What exactly does a coffee tree look like? What are the essential differences between Arabica and Robusta? Starting from botanical classification, this article systematically sorts out the complete classification system of the Coffea genus, and explains in detail the origins, growing conditions, flavor characteristics, and major subspecies of the two commercial varieties, Arabica and Robusta. You will learn about the anatomical structure of the coffee fruit, the spread paths of classic subspecies such as Typica and Bourbon, and the genetic connection between Yunnan small-bean coffee and Blue Mountain and Kona. Whether you are a beginner enthusiast or a seasoned professional, this basic knowledge about coffee varieties is worth reading. Front Street Coffee will also recommend variety information worth paying attention to in this article.
Most people only encounter coffee beans that have already been roasted. Unless you have lived or traveled in a coffee-producing region, it is hard to have the chance to see a coffee tree with your own eyes. This plant is pruned relatively short during the seedling stage, but once mature it can grow to about 30 feet tall, covered with dark green, symmetrically arranged waxy leaves. The fruit grows in clusters along the branches. After the white flowers are pollinated, the berries need a full year to mature. Because fruiting is a continuous cycle, it is not unusual for green and ripe fruit to hang on the same branch at the same time. Coffee trees usually live between 20 and 30 years and can adapt to a variety of climates, as long as temperatures do not fluctuate drastically. If given a choice, they prefer fertile soil, mild temperatures, abundant rainfall, and shaded sunlight.
Botanical Classification
Biologically, coffee belongs to the order Gentianales. This order contains more than 500 families and 6,000 genera of tropical trees and shrubs. The coffee family was first described by the Swedish botanist Linnaeus in the 18th century, who recorded Coffea arabica in his 1753 book Species Plantarum. Even today, botanists still disagree about the exact classification. Considering that coffee plants range from low shrubs to tall trees, that leaf sizes vary from 1 centimeter to 40 centimeters, that colors range from purple and yellow to dark green, and that an estimated 25 to 100 coffee species exist on Earth, it is not hard to understand why the debate exists.
Complete coffee classification:
Kingdom Vegetable
Sub-kingdom Angiospermae
Class Dicotyledoneae
Sub-class Sympetalae
Order Rubiales
Family Rubiaceae
Genus Coffea
Sub-genus Eucoffea
Species C. Arabica
C. canephora
In the current commercial coffee industry, the two coffee species that occupy important positions are Arabica and Canephora (more commonly known as Robusta).
The main Arabica coffee varieties include: Bourbon, Typica, Caturra, Mundo Novo, TICO, SAN RAMON, and Jamaica Blue Mountain.
The Arabica species originated from the original coffee trees found in Ethiopia. This variety can produce high-quality, mild, aromatic coffee beans and accounts for about 70% of total global production. On the international market, it also commands the highest prices. High-quality Arabica is suitable for cultivation at elevations between 2,000 and 6,000 feet above sea level—the ideal altitude varies depending on distance from the equator. The most critical factor is that the temperature must remain mild, neither too hot nor too cold, preferably between 59 and 75 degrees Fahrenheit, with annual rainfall of about 60 inches. Arabica is relatively adaptable, but sudden severe frost can be fatal. Cultivation is worthwhile because wild coffee grows on steep slopes and is extremely difficult to harvest. In addition, it requires extra care because Arabica is more susceptible to various diseases than Robusta. Arabica is self-pollinating. The beans are flatter and more elongated than Robusta, and their caffeine content is lower.
Robusta Coffee
The vast majority of the world's Robusta comes from west-central Africa, and it is also grown in Brazil, Southeast Asia including Indonesia and Vietnam. Although its output accounts for only 30% of the world total, its planted area continues to expand. From a genetic perspective, Robusta has fewer chromosomes than Arabica, and its coffee beans are rounder and smaller. The tree is more vigorous and has stronger resistance to viruses and parasites. These characteristics make cultivation simpler and less costly, and also allow it to tolerate higher temperatures. Robusta is suitable for growing at temperatures between 75 and 85 degrees Fahrenheit, with much lower altitude requirements than Arabica, and annual rainfall of 60 inches is sufficient. Like Arabica, it is also unable to withstand frost. Compared with Arabica beans, Robusta beans are noticeably inferior in taste and have 50% to 60% more caffeine. At first, it was used only in blends and instant coffee.
