Home roasting in a popcorn popper

Over at Engadget, there was a post on how to convert your air popcorn popper into a coffee roaster. An interesting bit of tech work, but they definitely made it more sound more difficult than it really is. And the commenters seemed certain that trying to use an air popper to roast coffee beans was a move likely to burn down the house. Clearly, they haven't roasted coffee before. I have used an air popper to roast beans successfully, without any serious modifications to the machinery - and without burning my house down, as I cleverly thought to do my roasting outside. In retrospect, this was an excellent move, as the process produces a fair amount of smoke.

Here are some tips and instructions for roasting your own coffee.

Use an older model, since they will typically get hotter than a more modern one. They have the added benefit of being inexpensive and you might even find a relative you can borrow one from.  Take the roasting process outside and use an extension cord (if need be). Wear goggles, because roasting the beans toasts the chaff (dried berry skin) off the beans and the popcorn popper projects the stuff into the air. Goggles will protect your eyes and allow you to be able to watch the roasting process more carefully, so you can get your beans to the desired color. An over mitt or very heavy gloves will help protect your hands while you work. Let the beans cool quickly in a colander and make sure they are completely cool before grinding them.

My good friend Clare, gave me the most excellent instructions for easy, home-roasted coffee:

Home Roasted Coffee
Buy a cheap hot-air popper.
Take the plastic top off.
Get a tin can and remove both ends. Attach the tin to the popper by tying it on.
Put about 150 g. green coffee beans in. Turn it on (outdoors).
Stir with the end of a long wooden spoon until the beans start to rotate by themselves.
Then they will go bright green, yellower, brown then a bit darker. They will start to "crack" this is called first crack - it will get more violent then stop cracking. After a few moments that cracking will start again. This is called second crack.
Turn off popper, unless you want very dark beans. Pour the coffee into a metal sieve (it is very hot, be careful) toss to cool down.  

The beans will look like this when they're done: dark and shiny.

[Photo by Nicole Weston]