Applied Science

Supercritical CO2 caffeine extraction (negative result -- more work needed) (2011x34)

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I tried to extract caffeine from green coffee beans using supercritical CO2, but I had no success. The beans underwent a strange transformation, becoming white and rubbery after 6 hours at 80*C in supercritical CO2. I also used water and ethanol as a cosolvent, thinking that the caffeine would end up in solution in the water/ethanol mix after the CO2 became subcritical. Do you have any advice about how this process is supposed to work?