Continuous precipitation with a compressed fluid antisolvent (PCA) has been used to produce fine particles of tartaric acid. Liquid solutions of tartaric acid in acetone, ethanol and methanol/ethanol mixtures have been sprayed into supercritical carbon dioxide used as antisolvent. Among the process parameters, pressure, temperature, flow rate of solvent and different nozzles have been tested. Furthermore, the effect of solute concentration was under investigation. (C) 2002 Elsevier Science B.V. All rights reserved.