Studies of pyrolysis of a coal charge containing various quantities of water from 0.8 to 15 wt.% in a two-stage reactor were performed. The rate of formation of solid carbon deposits was followed and some properties of high-temperature tars were investigated. These tars differ in elemental composition and hexane solubility. Hydrogen acceptor abilities were evaluated by reaction with tetralin at 320 degrees C and with decalin at 400 degrees C. Hydrogen transfer from decalin to several model organic compounds was also studied. The rate of carbon deposit formation and hydrogen acceptor abilities of tars are different for various quantities of water in the starting coal charge. The relation between the hydrogen transfer properties of tars expressed as the ratio of decalin hydrogen transfer (DHT) to tetralin hydrogen transfer (THT) and the rate of carbon deposit formation seems to indicate the importance of hydrogen transfer during secondary pyrolysis.