Coffee Botany 101
Let’s start at the root of it all… the coffee plant. Since coffee is not grown locally, many of us might not be familiar with how coffee is grown or what the plant looks like. In this post, we will take a few minutes to appreciate all of the parts of the plant that produces our beloved beverage.
Bear with us as we step into plant taxonomy class for a moment. Coffee is a member of the plant family Rubiaceae. (Fun fact: gardenias are also in this plant family!) The genus is called Coffea, and within that genus, there are over 120 species. The two species most popularly grown for coffee production are Coffea arabica and Coffea canephora (also known as robusta). Within these species are countless more subspecies and varieties.
The coffee plant is a woody shrub or small tree with glossy green leaves. It grows best at high elevations in the “coffee belt,” the region around the equator between the Tropics of Cancer and Capricorn. After planting, it takes about 3-5 years before a coffee tree will flower and fruit, but then it can continue producing for about 25 years.
Coffee plants have small, white, fragrant flowers, similar to jasmine. Although some coffee plants are able to self-pollinate, the help of pollinating insects like bees significantly increases yields. After pollination, it takes almost 9 months for the flower to turn into the ripe fruit, which are called coffee cherries. The cherries are green at first, and then they turn yellow and eventually red when they are ripe. They grow in clusters and do not all ripen at the same time, so coffee cherries are usually harvested by hand so that they can be picked at peak ripeness.
Inside each coffee cherry are two light green slippery seeds, or what we call coffee beans. Although there is not a lot of fruit surrounding the seeds, there are several distinct and important layers in the cherry. Just inside the tough red skin is a thin layer of sweet pulp and mucilage, followed by a papery parchment. Finally, a layer called the silverskin envelopes each seed. The silverskin is also called the chaff when it comes off in roasting. Understanding the anatomy of a coffee cherry is important to understanding the various processing methods that are used to prepare the seeds for transport and roasting.
It takes about 2,000 hand-picked cherries to produce just one pound of roasted coffee beans. A single tree yields only about that much each year. Needless to say, we are in awe of coffee trees and the patient, hard-working people that tend to them. Another day we will delve into how coffee is processed, transported, roasted and brewed, but we thank you for joining us in this lesson on coffee bean botany. Class dismissed!