Coffea
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The genus Coffea, is of the family Rubiaceae and contains the ten different species of coffee plants. This genus produces all the coffee that is consumed worldwide through the production of two small beans in the middle of a coffee trees' fruit. A tribe in Ethiopia first discovered the power of coffee and caffeine before 1000 AD. They noticed their herds had more energy after eating a certain berry. From there the world started to consume the drink daily and it became a normal way of life.[1] The number of Americans who consume coffee continues to rise and is at the highest point it has ever been, over 166 million Americans are drinking coffee everyday. [2]
Anatomy
The Coffee plant is a tree like shrub that can grow up to 5 meters tall.[3] All plants in the genus Coffea are dicots, meaning hey have two cotyledons so they have those characteristics of a dicot. This means that they have a primary taproot with much smaller secondary roots. This as well means that in their stems the vascular bundles are arranged in a ring formation instead of being scattered everywhere. Again being apart of the Dicotyledonae means that a plants leaves will have branched veins (Levine and Miller p 570). The coffee plant's leaves last year round, meaning they are evergreens. The leaves range in size depending on the species usually from 10-15 cm [4], but they all are dark green and shiny [5].
A coffee plant begins to develop flowers in about the third year of its growth. The flowers are white and have either five or six petals. The flowers usually don't last very long because they wilt and die soon after fertilization. A coffee plant, though, can produce up to 30,000 flowers in one year![6] This means that there will be many chances to produce a healthy offspring for each plant. A few years after a plant begins to produce flowers it will have the ability to produce fruit that can be harvested. After fertilization it will take 15 weeks for the ovaries to develop into the berry found on the plant.[7] The oval shaped fruit found on the coffee plant is called the cherry or the drupe. These berries are about half an inch long and contain two seeds. [8] They start off as green and then when they ripen they turn to a red color. It takes about 7 to 9 months to get to maturity, but if a berry is too ripe it will continue to darken until it is black.[9] Inside of the cherry there are two small beans located, surrounded by a protective pulp, the mesocarp [10].
Reproduction
The coffee plant has "perfect" flowers - containing both the female parts (the pistil), and the male parts (the stamen). On top of the pistil is the stigma, which can be sticky. The stamen produce a sticky substance called pollen. Pollination occurs when pollen from one of the stamen enters into the stigma of another plant of that same species. If a plant is pollinated by itself it is called self-pollination and if a plant is pollinated by a different plant it is called cross-pollination. Plants rely on insects, animals, or the wind to pollinate themselves. This can happen when an insect is trying to get nectar from a plant the pollen can rub off onto a leg and be transferred to another plant the next time he feeds. [11]
Ecology
Coffee grows in regions such as Brazil, Vietnam, Indonesia, India, Central America, East and West Africa, including Ethiopia, the coffee's native country. Depending on where the beans come from they can have different tastes, flavors, and aromas.
It can grow in a variety of soils as long as the soil is deep and acidic. The soil needs to be deep because their roots can grow between one and two meters. They also do better in higher altitudes, upwards of 1,375 meters. [12]
For human harvesting, the prime age of a coffee plant is between 30 and 40 years old, but there are some plants that are still healthy and over 100 years old. Beans can be harvested starting around the their 7th of 8th year of growth[13].
Human Uses
One of the most popular uses for the coffee beans is production of the drink, coffee. Seventy five percent of the world's coffee is produced by C. arabica, and the rest is mostly produced by C. liberica and the Robusta variety of C. canephora.[14] To begin the process of making coffee the berries of a coffee plant are hand picked and the flesh removed from around the bean. They are next fermented in water around a day to remove the pulp around the bean. Next they are roasted at 200 degrees Fahrenheit until they are somewhere in between a light and a dark brown color. [15] While they are roasting the sugars in the beans begin to caramelize. This process takes away from the sweetness of the bean, so the darker the roast the more bitter the drink. After this the beans are ground. The period in between grinding and roasting should be as short as possible for a fresh taste. The final step in preparing coffee is to brew the grounded mix. The brewing time should take approximately five minutes and a ratio of two tablespoons of coffee to every six ounces of water. There are many different types of machines that can be used for brewing, for example: the vacuum coffee pot, the automatic drip, and the French press. The main goal of brewing is to extract the different flavors of coffee while being mindful of how bitter it is. [16]
Gallery
Arabian Coffee
(C. arabica)
Robusta Coffee
(C. canephora)
References
- Coffea L. Itis.gov
- The Coffee Tree Just about Coffee and Kolb.
- Coffee arabica by James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Coffee Facts by Coffee Facts.
- Pollination by Missouri Botanical Garden. Biology of Plants.
- "U.S. coffee consumption shows impressive growth" Food & Drink Weekly. Feb 16, 2004. FindArticles.com. 02 Jun. 2008.
- The History of Coffee by Mr. Cappaccino.
- Biology, Miller/Levine, copyright 2008, published by Pearson Prentice Hall, pg 570
- Arabica and Robusta Coffee Plant by Coffee Resaerch Institute.
