What makes Peaberry Reserve Coffee so interesting is its anatomy. First, we will start with a little coffee bean lesson. When coffee is picked it is referred to as a coffee cherry. The bean lives inside the skin and fleshy pulp. The typical bean grows two beans to a fruit, flat against each other like halves of a peanut. (See image above.) On a rare occasion, about 5% to 10% of the time, the coffee cherry will contain only one bean. (See image below.) These beans are referred to as "peaberry" while the normal coffee beans are referred to as "flat berry".
This is considered a natural mutation of the coffee bean inside its cherry. The beans are smaller, denser, and rounder than regular beans, and don’t have that flat side. The Peaberry is found in all regions, so the distinction is solely on anatomy.
Image Above: Inside Peaberry Cherry
Why are they called a Reserve Coffee bean? It is impossible to tell a bean is a peaberry until after picking and processing. Once they are picked and processed then these lovely round beans need to be hand-sorted. Peaberry beans tend to roast differently. The alleged higher bean density may improve heat transfer in the roasting process and thus requires a slower roast. Thus the peaberry reserve coffee bean tastes different than the flat berry coffee bean from the same crop. Many peaberry fans note that the Peaberry Reserve Coffee has a sweeter and more flavorful taste profile.