A relatively dedicated group of home coffee roasters use drum roasters fitted onto a gas or wood fired grill to roast anywhere from one to five pounds of coffee at a time. Being one of the air roasting variety of coffee roaster, I decided I needed to come up with a drum roaster for cocoa beans and give it a try. Well I did just that. I took a perforated piece of light lead free sheet metal, rolled and riveted it into a cylinder and added a couple of endcaps of stove pipe to make a nice little 6" diameter, 12" drum. I mounted a rotisserie motor onto my grill (most have these mounts), drilled a square "hole" in each endcap to insert the rotisserie rod and placed a couple of locking collars on each side of the drum end to keep the whole thing in place and together. For my test run, I loaded the drum with two pounds of Carenero Superior, preheated the grill to about 550 F and started the whole thing rotating with the mounted motor. After about 5 minutes, it smell like brownies baking. Another few minutes and the cocoa beans started popping in what most coffee homeroasters would recognize as first crack. The cracks lasted a few minutes. I opened the grill, withdrew the drum on its rod, loosened one collar with a pair of pliers, and dumped the beans into a waiting bowl.
The previously slightly flat, dusty looking beans (remember, this is a luscious ugly duckling) were now plump, slightly shiny and a nice rich brown. After stirring and cooling a few minutes (while loading the next batch of beans in the drum), I cracked a few beans. They shelled effortlessly and tasted rich and sublime, with no hint of smokiness from the grill.
All told, I roasted up about 12 lb in an hour, about 15 minutes per batch, with three pound batches working very nicely. This is definitely the way to go for cocoa bean roasting in any quantity. Once I get a few more roasts under my belt, I will update the roasting section, along with some links where you can obtain drums and drum roasting information if you don't want to build your own.