What is a Peaberry?
What is so different about these cute little uniform beans, and why do we love them?
Inside a regular coffee cherry, two seeds typically develop, with their flat sides facing each other and their rounded backs facing outward. These seeds, once processed and roasted, become what we know as coffee beans.
A Peaberry, however, is a naturally occurring mutation where only one seed forms inside the cherry. This happens when one ovule fails to pollinate, allowing the single seed to grow larger and rounder due to the extra space. Peaberries are estimated to make up about 5–10% of a coffee harvest.
Not all single-seed cherries qualify as peaberries; some may develop a lone seed that still has the flat shape of a regular bean. Peaberries are usually separated from the rest of the coffee beans during post-harvest sorting, using processing machinery that sorts and screens coffee by size and weight.
In Brazil, peaberries are commonly known as “moka” and are more prevalent in one harvest season compared to the next. This variation is linked to environmental factors, including fluctuations in temperature and rainfall, which impact coffee plant physiology and flowering cycles. Certain climates, such as stress conditions during flowering can increase the occurrence of peaberries.
When we prepare samples in the Costa Cafe export office during the harvest season, we use a special screen number 12 to separate the Peaberries from the other screen sizes.
Last harvest we decided to make two lots of single producer peaberry after we split and cupped the different screened beans separately an liked them as lots of screen 15+ and Peaberry.
We are hands on and personally making these decisions during the harvest for the coffee that ends up here. This is a unique approach that most don’t get the opportunity to have and we are lucky to have this enabled by our direct relationship with origin.
What can we say about the quality of peaberries?
In some countries, there is a common belief that peaberries have a superior flavour profile because they do not have to share nutrients with a second seed. We have heard from clients that peaberries can have bright acidity, pronounced sweetness, and a more complex and concentrated flavour.
Additionally, they tend to have a higher density and when screened together they become a really uniform lot in size of each bean, which can affect roasting behavior making it – some say – easier to roast. Their round shape allows them to roll more efficiently in drum roasters, potentially leading to more even heat distribution. However, their denser structure can result in heat taking longer to reach the center of the bean.
The quality of a peaberry is ultimately influenced by the same factors as regular coffee beans—variety, altitude, processing methods, and overall farm management. High-quality peaberries exist, but their excellence is more a reflection of these factors rather than their shape alone.
Our conclusion is that while they remain an intriguing and desirable mutation, their quality is ultimately shaped by the broader aspects of coffee cultivation, processing, and roasting.
We personally find they have a little extra sweetness, which might be due to the extra mucilage that each little individual bean get to itself compared to a cherry with two beans. That’s not scientific though, it’s just our observation.
What do you think of peaberries?
Written by: Bruna Costa
