Q: I wonder if you can give me some guidance. I’m thinking about buying the following drum roaster to be used in conjunction with my outdoor gas grill: http://www.rkdrums.com/index.php/en/products/drk/2lb-roasters-sample/product/216-rk-2lb-drum-2lb-max Mostly I expect to do half lb batches which is about 25% of the max load. I’ve never used one of these so I thought I’d see if you know anything about it or care to comment. I know I’d have to rig up some sort of fan quenching device but I don’t think that will be a problem. I’d like your thoughts if you have any.
A: …haven’t visited RK Drums for a while. they’ve updated the site by a lot. My dad uses a BBQ drum roaster sometimes and all he’s said is that he goes through more gas than he’d like. Other than that, especially with only half a pound, you’re probably going to do well.
The length of roast will be a bit longer than a hot air roaster, so you’ll tend to get a bit more body as a side effect. But half a pound is pretty small, so that will speed things back up. Dad is probably trying to roast as much as he can per batch so it would for sure take him a while.
Have you ever tried using a heat gun? they’re pretty cheap and there’s a lot of control possible, especially because eight ounces isn’t a lot of coffee. But I think the RK drums are a well proven way to go.
You can build a super cooler out of a bathroom exhaust fan, from a walk down the heating duct isle. F ind a colander that nestles in some big duct and it just about builds itself. Just suck ambient air down through the beans and in a minute you’re cold. We have perfect colanders on our site. The real usefulness of a cooler is just to stop the roasting in its tracks. After that its just cooling down enough so you can handle the beans.
If you wanted to spend a bit there’s also the Gene Cafe Roaster. It roast up to 10 ounces at a time with control over heat and time, with a readout of where things are. Plus you can see the beans roasting.
But with the RK drums is definitely worth buying something from them rather than trying to build a drum from scratch.
‘jumped around a bit but I hope that’s useful info.
Q: I like the idea of a drum since I don’t have to worry about it breaking and if I want to, I can roast larger batches although I think a half pound is enough. The only headache is that I’ve got to roll out the grill, set it up, pre-heat it and so on so I think it’s a little project for a small batch which I’m usually in a rush to get done.
I haven’t tried a heat gun but I have one collecting dust. I figured it would be tough to get an even roast or consistent results. Do you just spray the beans in a bowl from the top? What do you think the life span the Gene is if you do a roast say every 7-10 days? Does it do OK at FC+ or Vienna?
A: I like the Genes a lot. Chaff collection is good, the beans are visible, there’s lots of control, you can roast a few ounces up to about 10 ounces. I think they’re well priced for what they do. Some fanatics will say the cooling isn’t fast enough, but they’re wrong 
The only thing you may be concerned about is smoke control in larger/darker batches. But that is true for any roaster. One thing the Gene has designed in is the ability to attach 3″ metal tube to it to route the smoke somewhere.
If you’re only roasting once a week or so the roaster should last many years. I just had a customer ask me about replacing the heater for a gene he bought in 2007. I don’t know how many roasts he’s done on it but he buys beans regularly. Some people have killed there machine prematurely but what’s true with any of the roasters is that back to back roasting will shorten their life.
Heat gun roasting is easy. After a few tries you’ll be an expert. If you Google HGDB (Heat Gun Dog Bowl) you find some old articles that go into way too much depth. Essentially you need a metal container that won’t tip over. One hand to hold the heat gun and one hand to do some stirring with a wooden spoon.
Stick the nozzle close to the beans and start stirring. By holding the heat gun closer or farther away you can control the heat instantly. You MAY want to work with a clock or just roast intuitively. Chaff will go all over the place but on the bright side you don’t need to winnow them. Some heat gun will run on cold too, so there’s your cooler. The whole process might take fifteen minutes plus or minus depending on batch size and degree of roast.
Roasts will tend to even out over time or just sneak up on them in the beginning with less heat and apply more heat as they turn tan. Watch that you don’t scorch them in the beginning. Once the moisture is driven off roasting will pick up speed.
One of my customers uses the side burner on his BBQ and a heat gun together. That seems like overkill to me, but he goes for as big a batch as possible.
A small batch with a heat gun might take 6-7-8 minutes. Going for a whole pound at once might take 20 or so.