Most coffees on my roaster hit first crack at 404 fahrenheit ... sometimes a bit earlier at 400 though. If I feel the roast is progressing at a good clip, with a solid Rate of Rise in temperature and roast reaction rate, I will tend to drop my burner temperature at 380 fahrenheit, 20 degrees shy of first crack. I make sure not to overreact though, as I don't want the coffee to stall as it goes exothermic in first crack.