The first batch I roasted, I used this covered pot on the gas stove. When the smoke and flying chaff got too bad, my wife kicked me out of the house. The first batch was under roasted and the caffeine content on a trail cup had me climbing the walls. After this, I did it outside on the barbecue grill. This worked pretty well, but required a more or less constant shaking of the pan to get as even a roast a possible. Because it was somewhat uneven, the first crack was hard to distinguish from the second and left me a bit uncertain when to stop. Nonetheless, it made for a good cup of coffee. It wasn't stale like just about all the coffee sold in the stores. Some people use a type of popcorn popper to roast coffee, but that kind of lacks the snob appeal that a real coffee roaster aims for.
Because this was a lot of work to do every week especially when it was windy, my wife picked out the perfect birthday gift. A Behmor 1600. A bit expensive, but buying the best coffee grown for about $6.00/lb and always having fresh roasted coffee is making it a great deal. This has several programmable settings for different roasts, and is (semi) smokeless. It is necessary to weigh the exact amount of coffee for the program you use, as even one ounce over or under will change the results. There are two stages at the end of the roasting process that tell you when it is done. The first is aptly named the first crack. The roasting coffee will at this point start to make a leisurely popping sound. Roughly 60 to 90 seconds later the sound will change and increase in intensity which is the fabled "second crack". This is when you stop and cool down the beans. Too long after the second crack will result in either (A). a fire, or (B) burned beans similar to "Char"bucks.
I buy my green beans from a local place that imports it by the ton. Luckily for me, they will also sell retail.
I bought my roaster from them.
This site also has pretty much everything you need to know about coffee, as well as selling the beans.
The container the coffee goes into is like a squirrel cage that rotates and has fins that keep the beans stirred up.
It is like a convection oven inside, with quartz heaters in the back and a fan that circulates the air.
Below is a clever trap for the chaff which helps keep the whole thing from catching fire and burning the house down. I say helps, because there are repeated warnings in the manual not to let it out of your sight when roasting. About a 20 minute process.
Green unroasted beans.
Above, you can see the little timer that I use in order to walk away from the roaster and return before the critical "almost ready to catch fire", second crack.
The flea market find coffee grinder I've had for 30 years or more.