In last Friday's cupping, we had interesting conversation about "quakers", which are coffee cherries that hold an under ripe coffee bean. 

Quakers will not take a roast, so they are easy to spot in batch of roasted coffee because they are the occasional very lightly colored bean.  The also impart a sour, bitter flavor when brewed.

Some folks consider the presence of quakers in their beans as an indicator of quality--Cook's Illustrated recenlty reviewed several store-bought pounds of coffee and compared them in terms of quality by counting the number of quakers per pound.

We watch for quakers in every batch of coffee, pulling them out whenever we see them. We think we do a pretty good job a getting good green coffee, because our collection of quakers is quite small.