Lightly roasted coffees can be almost tart, if the coffee being roasted is of high quality. They can also be delicately floral, reminiscent of the jasmine and orange scented coffee blossoms that gave rise to the beans over a year before (in the case of slow-to-develop high grown coffees). Yet, these characteristics stand alone in a lighter roast with little of the texture and smoothness that frame a darker roast.Some roasters will try to develop their coffees along a gradient, roasting quickly so that the outside of the bean develops faster than the inside, preserving some of the fruitier characteristics inside while allowing the flavors of the darker roast to rise near the surface of the bean. The risk here is that the inside will remain under-roasted, harsh and grassy, or that the outside will burn.
The darker roasted beans also undergo some obvious physical changes. The beans lose up to twenty per cent of their weight while nearly doubling in size. The greater weight loss of a dark roast in comparison with a lighter roast is consequently reflected in a higher price.