Coffee is cherished for its stimulating effects and complex flavor profile. This globally consumed beverage begins its life as a small, brightly colored fruit growing on the Coffea tree. The simple answer to whether coffee is a fruit is yes; the raw material for coffee is the seed found inside this fruit, commonly referred to as a coffee cherry.
The Botanical Classification of the Coffee Cherry
The coffee cherry is the fruit of the Coffea plant, which grows in clusters along the branches of the tree. Botanically, this fruit is classified as a drupe—a fleshy fruit with a thin skin and a central pit containing the seed, similar to a peach or an olive. Some botanists also categorize it as a berry due to its size and typical seed count.
The fruit is composed of several distinct layers. The outermost layer is the exocarp, a smooth, thick skin that transitions from green to red, yellow, or purple when ripe. Beneath this is the mesocarp, a sweet, fruity pulp that protects the developing seeds.
Immediately surrounding the seed is the endocarp, a thin, parchment-like shell. This fibrous layer must be removed during processing. A sticky, sugary layer called mucilage is found between the mesocarp and the endocarp, which significantly influences the final coffee flavor.
Deconstructing the “Bean”
The term “coffee bean” is a commercial misnomer, as the item is scientifically categorized as a seed, not a true bean from the legume family. The visual resemblance to true beans, such as kidney beans, led to the common name used worldwide. The seed is the reproductive part of the plant, contained within the fruit.
Most coffee cherries hold two seeds, nestled flat against each other within the parchment layer. A small percentage (around 5 to 10%) contain only a single, rounded seed, known in the industry as a peaberry. These seeds are primarily endosperm, the tissue that stores nutrients for the embryo.
A delicate, paper-thin layer called the silverskin adheres tightly to the surface of the seed. This layer is the last remnant of the fruit material. It is mostly shed as chaff during the roasting process, though a small amount can sometimes remain.
How the Fruit Becomes the Brew
To isolate the seed for roasting, the fleshy fruit layers must be removed in a process that significantly affects the final flavor. The two main methods used are the dry process and the wet process. These techniques determine how long the seed remains in contact with the fruit’s pulp and mucilage.
The dry, or natural, process involves laying whole cherries out to dry in the sun for several weeks. The fruit’s skin, pulp, and mucilage dry onto the seed, imparting a fruit-forward flavor profile before the dried layers are mechanically hulled off. This is the oldest form of processing.
The wet, or washed, process immediately removes the skin and most of the pulp using a mechanical depulper after harvesting. The seeds, still covered in mucilage and parchment, are then fermented in water tanks. This fermentation breaks down the mucilage before it is washed away, resulting in a cleaner, brighter, and more acidic flavor in the final cup.