I discovered another coffee type few days ago. It is known around the world for a long time but I just discovered it recently. It is rare, but not as rare as coffee alamid. Expensive but not as expensive either. A completely non-controversial coffee. I mean it never undergoes special treatment like passing via civet anus.
Can be gathered by patiently selecting beans from a group. Approximately 5% of harvest are of this type. As of date, no special interest about increasing its output. On the other hand, some merchants are raising civet cats for the purpose of alamid coffee production.
I accidentally read it on zeccupa.com (http://www.zecuppa.com/coffeeterms-bean-defects.htm). Here is their concise article.
A single rounded bean from a coffee cherry which bears one bean instead of the usual flat sided pair of beans. Also known as ‘caracol’, ‘perla’ and ‘perle’. Peaberries are frequently separated and sold as a distinct variety. Papua New Guinea and Tanzanian peaberries are good examples.
Another popular example I found on web is the 100% Kona Peaberry.
The peaberry, also known as caracol or caracoli, means snail. It is a coffee abnormality instead of variety. A single cherry should produce two beans instead. Single bean development results to rounder but smaller coffee. It roast differently and usually separated from the batch. Then roasted and sold as special coffee product.
Scientific information about peaberry are rare. Different coffee webs have common reasons why it is superior than regular: 1) Roast evenly, rounder edges allows better rolling around roasting machine. 2) Roast evenly two, higher density value allows more efficient heat transfer. and 3) It is believed, the substances intended for two beans are given to one, resulting to a better coffee end quality.