Condensed tannins from the bark of black wattle (Acacia mearnsii L.) were solubilized with phenol using HCl as a catalyst. The optimum reaction parameters (temperature, time, and acid concentration) of the dissolution were determined. The results showed a clear effect on the percentage of reacted phenol and residue tannin by temperature, time and, particularly, acid concentration. It was found that almost 77% of the phenol used could be reacted with the tannin, and about 90% of the tannin could be solubilized into phenol in the presence of HCl (as a catalyst) having a concentration of 5%. The optimum temperature, time, and acid concentration were 160 degrees C, 90 min, and 4%-5%, respectively. (c) 2005 Wiley Periodicals, Inc.