Supercritical Fluid Extraction

Supercritical fluid extraction is a separation process that uses a fluid, most often carbon dioxide, held above its critical temperature and pressure so it behaves partly like a gas and partly like a liquid, to selectively dissolve and extract compounds from a solid or liquid mixture. German chemist Kurt Zosel, working at the Max Planck Institute for Coal Research, developed and patented a supercritical carbon dioxide extraction process in the late 1960s and early 1970s, originally applied to decaffeinating coffee. Industrial supercritical carbon dioxide extraction plants were built in the late 1970s and 1980s, and the technique is now also used to extract hops flavoring, essential oils and other compounds without leaving behind solvent residue.