What is the drying phase in coffee roasting?

The drying phase is the first stage of the roast - the period when residual moisture in the green bean (typically 10–12%) begins to evaporate. Visually, the beans transition from green to yellow; aromatically, you go from grassy and vegetal to something sweeter, almost hay-like. Nothing dramatic is happening yet.

The Maillard reaction and caramelisation haven't kicked in, but the drying phase is critical preparation for what follows. It conditions the bean for the more reactive stages ahead - if it's rushed (too much early heat), the surface can develop unevenly; if it's too slow and drawn out, the roast loses momentum before it's built up enough to carry through development properly.

If you're building or debugging a roast profile, pay attention to how long you're spending in the drying phase and at what temperatures. Problems here don't always show up obviously, but they often appear as inconsistency further along the curve - a development phase that never quite lands where you expected it.