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.

Abstract: The process disclosed herein decaffeinates an aqueous caffeine feed solution by contacting it with a multi-phase extractant which comprises a continuous phase of a liquid, water-immiscible, caffeine-specific solvent and discontinuous aqueous phase dispersed therein. The caffeine is selectively extracted from the aqueous feed solution, leaving the solubles necessary for a good testing beverage due to the high combined selectivity of the extractant phases. Very low solvent-to-extract ratios are possible because the multi-phase extractant has a much improved partition coefficient as compared to the water-immiscible solvent.