Coffee bean
A coffee bean is a seed from the Coffea plant and the source for coffee. This fruit is often referred to as a coffee cherry, but unlike the cherry, which usually contains a single pit, it is a berry most commonly found having two seeds with their flat sides together. Even though the seeds are not technically beans, they are referred to as such because of their resemblance to true beans. A fraction of coffee cherries contain a single seed, called a "peaberry". Peaberries make up only around 10% to 15% of all coffee beans. It is a fairly common belief that they have more flavor than normal coffee beans. Like Brazil nuts and white rice, coffee beans consist mostly of endosperm.
The two most economically important varieties of coffee plants are the arabica and the robusta; approximately 60% of the coffee produced worldwide is arabica and some 40% is robusta. Arabica beans consist of 0.8–1.4% caffeine and robusta beans consist of 1.7–4.0% caffeine. As coffee is one of the world's most widely consumed beverages, coffee beans are a major cash crop and an important export product, accounting for over 50% of some developing nations' foreign exchange earnings. The global coffee industry is valued at $495.50 billion, as of 2023; the largest producer of coffee and coffee beans is Brazil. Other main exporters of coffee beans are Colombia, Vietnam, and Ethiopia.
History
Significant dates
- According to legend, the coffee plant was discovered in Ethiopia by a goat herder named Kaldi around 850 AD, who observed increased physical activity in his goats after they consumed coffee beans.
- The coffee plant was first found in the mountains of Yemen. Then by 1500, it was exported to the rest of the world through the port of Mokha, Yemen.
- First cultivation in India – 1600
- First cultivation in Europe – 1616
- First cultivation in Java – 1699
- First cultivation in Caribbean – 1715–1730
- First cultivation in Dutch East Indies – 1720
- First cultivation in South America – 1730
- Roasted beans first sold on retail market – 1865
- Important spray-drying techniques developed in 1950s, which along with freeze drying are a method to create instant coffee
Distribution
Coffee plants grow within a defined area between the tropics of Cancer and Capricorn, termed the bean belt or coffee belt.
Etymology
The Oxford English Dictionary suggests that the European languages generally appear to have adopted the name from Turkish kahveh, about 1600, perhaps through Italian caffè. Arab qahwah, in Turkish pronounced kahveh, the name of the infusion or beverage; said by Arab lexicographers to have originally meant "wine" or some type of wine, and to be a derivative of a verb-root qahiya "to have no appetite". Another common theory is that the name derives from Kaffa Province, Ethiopia, where the species may have originated.Coffee plant
The coffee tree averages from in height. As the tree gets older, it produces less fruit and slowly loses any pest- and disease-resistance. The coffee beans come from the seeds which contained in fruits from trees and shrubs naturally grown in African forests. Humans produce coffee by roasting, grinding and brewing the green coffee beans.Coffee plants are often grown in rows spaced apart depending on the desired density chosen by the farmer. Some farmers plant other trees, such as shade trees or other cash-crop trees, such as orange trees around them or plant the coffee on the sides of hills, because they need specific conditions to flourish. Ideally, Arabica coffee beans are grown at temperatures between and Robusta between and receive between of rainfall per year. More rain is needed at the beginning of the season when the fruit is developing and less later in the season as it ripens.
Two lesser known species grown for consumption are Coffea liberica and Coffea racemosa.
Processing
When the fruit is ripe, it is almost always handpicked, using either "selective picking", where only the ripe fruit is removed, or "strip-picking", where all of the fruit is removed from a limb all at once. Selective picking is often used to produce higher quality coffee because the cherries are picked at their ripest. Strip-picking is indiscriminate and will harvest unripe, ripe, and over-ripe fruit. To improve quality after strip-picking, the harvest must be sorted.Two methods are primarily used to process coffee berries. The first, "wet" or "washed" process, has historically usually been carried out in Central America and areas of Africa. The flesh of the cherries is separated from the seeds and then the seeds are fermented – soaked in water for about two days. This softens the mucilage, which is a sticky pulp residue that is still attached to the seeds. Then this mucilage is washed off with water.
The "dry processing" method, cheaper and simpler, was historically used for lower-quality beans in Brazil and much of Africa, but now brings a premium when done well. Twigs and other foreign objects are separated from the berries and the fruit is then spread out in the sun on concrete, bricks or raised beds for 2–3 weeks, turned regularly for even drying.
In Asia, a third type of processing exists, where the Asian palm civet eats coffee berries and excretes the beans. Because the civet prefers the taste of the ripest cherries, the civet selectively harvests the cherries. Its digestive system then processes the beans by breaking down the mucilage and pulp surrounding the seed. Once the seeds are excreted by the civet, they can be harvested, processed and sold as a niche product. Once they are finally processed, these beans are called kopi luwak, and are often marketed as a rare and expensive coffee.
Composition
The term "green coffee bean" refers to unroasted mature or immature coffee beans. These have been processed by wet or dry methods to remove the outer pulp and mucilage and have an intact wax layer on the outer surface. When immature, they are green. When mature, they have a brown to yellow or reddish color and typically weigh 300 to 330 mg per dried coffee bean. Nonvolatile and volatile compounds in green coffee beans, such as caffeine, deter many insects and animals from eating them. Further, both nonvolatile and volatile compounds contribute to the flavor of the coffee bean when it is roasted. Nonvolatile nitrogenous compounds and carbohydrates are of major importance in producing the full aroma of roasted coffee and for its biological action. Since the mid-2000s, green coffee extract has been sold as a nutritional supplement and has been clinically studied for its chlorogenic acid content and for its lipolytic and weight-loss properties. According to a 2024 publication, , the concentration of trace elements, alkaloids, and CGAs in coffee beans decreased with the increase in growing altitude, while the content of fatty acids increased, and the content of organic acids showed no obvious change trends.Nonvolatile alkaloids
is the alkaloid most present in green and roasted coffee beans. The content of caffeine is between 1.0% and 2.5% by weight of dry green coffee beans. The content of caffeine does not change during maturation of green coffee beans, but higher caffeine content is found in plants grown at higher altitudes. Lower concentrations of theophylline, theobromine, paraxanthine, liberine, and methylliberine can be found. The concentration of theophylline, an alkaloid noted for its presence in green tea, is reduced during the roasting process, usually about 15 minutes at, whereas the concentrations of most other alkaloids are not changed. The solubility of caffeine in water increases with temperature and with the addition of chlorogenic acids, citric acid, or tartaric acid, all of which are present in green coffee beans. For example, of caffeine dissolves in of water at room temperature, and at. The xanthine alkaloids are odorless, but have a bitter taste in water, which is masked by organic acids present in green coffee.Trigonelline is a derivative of vitamin B3 that is not as bitter as caffeine. In green coffee beans, the content is between 0.6% and 1.0%. At a roasting temperature of, 85% of the trigonelline is degraded to nicotinic acid, leaving small amounts of the unchanged molecule in the roasted beans.