffee is run off into a large wire- 

 bottomed box termed a " cooler," to the end of which is 

 fitted a powerful fan or "blower" used for forcing cold 

 air through the hot beans and preventing the volatile oil 

 from exuding, the coffee being thoroughly agitated 

 during the process, the hulls, chaff and stems being 

 removed meantime to a large extent by the fan and 

 sieve. Thirty-five to forty-five minutes is usually the time 

 consumed in the operation, the former for a "Light" 

 and the latter for a high or "Dark" roast, the entire pro- 

 cess of roasting, cooling and rebagging occupying about 

 one hour. In roasting, coffee loses in weight from 1 2 to 16 

 per cent, according to the age and nature of the coffee 

 under treatment and the extent to which the operation is 

 carried, the average, however, being 14 per cent, for old 

 and well-seasoned coffee, which accounts for the rela- 

 tively higher price — three to six cents per pound — of 

 roasted coffees, according to the price green and the loss 

 per cent, in roasting. But, it at the same time increases 

 in bulk — 100 volumes of raw coffee yielding from 150 to 

 160 volumes of roasted — that is, two pints of raw beans 

 will yield three pints roasted. It also loses from i to 2 

 per cent, more in the warm months of summer than in the 

 damp months of winter, for which reason it should not be 

 roasted as high in the former season as in the latter, owing 

 to its greater tendency to sweat and absorb the higher 

 temperature, thus causing the volatile oil to exude, and 

 dissipate and impart an astringent taste to the infusion. 

 When coffee is roasted light-brown, or until it assumes a 

 pale-chestnut color, the loss is from 1 3 to 14 per cent, the 

 quantity of extract obtained from such roast by means 

 of boiling water ranging from 20 to 2 1 per cent, of the 



