The Cafe Compadre allows coffee farmers to roast their own beans with solar energy, by concentrating the sun on a rotating drum containing the coffee beans. The sturdy device has been developed for use in rural areas and can be maintained locally. With the capacity to roast 1 kg of coffee beans in approximately 15–25 minutes, this roasting technology is comparable to the capacities of conventional roasting equipment of the same dimensions.
Based on a Scheffler-type parabolic solar concentrator, the technology concentrates the sun's rays onto a single focal point. This type of concentrator can be used with simple solar tracker systems.
At the concentrator's focal point is a drum with one side open, where the coffee beans are put in and sunlight enters. This open section allows the gases and moisture created during the roasting process to escape. Clad in black tiles, the drum's inner surface can absorb a large proportion of the sun's radiation. With an insulation system to boost its energy efficiency, the drum also has a small photovoltaic rotation system enabling even roasting. Finally, an air suction system cools the roasted beans on a stainless steel surface guaranteeing excellent quality in the roasted beans.
Conventional roasters are complex, costly machines calling for access to energy systems that are unavailable to local coffee producers. Compadre provides small-scale coffee farmers with this technology, allowing them to roast their own beans. Training is given to the farmer on how to operate the solar roaster, and the company also set up sales channels to distribute the coffee. The coffee is sold under the Compadre brand along with the farmer's name. Farmers involved in the program can earn up to three times more from their coffee. Compadre deployed a pilot scheme in 2015, and 600 kg of coffee beans were roasted by a single farmer.
Publicly available: Yes
Countries where available: Peru
Price range: 20 to 50 USD