Oily vs dry espresso beans

[patrickinpdx]

Any feedback on oily vs. dry espresso beans? Do oily beans affect crema? I guess my assumption is that espresso beans should be on the drier side.
Thanks

[another_jim]

Lighter roasts stay dry. Dark roasts are oily from the get go. Darker full city roasts will start out dry and get oily after 3 to 6 days. The taste is most dependent on light or dark roast, the oiliness is a side effect that does not affect the taste.

When I was growing up in Munich, the standard was a medium dark roast that oiled up after about 4 days, and dried out again after 14 or so. The shoppers' wisdom was to buy only beans that were oily, since the dry ones were either too fresh or too stale. This is apparently so ingrained in parts of Germany now that the mass roasters put vegetable oil on the lighter roasts. I regard the idea extent in some aficionado circles that oily is always bad, since the oil gets rancid, as a similarly silly food superstition.