Anatomy of the Coffee Fruit
Beneath the outer skin of the coffee fruit is a thin, jam-like mesocarp pulp. The inner fruit—that is, the coffee bean—is wrapped in a parchment-like sheath, and inside the sheath there are two coffee beans separated by a thin membrane. Biologists call this membrane SPERMODERM, but in the coffee trade it is more commonly called "silver skin."
From: NCA Translation: Peter Mett
What are Arabica coffee beans?
Arabica beans
Scientific name: Coffea arabica (Arabica beans)
Family and genus: Rubiaceae, Coffea
Coffee trees can mainly be divided into two major varieties: Arabica and Robusta (not commonly seen on the market).
The Arabica species is the most traditional Arabian coffee variety. It originated in East Africa. Before the 15th century, coffee was long monopolized by the Arab world, so Europeans called it "Arabian coffee."
Originally, all commercial coffee in the world was small-bean coffee, until a large-scale disease outbreak in the late 19th century led growers to begin searching for other disease-resistant varieties. At present, small-bean coffee is still the main coffee variety, accounting for about three-quarters of total world coffee production. It is mainly grown in Latin American countries, with some also grown in Indonesia and Pacific islands. Brazil, currently the world's largest coffee producer, has geographical and climatic conditions very suitable for the growth of small-bean coffee, and the main coffee variety grown there is also small-bean coffee. Brazil's coffee output accounts for more than one-third of total world production.
The fruit of small-bean coffee is smaller than that of medium-bean and large-bean coffee. The berry is oval and generally contains two seeds, the so-called "coffee beans."
Subspecies:
Among the Arabica series of small-bean coffee, three earlier subspecies are: Blue Mountain, Typica, and Bourbon. Jamaica Blue Mountain is widely recognized as the best coffee in the world. Typica coffee originated in Ethiopia and southeastern Sudan. It is the most widely cultivated coffee variety in the Western Hemisphere and has relatively high yields in Hawaii; Hawaii Kona is comparable to Blue Mountain coffee, with a price difference of only 1 to 3 US dollars. The Bourbon subspecies was introduced to the Americas in the 18th century by French settlers from Bourbon Island (today's Reunion Island, a French territory located in the Indian Ocean east of Madagascar). Today it is widely grown in producing areas in the Western Hemisphere such as Brazil, with limited cultivation in Yunnan, China. The caffeine content of the Bourbon subspecies is 20% to 30% higher than that of the Typica subspecies, but lower than that of most coffee subspecies. The primary branches initially grow upward at a 45-degree angle to the trunk and droop as they bear fruit. The nodes on the side branches are relatively dense, the yield is high, and production is relatively high. However, the berries are smaller and ripen faster, so it is not resistant to strong winds or heavy rain. Bourbon coffee is the variety second only to Typica among small-bean coffees. It bears more fruit and has higher yields, but the berries are smaller and ripen more slowly.
The small-bean coffee grown in Yunnan, China, is mainly the Typica and Bourbon subspecies. From a botanical perspective, Yunnan small-bean coffee is genetically related to the widely recognized finest Jamaica Blue Mountain and Hawaii Kona.
Arabica coffee tree
One of the most important coffee tree species in the world.
Arabica species (scientific name Coffea arabica). The place of origin of the Arabica species is the Abyssinian Plateau in Ethiopia (now the Ethiopian Highlands). It was initially mainly used as medicine, and in the 13th century the habit of roasting it for drinking was developed. In the 16th century it spread through the Arab world to Europe and further became a beverage loved by people all over the world.
