Improving Processing Technologies: Cacao Beans Phase Two

THE PROBLEM

Fermented and dried cacao beans have a higher value compared to raw cacao beans, but most smallholder farmers in Tabanan don't have access to the tools required for this process.
In our previous experiment using a three-tiered fermentation box and a solar dryer with cacao farmers in Tabanan, Bali, we found that the humidity level inside the solar dryer was too high due to the weather conditions and due to the material used for the roofing of the dryer. The plastic sheeting leaked during the rainy season which made the drying environment even worse.

The fermentation technique and solar drying facilities we first experimented with did not actually produce a better dried product compared to traditional methods. We now want to modify the solar dryer to see whether that will improve the drying results.

THE SOLUTION

We will modify the original solar dryer design by adding an exhaust fan and replacing the plastic roofing with polycarbonate. This will reduce the humidity level significantly, enabling the drying process to be more effective especially during wet weather.

In this experiment, we will test the quality and efficiency of the drying process, which is divided into two different methods with equal quantity of fermented beans:

1. HSD (Hybrid Solar Dryer) - drying the cacao with the hybrid solar dryer
2. FSD (Floor Solar Dryer) - drying the cacao by traditional open air drying methods

We will take a sample of cacao from each drying method and measure the following variables at the same time every day:

• Temperature (Celsius)
• Moisture content
• Drying quality
• Flavour characteristics
• Number of drying days needed to reach optimal moisture level

The results will be documented and analysed by the team. Based on this analysis, we will assess if the modifications have in fact improved the drying process and created a solar dryer that will be more cost-effective when compared to traditional methods.

THE EXPECTED IMPACT

We hypothesize that the modifications can improve the drying process and create a solar dryer that will be more cost-effective when compared to traditional methods. This may result in reducing the economic loss that farmers endure due to inefficient drying processes used for their agricultural harvest.

THE PROJECT RESULT

This project took place in Angkah village, Selemadeg Barat district, Tabanan, the second largest cacao producing regency in Bali. During the first phase of the experiment (Oct 2016 - Jan 2017) Kopernik learned that the fermentation and solar drying process we tested  did not produce a better quality product compared to traditional methods. This was due to design faults in the solar dryer which caused extremely high humidity levels. We learned that the plastic roofing material was inadequate as it leaked, and the lack of an exhaust fan meant there was no means for temperature regulation.

In the second phase of this experiment, we modified the solar dryer and assessed its effect on the drying results. We hypothesized that:

• The added exhaust fan and polycarbonate roofing would reduce the humidity level significantly, enabling the dryer to work more effectively;
• The modified solar dryer would produce a higher quality product in a shorter amount of time compared to the traditional floor solar drying (FSD) method.

Kopernik proved that the modified Hybrid Solar Dryer’s (HSD) performance improved significantly compared to the first phase. In the first phase, the moisture content of the cacao beans dried inside the HSD reached 20 percent on day 6 while the modified HSD reached 7 percent in the same timeframe. This equated to a 74 percent increase in drying effectiveness between the two versions of the HSD. When compared to FSD, the modified HSD has shown to be 14.8 percent faster than the FSD.

THE BROADER IMPACT

Download the project report above to read more.