AGRONOMY
What happens to our coffees before they ever leave origin? That might be something that you’ve thought about before, or maybe this is the first time. Either way, it’s worth taking a look at: a LOT happens on the farm before any coffee has even been purchased by a roaster or importer. It has a huge impact on what ends up in the cup. First, let’s take a brief look at the coffee plant.
Coffea arabica is native to the cloud forests of Ethiopia - where mountainous terrain and rainforests meet. There are a lot of other species of coffee, notably Coffea canephora, more commonly known as robusta. The exact origin of robusta is unknown, but we suspect it’s native to South Sudan - to Ethiopia’s north. Arabica is only found growing indigenously between 1000 and 2000 meters above sea level (MASL), but farms can be found anywhere from 0-2800 MASL. Whereas robusta can be grown at lower altitudes, higher temperatures, and under more direct sunlight, arabica is an understory plant. It grows beneath the shade of taller trees; it is not adapted well to full sun, and it likes daytime temperatures between 62-73F. It isn’t frost tolerant - sustained temperatures less than 39*F will kill the plant. However, a balance of altitude and latitude among other factors can result in compatible microclimates outside these parameters.
Most arabica plants in the wild are no more than three or four generations old - meaning, they still favor the climate of their native range. Their leaves are dark green in color with ruffled edges, and they grow in pairs along straight branches. Roots are concentrated in the first 30cm of soil and extend in a 1.5m circle around the single trunk. Unless the trees are trained or “stumped,” arabica has only one trunk. Flowers appear where the leaves meet in clusters of up to 16 (an “inflorescence”). The fruit develops along the stems when the flower fall. They’re quite beautiful; they have fie distinct petals and smell a lot like Jasmine. The coffee plant is entirely self-pollinating, though pollinators can certainly aid in the process.
And that’s key - coffee is a fruit! The coffee “bean” is actually the endosperm and seed of the coffee plant, and each cherry typically has two that face each other. Though we use the term “cherry” to refer to this fruit, it’s actually a “drupe.” Other drupes include peaches and apricots - they’re defined by the seeds having a distinct t line that splits open when it germinates and begins to grow (hence the line present in all coffee beans). Specifically, it’s a climacteric fruit, meaning that it continues to ripen after you pick it. Think bananas, tomatoes, or avocados. These fruits are usually harvested underripe so that they’re at peak condition when they reach the customer. However - coffee has optimal flavor only when the most ripe cherries are harvested. Perfectly ripe can become overripe in just a few hours, leading to fermenty “off” flavors. It’s imperative to begin processing coffee no less than 20 hours after it was picked. Typically this is done same day.
Unripe cherries range through shades of green, while ripe cherries are a deep ruby-red. Certain varieties can ripen to yellow, orange, or even pink. Overripe cherries can be grey-ish red, to purple, or even black. Many specialty procurers practice what’s known as “selective picking” - meaning they only harvest the ripest cherries. This will take several passes at the same plant, because coffee cherries don’t ripen all at the same time. The alternative is “strip picking,” or using a mechanical harvester or rake to pick all the ripe and unripe cherries at the same time. The decision is largely economic; selective picking can lead to much higher quality lots, but is much more labor-intensive. Thus a balance must be struck between labor costs and value added from picking more selectively. Additionally, some environmental factors are at play. The gradient of the slope the trees are planted on, the density of the planting, even the weather - do the plants have 1-2 flowerings, consistent with a defined wet and dry season, or continuous “flower showers” as is more common in tropical areas; all these influence the choice whether to selectively or strip pick.
After harvest, coffee needs to be processed, that is, we need to get to the seeds inside the fruit and properly dry them before exporting.