DMR is specific: compost is pasteurised properly when held at 58 to 59 degrees Celsius for 4 to 6 hours. The temperature is reached by narrowing the dampers and letting the mass heat itself at about 1 degree per hour, which takes roughly 10 to 12 hours.
The ceiling is firm. Above 60 degrees, DMR warns, all kinds of organisms are killed, including the thermophilic fungi essential for Phase II. The same manual lists temperature above 60 degrees during pasteurisation, together with poor aeration, as the trigger for olive green mould.