Abstract: An improved method for extracting caffeine from a coffee material, preferably raw coffee solids, with an extractant comprising supercritical carbon dioxide. Caffeine is continuously absorbed from the extractant with an aqueous wash solution in an absorber. This wash solution is continuously treated by reverse osmosis to form a caffeine-containing retentate stream and a permeate stream containing dissolved solids but substantially no caffeine. The permeate stream is recycled and used as wash water in the absorber or is used to prehydrate solid coffee materials, or both. The permeate stream comprises acidic dissolved solids.

Abstract: A process and apparatus for caffeine recovery from supercritical carbon dioxide is disclosed. The process involves countercurrent extraction of caffeine from supercritical carbon dioxide with water at pressures in excess of 1,000 p.s.i. in an unpacked extraction column. The apparatus includes an unpacked extraction vessel having a distributor therein for distributing water throughout substantially the entire cross-sectional area of the vessel.

Abstract: A method of continuously decaffeinating moistened, green coffee solids with supercritical carbon dioxide. Moistened, green coffee beans are moved periodically through an extraction vessel and contacted with continuously flowing supercritical carbon dioxide which extracts caffeine from the moist, green coffee beans. Caffeine is removed from the supercritical carbon dioxide by counter-current contact with wash water in an open vessel. The caffeine-depleted supercritical carbon dioxide is recirculated back to the extraction vessel and the caffeine-bearing wash water is subjected to concentration by reverse osmosis. Acidic, substantially caffeine-free permeate is directed back to the extraction system as wash water, or to moisturize the green coffee beans prior to extraction, or both.