Measure the desired amount of green coffee beans into a hot air popcorn popper and set aside its plastic chute at room temperature.
Use a can-opener to remove the top and bottom ends of a clean empty soup can. Take away its label and set it on the top of the popcorn maker in order to form a chimney.
Now switch on the popcorn popper and stand close to it, listening carefully. After 3 to 5 minutes, you will hear the bean’s first crack.
Let it run for another 2 to 3 minutes until your hear the second crack. You will observe a smoke emerging as a result of second crack. Now you can either switch off the popcorn popper after the second crack or simply let it go all the way through for a very dark roast – choice is all yours.
Now unplug the popcorn popper and remove the soup can chimney. Now immediately transfer the roasted beans into a large shallow pan or plate and cool them under a fan.
Once completely cool, transfer the roasted coffee beans to an air-tight jar or container and seal it tightly. Now store it somewhere away from heat, light and excessive moisture.