For what its worth, had a roast almost get away from me for the first time yesterday, was distracted by a minor problem at about 15 .5 mins, all was looking good, forgot about the roast for 30 secs, by the time I looked back they were smokin like hell and a couple of shades darker than I had intended, not a lost cause but could easily have been a bin job.
Lesson learned, keep your eye on the beans. :-[