Buying cocoa beans in our place is often frustrating. I often found good beans. Encounter bad and almost unusable from time to time. But finding beans with sour smell is very rare. I prefer sour smelling beans.
Here are the common post harvest practices for cacao in our place:
1) Cacao pod maturity is determined by tapping it with finger. Matured cacao ready for harvest has a hallow sound. This is true because a space is created between seeds and the pod as it ripens.
2) Pod is broken carefully with a sharp bolo. Then the beans are sucked by mouth (sinusupsop in Tagalog term) without ingestion to aid the removal of adhering pulp. Then washed in several changes or water. Sand is often mixed to hasten the process. Alternatively, beans can be washed with water right away.
3) Beans are dried under the sun and stored.
Please read again method number 2. There is nothing wrong with it but there is a better process. Cocoa beans should be fermented before drying. Fermentation process allows the development of chocolate flavors. Unfermented cocoa beans are of inferior quality.
How to ferment cocoa beans. I often tell this process to cacao farmers.
1) Harvest matured cacao pods. See above for maturity assessment.
2) Break the pod carefully to avoid breaking of beans. Place the beans in tumbler and cover with banana leaves.
3) Allow to stand for seven days. Natural fermentation will occur.
4) Wash fermented beans in water. Fermentation facilitates the removal of adhering pulp. Mixing sand is not necessary.
5) Dry under the sun.