![Antonio Durbe, left, and Daniele Tummei collect freshly toasted coffee grains from the Purosole, Pure Sun, solar light coffee roaster, in Rome. The electrical engineers invented a plant that just needs a piece of land about the size of half a tennis court and sunny weather to toast up to 50kg of coffee an hour. No gas, no electricity, just sun rays concentrated by a set of mirrors on a rotating steel basket filled of fresh coffee grains. (AP Photo/Andrew Medichini)](https://images.livemint.com/static/static/1x1_img.gif?impolicy=slurrp-20210601&width=880&height=500)
Antonio Durbe, left, and Daniele Tummei collect freshly toasted coffee grains from the Purosole, Pure Sun, solar light coffee roaster, in Rome. The electrical engineers invented a plant that just needs a piece of land about the size of half a tennis court and sunny weather to toast up to 50kg of coffee an hour. No gas, no electricity, just sun rays concentrated by a set of mirrors on a rotating steel basket filled of fresh coffee grains. (AP Photo/Andrew Medichini)
![The engineers overlook the functioning of the Purosole, Pure Sun, solar light coffee roaster, (AP Photo/Andrew Medichini)](https://images.livemint.com/static/static/1x1_img.gif?impolicy=slurrp-20210601&width=880&height=500)
The engineers overlook the functioning of the Purosole, Pure Sun, solar light coffee roaster, (AP Photo/Andrew Medichini)
![A steel basket containing fresh coffee grains rotates while toasting them in Purosole. Pure Sun, solar light coffee roaster, (AP Photo/Andrew Medichini)](https://images.livemint.com/static/static/1x1_img.gif?impolicy=slurrp-20210601&width=880&height=500)
A steel basket containing fresh coffee grains rotates while toasting them in Purosole. Pure Sun, solar light coffee roaster, (AP Photo/Andrew Medichini)
![Daniele Tummei checks the functioning of the Purosole, Pure Sun, solar light coffee roaster, (AP Photo/Andrew Medichini)](https://images.livemint.com/static/static/1x1_img.gif?impolicy=slurrp-20210601&width=880&height=500)
Daniele Tummei checks the functioning of the Purosole, Pure Sun, solar light coffee roaster, (AP Photo/Andrew Medichini)
![Sun is reflected in the mirrors of the Purosole, Pure Sun, solar light coffee roaster. (AP Photo/Andrew Medichini)](https://images.livemint.com/static/static/1x1_img.gif?impolicy=slurrp-20210601&width=880&height=500)
Sun is reflected in the mirrors of the Purosole, Pure Sun, solar light coffee roaster. (AP Photo/Andrew Medichini)