Coffee contact roasting

The /Invar of an edible substance is the combined sensation of taste and odor as perceived by the eater/drinkcr of that substance. Although the components Jlufood substances, the full aspects of flavor require intimate contact between substance and consumer. The odors emanating from a bakery tend to be richer and more pleasant than the bread itself the flavor of coffee seldom attains the richness of aroma lhat one perceives in the vicinity of a coffee roasting plant. Flavor is a unique combination of nerve impulses on the brain centers as the result of actions upon receptors located on the longue and in the lining of [he nose. II is thus the result of interaction between the food substance and the consumer. 

Extraction of nicotine from tobacco using supercritical fluid is carried out in a manner quite similar to the decaffeination of roasted coffee described in U.S. 3,843,824. Tobacco is first contacted with dry supercritical CO2 which extracts the aroma constituents. The C02-aroma stream is expanded to subcritical conditions via expansion across a valve the aromas precipitate from soludon. The CO2 vapor is recompressed, is adjusted in temperature to supercritical conditions via heat exchangers, and is recycled to the extractor via a compressor. The aromas extracdon step condnues until the aroma constituents are removed from the tobacco. 

Luwaks, apparently, love coffee, but their tastes are very particular. They will eat only the choicest beans. The luwak s digestive system, however, cannot handle the beans very well — a few hours after it eats coffee beans, the luwak eliminates them in a partially digested form. Somehow, the chemistry of the beans changes when they come into contact with the animars digestive juices. When the partially digested beans are roasted, the coffee they produce is extremely tasty and full-bodied. 

Among coffee lovers there is some controversy about the best method to remove the caffeine from coffee beans. Direct contact decaffeination uses an organic solvent (usually methylene chloride) to remove the caffeine from the beans. When the beans are subsequently roasted at 200°C, virtually all traces of the solvent are removed, because methylene chloride boils at 40°C. The advantage of direct contact decaffeination is that the method removes only the caffeine (and some waxes), but leaves the substances responsible for the flavor of the coffee intact in the bean. A disadvantage of this method is that all organic solvents are toxic to some extent. 

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