JAKARTA - Coffee and sunshine, apart from a warm atmosphere, what else can be produced from the two? If asked two Italian engineers, the answer is green coffee.
There are Antonio Durbe and Daniele Tummei, two engineers who have spent the last six years building and perfecting a solar-powered coffee roaster. How to roast coffee beans without electricity or gas.
The result is a system that requires a plot of land the size of half a tennis court, as well as sunny weather to roast up to 50 kilograms (110 pounds) of coffee per hour, citing the Daily Sabah November 7th.
The factory is run entirely by energy from the sun. The sun's rays are concentrated by a set of mirrors on the coffee roaster. Some of the electrical parts are powered by small solar panels.
Computer-controlled sensors allow the mirror to follow the sun throughout the day, to then focus its light on a rotating steel basket filled with fresh coffee beans.
The basket reaches a peak temperature of about 240 to 250 degrees Celsius (450 to 480 degrees Fahrenheit), depending on the brightness of the sun, and can roast the seeds in 20 minutes.
The process is not only environmentally friendly and economical. According to Durbe and Tummei, it also better preserves the aroma of the coffee, giving it a richer taste.
Unlike conventional hot air ovens, which are usually gas powered, the concentrated sunlight roasts the coffee without heating the surrounding air, penetrating the grain in a more uniform manner and without burning the outside.
Naturally, this system relies on good weather. On an overcast day or after the sun goes down, coffee lovers need to move elsewhere.
However, in sunny southern Italy, a factory with 40 mirrors is capable of roasting up to 30,000 kilograms (66,000 pounds) of coffee a year, saving about 60,000 kilowatt-hours of electricity, according to its inventors.
Their purosole, or pure solar coffee, can be purchased online, but the main goal of the inventors was to sell their solar coffee roasting plant to environmentally sensitive small businesses. Currently, they operate their factory in a friend's garden.
This system can also be used for other purposes. At the end of a long day of work, Durbe and Tummei place the grill in front of the mirror to prepare a delicious sunshine barbecue.
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