made by soaking green coffee beans with
water to dissolve the caffeine, extracting the
caffeine from the beans with a solvent
(methylene chloride, ethyl acetate), and
steaming the beans to evaporate off any
remaining solvent. In the “Swiss” or “water”
process, water is the only solvent used, the
caffeine removed from the water by charcoal
filters, and the other water-solubles are then
added back to the beans. Some of the organic
solvents used in other processes have been
suspected of being health hazards even in the
tiny traces left in the beans (around 1 part per
million). The commonest, methylene chloride,
is now thought to be safe. More recently,
highly pressurized (“supercritical”) and
nontoxic carbon dioxide has been used. Where
ordinary brewed coffee may contain 60–180
milligrams caffeine per cup, decaffeinated
coffee will contain 2–5 mg.
Instant Coffee Instant coffee became