Excelsa Coffee: Cultivating the Resilient, Aromatic Bean
worldreview1989 -Excelsa coffee (Coffea liberica var. dewevrei, though often still referred to as Coffea excelsa) is one of the four main commercially cultivated coffee species, standing alongside the dominant Arabica and Robusta, and its close relative, Liberica. Often overlooked in the global market, Excelsa is a true hidden gem, prized for its complex, unique flavor profile that ranges from fruity and tart to dark, rich, and smoky. More importantly for the future of coffee, it is a highly resilient species, making it an increasingly important crop in the face of climate change.
 |
| Excelsa Coffee: Cultivating the Resilient, Aromatic Bean |
Cultivating Excelsa presents a unique set of challenges and rewards. Its arboreal nature (growing like a tree rather than a bush) and particular ecological requirements demand specific attention from farmers.
I. The Optimal Growing Conditions for Excelsa Coffee
Excelsa's strength lies in its hardiness and adaptability, particularly its ability to tolerate warmer climates and poorer soils than Arabica. However, to produce high-quality beans, specific environmental conditions are ideal.
1. Climate and Elevation
Unlike Arabica, which requires high altitudes and cooler temperatures, Excelsa is known for its versatility across various elevations, though optimal growth is often achieved in the mid-range.
Altitude: Excelsa can thrive from near sea level up to about 1,300 meters above sea level (m.a.s.l.). The ideal range is often cited between 1,000 to 1,300 m.a.s.l., where the cooler temperatures encourage slower maturation and better flavor development, though some reports indicate successful growth at much lower elevations (0-750 m.a.s.l.), showcasing its broad adaptability.
Temperature: It prefers a tropical climate with consistent warmth. The ideal temperature range is typically $20^{\circ}\text{C}$ to $28^{\circ}\text{C}$ ($68^{\circ}\text{F}$ to $82^{\circ}\text{F}$). Its heat and drought tolerance make it a beacon of hope for farmers in regions struggling with rising global temperatures.
Rainfall: Excelsa requires ample rainfall, ideally an average annual rainfall of 1,500 to 2,500 mm. High humidity is also key to its optimal growth.
2. Soil Requirements
Soil quality plays a critical role in the health and productivity of the tall Excelsa tree.
Soil Type: Excelsa generally prefers well-drained, rich soil. It is known to flourish in red basalt soil, particularly in areas like Vietnam's Central Highlands, which provides the necessary pH and nutrients. It also does remarkably well in peat soils or sandy/clay loam, demonstrating its ability to thrive where other coffee species fail.
Soil pH: The ideal soil acidity is slightly acidic, generally ranging from pH 5.0 to 6.5.
Root System: Excelsa coffee plants possess a deep, robust root system. This characteristic not only provides stability for the tall tree but also grants it superior drought resistance, allowing it to draw moisture from deeper soil layers during dry spells.
3. Shade and Resiliency
Shade: While Excelsa can tolerate full sun, it is often grown in partial shade or dappled sunlight. Shade-grown coffee typically yields a more complex flavor profile and contributes to higher biodiversity on the farm.
Pest and Disease Resistance: A major advantage of Excelsa is its impressive natural resistance to many common coffee diseases that plague Arabica and Robusta, such as coffee leaf rust (Hemileia vastatrix). This resilience makes it a low-maintenance and potentially more sustainable crop, reducing the need for chemical interventions.
II. The Cultivation Process: From Seed to Harvest
Growing Excelsa is similar to other coffee varieties in the initial stages, but its unique growth habit—as a towering tree—introduces specific requirements for planting and maintenance.
1. Nursery and Germination
Seed Selection: High-quality, viable seeds from healthy, productive parent trees are selected.
Germination: Seeds are planted in a nursery bed or specialized soil medium. Excelsa seedlings are typically nurtured in the nursery for 6 to 8 months until they are strong enough for transplanting. This meticulous initial stage is crucial for the plant's long-term health.
2. Transplanting and Spacing
Due to its potential height (it can reach up to 15-20 meters) and expansive canopy, Excelsa requires much more space than Arabica or Robusta bushes.
Field Preparation: The field should have well-prepared, nutrient-rich soil with good drainage.
Planting Density: Excelsa trees need ample space to spread their roots and branches. Recommended spacing is often about 3–4 meters between rows and 2–3 meters between individual plants. This wide spacing ensures each tree receives enough sunlight and air circulation, and makes future pruning and harvesting feasible.
3. Tree Management and Pruning
The arboreal nature of Excelsa necessitates different management techniques than those used for the more shrub-like Arabica and Robusta.
Pruning (The Essential Task): Regular, skillful pruning is mandatory to manage the tree's height. If left untended, Excelsa can grow too tall to be harvested efficiently. Farmers "control" the height—often keeping it to a manageable 4-5 meters—through a rigorous pruning schedule. This process is an art, as poor pruning can severely affect yield.
Fertilization: Regular fertilization, especially during the growth and flowering stages, is required to support its high productivity and large biomass.
Patience: Excelsa is a slow-maturing plant. It takes approximately 3.5 to 4 years before the first significant harvest.
4. Flowering and Maturation
Excelsa has a notably long and staggered reproductive cycle compared to other coffee types.
Flowering: The trees flower multiple times during the harvest season.
Fruit Maturation: Excelsa coffee cherries have an exceptionally long maturation period, taking about one full year from the flower bloom to the final ripe fruit. This prolonged period is thought to contribute to the bean's complex and deep flavor.
5. Harvesting and Processing
Harvesting: Given the staggered maturation and the height of the trees, Excelsa cherries are typically hand-picked to ensure only fully ripe cherries are collected. This selective picking process is vital for quality, as the long maturation cycle means under-ripe cherries can significantly detract from the final cup.
Processing: The large, irregularly shaped beans are processed using either the wet (washed) or dry (natural) method. The choice of method significantly impacts the final flavor, with natural processing often enhancing the bean's characteristic fruity and dark-chocolate notes.
Conclusion
Excelsa coffee cultivation is a blend of tradition and forward-thinking resilience. While it demands patience and meticulous tree management due to its immense size, its ability to thrive in varied, often challenging, tropical environments—especially those affected by increasing heat and drought—positions it as a vital species for the future of global coffee. For farmers in Southeast Asia (like Vietnam, the Philippines, and Indonesia) and emerging coffee regions, mastering the cultivation of the Excelsa tree is not just about growing a unique product; it is about embracing a climate-smart future for coffee.