While my Gene is temporarily out of heat, I thought I will have a play with this gas-top roaster I have that hasn’t seen coffee in probably 15 years. It’s a copper chamber with a stand to go over a gas stove, with a little electric motor to spin it on its axis to agitate the beans. You need to gauge the roast mainly by the sound of the cracks, as you can’t see what is going on inside. A little smoke that escapes can give some indication, and you can also take it off the heat and draw a sample if you want, but experiment and experience is key.
By far the main problem for me is that I only have a simple camping gas stove that is fed with a very small gas bottle, so have close to zero control over the heat. The first roast I did was fine, but on the second the flame got weaker during the roast (even though the gas bottle was half full), and this slowed down things considerably. If I wanted to use this as a regular roaster, I think a proper gas stove, ideally mains powered, is a must.
The second issue with this device is that it has nothing inside the chamber to scope the beans. It is like a guinea pig wheel, so the beans at the bottom can stay at the bottom even though the drum is spinning. And indeed, in the first roast I did I got a couple of burned beans which I assume got stuck at the bottom of the drum. It is possible to remove the drum in the middle of roasting and shake it to move the beans around and get a more even roast (I did this in the second batch).
When the roast is done, you need to move the beans somewhere to cool them and get rid of the chaff. I used a colander in a cardboard box, with a hole for a vacuum cleaner to suck out the air. This worked nicely and cooled the beans very fast.
Overall, if I had a good, strong and stable gas hob, and had no other choice, I guess I might be able to get used to roasting like that. However, after being spoiled by the ease of use and convenience of an electric appliance that can handle both the roasting and cooling (such as Gene Café), roasting as I did today seem like a hassle. As an emergency backup, or an experiment, it was quite fun to do.
Last, but not least – how is the coffee? I will have to wait a few days for it to degas and see. I am not expecting miracles, as the first batch looks a bit too dark and the second not very even because of the gas running out in mid roast. But who knows – I might be surprised.:)