The coffee tree is a tropical evergreen shrub that grows between the Tropic of Cancer and the Tropic of Capricorn. Coffee is considered as one of the most traded commodities in the world. This amazing drink has dozens of nuances, fragrances, flavors and variations.
There are quite of few species of the coffee plant. However, most of the coffee that we drink today is made utilizing one of the below species:
Arabica: considered as more prestigious and better in quality since its cultivation needs more care than the other species.
Robusta: is a little cheap and inferior in quality, more robust and not requiring so much care as the Arabica. The Robusta can flourish in hot and harsh conditions.
Now, coffee is often grown in mountainous areas. This limits the usage of mechanical harvesters and most of the ripe coffee cherries are therefore picked by hand. The main exception to this rule is Brazil, where coffee is harvested using machine tools. This is due to the relatively flat landscape in the country.
A coffee tree yields around 2-4 kilos of cherries. If you are a great picker, you could harvest up to 90 kilos of cherries per day. This would easily translate into 18 kilos of coffee beans.
Typically, coffee is harvested by either of the two below mentioned methods:
Strip picked: In this method, all the cherries are stripped off the branch at one time. This can be done via hand or machine.
Selectively picked: In this method, only ripe cherries are harvested. These are typically picked by hand. Since this method is more costly and labor intensive, it is only used for finer Arabica beans.
The next logical step to harvesting is processing. You would need to remove coffee seeds from the ripe fruit and then dry them. There are two prevalent methods to process your coffee:
The dry method: This method involves drying the whole cherries. You need to sort and clean the harvested cherries by hand. The overripe, unripe or damaged cherries are discarded. This can be done by floating the cherries in water. The coffee cherries are dried out in the sun and turned by hand in order to ensure even drying.
The wet method: This method incorporates the use of specialized equipment and availability of water. You would first need to clean the ripe cherries and then use a specialized machine that can separate the skin and flesh of the cherries from the beans. This leaves the beans with a slippery outer covering, which is further cleaned using large tanks. Drying is accomplished in sun or through the use of a mechanical dryer. The parchment is removed by cleaning, sorting and grating just before sale.
ROASTING AND GRINDING
During the process of roasting, the distinctive coffee taste aroma constituents are formed, in addition to the typical brown color of the beans. There are more than 1000 different aroma components of coffee. It is possible to achieve the specific flavor profile of the final coffee based on the preferences of the consumer by variation in the roasting conditions. Typically, the green coffee beans are heated to between 180ºC and 240ºC for 1.5 to 20 minutes. A darker color and more intense aroma can be achieved through stronger roasting.
Coffee is classically roasted in horizontal rotating drums that are heated from below. It may also be roasted in fluidized bed roast chambers where the coffee is heated and moved by hot air. In the process of industrial coffee manufacturing, these burners are heated with gas or oil. The next step to roasting involves cooling the beans to room temperature. They can now be packaged as whole beans ready from sale.
The roasted coffee beans are ground based on requirement. This is done in a coffee grinder. It is important to note that the grind size should be adapted for each intended use (espresso machine, filter brew, instant coffee) since this influences the taste in the cup.
The process of removing almost all caffeine from the beans is termed as decaffeination. It is carried out before the process of roasting while the beans are still ‘green’. The decaffeinated coffee must contain 0.1%, or less, caffeine in roasted coffee beans. The level for soluble or instant coffee is 0.3%, or less.
The process of decaffeination is achieved in food manufacturing plants and involves:
Bulging or inflaming the green coffee beans with water or steam in order to extract caffeine.
Extraction of caffeine from the beans. This is accomplished through use of water, a solvent or activated carbon.
Drying and dehydrating the decaffeinated coffee beans back to their normal moisture level.
Besides water, the solvents typically used during decaffeination are methylenechloride (Dichloromethane, or DCM), ethyl acetate, or supercritical CO2.
The process of manufacturing may vary from one factory to another. In general, the water or the solvent is circulated around the water soaked beans which results in caffeine to be released. The mixture is then drained from the extracting vessel. This process is repeated several times, until only a tiny amount of caffeine is left in the bean.
THE SCENE OF COFFEE PRODUCTION TODAY
Today, coffee is cultivated in approximately eighty countries in Central and South America, the Caribbean, Asia and Africa. Around three-quarters of coffee cultivated worldwide is Arabica. It is cultivated throughout Central and East Africa, Latin America, India and, to some extent, Indonesia. Robusta coffee is cultivated in West and Central Africa, South-East Asia and Brazil. Brazil is the largest coffee exporting nation; however Vietnam has now emerged as a major producer of Robusta beans. Indonesia is the largest producer of washed Arabica coffee.