Rome – By combining Italy’s two joys – coffee and incense – some engineers in Rome have created an eco-friendly way of roasting coffee beans without electricity or gas.
Antonio Durbe and Daniele Tuumei have spent nearly six years building and perfecting their Sunlight Coffee Roasters.
The result is a system that requires a ground piece about half the size of a tennis court and sunny weather to roast 50 kilograms (110 lb) of coffee in one hour.
The plant is completely run by the energy of the sun. The sun’s rays are focused by a set of mirrors on the coffee roaster and even some of the electrical parts are powered by a small solar panel. Computer-controlled sensors allow mirrors to follow the sun throughout the day and focus its light onto a rotating steel basket containing fresh coffee beans. The basket reaches peak temperatures of about 240–250 C (450–480 F), depending on the brightness of the sun, and can roast the beans in 20 minutes.
The process is not only environmentally friendly and economically convenient. According to Durbe and Tummei, it better preserves the aroma of the coffee, giving it a richer flavor. Unlike traditional hot-air ovens, which are usually gas-powered, concentrated sunlight roasts the coffee without heating the air around it – roasting the grains in a more uniform manner and without burning the exterior.
Naturally, the system depends on good weather. On cloudy days or after sunset, coffee lovers have somewhere to turn.
However, in southern Italy, a plant with 40 mirrors is capable of roasting 30,000 kilograms (66,000 lb) of coffee per year, saving about 60,000 kilowatt-hours of electricity, according to the inventors.
Their Purosol, or Pure Sun, coffee can be purchased online, but the inventors’ main goal is to sell their solar coffee roasting plant to small businesses that are more environmentally sensitive. Right now he is running his own plant in a friend’s garden.
The system can also be put to other uses. At the end of a long work day, Derbe and Tummi set up a grill in front of the mirrors to prepare some delicious sunny barbecue.