29/03/2014
History of Coffee production is the industrial process of converting the raw fruit of the coffee plant into the finished coffee. The cherry has the fruit or pulp removed leaving the seed or bean which is then dried. While all green coffee is processed, the method that is used varies and can have a significant effect on the flavor of roasted and brewed coffee.
Coffee goes through several stages as it progresses from its birthplace high among the mountains to its ultimate destination at the table. Let’s take a brief look at the journey from branch to cup.
Cultivation Process, Picking and Harvest
Coffee cultivation is both time-consuming and labor-intensive as the plants take years to mature and must be harvested by hand. Only vigorous, healthy plants, aged from 5 to 6 years in age. The cherries ripen around eight months after the emergence of the flower, by changing color from green to scarlet-red, and it is at this time at the optimal stage they are eventually selected for the final harvest. The coffee crop is picked by hand, a labor-intensive and difficult process. Cultivators must carefully examine and select only those specimens clearly bearing the most outstanding characteristics of the specific varietal to be produced. This is known as a selective picked method. Fruit are selected from those parts of the branch with the fullest production, while fruit at the extremities of branches is usually left untouched. This technique helps prevent unwanted cross-pollination. In warmer, equatorial climates, trees can display blossoms, ripening fruit, and mature cherries all on the same branch. Pickers rotate among the trees every 8–10 days, choosing only the cherries which are at the peak of ripeness. It usually takes 2–4 years after planting for a coffee plant to produce coffee beans that are ripe enough to harvest. The plant eventually grows small white blossoms that drop and are replaced by green berries. These green berries will become a deep red color as they get more and more ripe. It takes about 9 months for the green coffee plants to reach their deepest red color. Because this kind of harvest is labor intensive, and thus more costly, it is used primarily to harvest the finer arabica beans. Altitude, rainfall, and climate are all critical to the quality of the coffee harvest. Puerto Rico's lofty central mountain range, known as La Cordillera Central which is located in the “coffee bean growing belt”, offers one of the world's most idoneous settings for year-round coffee cultivation.
Processing Wet or Dry
Two principal methods exist for processing coffee beans once they are harvested. Traditional dry processing is less labor-intensive and less expensive. However, due to a loss of quality, dry processing is primarily used today in Brazil and parts of Africa for the mass production of lower-quality beans. Dry processing is also highly climate-dependent, as the beans are ordinarily sun-dried, which renders the process somewhat unpredictable in nature. The drying operation has to be done properly, since it can affects the final quality of the green coffee. A coffee that has been over-dried will become brittle and produce too many broken beans during hulling (broken beans are considered defective beans). Coffee that has not been dried sufficiently will be too moist and prone to rapid deterioration caused by the attack of fungi and bacteria.
Wet processing is the much more accepted method for the production of higher-grade coffee. In wet processing, harvested cherries are carefully directed down a series of water channels where they receive an initial cleansing. Unripe fruit tends to sink to the bottom while ripened fruit will continue to float.
Structure of coffee berry and beans:
1: center cut
2: bean (endosperm)
3: silver skin (testa, epidermis)
4: parchment (hull, endocarp)
5: pectin layer 6: pulp (mesocarp)
7: outer skin (pericarp, exocarp)
Pulping
The coffee bean used for roasting is not the cherry itself-but rather, its enclosed seeds. Seeds are flat in shape and are normally found in pairs: two per cherry. To get ready for roasting, these seeds must first be physically separated from the surrounding fruit flesh. This process, known as ‘pulping', should be done the same day of harvest to ensure optimal quality. After the pulp has been removed what is left is the bean surrounded by two additional layers, the silver skin and the parchment. The beans must be dried to a water content of about 10% before they are stable. Coffee beans can be dried in the sun or by machine but in most cases it is dried in the sun to 12-13% moisture and brought down to 10% by machine. Drying entirely by machine is normally only done where space is at a premium or the humidity is too high for the beans to dry before mildewing.
When dried in the sun coffee is most often spread out in rows on large patios where it needs to be raked every six hours to promote even drying and prevent the growth of mildew. Some coffee is dried on large raised tables where the coffee is turned by hand. Drying coffee this way has the advantage of allowing air to circulate better around the beans promoting more even drying but increases cost and labor significantly.
After the drying process (in the sun and/or through machines), the parchment skin or pergamino is thoroughly dry and crumbly, and easily removed in the Hulling process. Coffee occasionally is sold and shipped in parchment or en pergamino, but most often a machine called a huller is used to crunch off the parchment skin before the beans are shipped.
Hulling
The first step in dry milling is the removal of what is left of the fruit from the bean, At this stage, the beans themselves are still encased in a silky, protective inner skin known as the "parchment." whether it is the crumbly parchment skin of wet-processed coffee, the parchment skin and dried mucilage of semi-dry-processed coffee, or the entire dry, leathery fruit covering of the dry-processed coffee. Hulling is done with the help of machines, which can range from simple millstones to sophisticated machines that gently whack at the coffee. This by mechanical friction which physically tears the husk away from the bean.
Cleaning and Sorting
After hulling, the beans are typically olive-green in color and consequently, coffee is often referred to as "green coffee." Most fine coffee goes through a battery of machines that sort the coffee by density of bean and by bean size, all the while removing debris that may have become mixed with the coffee during drying. First machines blow the beans into the air; those that fall into bins closest to the air source are heaviest and biggest; the lightest (and likely defective) beans plus chaff are blown in the farthest bin. Other machines shake the beans through a series of sieves, sorting them by size. Finally, a machine called a gravity separator shakes the sized beans on a tilted table, so that the heaviest, densest and best vibrate to one side of the pulsating table, and the lightest to the other. The final step in the cleaning and sorting procedure is called color sorting, or separating defective beans from sound beans on the basis of color rather than density or size. Color sorting is the trickiest and perhaps most important of all the steps in sorting and cleaning. With most high-quality coffees color sorting is done in the simplest possible way: by hand. Teams of workers pick discolored and other defective beans from the sound beans. The very best coffees may be hand-cleaned twice (double picked) or even three times (triple picked). Most specialty coffees have been cleaned and sorted in this way.
Grading
Grading is the process of categorizing coffee beans on the basis of various criteria such as size of the bean, where and at what altitude it was grown, how it was prepared and picked, and how good it tastes, or its cup quality. Coffees also may be graded by the number of imperfections (defective and broken beans, pebbles, sticks, etc.) per sample. For the finest coffees, origin of the beans (farm or estate, region, cooperative) is especially important. Growers of premium estate or cooperative coffees may impose a level of quality control that goes well beyond conventionally defined grading criteria, because they want their coffee to command the higher price that goes with recognition and consistent quality.
Roasting
Now the beans are ready for roasting. The application of smooth, uniform heat elicits qualities of both flavor and aroma from the bean critical to its final performance. The bean physically swells. Color changes as well, now acquiring the characteristic nutty-brown to dark chocolaty-brown tones associated with the beverage itself.
Decaffeeination (When Required)
Decaffeination is the process of extracting caffeine from green coffee beans prior to roasting.
