>I usually took that to be an indicator of freshness.
I've only heard it described as a flaw. None of the recently and well-roasted beans from the local roasters I visit sell oily beans. But Starbucks? Or typical grocery coffee? Usually always dark and oily.
Surface oils are not an indicator of quality either way. The roasting process brings oils to the surface, so darker roasts tend to have more surface oils. From what I understand, the oils appear a few days after roasting, and then dry out/reabsorb after a few weeks.
Mostly how I see it too.
I roast my own and I like it quite dark. I stop roasting when the first bit of oil appears and sprinkle water on to slow things down. The oil keeps coming out until the heat leaves, so getting the heat out of it is my objective. Stir and a little water, and wait until it cools about to touch.
The oil doesn’t seem to keep coming out after the heat has left.
I've only heard it described as a flaw. None of the recently and well-roasted beans from the local roasters I visit sell oily beans. But Starbucks? Or typical grocery coffee? Usually always dark and oily.