The coffee plant produces a round, red fruit about the size of a grape, known as a “coffee cherry.” While there is some variation in size and density – depending on the location and type of tree, about 90% of the Arabica cherries harvested have two coffee seeds (or beans) inside.
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In the other 10% of Arabica crops, one of the seeds sometimes fails to develop, and the other grows to fill both spaces. This single-bean is known as a peaberry, and while it could be seen as a defect, is actually often sorted out as a distinct group. This is easy to do, peaberries are significantly smaller than standard beans, with a more rounded shape.
Peaberries don’t necessarily taste any better or worse than their standard counterparts, however, sometimes a peaberry crop can display a distinct intensity or sweetness. This could be due to only one bean receiving all the nutrients, potentially producing a more concentrated flavor. Peaberries also roast differently because of their rounded shape, and this can have an effect as well.
From our Roastmaster –
Because peaberries are rounded (versus the flat shape of a normal coffee bean) they tend to roll in the roasting drum rather than tumble which contributes to a more uniform roast. Also, peaberries are only one size, whereas a normal coffee bean might be a blend of 2 or more sizes. Thus, having a uniform screen size also contributes to the uniformity of the roast.