Where Do Coffee Beans Originate From, and Why Sizes Vary?

Ethiopian coffee beans often look uneven in size, roast color and density within a single batch, more so than Kenyan beans. The cause lies in genetics and logistics: Ethiopia holds close to two thousand registered coffee varieties, 1,927 native and 128 introduced, and cherries from many smallholders are pooled at centralized processing stations, so shapes and sizes mix together.

Where do coffee beans originate from matters here, since Arabica itself arose in Ethiopia. That genetic range produces long, short, thin and plump beans side by side. Processing adds another variable: natural, washed and semi-washed methods each change how the parchment, mucilage and silver skin are removed, and how evenly the green coffee dries before hulling.

Many coffee enthusiasts notice a phenomenon when they encounter coffee beans from African origins: Ethiopian beans are generally more inconsistent in size than Kenyan beans, with noticeably lower uniformity. Whether it's Yirgacheffe or Sidamo, washed or natural, it's common to see obvious differences in particle size and roast color within the same batch. Behind this phenomenon lie both the genetic diversity of Ethiopia's nearly two thousand coffee varieties and its unique cultivation patterns and centralized processing methods. This article will systematically review the variety classification and cultivation systems of Ethiopian coffee, and introduce three primary processing methods—natural, washed, and semi-washed—to help readers fully understand the roots of the morphological differences in African beans.

The green coffee beans we typically purchase have silver skin attached to their surface, not parchment layer. To understand this, we need to first recognize the structure of the coffee cherry. From outside to inside, it consists of the outer skin (exocarp), pulp (mesocarp), mucilage layer, parchment layer (endocarp), silver skin, and the seed. The parchment layer is what we commonly call the parchment. After primary processing, coffee is obtained as beans with parchment still attached; the hulling process is only carried out once the sales destination is determined.

If you have a particular preference for coffee from African origins, it's not hard to notice a pattern: compared to Kenya, Ethiopian beans tend to be uneven in size, with significantly lower uniformity. Whether it's Yirgacheffe or Sidamo, whether washed or natural processed, sometimes within the same batch you can observe obvious differences in roast color and particle size. This size inconsistency stems from two factors: the abundance of varieties and centralized processing.

Let's first get to know Ethiopia's coffee cultivation and harvesting methods.

Ethiopia is a country full of legend; the Arabica coffee we can drink and those we have never tasted all originate from this place. Ethiopia has nearly two thousand registered coffee varieties, including 1,927 native varieties and 128 introduced foreign varieties. Looking at appearance alone, Ethiopian coffee varieties are like a "grand garden"—long, short, thin, plump, there's everything you could imagine.

Long-shaped beans are distributed across all coffee-growing regions in the country. Based on observed proportions, the western Jimma area, including Limmu and Kaffa, has a higher occurrence of long-bean varieties. For example, Front Street Kaffa Forest contains quite a few long beans that, when brewed, display a citrus-honey character similar to Geisha. In Sidama or Yirgacheffe, however, the proportion of such varieties is relatively lower.

Small-bean varieties are more rounded in shape, with very small bean size, mostly between 14 and 15 screen sizes. This variety is probably the most familiar to everyone, frequently seen in Sidama and Yirgacheffe growing regions. Front Street has found it in samples from Harrar, and also encountered it in green coffee beans sold locally in Jimma. Compared to other areas, Sidama, Yirgacheffe, and the surrounding Arsi and Guji regions grow more of these small-bean native varieties. Front Street Huakui, Front Street Gedeb Cooperative, and Front Street Hamasho all belong to the more miniature type.

In addition to the rich variety, coffee cultivation patterns also intensify the degree of variety mixing in Ethiopian coffee beans. Ethiopian coffee cultivation can be divided by scale and pattern into: ● Forest coffee (8-10%): Coffee trees grow symbiotically with other crops in primary forests, without human management; farmers periodically go to harvest coffee cherries. ● Semi-forest coffee (30-35%): Coffee tree growing areas are located between the forest and farmers' living areas. Coffee trees, like forest coffee, are naturally growing varieties; farmers manage the growing areas and plant other cash crops. ● Garden coffee (50-55%): Coffee trees are planted around farmers' living areas, mostly planted by the farmers themselves. ● Plantation coffee (5-6%): Operated by large private growers, with more processing facilities and production capacity.

Coffee cultivation in Sidama and Yirgacheffe mostly falls under the garden coffee model, where coffee farmers plant coffee trees near their own living areas, harvest them themselves during harvest season, and then send them to processing stations near water sources for centralized processing (or they are centrally purchased by middlemen). Except for a few capable estates that can independently complete cultivation, harvesting, and green bean processing, many coffee beans from different regions and different varieties are mixed and processed by processing stations, then sent to auction houses for official grading and classification.

This is precisely why many Ethiopian coffee beans are named and distinguished by processing station or cooperative, and it is also one of the roots of multiple varieties being mixed within the same batch. Even coffee beans produced in different batches by the same processing station may have significantly different flavors. Taking Yirgacheffe as an example, Front Street Gedeb Cooperative, Front Street Konga Red Cherry, and Front Street Worka Cooperative present distinctive flavor profiles due to different origins and processing methods.

The natural method, also known as the dry process or drying method. Coffee cherries are spread out on large drying beds to be exposed to sunlight, and raked daily to ensure even drying. When the skin and pulp have dried to a moisture content of about 12%, the cherries are sent to machines to remove the skin and pulp.

Process: Sun-drying on beds - depulping - impurity removal - hulling - grading - packaging The natural method is a traditional and simple processing method, commonly seen in arid regions such as Brazil. Green beans obtained through natural processing have a rough surface and more silver skin than washed beans, but less silver skin remains during roasting.

Representative coffee beans: Front Street Gesha Village Red Label, Front Street Gesha Village Gold Label, Front Street Chaka, Front Street Kaffa Forest, Front Street Huakui

The washed method, also known as the wet process. Coffee cherries undergo floatation to remove twigs, leaves, stones, and other impurities, then are depulped. The depulped coffee fruit is soaked in water. The cherry contains a sticky mucilage layer, which is removed by soaking in water and using fermentation. Fermentation time ranges from 8 to 48 hours, during which constant attention is required to avoid contamination that could spoil the coffee beans. After fermentation is complete, the mucilage layer can be removed by gently rubbing with hands.

Process: Floatation - depulping - fermentation - washing - drying - hulling - grading - packaging It should be noted that washed coffee beans should be promptly rinsed clean and dried to avoid secondary fermentation causing contamination. The washed method is commonly found in origins with abundant water resources such as India. Washed coffee beans have a glossy surface, less silver skin, quality that is easy to control, and relatively uniform flavor.

Representative coffee beans: Front Street Yirgacheffe, Front Street Gedeb

Semi-washed method After floatation, the skin and part of the mucilage layer are removed, washed with water, and then dried in the sun.

Process: Floatation - depulping - washing - sun-drying Coffee beans processed by the semi-washed method have a sticky surface because some mucilage remains on the parchment.

The above content is compiled by CoffeeHunters, a coffee news website.