CHAPTER 2: THE PROCESS OF COFFEE PRODUCTION From coffee seed to cup The process of creating coffee, beginning with a seed and arriving in a cup to be consumed by a customer, consists of a typical series of steps to produce the coffee that many enjoy. A coffee bean begins as a seed and after being dried, roasted and ground, it is ready to be brewed into coffee. Planting Coffee seeds are typically planted in large beds of shaded nurseries. Once they sprout, the seedlings are removed from the seed bed to be planted in individual pots in carefully formulated soils. The planting phase often takes place during the wet season to allow for the soil to remain moist. During this phase, the seedlings are watered frequently and are shaded from sunlight until they are robust enough to be planted permanently. Figure 1 www.coffeeresearch.org
Harvesting It takes three to four years passes for the newly planted coffee to bear fruit. When they are ripe and ready to be harvested, the coffee cherries become a bright, deep red color. All coffee is harvested in one of two ways. When strip picked, all of the cherries are stripped off the branch at one time, which is done either by machine or by hand. Being selectively picked, on the other hand, means that only the ripe cherries are harvested after being picked individually by hand. The selective picking method is more labor intensive and, therefore, more costly. As a result, it is primarily used to harvest the finer Arabica beans. Initially, the undeveloped and overripe coffee cherries are separated from the good coffee cherries. This is easily done using the idea that bad coffee cherries will float in water. Once the floaters and sinkers are separated, the floaters are sent to be dried and are often slated for internal consumption. Meanwhile, the ripe and green cherries are Figure 2 www.coffeeresearch.org sent to the coffee pulping machines.
The green coffee cherries are removed from the ripe cherries. Internal coffee pulping machinery works at monitoring the internal pressure. The pressure pushes the coffee against a screen with holes that have a diameter large enough for only a coffee bean, therefore, rejecting cherries from passing through. Ripe cherries are soft and break so that the coffee seed is released through the screen. Green cherries are hard and cannot be pulped. The pressure inside the barrel determines how many cherries will be pulped since high pressure will cause all of the cherries, including the harder green beans, to pass through and be pulped. An error allowance of about 3% is accounted for to ensure that no green cherries are mistakenly pulped. After this, pulp and coffee beans are separated by a centrifugal force and barrel screen system. Fermenting Coffee beans covered in mucilage are either sent to air dry naturally as pulped natural coffees or are sent to coffee fermentation tanks. Fermentation tanks remove mucilage before drying the coffee bean. Higher quality coffee can be separated at this point based on density. The highest quality coffees are densest and should be fermented in their own tank. Molecular density sorting is utilized to separate broken, small, undeveloped, and otherwise defective coffee beans. Density sorting follows two to three stages. The first stage removes dense rocks and stones from the coffee. In the second stage, the Figure 3 www.theaustralian.com.au coffee is hulled and the debris is removed. The third stage, the most important stage of the process, uses a densimetric table to separate
coffee into three or more densities. Light and less dense coffee beans are placed into one section of the table, and dense high- quality coffee beans move to another side of the table. In addition, any remaining debris is eliminated using this table. A coffee mill that is working towards attaining the highest quality coffee may further run the dense high- quality coffee beans through the table to even further separate any small deviations in density. Pulped coffee beans are combined into cement tanks with water and ferment for 16-36 hours. Coffee fermentation time depends on the amount of coffee fermenting, water temperature, and humidity conditions. The process that occurs to remove the mucilage during fermentation is hydrolysis of the protopectin and degradation of the pectin by enzymes. Feeling the coffee beans to see if they are still encased in mucilage is one way of determining when fermentation is complete. The result of fermenting for too long is not desired. When coffee beans are fermented for 36-72 hours, stinker beans develop. Lactic, acetic, and propionic acids are produced in this process and are believed to prevent the traditional fermentation taste by inhibiting mold growth that would occur when drying in humid conditions. Drying The pulped and fermented beans are dried to approximately 11-12% moisture content to properly prepare them for storage. They are rotated regularly or machined- dried in large tumblers. Based on a study in Kenya, it was reported that there are six stages to drying coffee. 1) Skin drying. Moisture 55-45%. 2) White Stage drying. Moisture 44-33%. 3) Soft Black stage. Moisture 32-22%. 4) Medium Black Stage. Moisture 21-16% Figure 4 http://www.ncausa.org/about- Coffee/10- Steps- from- Seed- to- Cup
5) Hard Black Stage. Moisture 15-12% 6) Fully dry coffee and conditioning. 11-10%. Roasting In the roasting step, green coffee is processed into scented brown beans which is typically what consumers think of coffee as. Roasting machines have a temperature of about 550 degrees Fahrenheit. To keep the beans from burning, they are constantly moving in the machine throughout the process. Once the beans reach an internal temperature of about 400 degrees Fahrenheit, their color begins to turn brown and the caffeol begins to emerge in a process known as pyrolysis. After being roasted, the beans are cooled instantly by air or water. Figure 5 www.coffeeresearch.org Grinding The grinding step provides the sole purpose of obtaining the most flavor for the cup of coffee. The ideal grade of grind is determined by the length of time the grounds are in contact with water. When the grind is finer, the coffee should be prepared more quickly. As a result, coffee ground for an espresso machine is much finer than that of coffee brewed in a drip system. Grinding and brewing coffee is the final step in the process and turns the coffee into a drink. Figure 6 zamnar.com
References http://www.coffeeresearch.org/agriculture/flavor.htm http://www.ncausa.org/about- Coffee/10- Steps- from- Seed- to- Cup http://www.coffeeresearch.org/agriculture/densitysort.htm http://www.coffeeam.com/methods- of- coffee- processing.html