Thank you for that work Anu, and I think you gave a good overview of the various aspects of coffee sorting. For proceeding with the design of our open source optical coffee sorter, we are looking for additional details about the manual sorting process:
- How much can one worker sort per hour (under bad, average and good working conditions)?
- What is the typical error rate of humans when sorting coffee? (Look up “double picked” and “triple picked” coffee, which means the coffee goes through human sorting twice or thrice. There have to be statistics how much it improves through these added steps, and ways to calculate the error rate of the previous steps based on that. Can you try to make these calculations please.)
- What do workers in manual coffee sorting earn? 10-20 wage examples covering different countries and different employers (family farm, coop, large business) will give us a good impression already. Converting the wages in PPP (purchasing power parity) in addition to showing the in the local currencies will help us comparing them.
- How many hours can a person work per day for sorting coffee, and how does it affect the speed and error rate of the sorting if people work more or less than this?
- What are health issues experienced by people sorting coffee manually as their job? (I assume posture problems like neck tension, back pain etc.)
- What about work satisfaction? (Anecdotal evidence / stories are ok. We know that this is influenced by many factors which are hard to quantify for us via Internet, but you can also try to find a study about this very topic …)
When you find these, could you add them to your post above please? Much appreciated!