The coffee plant, scientifically classified under the genus Coffea, is the tropical evergreen responsible for the world’s most consumed beverage. It is a member of the Rubiaceae family, which also includes gardenia and cinchona. This woody perennial starts as a simple seedling and matures into a productive, flowering specimen that provides the seeds we roast and brew.
Overall Structure and Growth Habit
The coffee plant naturally grows as a small tree or large shrub, exhibiting a conical or columnar shape when unpruned. In its wild state, particularly the Coffea arabica species, the plant can reach heights of 30 to 39 feet (9 to 12 meters). The primary vertical shoot, known as the orthotropic stem, supports the horizontal, fruit-bearing branches called plagiotropic shoots. These branches grow in pairs along the main trunk, giving the plant a distinctive layered appearance.
In commercial cultivation, however, growers rarely allow the plant to reach its full potential height. The trees are aggressively pruned to maintain a manageable size, typically between 5 and 10 feet (1.5 to 3 meters). This practice facilitates easier harvesting, which is often done by hand, and helps the plant dedicate more energy to fruit production. C. arabica tends to be smaller and more delicate than the more robust C. canephora (Robusta).
Distinctive Features of the Foliage
The plant’s foliage is a hallmark of its tropical nature, consisting of leaves that are dark green, glossy, and possess a waxy texture. These leaves are typically elliptical or oval in shape, measuring 4 to 6 inches (10 to 15 centimeters) long. They are arranged in an opposite pattern on the lateral branches. The surface of the leaf often appears slightly wavy along the margin, providing a subtle texture to the smooth, deep-green canopy.
The thick, waxy cuticle of the leaves helps the plant retain moisture and protects it from the intense tropical sun. New growth often emerges with a lighter, sometimes bronze or purplish tint, eventually hardening into the mature dark green color. This dense, evergreen foliage allows the plant to photosynthesize year-round, supporting the continuous, multi-stage growth cycle of its fruit.
The Progression from Flower to Fruit
The reproductive cycle begins with a bloom of small, star-shaped white flowers that appear in dense clusters along the branches. These blossoms emit a powerful, sweet fragrance often likened to jasmine, signaling the start of the fruiting period. Following successful pollination, the flower quickly gives way to a tiny, hard green fruit, which is botanically classified as a drupe and commonly referred to as a coffee cherry.
The fruit remains green and firm for many months as the seeds inside develop and mature. The color changes from a uniform green to a vibrant shade, most often deep crimson red, although some varieties ripen to bright yellow or orange. These fully ripened cherries resemble small, lustrous jewels clinging tightly to the branches.
Anatomy of the Coffee Cherry
The coffee bean is the seed found inside the ripe cherry, protected by several distinct layers of fruit tissue. The outermost layer is the exocarp (the smooth, colored skin). Beneath this is the mesocarp, a thin layer of sweet, sticky pulp. Next is the parchment, or endocarp, a tough, papery hull that completely encases the seeds.
Within the parchment, the seeds are typically nestled face-to-face. Each seed is further covered by a delicate, silvery membrane known as the silverskin. In approximately 5 to 10% of cases, only one seed develops inside the fruit; this single, rounded seed is known as a peaberry.