CARBON DIOXIDE EXTRACTION

A method of preparing an extract from a material comprises contacting the material to be extracted with carbon dioxide in the liquid state to dissolve the matter to be extracted in the liquid carbon dioxide, heating the solution of extract to evaporate carbon dioxide from the solution of extract, compressing and condensing the evaporated carbon dioxide vapor to re-form liquid carbon dioxide, and re-cycling the liquid carbon dioxide to contact the material to be extracted. At least part of the heat evolved from the carbon dioxide vapor after its compression and during its change of state from vapor to liquid carbon dioxide is used to cause the change of state of the liquid carbon dioxide in the solution of the extract to evaporate the carbon dioxide from the solution of the extract. A plant for the preparation of an extract of hops by extraction with liquid carbon dioxide is also disclosed together with modifications of the plant to enhance the recovery of hop oils or obtain a separate extraction of the hop oils.