Reduce power of popcorn popper for roasting coffee I've been roasting coffee for a couple of years now, and I've always used a popcorn popper.  I'm interested in taking things a bit more seriously and would like to be a bit more meticulous when it comes to roast level.  I find that my popcorn popper (1200 W) roasts coffee a little too quickly, to the point that it becomes difficult to get a precise and consistent roast level from time to time.  Does anyone know of anyway that I could reduce the power of the roaster?  If it roasted at a lightly slower pace I feel like I would have better control over the process.  I've heard people suggest plugging it in through an extension cord or a power strip, which will reduce the power going to the popper.  Is there a more principled or controlled way of doing this?  Some sort of device that goes in between the popcorn popper plug and the outlet that would let me adjust the power at a fine granularity would be ideal.  Does this sort of technology exist?  Perhaps a sort of light switch dimmer would work?
Rather than playing with electricity and wiring you could actually just move the roasting bed/area away from your heat source and accomplish close to the same thing.  

I started roasting with a popper as well.  The hole in the popper was roughly 3 inches so I got a 3 to 4 inch duct adapter, a 4 inch flour sifter and mushed it all together, similar to this.  The result was that I moved the coffee away from the heat source.  The sifter also allows you to stir and get more even results.  I think I went from 4 to 5 minute roast time to 7 or 8 minutes with this method and the parts were very cheap. 

I believe the forum post for that picture actually has additional mods close to what you may be looking for if you actually want to take your popper apart and try rewiring it.