The Subtle Art of Selective Picking

Picking and harvesting coffee berries is a crucial step in production. It is a complex process that requires careful attention to detail to ensure that the highest quality beans are collected. The methods for collecting coffee beans vary depending on your location, the resources available, and the topography of the plantation. However, in all cases, the goal is to collect healthy and ripe coffee cherries to ensure a high-quality cup.

What should you take into consideration when harvesting your crop?

  • Time of harvesting

As mentioned in a previous article [1], coffee beans develop in 5 phases. The ripening process starts during the last two phases (about nine months after flowering). At first sight, it might seem that a coffee bean is ready to be picked once it has turned from green to red. However, there are different shades of red. You must make sure that most of your crop has reached a 95% maturation level. Traditionally, farmers learned to get a feeling of when the time was right by observing the bean’s color hue and consistency. A coffee cherry that is ready has a dark red color, its pulp is softer and full of its natural honey. The best way to determine this is by using a refractometer to check if the berries have reached a range of 18 to 22% of Brix degrees.[2]

To define the range of Brix degrees, do as follows:

  1. Take a sample of berries from each of the cultivated lots.
  2. Squeeze honey from the pulp of random cherries.
  3. Place two drops of extracted honey on the refractometer’s prism and close the lid.
  4. Hold the refractometer facing the light and look through the lens to find the boundary between the light and dark zones to determine the Brix degrees.

Coffee tree harvesting methods

Collecting the coffee beans can be performed mechanically, semi-mechanically, and manually. The first method requires using machinery to collect the beans from the trees. In this process, the entire tree is shaken, and the beans are collected by the tractor. This method is efficient and quick. Brazil has fully mechanized its coffee harvesting process, making it (among many other reasons) the largest coffee-producing country in the world and one with the most efficient method of collecting grain. [3]

Coffee tree Harvesting - Coffee Berries Picking

The cons of the method mentioned above are that it can also result in the collection of under-ripe or damaged beans. This means that later in the process, damaged and under-ripe green coffee cherries must be removed either manually or with a specialized selective machine. Also, with this harvesting method, Coffee trees experience a lot of stress resulting in possible damage to lateral branches and loss of foliage. As a result, coffee producers must include elements in their nutritional and fertilization plan to support the plant’s recovery and promote vegetative growth after harvest.

The semi-mechanical method combines the use of portable machinery and manual labor in coffee harvesting. The lance stripping machine is used to strip the cherries from branches and can be powered by pneumatic, internal combustion, or electric systems. This method is utilized in difficult terrains-fields with steep slopes in mountainous regions. Brazil utilizes the semi-mechanical method on its highland coffee plantations, and countries like Colombia are gradually adopting it. [4][5].Coffee tree Harvesting - Coffee Berries Picking

A nylon cover is placed in the ground around the tree, and the lance is manually passed through its branches. The ripe coffee beans fall into the nylon as it is shaken. The beans are then hand-picked and sorted if necessary. This method produces a higher-quality harvest but requires more labor and time compared to the fully mechanical method. Additionally, some leaves and under-ripe cherries may fall during this process. This will require a further selection step to separate the ripe beans. [6]

Finally, the manual process is the most labor-intensive method, where coffee cherries are hand-picked by workers. This method is the most time-consuming but results in the highest quality harvest, as only ripe and healthy cherries are collected. This is because the selective process starts right from the beginning. As the workers begin to cut the berries, they only select the fully ripe ones, leaving the green and unmatured ones for another day. Also, dried berries are left to be picked at the end of the harvest.

Selective picking at El Chorro Coffee Plantation

During this process, the trees undergo less stress, and the damage caused to the lateral branches is significantly lower. Selective picking also requires a certain feel-experince from the workers to understand which berries are ready by holding them in their hands. When the coffee cherry is fully ripe, it detaches easily from the branch.

Coffee tree Harvesting - Coffee Berries Picking

However, it must be done carefully to ensure that de berry’s peduncle stays in the branch. Leaving it will cause less damage to the lateral branches and guarantee that they will continue producing beans during the next harvest.

Incorrectly picked coffee berry. The peduncled should not be detached from the branch.

After harvesting each coffee tree, cultural practices must be performed, such as picking up fallen fruits from the ground. This is extremely important because it eliminates the possibility of leaving behind coffee beans that could serve as breeding grounds for the Coffee Berry Borer pest.

Dried coffee berries

Depending on various factors such as altitude, level of shadow and sun exposure, or even circumstances of irrigation (both natural and artificial), a significant amount of beans might ripe later; so, you might need to undergo between two or three more rounds during the following weeks to make sure most of the grains have been collected. During the last round, make sure you also collect the dried berries to leave your plantation as neat as possible for the next harvest.

Manual and selective picking remains the most effective way to produce a high-quality yield, despite its challenges (such as the longer picking time, physically demanding conditions for workers, and the mountainous terrain where coffee is often harvested). However, recent factors like fluctuating coffee prices and socio-political issues have contributed to high migration from rural areas and, therefore, decreased manual labor.

Regardless of the method used, it is essential to properly handle and store the coffee beans after recollecting them. The moment the cherries are picked, they start a slow decomposition process. So, you should not leave your sacks of coffee lying around. They must be collected and sent the same day at the coffee mill or coffee processing unit-facility, where the bean starts a whole new journey leading to your cup.

References

[1] See article: Taxonomy, morphology, and Cycles in Coffea Arabica

[2] Image is taken from: https://www.electronicadiy.com/products/refractometro-de-0-a-90-grados-brix

[3] Case IH coffee harvester. Image is taken from https://www.caseih.com/apac/en-int/products/harvesters/coffee-express-200-multi

[4] Stihl Semi-mechanical harvester. Image is taken from: https://www.stihl.com.co/Productos-STIHL/Motores-Multifuncionales/Acoples-Multifuncionales/273509-73164/SP-KA.aspx

[5] Stihl Semi-mechanical harvester. Image is taken from Sthil manual: https://manuals.plus/es/stihl/manual-de-accesorios-de-la-cosechadora-sp-km#axzz7sEoZ9cr6

[6] Knockdown Coffee Harvester. Image taken from: https://brudden.com.br/es/derribadores-de-cafe/derribadora-selectiva-de-cafe-dsc-18/

Cosecha de café con el equipo portátil Stihl, CENICAFÉ Colombia, 2009 https://issuu.com/revistaelcafetalero/docs/cosechadora_de_cafe_mecanica_portat/17

African Journal of Agricultural Research, 2015 https://academicjournals.org/journal/AJAR/article-full-text-pdf/6AAAE9F53971

https://academicjournals.org/journal/AJAR/article-full-text/6AAAE9F53971

Coffee plant History and general Information

Coffee Plant Information – Morphology

Coffee Genetics and Variety Selection

How to Select, and Treat Coffee Seeds

Germination of Coffee Seeds and Creation of Seedbeds for Planting

Coffee Trees Planting and Plant Spacing

How to Prune your Coffee Trees in an Agroforestry System

Shade-Grown Coffee in an Agroforestry System

Coffee Tree Flowering and Pollination

From Rainwater Harvesting to Irrigation of Coffee Trees

Coffee Tree Fertilization Requirements

Weed Management in a Coffee Plantation

Coffee Major Pest and Diseases and Control Measures

Coffee tree Harvesting – Coffee Berries Picking

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