Seed Extraction
Welcome back! In our first two blogs, we talked about coffee as a crop and general coffee-growing region influences on the roasting recipe. In this article, explanations of three types of seed extractions from these cherry-like fruits are discussed along with their influence and development of inherent flavors that find their way into your morning cup.
Coffee is grown on an evergreen shrub with multiple species having their own distinct flavors and favored growing conditions. White flowers grow in clusters along branches, often smelling of orange blossoms with a hint of jasmine. Pollinated flowers produce small, green fruit ripening at different times along the branches turning green to deep red hues. Because coffee is the roasted seed of these fruits, the skin and pulp must be removed, generally using one of three methods, dry, wet, and honey process.
The dry method is also referred to as “natural” processing. Every crop season, throughout coffee growing regions, any concrete surface, including courtyards, basketball, or soccer areas is covered in rows of ripened coffee cherries. Sophisticated farms or processing sites have elevated stacked trays of metal mesh. Coffee cherries are spread in single layers manually rotated with rakes and hoes for even sun exposure. The skin and pulp shrivel and dry on the seed. Once dehydrated, the cherries are gathered and agitated, sluffing off dried fruit flesh, and exposing the seed.
Dry processing is utilized in areas of water scarcity, on islands, or in areas of low rainfall. When the fruit pulp is allowed to dry on the bean, flavors are retained. Often these coffees have intense tasting profiles with often earthy, red wine and spicy notes. Dry processing requires significant surface area and the controlled drying is manually intensive.
Wet processing occurs in tanks where coffee cherries are water-soaked, weakening the skin and loosening the pulp. They are mechanically compressed, freeing the seed while separating it from the pulp. Dried on surface lots in the sun, or on low heat in large spinning cylinder dehydrators, seeds are quickly processed. Wet processed coffees are often recognized by their “bright” characteristic, and “fleeting” finish, meaning they don’t linger as an after taste.
Honey processing is a newer de-pulping style. It follows the same regiment as wet-processed coffees, but are allowed to ferment a bit prior to being separated and dried. Honey processed coffees have a distinct flavor, regardless of the growing region, and are often described as having a slight honey hint.
These descriptions are greatly simplified. The hard work that happens at origin is multistep and heavy in manual labor. Many uncontrollable conditions can ruin a crop post-harvest. An unexpected rainfall can ruin months of work in a short afternoon and all processing has its own precision creating consistent flavors buyers look for each year.
Consistency is key in all aspects of the coffee journey. In our next article, we will take a peek into roasting coffee and the precision required to make that morning coffee the same from one bag to the next.