Among the world's coffee beans, Arabica accounts for about 65% to 80%. Its excellent flavor and aroma make it the only one among these native species that can be drunk directly and on its own. However, its resistance to drought, frost damage, pests, and diseases is relatively low, especially to leaf rust, coffee's greatest natural enemy, so producing countries are all committed to improving varieties. For example, Sri Lanka, as is well known, was once one of the famous coffee-producing countries, but at the end of the 19th century, due to the rampant spread of leaf rust, not a single coffee estate was spared. After that, Sri Lanka turned to developing black tea and, together with India, became a black tea kingdom.
The Arabica species is a relatively large shrub. Its leaves are oval and dark green, and its fruit is also oval, generally containing two slightly flat beans. The beans are small and round, with an elongated oval shape on the front and a narrow, curved S-shaped center crack. The arc on the back of the bean is relatively smooth. Its caffeine content is about 1% to 1.7%.
Arabica coffee trees mostly grow at elevations between 900 meters and 2,000 meters. They are relatively cold-tolerant, with a suitable growing temperature of 15 to 24°C. They require relatively high humidity, with annual rainfall of no less than 1,500 milliliters, and they also have relatively high requirements for cultivation techniques and conditions.
The main producing areas of Arabica coffee beans are South America (except parts of Argentina and Brazil), the countries of Central America, Africa (Kenya, Ethiopia, and other places, mainly East Africa), and Asia (including Yemen, India, and parts of Papua New Guinea). A small amount of Arabica coffee beans is also grown in Yunnan, Hainan, and Taiwan in China.
Arabica coffee
Arabica coffee, also known as Arabian coffee, had its taxonomic position determined by Linnaeus in 1753. It produces Arabica coffee beans, which can be considered high-quality coffee beans throughout the world and are also the only coffee that can be drunk without any added ingredients.
The two best varieties of Arabica coffee are Typica coffee and Bourbon coffee, but other varieties have also developed well, including Caturra coffee (grown in Brazil and Colombia), Mundo Novo coffee (from Brazil), Tico coffee (widely planted in Central America), and the famous Jamaica Blue Mountain coffee.
Arabica coffee trees are suitable for cultivation in countries located between the Tropic of Cancer and the Tropic of Capricorn at elevations of about 1,000 to 2,000 meters with mountainous terrain. They grow on well-drained, fertile hillsides and require abundant sunlight, a continuous rainy season, and ample rainfall, a seasonal climate with temperatures of 15 to 24 degrees, mild daytime temperatures that are not excessively hot, and less than two hours of direct sunlight. Therefore, farmers usually interplant many taller, similar varieties of trees in coffee plantations for shade. Nighttime temperatures are around 15 degrees. If the temperature is too high, the coffee berries will develop too quickly and will not produce small, intensely flavored, hard, high-quality Arabica coffee. If it is too low and frost occurs, the coffee trees will freeze to death.
Arabica coffee trees are usually relatively large shrubs, with green, oval leaves and relatively poor resistance to rust disease. Their lifespan ranges from 20 to 30 years (depending on production conditions and the level of care), after which they must be replanted. They generally yield once every 3 to 4 years. The fruit is oval and generally contains two relatively flat coffee beans with winding grooves, somewhat like peanuts. If there is only one, it is called a peaberry. Its output accounts for about 70% of total world coffee production.
Robusta coffee Robusta
Robusta coffee, more precisely Coffea canephora, produces Robusta coffee beans. Because its flavor is relatively poor and its caffeine content is 2 to 3 times that of Arabica coffee, it is usually used to supply large-scale coffee industries for instant coffee and as a supplement to Arabica coffee.
Robusta coffee trees can grow in lower mountainous areas and prefer a warm equatorial climate, with temperatures stable within the range of 24 to 29 degrees. They have relatively strong resistance to rust disease and also have relatively high yields. Robusta coffee trees are very robust shrubs or small trees, more than 10 meters tall, but with relatively shallow roots. The maturation period lasts as long as 11 months. Robusta coffee beans are relatively round in appearance, with the side of the center crack somewhat swollen, and the groove is very straight, much like half a soybean. They are mostly produced in west-central Africa, throughout Southeast Asia, and Brazil's Conilon region.
The above content is compiled by CoffeeHunters, a coffee news website.
