Coffee Plant Biology: From Seed to Cherry

Brewed beverage made from seeds of Coffea genus.

Coffee, a beloved beverage worldwide, begins its journey as a small seed in a fruit known as a coffee cherry. The two main species of coffee plants are Coffea Arabica and Coffea Canephora, more commonly known as Robusta.

Arabica vs Robusta

Arabica plants, which account for about 60% of the world's coffee production, are generally considered to produce higher quality coffee. They are grown at higher altitudes and require a specific climate, with temperatures between 15-24°C (59-75°F). Arabica beans are oval-shaped and have a sweeter, softer taste, with tones of sugar, fruit, and berries.

Robusta plants, on the other hand, are more resilient and can grow at lower altitudes. They can withstand a wider range of temperatures and are less susceptible to pests and diseases. Robusta beans are rounder and have a stronger, harsher taste, with a grain-like overtone and peanutty aftertaste.

The Life Cycle of a Coffee Plant

A coffee plant begins its life as a seed, which is usually planted in large beds in shaded nurseries. After 6 to 8 weeks, the seed germinates and a plant with two cotyledon leaves will emerge from the soil.

The seedlings are then moved to individual pots where they will be carefully watered and shaded from bright sunlight until they are ready to be planted. Coffee plants can live up to 100 years, but they are most productive between the ages of 7 and 20. Proper care can maintain a plant's productivity for longer.

The Anatomy of a Coffee Cherry

The coffee cherry is a small fruit that grows on the coffee plant. It typically contains two seeds, which we know as coffee beans. The cherry's outer layer is called the exocarp, followed by the mesocarp (a sweet pulp), and the endocarp (a protective parchment). Inside, the two coffee beans are surrounded by a thin membrane known as the silverskin.

The Impact of Climate and Altitude

Coffee plants require a very specific climate to thrive. They need a constant temperature between 15-24°C (59-75°F), without the temperature fluctuations found in most temperate climates. They also require a significant amount of rainfall, ideally between 1500-3000 mm annually.

Altitude also plays a significant role in the flavor profile of coffee. Higher altitudes, with their cooler temperatures and more abundant rainfall, tend to produce coffee with higher acidity and more nuanced flavors. Lower altitudes yield coffee with lower acidity and more robust flavors.

Understanding the biology of the coffee plant is crucial to appreciating the complexity and variety of flavors we enjoy in our coffee cups. From the species of the plant to the altitude of its growth, each aspect contributes to the unique taste of every coffee bean.