Hot Air Popper
The cheapest and simplest is to use a (cheap) electric hot air popper. The old favorite is the West Bend Poppery, but you can use anything as long as the vent holes (where the hot air comes in) are on the sides rather than the bottom.
I've roasted a lot of coffee this way. It works, but there are a few downsides. The biggest problems:
- The circuation is designed for popcorn, which expands a lot more than roasted coffee beans. I've needed to stir the beans manually in order to get an even roast. They don't have to be stirred constantly, but you can't just drop the beans in and walk away.
- The capacity is pretty low, especially when you take the circulation into account. I can only roast a half a cup at a time, which is pretty slow.
- The temperature doesn't get quite high enough to really bring the flavors out. The roast is good, but it's really mellow.
![alt text](https://farm5.static.flickr.com/4067/4698574374_4fe844082d.jpg)
[source: Chris g Collision, Flickr Creative Commons]
I've read about modifications you can make that will improve these: changing out resistors, modifying the airflow, and even hooking up an Arduino to control the heat a lot more closely, but it seems like more work than I've wanted to invest in the process.
Heat gun / metal dog bowl method
My brother's moved on to this approach, and I'm soon to follow. The benefit of a heat gun is that the temperature is high enough to get a good roast, and the airflow is high enough that you can roast a few cups of coffee at a time.
![alt text](https://farm3.static.flickr.com/2722/4381304990_9cca36e5b1.jpg)
[source: Ocell, Flickr Creative Commons]
More Insanity
Sweet Maria's sells green coffee beans, and lists a huge amount of home roasting methods, including Weber Kettle conversions. The sky's the limit, but I'd start small with the air popper or the heat gun first.
I'd do this outside
Some methods have you roasting the coffee in your kitchen - in the oven, on the stove, etc. I wouldn't want to do this myself, for two reasons. The beans have thin husks on them, which come off as the beans are roasted. They're messy, and I wouldn't want them flying around my kitchen. Also, roasting coffee doesn't smell as good as you'd think it would.
Sources of more info:
Since ovens cook by heat radiation, you want to expose as high a proportion of the surface area as possible, which is why most roasts are vaguely cubic or cylindrical in shape. Any part of the meat that's pressed against the pan (i.e. the bottom of the roast) isn't going to get that nice brown crust.
It's also very important with slow-cooking methods that require you to put some liquid at the bottom of the vessel; obviously you want as little of the meat as possible to be in the water, so that most of the work is done by steam.
Tying (or more accurately, trussing) the meat is simply how you maintain the shape in the oven. If you don't truss it, then you'll not only end up with a very flat roast, you'll also end up with uneven cooking, and only the top will be browned since there are no "sides" to speak of.
It's similar with chicken and other birds; you truss the legs so that the oven has a chance to crisp them up on all sides, not just the top.
Best Answer
I believe so. Technically you can use the hood of your car. Rosting coffee (and nuts) is about the heat, not the material. Just keep the heat gentle, give it its 15 minutes or so and don't "french roast" is to death.
And tell how it came out.