Premium coffees are most often classified by their geographical origin – for example, Kenyan AA coffee or Sumatran coffee. The term "peaberry," though, is not a geographical identifier for coffee. Rather, the design of a coffee as a "peaberry" relates to the type of coffee bean itself.

Typically, the coffee cherry, or fruit, that forms on a coffee plant contains a bean that forms two halves. These typical beans are flat on one side. Sometimes only one of the two seeds becomes fertilized. In that case, the coffee cherry contains a single bean. This single bean is round or oval in shape, similar to a pea. Thus, such an individually formed coffee bean is known as a "peaberry," or less often as a "caracol." Roughly five percent of all coffee beans are reported to be peaberries, so there is no question that peaberry coffee is rare.

In high grade Arabica coffees, peaberries are generally separated from regular "flat" coffee beans. A coffee labeled as a "peaberry" should contain only peaberry beans. Peaberry coffees – in contrast to regular coffee beans – are claimed to provide a superior taste. One school of thought argues that peaberry beans are superior to regular beans due to the roasting process. Since the peaberries are oval in shape, they roll easily in the roasting chamber, thereby providing a more even roasted bean.

Another argument for the superiority of peaberry coffee is the flavor of the bean itself. The single peaberry bean is smaller and more dens than the two typical beans. As only one bean is formed, the sole bean is frequently reported to be more robust in flavor and more acidic (generally good for taste) than regular Arabica coffee beans. Still others argument that the superiority of peaberry coffee beans comes from the rigorous selection process whereby the regular beans are separated out from the peaberries.

Peaberry coffee is also designed by its geographic origin. For example, one of the most popular peaberry coffees is Tanzanian Peaberry. Even the most expensive coffees such as Kona and Jamaica Blue Mountain come in peaberry varieties. So the next time you purchase a single origin coffee you may want to try a peaberry variety to see if you can taste the difference. Although still hard to find at traditional retail establishments, premium peaberry coffees are now readily available through online stores.