Abstract Pyrolysis total volatile yields obtained (in helium and hydrogen) using a wire-mesh reactor at pressures up to 160 bar and heating rates between 1 K s −1 and 1000 K s −1 are compared with hydropyrolysis total volatile (and tar) yields at pressures up to 100 bar and a heating rate of 5 K s −1 to 590 °C obtained in a hot-rod (fixed-bed) reactor. Comparisons of product distributions from the two reactors are used to highlight some of the difficulties encountered in collecting and interpreting hydropyrolysis data as a function of reactor geometry, hold time, heating rate and hydrogen pressure. A common sample of Linby (low rank British bituminous) coal was used in all experiments.