How Are Coffee Beans Harvested?

The Coffee Plant

Coffee grows on a large plant that is so tall, many refer to it as a tree. Coffee producers, however, tend to keep the plants at a shorter height to make it easier for them to harvest the beans. When coffee trees are first planted, it can take 3 to 4 years for them to produce blossoms. Once white blossoms appear, they will produce the coffee fruit. While we think of coffee as a "bean," it is actually the seed that is found inside of the coffee tree fruit, called a cherry.

Harvesting the Coffee Fruit

When the cherries on the coffee plant turn ripe, they are harvested by being stripped from the plant. They fall onto a large sheet, and they are tossed into the air, which separates the cherries from the plant debris, which is carried away by the wind. The coffee cherries must be processed quickly after being harvested. There are two methods of processing coffee: wet and dry. The wet method of processing coffee happens within 24 hours of picking the cherries. The pulp is removed from the cherries on a machine, and the skin and pulp is washed away. During the dry method of processing coffee, the cherries are laid in the sun until they dry and you can hear the beans rattling inside. The shells are crushed, and the beans are removed. Drying in the sun can take up to 10 days.

Processing the Coffee

Once the beans have been removed from the cherries, they are then put into a tank where they are fermented for 48 hours. After fermentation, they are put out to dry in the sun, either on terraces or tables.The final stage of drying takes place in a mechanical dryer, which finalizes the drying process in 5 to 6 hours. After being dried, the beans are hulled. Hulling is a process in which all of the layers of skin covering the bean are removed and the beans are shined. After hulling the beans are then separated by size and color.

While there are places where separating by size is still done by hand, it is most often done by machinery. Some machines separate the beans first by weight, shaking the beans on a pulsating table. The heavy beans flow to one side while the lighter, poorer-quality beans go to the other. The preferred method of sorting by color, however, is still the hand method. Beans that are too dark or too light are removed, as well as very lightweight beans.

The Final Stage

At this point the beans are shipped to be roasted. They are still green in color when they are unroasted. During the roasting process the beans are put into large drums that are heated to temperatures of 550 degrees F (288 degrees C). The drums tumble the beans to prevent burning. The heat brings the oil out of the beans, and this is when they begin to turn brown. When they get to a temperature of about 400 degrees, they begin to pop. The beans typically pop twice, and it is after the second pop that the beans are considered done. The length of time the beans are roasted is how we get the different varieties of coffee, from typical mass-production coffee that roasts for about 8 minutes, to dark espresso coffees that roast for up to 15 minutes.

Resources

• More Info on Coffee Bean Sorting
• Coffee Research