The coffee threshing process consists of removing the husk from the parchment or dry cherry beans until it is transformed and classified mechanically and electronically into green or excellent coffee, making it ready for export. This phase is defined by the "mechanical and optical selection process (which some call dry milling), where the parchment coffee is converted into green coffee". Depending on their physical (size, color, density and humidity) and sensory (fragrance, aroma, flavor) characteristics, the beans are classified into specialty coffee, commercial coffee and pasilla.
The threshing process has a very high importance in the quality of coffee, as it is the final part of the production chain prior to roasting. It is a key factor that must be carefully managed in order not to lose all the effort made by coffee growers.
Definitely, the threshing process is a process that is little known by consumers of specialty coffee but, without a doubt, it plays a determining role in guaranteeing the quality, flavor and aroma. Therefore, it is important to take into account all the points such as the adequate machinery and space, the trained personnel and the knowledge of the coffee to be processed, in order for this phase of the process to be carried out successfully.
It should be noted that threshing is not a single procedure but a set of processes that include:
- Pre-selection of the beans
- Threshing or mechanical removal of the parchment
- Classification by mesh or size of the grains
- Densimetric selection
- Selection by optical reader
- Manual sorting
- Packing in suitable packaging
In this way, threshing is a production line that integrates several processes and each one must function as an orchestra: harmoniously. In this way, the grains will maintain the quality with which they left the farm.